Merge pull request 'The mouth refuses a Persona send when the room moved past what she held' (#1) from eureka-body/optimistic-send-mouth into main

A send queued at the room gate passed the brake check at entry only, so a
brake placed while it waited still let the PUT through. The check now also
runs inside the gate, just before the PUT, and answers a typed Brake refusal.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

Directory.Build.props

@@ -0,0 +1,7 @@
+<Project>
+
+  <PropertyGroup>
+    <RestorePackagesWithLockFile>true</RestorePackagesWithLockFile>
+  </PropertyGroup>
+
+</Project>

Dockerfile

@@ -1,19 +1,19 @@
 FROM mcr.microsoft.com/dotnet/sdk:8.0 AS build
 WORKDIR /src
 
-COPY src/Bifrost.Web/Bifrost.Web.csproj src/Bifrost.Web/
-RUN dotnet restore src/Bifrost.Web/Bifrost.Web.csproj
+COPY Directory.Build.props .
+COPY src/Bifrost.Web/Bifrost.Web.csproj src/Bifrost.Web/packages.lock.json src/Bifrost.Web/
+RUN dotnet restore src/Bifrost.Web/Bifrost.Web.csproj --locked-mode
 
 COPY . .
 RUN dotnet publish src/Bifrost.Web/Bifrost.Web.csproj \
     --configuration Release \
     --output /app/publish \
-    /p:UseAppHost=false
+    /p:UseAppHost=false /p:RestoreLockedMode=true
 
 FROM mcr.microsoft.com/dotnet/aspnet:8.0-bookworm-slim AS runtime
 WORKDIR /app
 ENV ASPNETCORE_URLS=http://0.0.0.0:5080 \
-    ASPNETCORE_FORWARDEDHEADERS_ENABLED=true \
     DOTNET_RUNNING_IN_CONTAINER=true
 
 EXPOSE 5080

docs/bridge.md

@@ -196,15 +196,7 @@ The command is a dry-run shape probe for public surfaces that are real enough to
 
 Bifrost's native Discord gateway is the conversation observer. A direct mention of the Bifrost bot, or a reply to one of its messages, becomes an immutable typed `bifrost.discord.persona_conversation_event.v0` only when the guild and channel have one exact Persona target binding. Bot-authored, ambient, empty, over-1200-character, unbound, and ambiguously bound messages do not enter the conversation path. The 1200-character cap is the shared signed alpha boundary with Epiphany. The observation store is Bifrost-private working state, never an actuator queue, and insert collisions must contain exactly equal content. VoidBot does not observe, schedule, or answer for the target Persona.
 
-Persona replies cross back through two explicit CultMesh surfaces. Epiphany is
-the sole writer of `epiphany.persona_discord_delivery_request.v0`; Bifrost
-reads that surface, authenticates the dedicated Persona-mouth signer, journals
-external execution before touching Discord, and is the sole writer of
-`bifrost.persona_discord_delivery_receipt.v0`. Epiphany reads receipts but
-never receives the Discord token or write access to Bifrost private state.
-`unknown` is terminal for automatic transport retry: an external post may have
-happened, so restart recovery must not manufacture a duplicate. Failed and
-unknown outcomes remain Persona pressure for explicit resolution.
+Persona speech goes out through Matrix, not Discord. `tools/persona-matrix-mouth.mjs` is the one process for every Persona (`PERSONAS`, a list of slugs): it holds each Persona's Matrix access token as its own systemd credential (`matrix-token-<persona>`) and nobody else holds any. Per Persona it keeps one `/sync` loop over the configured rooms and the account's direct rooms (a DM invitation from an account on `MATRIX_SERVER_NAME` is accepted while that Persona's brake is released, and one from any other server is declined), one cursor and one delivery sequence. A delivery carries the sender's Matrix id, the event's `m.mentions` user ids and whether the room is a DM. Reading wakes nothing and acks nothing: the heartbeat polls with the non-consuming `gamecult.persona.chat_pending_request.v1`, and only `chat_ack` advances a position. The mouth speaks on a `gamecult.persona.chat_send_request.v1` and joins rooms only while that Persona's brake (`/etc/gamecult/minds/<persona>/control.cc`) is released. One loopback CultNet RUDP endpoint serves all of them; a request naming an unlisted Persona gets a typed `chat_refusal` (`UnknownPersona`). Document shapes: `tools/persona-chat-documents.mjs`; golden bytes: `tests/fixtures/persona-chat-v1/`. The Discord posting actuator, its permit and its RUDP listener are removed.
 
 Bifrost admits an observation only when guild, channel, target runtime, canonical repository, Persona, producer, and producer runtime match a preconfigured `bifrost.persona_feedback.target_binding.v0` document in Bifrost's private provider store. That binding also owns source visibility, data classification, and the delivery-store target. Bifrost never infers public visibility from Discord identifiers. It classifies the author using its own `bifrost.discord.actor_link.v0` state: a match yields `linked_governance_feedback`; absence yields `unlinked_social_feedback`. Neither class grants adoption, work, release, or deployment authority.
 

docs/concept-mill-votes-target.md

@@ -0,0 +1,128 @@
+# Concept Mill votes through Bifrost: map
+
+Status: Imagination mapping pass 2026-10-08, revised after the rulings `aetheria-release:ruling:concept-mill-votes-open` and `aetheria-release:ruling:concept-mill-votes-anonymous`. Committed 2026-10-10 as the target of the `concept-mill-votes` campaign. Body facts re-verified and cut specs admitted 2026-10-10 by `imagination-mill-votes` against Bifrost `bf83a93`. Its invariants, rulings, questions and cut specs are typed state in the eureka mind; this file keeps the body facts and rationale. Where they differ, the mind is right.
+
+Operator's words: "I want to track upvotes and downvotes on there, if possible." Then: "Yggdrasil is the obvious place. Doesn't Bifrost have discussions and voting?" Rulings: "anyone can vote, votes are public (we can filter by members if we wanted to)", then "anonymous, too, I mean anyone".
+
+Short answer: Bifrost has two voting-like things, and neither fits the Mill. Governance topics take support and objection only as free-text comment stances, in a command-line CultCache file the web app never reads, not tied to accounts. Motions have real one-account-one-vote records, but they are tier-weighted decisions that close by deadline. Bifrost is the right home, but the Mill needs a small new record in it that admits anonymous voters, which nothing in Bifrost does today, plus an anti-stuffing defence, a public read endpoint and a vote page. The live deploy is off-main, and that is settled first.
+
+## Body facts
+
+Bifrost head `bf83a93` (2026-10-10; `20d5efa` plus the prior-art note, docs only). Paths are relative to `F:\Projects\Bifrost` unless named. Facts 1-13 were taken at `160fac2` on 2026-10-08; the source files they cite are unchanged at `bf83a93` (the two commits since touch only `docs/`). Facts 14 onward were re-probed on 2026-10-10 by `imagination-mill-votes`; scripts are in that agent's scratch directory (`ygg-probe*.sh`).
+
+### What a topic is in code
+
+1. Topics and comments exist only in a Node CLI, `tools/governance-threads.mjs`. Its store is a CultCache file, `.bifrost/governance-threads.cc` (`tools/governance-threads.mjs:18`), and its types are `bifrost.governance.topic` and `bifrost.governance.topic-comment` (`:48-111`). The commands are `open`, `comment`, `approve`, `promote`, `list`, `show` and `digest` (`:113-155`, `:582`).
+2. A topic is an agent-dispatch work thread. It has `jurisdictionRepoName` (required), `jurisdictionAgentIdentity`, a status lifecycle `open → consensus_ready → approved → dispatched → closed` (`:52`), and `promote`, which renders the topic into an agent update request (`:324-405`).
+3. Support and objection are comment stances, not votes. The valid set is `comment, proposal, support, objection, question, approval, summary, receipt` (`:53`). A comment has `authorKind` (default `"agent"`) and `authorId`, a free string from `--author` (`:232-241`). Nothing enforces one stance per author: each call writes a new `comment_<uuid>` (`:233`). Retraction is not possible. `authorId` is not tied to a Bifrost `UserAccount`.
+4. The web app has no topic type, page or store. It knows topics only as `GovernanceActivityReceipt` rows in Postgres, with kinds `TopicOpened/Commented/Approved/Promoted` (`src/Bifrost.Web/Domain/BifrostModels.cs:235-240`, `:1050-1066`; `Features/Bridge/GovernanceActivityReceiptService.cs`).
+5. No topic store exists anywhere looked. `.bifrost\` holds only `bridge-receipts.cc`. A read-only `find` on Yggdrasil under `/srv /home /var/lib` found no `governance-threads.cc` (ran under `sudo -n` with errors silenced, so likely but not proven).
+
+### How motions and votes differ
+
+6. Motions and votes are EF Core entities in Postgres: `Motion` (`BifrostModels.cs:665-700`) and `Vote` (`:702-721`, with `VoteChoice For/Against/Abstain` at `:110-115`).
+7. A vote is one per account per motion: unique index on `(MotionId, UserAccountId)` (`Data/BifrostDbContext.cs:280-283`). Recasting upserts it (`Features/Motions/MotionGovernanceService.cs:63-82`).
+8. Votes are weighted: `Weight = actor.EffectiveVotingWeight` (`MotionGovernanceService.cs:72,80`), 0 unless the membership is `Active`, otherwise `max(1, sum of current tier snapshot weights)` (`BifrostModels.cs:357-361`).
+9. A motion has a category with an approval threshold, `ClosesAtUtc`, and a pass/fail resolution (`MotionGovernanceService.cs:95-131`, `MotionCategoryPolicy.cs`). It is a decision, not a standing rating.
+
+### Who can act
+
+10. Every member surface is behind `ActiveMember`: `AuthorizeFolder("/App", ActiveMemberRequirement.PolicyName)` (`src/Bifrost.Web/Program.cs:57`). The handler succeeds only when `Membership.Status == Active` (`Features/Membership/ActiveMemberAuthorizationHandler.cs`, `Features/Shared/CurrentBifrostActor.cs:17`). Admin-only page handlers additionally check `Actor.CanManageMembership` and return `Forbid()` (`Pages/App/Members/Index.cshtml.cs:37-39,95-97`).
+11. An account becomes `Active` by bootstrap admin GitHub login (`Features/Shared/ApplicationBootstrapper.cs:44`, `MembershipSynchronizationService.cs:133`), admin approval (`Pages/App/Members/Index.cshtml.cs:92-105`), or a Heimdall member-access claim (`Features/Heimdall/HeimdallAuthService.cs:158,186`). GitHub sign-in with an invitation lands in `PendingApproval`, without one in `Authenticated` (`MembershipSynchronizationService.cs:61`).
+12. Anyone can register natively, and doing so proves nothing: `POST /auth/bifrost/register` is anonymous (`Program.cs:286-316`), takes an identity name and display name, creates an `Authenticated` account and sets the cookie (`Features/Membership/BifrostIdentityService.cs:15-58`). No credential, no native sign-in route. As a voter a native account is indistinguishable from anonymous.
+13. No public read path exists: anonymous routes are only health, readiness, auth, webhooks, patron intake and patronage checkout (`Program.cs:211-522`); the Eve governance surface requires `ActiveMember` (`Program.cs:473-488`); no CORS and no rate limiter are configured (`git grep -i -E 'AddCors|UseCors|RateLimit|ForwardedHeaders' bf83a93 -- 'src/*.cs'` returns nothing).
+
+### Deployed versus repo
+
+14. Live release `/srv/bifrost/app/releases/20260723-daedcc4` (`readlink -f /srv/bifrost/app/current`, 2026-10-10 02:58Z), `bifrost.service` active since 2026-08-21 10:51 UTC, `ExecStart=/usr/bin/dotnet /srv/bifrost/app/current/Bifrost.Web.dll`, `EnvironmentFiles=/srv/bifrost/env/bifrost.env`, `ASPNETCORE_ENVIRONMENT=Production`, listening on `127.0.0.1:5080`. Earlier releases are bare UTC timestamps (`20260610073418` … `20260618144854`); the `-daedcc4` suffix was added by hand, the deploy script does not write it (fact 16).
+15. `daedcc4` ("Fix EF migration discovery metadata", 2026-07-15) is not on main: `git branch -a --contains daedcc4` lists only `origin/codex/bifrost-migration-metadata`, which is `bd3a5a9` (an ancestor of main) plus `daedcc4` alone. `git merge-tree --write-tree bf83a93 origin/codex/bifrost-migration-metadata` is clean. Main has `cde3a78`, which deleted the HTTP bridge routes `/bridge/actions/*`, `/dispatch/runs/*`, `/transport/receipts`, `/governance/receipts` and `POST /eve/governance/commands` (369 lines of `Program.cs`); main's `PlatformEndpointsTests.Removed_http_bridge_routes_are_not_mapped` pins their absence.
+16. Deploys are manual: `gamecult-ops/scripts/deploy-bifrost-alpha.sh` (33 lines, gamecult-ops `1e95674`; the deploy files are unchanged since `44889b1`) unpacks `/srv/bifrost/bifrost-publish.tar` into `releases/$(date -u +%Y%m%d%H%M%S)`, repoints `current`, restarts. It takes no revision and records none. `runbooks/bifrost-alpha-deploy.md` step 3 publishes with `dotnet publish` from the operator's checkout `F:\Projects\Bifrost` (`:101-115`), step 2 lists the env keys (`:63-89`). Idunn does not manage Bifrost (`:162-164`). The inventory's "Bifrost alpha live state" block (`gamecult-ops/inventory.md:923-933`) records no revision.
+17. No caller of the routes `cde3a78` deleted, over the whole retained nginx access log (2026-09-26 00:46 to 2026-10-10 02:58, 473,581 lines, all vhosts): zero requests to `/bridge/actions`, `/dispatch/runs`, `/transport/receipts`, `/governance/receipts` or `/eve/governance/commands`. The only `/governance/*` hits were ten scanner GETs on 2026-10-07 (`/governance/providers`, `/governance/budgets`, …, all 400). No systemd unit, timer or crontab on Yggdrasil names the bridge tools or `127.0.0.1:5080` except `bifrost.service` itself, and no non-nginx connection to `:5080` was established at probe time. The bifrost journal holds 1 line in 30 days, so the app's own logs cannot witness traffic.
+
+### Data Protection on the live host
+
+18. The live env file sets no `DataProtection__KeysPath` (key names only: `AllowedHosts`, `Bootstrap__*`, `ConnectionStrings__Bifrost`, `GitHubApp__EnableWebhookSync`, `GitHubOAuth__*`, `Heimdall__*`, `Host__*`, `Stripe__*`). So `Program.cs:113-119` never calls `PersistKeysToFileSystem`, and ASP.NET Core's default applies: the service runs as `bifrost` with `HOME=/srv/bifrost`, and the key ring is `/srv/bifrost/.aspnet/DataProtection-Keys` with two keys (created 2026-04-22 and 2026-07-22, the 90-day roll; prior-art note `docs/research/anonymous-vote-stuffing-prior-art.md:65-69`). A third, unused directory `/srv/bifrost/data-protection-keys` holds one key from 2026-07-15. Keys therefore persist across restarts today by accident of `HOME`, not by configuration.
+19. The service's working directory resolves to the release directory: `readlink /proc/<MainPID>/cwd` = `/srv/bifrost/app/releases/20260723-daedcc4`. Data Protection's default application discriminator is the content-root path (prior-art note `:67`), so every deploy into a new release directory isolates payloads protected by the previous release: auth cookies, antiforgery tokens and any future device token stop decrypting after each deploy. Mechanism from source docs plus this probe; not observed as logged-out users. `SetApplicationName` is not called anywhere (`git grep SetApplicationName bf83a93` is empty).
+
+### Proxy and client address
+
+20. nginx sends `X-Real-IP`, `X-Forwarded-For` (`$proxy_add_x_forwarded_for`), `X-Forwarded-Proto` and `X-Forwarded-Host` (live `/etc/nginx/sites-enabled/bifrost*:12-19`), and proxies to `127.0.0.1:5080`. `Program.cs` never calls `UseForwardedHeaders` (fact 13 grep), so `RemoteIpAddress` is `127.0.0.1` for every request and any per-client limit puts every visitor in one bucket.
+
+### Code and test substrate
+
+21. Main lacks EF migration discovery metadata on seven migrations: `20260622142000_AddBridgeActionIdentityProvenance`, `20260622202000_AddBridgeActionTargetSurfaceName` and `20260705190000_AddPatronSupportProjectAttribution` have neither `[DbContext]` nor `[Migration]`; `20260608210000_AddHeimdallUserIdentity`, `20260609143000_AddPatronSupportDerivation`, `20260609160000_AddExternalPatronProviderIntake` and `20260622165000_AddBifrostNativeIdentity` have `[Migration]` only; none of the seven has a `.Designer.cs`. EF discovers a migration only with both attributes, so `MigrateAsync` from main would skip them on a fresh database. `daedcc4` adds exactly those attributes (17 lines). The other five migrations have Designer files and are discovered. Migrations run at startup when `Bootstrap:ApplyMigrationsOnStartup` is true (`Features/Shared/ApplicationBootstrapper.cs:17-21`); the live env sets that key.
+22. Tests use EF InMemory (`tests/Bifrost.Web.Tests/Support/TestWebApplicationFactory.cs:52-58`), which enforces no unique index; a uniqueness rule must be proven in service code and in the model/migration metadata, not by an InMemory insert failing. `TestAuthHandler` offers two actors only: the bootstrap admin `test-admin`, or anonymous via header `X-Test-Anonymous` (`Support/TestAuthHandler.cs:17-37`). `CurrentBifrostActor` is a public record with a public constructor (`Features/Shared/CurrentBifrostActor.cs:5`), so service tests can build account and member actors directly. `Program` is `public partial` (`Program.cs:582`).
+23. Startup configuration rules live in one owner, `Features/Shared/StartupConfigurationValidator.cs`, which skips Development and Testing and throws on a missing production key (`:15-74`).
+24. The shared layout loads HTMX from `https://unpkg.com/htmx.org@1.9.12` (`Pages/Shared/_Layout.cshtml:65`); no page posts with `hx-post` today. Admin and vote handlers use plain Razor page handlers with `RedirectToPage()` (`Pages/App/Motions/Index.cshtml.cs:56-61`).
+25. Verification on Yggdrasil: `ygg-verify.sh`'s `dotnet` alias is `mcr.microsoft.com/dotnet/sdk:10.0`, which has no .NET 8 runtime for this `net8.0` test project; passing the image name `mcr.microsoft.com/dotnet/sdk:8.0` works (any other value is used as an image name). At `bf83a93`, `dotnet test tests/Bifrost.Web.Tests/Bifrost.Web.Tests.csproj -c Release --filter "FullyQualifiedName!~BridgeCliTests&FullyQualifiedName!~ProviderAdvertisementTests"` passes 29 of 29 (scratch log `bifrost-base-test-2.log`; that run's filter excluded only `BridgeCliTests`, and the two `ProviderAdvertisementTests` failed for want of Node). The other 37 tests shell out to Node: with no Node they fail to start the process; with Debian's Node 18 they fail on newer Node APIs (`bifrost-base-test-3.log`, 30 pass, 36 fail). Starfire has Node 24 and SDK 10.0.202 only. None of the cuts touch the Node tools.
+
+### The Mill page
+
+26. The Mill is committed and merged: AetheriaLore `origin/main` `6980087` ("Merge concept-mill-spa"). `Aetheria/Game Design/Concept Mill.md` is now 10 lines of front matter and prose; the viewer is the Quartz component `site/quartz/components/AetheriaConceptMill.tsx` with `scripts/aetheriaConceptMill.inline.ts` (417 lines) and `styles/aetheriaConceptMill.scss`. Its data source is `scripts/concept-mill/ships.yaml` (581 lines); `node scripts/concept-mill/build.mjs` writes the manifest `site/quartz/components/data/conceptMill.json` (embedded in the page) and render derivatives, skipping derivatives that already exist unless `--force` (`build.mjs:51-60`), and loads `js-yaml` and `sharp` from the sibling `F:\Projects\GameCult-Quartz` checkout (`:22-25`).
+27. Concept identity is the ship `id` in `ships.yaml`; there are 27 ships today (`bison vasuki squatter raft gentle-giant shellback lamp-shy zera nakovalnya oboz shchit glushitel key-light shepherd rake dine-and-dash party-favors finders-keepers tattletale ghost-fare odd-job one-pass bulldog breakup-song 50-f live-wire homestead`). The build refuses duplicate ship ids (`build.mjs:94-96`). Each ship has one or more render variants with their own ids; the URL hash is `#ship` or `#ship/variant` (`aetheriaConceptMill.inline.ts:3,178-192`). The 2026-10-08 "19 card slugs" are gone.
+28. The vote slot already exists and is switched off. `ships.yaml:22-27` holds `votes: { enabled: false, endpoint: null, bifrostUrl: null }`, copied into the manifest (`conceptMill.json:16-19`). When enabled, the script fetches `endpoint` once with `credentials: "omit"`, reads `tallies[ship.id]` as `{ up, down, members?: { up, down } }`, shows `▲ up ▼ down` (members not shown), and links `${bifrostUrl}/${ship.id}` as "Vote on Bifrost" (`inline.ts:163-174,284-287`). On fetch failure the slot shows `—`. Tallies are per ship, not per render.
+29. The Aetheria site's origin is `https://aetheria.gamecult.org` (`site/quartz.config.ts:66` `baseUrl: "aetheria.gamecult.org"`).
+
+## Rulings in force
+
+The rulings are typed state: `aetheria-release:ruling:concept-mill-votes-open`, `aetheria-release:ruling:concept-mill-votes-anonymous`, and `concept-mill-votes:ruling:public-means-counts` (Self's defaulted reading that "public" means counts split by voter class, no per-voter identity).
+
+Derived from them, not asked separately:
+
+- **Counts are raw: one voter, one mark.** Patron weight cannot apply to anonymous voters, and the member filter replaces it as the "members' opinion" view.
+- **Concept art stays out of governance.** Mill votes are their own record, not topics or motions (facts 2, 8, 9). Neither can admit an anonymous voter.
+- **Substrate is Postgres beside `Vote`,** to keep the optional foreign key to `UserAccount` in one transaction. "Bifrost web state is off CultCache" remains standing doctrine debt; this feature does not pay it down.
+
+## Authority map
+
+- **Concept identity.** Owner: the Mill's data in AetheriaLore, `scripts/concept-mill/ships.yaml`, ship `id` (fact 27). Bifrost stores keys and never invents one. Renaming a ship changes its name, never its key. A render variant is not a subject.
+- **Concept subjects.** Owner: Bifrost `ConceptSubject` (`(Collection, Key)` unique, plus `Title`, `RegisteredAtUtc`, `RetiredAtUtc`). One writer, `ConceptSubjectRegistry`, reached from one admin page that takes the Mill's generated manifest (the owner's artifact) and applies an idempotent plan: add, rename, retire-on-explicit-choice, revive. The vote path cannot create subjects.
+- **Voter identity.** Owner: `VoterIdentity.For(actor, deviceId)`, a pure function, plus a `VoterKeyResolver` that only reads or mints the device cookie and calls it:
+  - signed in: key `account:<UserAccountId>`, class `Member` if `CurrentBifrostActor.IsActiveMember` at cast time, else `Account`;
+  - otherwise: key `device:<id>`, class `Anonymous`, where the id is a random GUID protected by Data Protection in an HttpOnly, Secure, SameSite=Lax, first-party cookie on `bifrost.gamecult.org`.
+  The resolver does not own membership; it reads it. When the cookie is minted is the open question `concept-mill-votes:question:device-cookie-consent`.
+- **Votes.** Owner: `ConceptAppraisal` rows: `SubjectId`, `VoterKey` (`(SubjectId, VoterKey)` unique), `Stance` (`Up`/`Down`), `VoterClass` stamped at cast, `UserAccountId` nullable, `NetworkTag` and `CastAtUtc`. One writer, `ConceptAppraisalService` (Cast, Retract, Purge, plus read-only Tally and subject view). Rate limiting stands in front of it; uniqueness is enforced inside it and by the unique index, with a unique-violation on insert retried as a stance change.
+- **Network prefix.** Owner: one function, `NetworkPrefix`, mapping a client address to its configured IPv4/IPv6 prefix (IPv4-mapped IPv6 folded to IPv4). The audit `NetworkTag` (HMAC-SHA256 of the prefix under a configured secret) and the rate-limit partition both read it; no second prefix computation exists.
+- **Tallies.** Derived only: per live subject, per stance, all and members, computed from rows and never stored as counters.
+- **Public tally export.** The JSON xenos boundary: anonymous `GET /public/concepts/{collection}/tallies` returning `{ key: { up, down, members: { up, down } } }` for every live subject; no voter keys, account ids or tags; CORS for the configured origins only (`https://aetheria.gamecult.org`), `GET`, no credentials; `Cache-Control: public, max-age=60`. It owns nothing.
+- **The Mill page.** Read only. Its existing vote slot (fact 28) fills from the export and links to `https://bifrost.gamecult.org/mill/aetheria-concept-mill/<ship id>`. Voting happens on Bifrost's own origin, which keeps the device cookie first-party.
+- **Client address.** `UseForwardedHeaders` trusting loopback only makes `RemoteIpAddress` the real client. It is a rate-limit bucket and an audit tag, never a vote key.
+- **Key ring.** Data Protection keys live at a configured path with a fixed application name, so tokens survive restarts and deploys; production refuses to start without the path.
+- **Demotions:**
+  - Governance topic support and objection are not vote owners.
+  - `Vote.Weight` and patron tiers stay governance-only.
+  - The static page owns no count.
+  - The client IP is not an identity.
+  - The content-root path is no longer the Data Protection discriminator; the fixed application name is.
+  - The `HOME`-default key ring is no longer an owner; the configured `DataProtection:KeysPath` is (pointed at the same directory, so existing keys are retained).
+
+## Anti-stuffing defence (implementation duty)
+
+Prior art: `docs/research/anonymous-vote-stuffing-prior-art.md` (Eyes, 2026-10-10, Bifrost `bf83a93`). It replaces the from-memory list this section used to carry. Its section "Where the current design's assumptions are contradicted" (`:92-98`) changed the design as follows:
+
+1. **Device token: one vote per device per concept.** Kept. Its one-year life depends on persisted, retained keys and a stable discriminator (note `:65-69,95`; facts 18-19), so Cut 1 makes both configuration. Whether the cookie needs a notice or consent is the operator's question `device-cookie-consent` (note `:74-77,97`); the recommended option mints it only when a visitor casts a vote, with a one-line notice.
+2. **Network rate limits.** Kept, in-box ASP.NET Core rate limiter, partitioned by `NetworkPrefix` for anonymous voters and by account when signed in. The prefix lengths are configuration, not design: the note found no evidence for a /24 IPv4 bucket, and per-/64 IPv6 buckets are spread across by delegated prefixes and privacy rotation while larger buckets catch mobile users (`:57-61,96`). Hands proposes defaults and limits; Soul probes them. Partition keys come only from `RemoteIpAddress` after loopback-only forwarded headers or from an account id, never from raw client input (note `:45`).
+3. **Audit and purge.** Kept. The note confirms large sites rely on after-the-fact detection and also documents their false positives and unpublished thresholds (`:14-16,98`); Purge leaves an audit event so a correction is itself reviewable.
+4. **Escalation, not built now:** proof of work. ALTCHA has no official .NET server, only community packages that need a production replay store (`:27,94`), and PoW is weak against determined attackers (`:34-37`). Not specified until audit shows stuffing. Turnstile and reCAPTCHA stay refused (third party on the vote path).
+
+Vote fuzzing and voter-history weighting (note `:98`) are not adopted: raw public counts are the ruling.
+
+Where it lives: Bifrost web code only. nginx gets nothing new (`limit_req` would be a second, unobservable owner of the same budget). The static site gets nothing.
+
+## Cut order and rationale
+
+The cut specs are typed state (`concept-mill-votes:cut_spec:cut-<label>.r1`); this section keeps only why the order is what it is.
+
+- **0a, 0b: subtraction first.** Production runs `daedcc4`, which main does not contain. Merging that branch (not cherry-picking) makes the live revision an ancestor of main, so the branch can be retired and the live release is on main without redeploying anything new; then 0b deploys main through a revision-recording deploy and names the revision in the inventory. Behaviour cuts come after, so their deploy (Cut 6) starts from a known base.
+- **1: host trust plumbing.** Forwarded headers and the key ring are prerequisites of the rate limits (fact 20) and the device token (facts 18-19). Its runbook consequence (the env key) is written by Cut 6, which is the only cut that deploys behaviour.
+- **2: the record.** Subjects, appraisals, the pure voter-identity function, the network prefix and tag, and the one writer. No HTTP surface, so it is testable without the page.
+- **3: registration**, the only subject writer, before anything can be voted on.
+- **4: the public export and CORS.** Rate limits moved out of this cut (the 2026-10-08 map had them here) to land with the path they guard.
+- **5: the vote page and voter key resolver**, blocked on `device-cookie-consent` for when the cookie is minted and what the page says.
+- **5b: rate limits on the cast path**, after 5 because the policies attach to its handlers; the end-to-end limiter test also proves Cut 1's forwarded-header wiring.
+- **6: deploy** with the new env keys, registration seeded from the Mill manifest.
+- **7: the Mill turns its vote slot on**, after the endpoint is live.
+
+## Open questions
+
+`concept-mill-votes:question:device-cookie-consent`, raised in Cut 5. Nothing else is open with the operator.

docs/context.md

@@ -18,8 +18,10 @@ The product center is the Labor Platform loop: eligible participants express pol
   - source of deployment and infrastructure conventions
   - documents Yggdrasil, nginx, systemd, and local-Postgres patterns
 - `E:\Projects\Heimdall`
-  - owns OAuth, linked accounts, token custody, signed claims, grants, consent, and revocation
-  - Bifrost consumes Heimdall identity/capability facts instead of becoming the credential vault
+  - authenticates: owns OAuth, linked accounts, token custody, signed claims, grants, consent, and revocation
+  - does not issue GameCult identity: its account id (`HeimdallAccountId`) is an authenticator handle, never who a person is on GameCult
+  - Bifrost consumes Heimdall authentication/capability facts instead of becoming the credential vault
+  - remaining scar: Heimdall still mints its own account id in code (`src/app.ts` `createAccount`); chat does not need that to move, so it has not
 - `E:\Projects\VoidBot`
   - observes Discord, packages consensus, and runs repo Persona heartbeats
   - should call Bifrost for governed GitHub/Discord/Reddit/intake crossings instead of becoming hidden transport authority
@@ -55,7 +57,7 @@ After bootstrap, the next session should start implementing the first vertical s
 
 - member alpha first
 - invite-only onboarding
-- GitHub as the only auth provider in v1
+- Bifrost is the GameCult identity issuer: `UserAccount.Id` is the subject, and Bifrost is the OIDC provider for chat (`docs/oidc-issuer.md`); GitHub, native, and Heimdall-linked sign-in only authenticate into it
 - GitHub issues and internal tasks both supported
 - app-native governance and voting
 - priority and reward pressure should be transparent and auditable

docs/jurisdiction-map.md

@@ -103,6 +103,8 @@ This keeps Reddit useful without making subreddit mechanics the secret constitut
 - signed identity and capability claims
 - grants, consent, revocation, and capability evaluation
 
+Heimdall authenticates; it does not issue GameCult identity. Bifrost owns the identity (`UserAccount.Id`, `NormalizedBifrostIdentity`) and issues it to chat as an OIDC provider (`docs/oidc-issuer.md`). `HeimdallAccountId` is an authenticator handle that links a Heimdall account to a Bifrost identity.
+
 Bifrost consumes Heimdall claims. It does not become the key vault. The split is bridge versus gate: Heimdall decides who may cross under which grant; Bifrost moves authorized work across public protocols and records where it landed.
 
 ### Patron Collection Crossing
@@ -153,7 +155,7 @@ Repo Personas may generate bridge requests. They do not own the bridge itself.
 
 | Concern | Owner | Reason |
 | --- | --- | --- |
-| Who is this actor? | Heimdall | Identity and account custody must stay with the auth authority. |
+| Who is this actor? | Bifrost (identity) with Heimdall (authentication) | Bifrost issues the identity; account custody and credential proof stay with the auth authority. |
 | Is this actor allowed to request this crossing? | Heimdall plus Bifrost | Heimdall issues grants; Bifrost applies bridge-domain policy. |
 | What work is being requested? | Bifrost | The request shape, priority, provenance, and lifecycle are governance concerns. |
 | How does interest become reward pressure? | Bifrost | Priority, bounty growth, vote weight, and reward allocation are Labor Platform concerns. |
@@ -205,6 +207,7 @@ This is not the final hosted control plane. It is the current bridge actuator an
 - Do not add Bifrost-scoped Discord transport or dispatch receipts to arbitrary repo Persona scripts. Call Bifrost.
 - Do not add Bifrost-scoped Reddit posting or Persona flair handling to arbitrary repo Persona scripts. Call Bifrost.
 - Do not put OAuth credentials or account custody into Bifrost helper scripts as the long-term plan. Use Heimdall claims.
+- Do not hand Heimdall ids, GitHub ids, or display names out as the GameCult subject. The OIDC `sub` is `UserAccount.Id`, and the localpart is `NormalizedBifrostIdentity`, minted once.
 - Do not make CultCache documents decide policy. They store packets; Bifrost gives those packets meaning.
 - Do not let a repo Persona turn a proposal into endless Aquarium pressure once it has enough shape. Route it to Bifrost as a reviewable artifact.
 - Do not expose bridge debug noise to public channels. Public receipts should say what happened, which Bifrost topic or work item owns it, where it landed, and what comes next.

docs/oidc-issuer.md

@@ -0,0 +1,113 @@
+# Bifrost OIDC issuer
+
+Bifrost is the GameCult identity issuer. It runs an OpenID Connect provider on its public host so that Matrix
+Authentication Service (MAS) can sign chat users in with their Bifrost account. Heimdall authenticates people into
+Bifrost; it does not issue the identity chat sees.
+
+The provider is OpenIddict (`OpenIddict.AspNetCore` and `OpenIddict.EntityFrameworkCore`, 7.7.1). Bifrost owns two
+decisions at the authorize endpoint: who the chat user is, and whether they may get a session.
+
+## Endpoints
+
+The issuer is `Host:PublicBaseUrl`, normalized by .NET into an absolute URI. For a bare host that adds a trailing
+slash, so for `https://bifrost.gamecult.org` the issuer string is `https://bifrost.gamecult.org/`. Configure MAS with
+that exact string.
+
+| Endpoint | Path |
+| --- | --- |
+| Discovery | `/.well-known/openid-configuration` |
+| JWKS | `/.well-known/jwks` |
+| Authorization | `/connect/authorize` |
+| Token | `/connect/token` |
+| Userinfo | `/connect/userinfo` |
+
+Only the authorization code flow exists, and PKCE (S256) is required. There is no implicit, hybrid, password,
+client-credentials or device flow, no refresh token, and no dynamic client registration. The token endpoint takes
+`client_secret_basic` only. Scopes are `openid` and `profile`.
+
+## The one client
+
+Exactly one client is registered, from configuration, and seeded or updated at startup; every other application
+row (with its authorizations and tokens) is deleted at startup. Any other `client_id`, an unregistered `redirect_uri`, or a request without PKCE is refused by the
+provider before any sign-in redirect.
+
+## Configuration
+
+The section is `Bifrost:Oidc`. Absent, the provider surface is not mapped at all and discovery answers 404. Present,
+it must be complete: an unreadable or wrong-shaped file stops startup with a message that names the setting and never
+echoes its value.
+
+| Setting | Meaning |
+| --- | --- |
+| `Bifrost:Oidc:SigningKeyPath` | PEM file with an EC P-256 private key. Tokens and id_tokens are signed ES256; JWKS publishes exactly that key. A non-P-256 or public-only key stops startup. |
+| `Bifrost:Oidc:EncryptionKeyPath` | File holding 32 random bytes as base64 (`openssl rand -base64 32`). Encrypts the tokens OpenIddict issues, the access token and the parked authorize request among them. |
+| `Bifrost:Oidc:Clients:Mas:ClientId` | The client id MAS presents. |
+| `Bifrost:Oidc:Clients:Mas:ClientSecretPath` | File holding the client secret. |
+| `Bifrost:Oidc:Clients:Mas:RedirectUri` | MAS's callback URL, registered exactly. |
+| `Bifrost:Oidc:Clients:Mas:BackchannelLogoutUri` | Optional. MAS's back-channel logout URL, `https://<mas>/upstream/backchannel-logout/<provider ULID>`; absolute http(s) or startup fails. Unset: no logout is sent and no authorization is revoked. |
+
+There are no development or ephemeral keys in the host. Key files are provisioned like the other
+`[workload.secret_files]` paths.
+
+## Claims
+
+| Claim | Value |
+| --- | --- |
+| `sub` | `UserAccount.Id`, formatted `D` |
+| `preferred_username` | `NormalizedBifrostIdentity` (minted once; there is no rename path) |
+| `name` | `DisplayName`, else `BifrostIdentity` |
+
+No e-mail, no Heimdall id, no GitHub id, and no membership detail leaves Bifrost.
+
+## Who may sign in
+
+The authorize endpoint reads the cookie session and the same actor facts the `/App` policy reads.
+
+- No session: challenge to `/auth/sign-in`, which resumes the original request after sign-in. OpenIddict parks the
+  full request (its request token, in the OpenIddict token table, expiring after ten minutes, spent when used) and
+  the return path carries only a short `request_uri`, so `LocalReturnPath.MaxLength` stays 256.
+- Signed in, membership not `Active`: redirect to the client's `redirect_uri` with `error=access_denied` and
+  `error_description=The account is not an active GameCult member.`
+- Signed in, `Active`, but `NormalizedBifrostIdentity` empty: `error=access_denied` with
+  `error_description=The account has no Bifrost identity.`
+- Signed in and `Active`: a code is issued.
+- Token endpoint: membership is read again; an account no longer `Active` gets `invalid_grant` and no tokens.
+
+## Back-channel logout
+
+When `BackchannelLogoutUri` is set, a hosted reconciler (`OidcLogoutReconciler`) runs every 30 seconds. It lists the
+subjects holding valid authorizations of the MAS client; for each subject whose membership is not `Active` (the same
+reading the token and userinfo endpoints use; a deleted account or a subject that is not an account id counts as not
+`Active`) it POSTs one OIDC back-channel logout token to MAS, and only after a 2xx revokes that subject's authorizations,
+which also invalidates their tokens. Membership is never written by this path: any way of leaving `Active` (admin
+action, sync, a database edit, a future suspend) is covered because the work is derived from membership state.
+
+The token is an ES256 JWT signed with the issuer key, header `typ` `logout+jwt`, with `iss` as the id_token carries it,
+`aud` the MAS client id, `sub` the account id, `iat`, `exp` two minutes later, a fresh `jti` and the
+`http://schemas.openid.net/event/backchannel-logout` event. It carries no `nonce` and no `sid`; MAS finds the sessions
+by `sub`. It is sent as `application/x-www-form-urlencoded` field `logout_token` with a 10 second timeout, and the
+response body is never logged.
+
+Failure handling is per subject, in memory: a 5xx, a timeout or a network fault backs off exponentially from 30 seconds
+to 15 minutes; a 400 (token refused) or 404 (unknown provider ULID) is a configuration fault, logged by status only,
+and retried at the 15 minute cap. Nothing is revoked until MAS answers 2xx. A restart loses the backoff and nothing
+else: the authorizations table is the queue, so a later-set URI also catches up on earlier demotions.
+
+Tradeoff: delivery latency is up to one tick, and a member demoted and re-promoted inside one tick keeps their sessions.
+
+MAS verified at v1.28.0 (`crates/handlers/src/upstream_oauth2/backchannel_logout.rs`): the token is checked like an
+id_token (`iss`, `aud`, `alg`, JWKS signature), `exp` and `iat` are required, `sub` or `sid` is required, `nonce` must be
+absent. Owed on the MAS side (gamecult-chat): the provider's `backchannel_logout_uri` and
+`on_backchannel_logout: logout_all`. Re-check against the MAS version pinned there.
+
+## MAS configuration
+
+Configure MAS's upstream provider with the issuer above, the client id and secret, the token endpoint auth method
+`client_secret_basic`, the id_token signing algorithm `ES256`, scope `openid profile`, and a localpart claim import
+from `preferred_username`. MAS mints the Matrix localpart on first sign-in, so the claim must never change for an
+account.
+
+## Remaining scar
+
+Heimdall still mints its own account id in code (`src/app.ts` `createAccount`). That id is an authenticator handle
+and chat does not need it to move.

docs/research/2026-10-29-estate-tally-game-theory/README.md

@@ -0,0 +1,330 @@
+# Eyes: estate internal tally, game-theory probes (2026-10-29)
+
+Fork: Fork Desk question 39, `eureka-body:question:estate-internal-tally` (InForce; options proportional | winner-take-all; Self's recommended: proportional). Context ruling `eureka-body:ruling:governance-estate-blocks`. Session self-2026-10-29-eureka. Facts and measured results only, no recommendation.
+Operator additions folded in (her words relayed by the Self): within-bloc vote-power curves ("Patrons vote power scales with donation total, but it's logarithmic... Member vote should scale with contribution... via a lower exponent"); present case ("I'm the only active member"); renormalization ruling ("normalize it by who actually voted").
+
+## Code, outputs, model
+Dir `sims/` (numpy 2.5.4, Python 3.13, `python -I <script>`; each `X.py` writes `X.out.md`, full tables there):
+`power.py` exact Banzhaf/Shapley and two-tier individual power; `mc.py` Monte Carlo outcomes; `weights.py` within-bloc curves; `growth.py` present case and growth path; `strat.py` misreport/abstention and logrolling; `noshow.py` no-show and quorum under renormalization; `lone.py` lone-estate bounds (her absent).
+- Pass rule as in Bifrost `MotionGovernanceService`: For/(For+Against) >= q, abstain excluded. Every tally renormalizes over estates with at least one For/Against ballot (the ruling); a WTA tie casts nothing, so a tied estate also drops out. Ties at exactly q pass (>=).
+- Sizes unless stated: Minds 8, Members 15, Users 30 voting (roll 300, 10% turnout), Patrons 4. Weight seeds M/Me/U/P: equal 25/25/25/25; minds-heavy 40/30/20/10; members-heavy 20/45/20/15.
+- "A priori" = Banzhaf coin-flip voters. "Motion model" (mc, weights W3): merit m~N(0,1), bloc taste e~N(0,1), bloc support p_b=logistic(1.7(0.6m+0.8e)); Minds intra-class correlation (ICC) via a shared beta-binomial propensity. ICC 0.44 is Kish-calibrated to Kohli 2026 (9 LLM judges ~ 2 effective votes, cited in the Bifrost prior-art note).
+- Assumptions, not data: Member contribution = operator holds share S (0.5/0.8/0.95) of the total, the rest a Pareto(1.16) quantile ladder; Patron donations [10, 50, 200, 5000].
+- Bug caught and fixed mid-run: the first mc.py drew per-voter propensities, which gives no correlation; results below are from the fixed shared-propensity version.
+
+## 1. Unitary blocs: a priori power (power.out.md)
+| weights | q | Banzhaf M/Me/U/P | Shapley M/Me/U/P | veto blocs |
+|---|---|---|---|---|
+| equal | .15/.5/.66 | .25 each | .25 each | none |
+| minds-heavy | .15 | .33/.33/.33/0 (Patrons dummy) | same | none |
+| minds-heavy | .5 | .42/.25/.25/.08 | .42/.25/.25/.08 | none |
+| minds-heavy | .66 | .50/.30/.10/.10 | .58/.25/.08/.08 | Minds |
+| members-heavy | .5 | .17/.50/.17/.17 | same | none |
+| members-heavy | .66 | .20/.40/.20/.20 | .17/.50/.17/.17 | Members |
+- Power is not weight: 40/30/20/10 at q=.5 gives Members and Users equal power; 10% Patrons are a dummy at q=.15.
+- Meta-vote on weights (the ruling votes on block sizes): a reallocation of weight is a divide-the-dollar game. A simple game's core is nonempty iff it has a veto player (standard; e.g. Osborne & Rubinstein 1994 ch. 13) [M]. With no veto bloc (most rows) every weight vector can be beaten by a winning coalition that moves weight to itself. Where a veto bloc exists (minds-heavy .66, members-heavy .66), that bloc must be in any reweighting coalition. At equal weights and q > .75 every bloc is a veto player.
+
+## 2. Individual power inside blocs, a priori (power.out.md)
+P(one voter flips the motion); sizes 8/15/30/4.
+| weights | q | rule | Mind | Member | User | Patron | max/min |
+|---|---|---|---|---|---|---|---|
+| equal | .5 | WTA | .118 | .096 | .064 | .158 | 2.5 |
+| equal | .5 | prop | .143 | .077 | .038 | .296 | 7.7 |
+| equal | .66 | WTA | .118 | .096 | .064 | .158 | 2.5 |
+| equal | .66 | prop | .026 | .015 | .007 | .047 | 6.5 |
+| minds-heavy | .5 | WTA | .169 | .108 | .051 | .061 | 3.3 |
+| minds-heavy | .5 | prop | .234 | .091 | .030 | .115 | 7.8 |
+| members-heavy | .5 | WTA | .037 | .189 | .016 | .058 | 11.5 |
+| members-heavy | .5 | prop | .125 | .151 | .033 | .189 | 5.8 |
+- Under prop each voter's marginal weight is w_b/n_b, so individual power scales ~1/n. Under WTA it scales ~1/sqrt(n) (Penrose). WTA compresses individual inequality, except where the council game makes a bloc near-dummy (members-heavy WTA: Users .016).
+- At q=.66 with coin-flip voters, prop individual power collapses (a bloc share rarely sits near the threshold). WTA is unchanged at equal weights (3 of 4 blocs either way).
+- Penrose sqrt shares for 8/15/30/4: 19.9/27.3/38.6/14.1. Using Minds n_eff 1.96 instead of 8: 11.0/30.4/43.0/15.7. Under sqrt weights the WTA individual powers are .093/.084/.096/.122, roughly equal (4 blocs is too few for exactness). Headcount weights make prop exactly equal (.106 each) but make WTA Minds and Patrons dummies (0) and Users a dictator.
+
+## 3. Monte Carlo, motion model (mc.out.md; Minds ICC .44)
+| weights | q | P(pass) prop | P(pass) WTA | P(outcomes differ) |
+|---|---|---|---|---|
+| equal | .15 / .5 / .66 | .934/.501/.265 | .838/.594/.404 | .098/.119/.148 |
+| minds-heavy | .15 / .5 / .66 | .913/.500/.299 | .796/.537/.357 | .122/.118/.091 |
+| members-heavy | .15 / .5 / .66 | .932/.500/.270 | .838/.500/.342 | .101/.111/.113 |
+- The two rules disagree on 9-15% of motions in every configuration. Prop is the weighted popular share, so each disagreement is a WTA referendum paradox (Nurmi 1998) [M]. WTA flattens the effective threshold: passes less at .15 and more at .66, because a bloc that clears its internal majority casts 100%.
+- Single-voter pivot (equal, q=.5), prop vs WTA: Mind .050/.021, Member .026/.023, User .013/.012, Patron .100/.076.
+- Minds correlation (equal, q=.5):
+
+| Minds ICC | n_eff of 8 | mean abs(Minds share - .5) | Mind pivot prop | Mind pivot WTA | P(Minds 4-4 tie) | P(rules differ) |
+|---|---|---|---|---|---|---|
+| 0 | 8.0 | .280 | .051 | .040 | .107 | .115 |
+| .44 | 1.96 | .379 | .050 | .020 | .054 | .119 |
+| .8 | 1.21 | .458 | .049 | .006 | .017 | .124 |
+| 1 | 1.0 | .500 | .047 | 0 | 0 | .126 |
+  Correlation pushes the Minds split toward 0/8 or 8/0, so prop and WTA deliver nearly the same Minds cast. Under WTA one Persona's flip almost never matters at ICC >= .44; under prop each Persona keeps a 1/8 slice regardless.
+- Users turnout (equal, q=.5): at turnout 1/3/10/30%, P(the WTA cast misstates the population majority) = .18/.12/.08/.04 and the mean prop share error = .19/.11/.06/.03. P(motion differs from the full-turnout result) is prop .077/.044/.024/.014 vs WTA .062/.040/.024/.014. The rules are about equal here.
+- Faction capture (Users population support .3, 9 random voters + k coordinated): P(WTA Users cast For) for k=0/3/6/9 = .10/.27/.80/.96; prop share .30/.48/.58/.65. Under WTA a 6-voter faction takes the whole Users weight 80% of the time; under prop it moves the share by .28.
+
+## 4. Within-bloc power curves (weights.out.md)
+Kish n_eff = (sum w)^2 / sum w^2. "Top" = the operator (Members) or the largest donor (Patrons). Internal Banzhaf = P(top's flip changes the bloc's WTA cast).
+| bloc | curve | S | n_eff | top share | top internal Banzhaf |
+|---|---|---|---|---|---|
+| Members 15 | one-each | - | 15.0 | .067 | .21 |
+| Members 15 | k=1 / 2 / 3 / 5 | .5 | 3.6 / 10.1 / 12.9 / 14.3 | .50 / .22 / .15 / .11 | 1.0 / .67 / .48 / .33 |
+| Members 15 | k=1 / 2 / 3 / 5 | .8 | 1.6 / 6.1 / 10.4 / 13.5 | .80 / .36 / .23 / .14 | 1.0 / .96 / .70 / .47 |
+| Patrons 4 | one-each / k=1 / log(1+d) | - | 4.0 / 1.1 / 3.3 | .25 / .95 / .42 | .75 / 1.0 / .75 |
+| Patrons 4 | k=3 / 5 / 10 | - | 2.4 / 3.2 / 3.8 | .59 / .45 / .35 | 1.0 / .75 / .75 |
+(The k=1, S=.5 row is an exact 50% tie with the rest, scored pivotal because tie-to-win counts as a change. Internal Banzhaf .75 for 4 one-each Patrons has the same cause.) On this donation ladder log(1+d) flattens like d^(1/5); d^(1/3) still leaves the top Patron dictating the bloc under WTA.
+Operator's whole-tally pivot (a priori, Patrons log(1+d); W2):
+| seed | q | S | one-each | k=1 | k=2 | k=3 | k=5 | (Mind / User, k=3) |
+|---|---|---|---|---|---|---|---|---|
+| equal | .5 | .5 prop/WTA | .069/.089 | .50/.42 | .23/.29 | .16/.20 | .12/.14 | .13/.11, .035/.059 |
+| equal | .5 | .8 prop/WTA | - | .75/.42 | .38/.40 | .24/.30 | .15/.20 | |
+| equal | .66 | .8 prop/WTA | - | .25/.42 | .09/.41 | .06/.30 | .04/.20 | |
+| members-heavy | .5 | .8 prop/WTA | .15/.18 | 1.0/.84 | .75/.81 | .50/.59 | .32/.40 | |
+- Under WTA her power is capped by the Members bloc's council power: about .42 at equal weights and .84 at members-heavy, reached once she dictates the bloc. Under prop it is uncapped at q=.5 (members-heavy k=1 S=.8: .999, which makes her near-dictator of the whole tally). At q=.66 prop shrinks every individual's power and WTA does not.
+- Exponent sensitivity, motion model (W3; equal, q=.5, S=.5, baseline Members k=3 and Patrons log): P(outcome changes vs baseline) for Members one-each/k=1/k=2/k=5 is prop .014/.051/.010/.007, WTA .014/.061/.012/.008. For the Patron curve one-each/k=1/k=3/k=5/k=10 it is prop .027/.080/.026/.006/.013, WTA .032/.033/.033/0/0. Outcomes move by 1-8%. Her pivot moves more: .025 (one-each) to .21 (k=1) prop, and .022 to .30 WTA.
+
+## 5. Present case and growth (growth.out.md, noshow.out.md; renormalized)
+Present case: Members = her alone, Minds 8, Users and Patrons empty, so only two estates are live and their weights renormalize. P(pass | she votes For / Against / stays home), Minds coin-flip (N2):
+| seed (M,Me) | q | prop | WTA |
+|---|---|---|---|
+| 25,25 | .5 | 1.00 / .004 / .64 | 1.00 / .36 / .36 |
+| 25,25 | .66 | .86 / 0 / .15 | .64 / 0 / .36 |
+| 40,30 | .5 | .996 / .035 / .64 | .64 / .36 / .36 |
+| 20,45 | any | 1.00 / 0 / home .64 (.5), .15 (.66) | 1.00 / 0 / .36 |
+- Equal seed, q=.5: under prop she decides the motion 99.6% of the time (Minds share must hit 8/0 to beat her Against). Under WTA her Against is overridden whenever the Minds majority is For (25 vs 25 ties and passes at >=). Minds-heavy WTA: a unanimous Minds bloc decides alone (her pivot 0.000 with correlated Minds). Members-heavy: she is dictator under both rules.
+- With 3 Users + 1 Patron present (G1), equal q=.5: her pivot is .50 prop / .41 WTA.
+When her single vote stops deciding the Members bloc under WTA (share <= .5; G2):
+| curve | S=.5 | S=.8 | S=.95 |
+|---|---|---|---|
+| one-each | n=2 (tie), n>=3 | n=2 (tie), n>=3 | n=2 (tie), n>=3 |
+| k=5 | n>=2 (tie at 2) | n=3 | n=5 |
+| k=3 | n>=2 | n=5 (n=3 at .501) | n=10 |
+| k=2 | n>=2 | n=10 | n=50 |
+| k=1 | always tied at .5 | never | never |
+Growth path, her whole-tally pivot (equal seed, q=.5, Users 10, Patrons 2): alone .72 prop / .43 WTA. n=5, S=.8: k=1 .60/.43, k=3 .31/.38, k=5 .24/.22, one-each .15/.16. n=20, S=.8: k=3 .16/.29, k=5 .10/.18, one-each .04/.08. Members-heavy seed, n=20, S=.8, k=3: .38/.59.
+
+## 5b. Lone estate bounds, she absent (lone.out.md)
+Operator ruling relayed: "But they totally should be able to make decisions without me if I'm not there to vote". Under renormalization the Minds estate is then the whole tally.
+- Quorum floors a lone, fully turned-out Minds estate meets:
+  - Headcount floor: 8/9 = .889 of eligible individuals.
+  - Estate-weight floor (Minds weight over live-eligible estate weight): .500 equal, .571 minds-heavy, .308 members-heavy.
+  - Any floor above these values requires her turnout. The at-least-two-estates floor (section 6 N1) requires her by construction while Users and Patrons are empty, so it is kept only as a later-membership comparison.
+- Category thresholds (Bifrost `MotionCategoryPolicy`), lone Minds, all 8 voting. Columns: Personas needed under prop, then P(pass) in the motion model at Minds ICC 0 / .44 / 1:
+  - Bugs .15: 2 needed; .78/.65/.50
+  - Cosmetics .30: 3 needed; .66/.59/.50
+  - Balance .40: 4 needed; .55/.53/.50
+  - Features and NewContent .50: 4 needed; .55/.53/.50
+  - FundamentalDesign .66: 6 needed; .34/.42/.50
+  - Under WTA a lone estate casts 100% For or 100% Against, so the ratio is 1 or 0 and every category passes on a 5-of-8 majority: .45/.47/.50. Category thresholds are inert for a lone estate under WTA and binding under prop.
+  - At ICC 1 (one effective Mind) both rules give .50 at every threshold: the threshold stops discriminating when the estate votes as one.
+- Delay-plus-cancel window: P(she is back before effect), absence ~ Exponential(mean A); this measures the chance a cancel opportunity exists, not that it is used.
+
+  | delay D | A=1 day | A=3 days | A=7 days | A=14 days |
+  |---|---|---|---|---|
+  | 1 day | .63 | .28 | .13 | .07 |
+  | 3 days | .95 | .63 | .35 | .19 |
+  | 7 days | 1.00 | .90 | .63 | .39 |
+  | 14 days | 1.00 | .99 | .86 | .63 |
+
+  Prior-art delays (Bifrost prior-art note, section 5 and section 1):
+  - Compound Timelock: 2 days.
+  - OpenZeppelin Timelock: exists so users can "exit the system if they disagree" before a decision executes; a canceller role; a guardian may cancel at any stage.
+  - Olympus Bravo: veto guardian until execution.
+  - Apache: votes run at least 72 h.
+  - Rust FCP: 10 days, and a raised concern blocks.
+  - Beanstalk had no delay; its governance attack drained ~$76M.
+
+## 6. Strategic probes
+S1 (strat.py, exhaustive; sizes 3/3/2/2, sincere profiles, no quorum): 0 profitable misreports or abstentions under either rule at any q or seed. The For/(For+Against) ratio is monotone and participation-safe without a quorum. With a cast-weight quorum (>= 50% of estate weight), WTA produced 144-288 profitable abstentions per 10240 cases: an abstention creates an internal tie, the estate drops out, and quorum fails. Prop produced 0.
+N1 (noshow.py, renormalized, quorum floors). Columns: individual profitable deviations / hers / profitable estate stay-home. Present case 8/1/0/0, 512 profiles:
+- No quorum: 0 / 0 / 0 in every seed, q and rule.
+- Headcount quorum (>= half of eligible): 0 individual deviations. Estate stay-home is profitable in 56-93 profiles, because with only 9 eligible the Minds estate staying home breaks quorum.
+- "At least two estates": WTA equal q=.5 gives 93 / 93 / 186; prop gives 1 / 1 / 94. Her staying home kills any motion she opposes, because with Users and Patrons empty she is the second estate. Minds-heavy q=.5: prop 9 / 9 / 101, WTA 93 / 93 / 93. At q=.66 most of these drop to 0 (prop equal still 56 estate cases).
+- Mixed 3/1/2/1 with everyone voting: 0 under every floor. The no-show leverage comes from empty estates, not from the rule itself.
+S2 logrolling (6-motion agendas, 1500 each, greedy mutually profitable pairwise trades; welfare = sum of bloc utilities). Unitary blocs can deliver their whole weight; proportional blocs' leadership moves the share by delta:
+| seed | bloc type | P(>=1 trade) | mean trades | mean welfare change | P(welfare falls) | P(a non-trader loses) | P(a trader ends worse) |
+|---|---|---|---|---|---|---|---|
+| equal | unitary | .615 | 1.04 | +.168 | .245 | .397 | .234 |
+| equal | prop delta .5 | .430 | .66 | -.396 | .338 | .305 | .127 |
+| equal | prop delta .2 | .127 | .17 | -.027 | .071 | .093 | .017 |
+| minds-heavy | unitary | .615 | .90 | +.016 | .302 | .484 | .184 |
+| minds-heavy | prop delta .5 | .324 | .44 | -.306 | .230 | .261 | .076 |
+- Unitary blocs find trades on most agendas. Trades raise mean welfare (equal seed) but impose losses on a non-trading bloc in 40-48% of agendas and leave a trader worse than sincere in 18-23%, which is Riker & Brams's paradox of vote trading at bloc scale. Partial-delivery blocs trade far less. The negative mean welfare at delta .5 is a model result (proportional shares near .5 flip low-stakes motions) that I have not cross-checked.
+
+## 7. Literature (one or two lines each; [V] = verified by search this pass, [M] = from memory, not fetched)
+- Putnam 1988, "Diplomacy and Domestic Politics: The Logic of Two-Level Games", Int. Org. 42(3):427-460 [M]. A deal must lie in each side's domestic win-set; a smaller win-set gives bargaining advantage (the Schelling conjecture), with the risk of involuntary defection. Mapping: a bloc parliament that ratifies the bloc position is a level-II ratifier. A prop bloc has no ratified position to bargain from.
+- Schelling 1956 "An Essay on Bargaining", AER 46(3); Strategy of Conflict 1960 [M]. Binding oneself (burning bridges) is power. A unitary bloc whose position is fixed by an internal vote is a visible commitment device; prop splitting commits nothing beyond the count.
+- Tests of the conjecture [V]. Mo 1995 APSR 89(4):914-924: a negotiator may gain by giving an agent veto, but only when the agent's preferences are extreme enough and depending on what the other side knows. Iida 1993 JCR and 1996 Public Choice: incomplete information about domestic preferences drives ratification failure; two-sided constraints give relatively equitable outcomes. Tarar 2001 JCR 45(3):320-340: with both sides constrained and incomplete information, the opposite of the conjecture can occur. All four estates having parliaments is the two-sided case.
+- Diermeier & Feddersen 1998 APSR 92(3) [M]: the vote-of-confidence procedure makes coalitions cohesive, and cohesion raises a coalition's value in legislative bargaining. This is the party-discipline analogue: a disciplined unit outbargains an undisciplined one. Krehbiel 1993 "Where's the Party?" and Cox & McCubbins 1993 dispute how much discipline is real.
+- Riker & Brams 1973 "The Paradox of Vote Trading", APSR 67(4) [M]: individually rational trades can leave all parties worse off. S2 measures it.
+- Snyder, Ting & Ansolabehere 2005 "Legislative Bargaining under Weighted Voting", AER 95(4) [M]: in Baron-Ferejohn bargaining, expected payoffs track minimal-integer-representation weights rather than Banzhaf/Shapley. This applies to the weight meta-vote as distributive bargaining among unitary blocs.
+- Penrose 1946 JRSS 109; Banzhaf 1965 Rutgers L. Rev. 19 [M]. Two-tier WTA equalizes individual power with sqrt(n) weights. Banzhaf 1968 "One Man, 3.312 Votes" showed large US states' unit rule over-empowers their voters [M].
+- Jagiellonian compromise [V]: Słomczyński & Życzkowski; sqrt-of-population weights with quota ~62% (61.5% for EU-27) (arXiv cond-mat/0405396, 0712.2699). Poland tabled it in 2007; the Council adopted the double majority instead.
+- Gelman, Katz & Bafumi 2004, BJPS 34(4):657-674 [V]: the coin-flip model overstates decisiveness in large units; empirically, proportional weights are "basically fair" and sqrt is not. Kirsch 2007 (Homo Oeconomicus) [M]: with correlated voters the optimal two-tier weights move from sqrt(n) toward n. The Minds correlation table above is a local instance: a high-ICC bloc of 8 has n_eff ~ 2.
+- Coleman 1971 [M]: separates the power to initiate action from the power to prevent it. The thresholds .15 vs .66 shift power between these two, which is visible in the q rows of section 2.
+- Electoral college unit rule [M]. Pathologies: campaigning and policy concentrate in swing states (Strömberg 2008 AER 98(3)); referendum paradox (Nurmi 1998 SCW 15). Faithless electors are bound by state law (Chiafalo v. Washington, 2020); in a bloc parliament the analogue is a Persona breaking the bloc mandate.
+- Estates-General 1789 [M]: vote by order (each estate one unitary vote) vs by head; the Third Estate refused the unitary-order rule and declared itself the National Assembly on 17 June 1789. Precedent: a unitary-estate rule is contested when one estate's size outgrows its weight.
+- Lijphart 1969 World Politics 21(2); Democracy in Plural Societies 1977 [M]. Consociationalism has four pillars: grand coalition, segmental autonomy, proportionality and mutual veto. Segmental autonomy fits each estate running its own internal process; mutual veto corresponds to the q > .75 equal-weight case in section 1.
+- Hirschman 1970 [M]: exit, voice, loyalty. In section 5 no-show acts as exit-as-leverage when an estate is the quorum's second member.
+
+## 8. Candidate articulations of the hunch: what the evidence shows
+- Credible commitment / paradox of weakness. Supported in theory by Putnam, Schelling, Mo and Diermeier-Feddersen; qualified by Mo (needs an extreme agent) and reversed under two-sided incomplete information (Tarar). In sim, only unitary blocs can deliver whole-weight trades (S2: 61.5% of agendas vs 12.7% at delta .2).
+- Power games in the open. Supported in structure: unitary blocs have 2^4 = 16 coalitions and the trades are pairwise and nameable. Under prop, influence travels through individual cross-bloc switching (prop pivots are per-individual, section 2). Contradicted in part by S2: open bloc trades still harm a non-trading bloc in 40-48% of agendas (Riker-Brams).
+- Internal deliberation absorbs correlated noise. For Minds at ICC >= .44, prop and WTA already cast nearly the same weight (section 3), so the internal rule matters little there; a parliament would decide which Persona's argument wins, not the tally. For Users at low turnout, both rules carry the same sampling error (.08 at 10%), and WTA is more capturable by a small faction (k=6: 80%).
+- Legibility of who owes whom. Unitary trades are pairwise records; under prop the "debt" is spread over individuals. No source measured this directly. Not found.
+- Individual equality cuts the other way. WTA two-tier is Penrose-equalizable with sqrt weights; prop needs headcount weights. Gelman et al. and Kirsch argue that correlation pulls the fair weights back toward proportional.
+- Operator dominance. Under WTA her ceiling is the Members bloc's council power (.42 equal, .84 members-heavy). Under prop at q=.5 her influence has no such ceiling. Her internal dictatorship of Members ends at the n shown in the section 5 table.
+- Renormalization with no quorum: participation-safe in every exhaustive probe. Adding any quorum floor while estates are empty hands the sole Member, or the Minds estate, a stay-home veto. The two-estates floor conflicts with the "decide without me" ruling today. The bounds that remain on a lone Minds estate are a headcount floor <= .889, category thresholds (binding only under prop, and void at ICC 1), and a delay window whose cancel opportunity depends on her absence length (section 5b).
+
+## 9. Third rule: `bloc-parliament-at-threshold` (bpt)
+Each live bloc casts its whole weight For iff its internal For share (abstain excluded) >= the category threshold q, else Against. The council then needs weighted For >= q over live estates (renormalized). Code `estate-sims\third.py` (out `third.out.md`) and `estate-sims\bounds.py` (out `bounds.out.md`). The model and draws are the same as sections 3-6 (Minds ICC .44, sizes 8/15/30/4).
+- **bpt vs WTA at q=.5:** these differ only at exact internal ties. A 4/8 Minds split casts For under bpt (.5 >= .5) and nothing under WTA. With continuous shares (logrolling) the two are identical.
+
+**Aggregate bounds** (all four estates live; lowest weighted popular For share that can pass / highest that can fail; prop is exactly q / just under q). bpt applies q twice, so it widens the band on both sides:
+| seed | q | WTA | bpt |
+|---|---|---|---|
+| equal | .15 | .125 / .500 | .037 / .150 |
+| equal | .5 | .250 / .625 | .250 / .625 |
+| equal | .66 | .375 / .750 | .495 / .830 |
+| minds-heavy | .66 | .350 / .800 | .462 / .864 |
+| members-heavy | .66 | .400 / .825 | .528 / .881 |
+- Equal seed, q=.15: one bloc with 15% internal For passes the motion, so 3.7% weighted support suffices.
+- Equal seed, q=.66: three blocs at 66% pass with 49.5% support, while four blocs at 65.9% fail with 65.9% support.
+
+**Outcomes** (T1): P(pass) prop / WTA / bpt, then P(outcomes differ) bpt-prop / bpt-WTA / prop-WTA:
+| seed | q | P(pass) | differ |
+|---|---|---|---|
+| equal | .15 | .934 / .838 / .985 | .050 / .147 / .098 |
+| equal | .5 | .502 / .594 / .676 | .179 / .082 / .119 |
+| equal | .66 | .265 / .405 / .233 | .080 / .171 / .148 |
+| minds-heavy | .5 | .502 / .537 / .575 | .126 / .038 / .117 |
+| members-heavy | .66 | .271 / .343 / .194 | .099 / .149 / .113 |
+- bpt is the most permissive rule at .15 and the strictest at .66. At .5 it passes more than WTA because internal ties count For.
+
+**Pivots and correlation** (T2, T3; equal seed):
+- Single-voter pivot M/Me/U/P under bpt:
+  - q=.15: .002/.004/.002/.017
+  - q=.5: .018/.019/.010/.082
+  - q=.66: .018/.018/.010/.068
+- For comparison at q=.5: prop .050/.026/.014/.102; WTA .020/.023/.011/.076.
+- Single-Persona pivot by Minds ICC 0 / .44 / .8 / 1:
+
+  | q | prop | WTA | bpt |
+  |---|---|---|---|
+  | .15 | .020 / .020 / .021 / .021 | .024 / .014 / .004 / 0 | .006 / .002 / .001 / 0 |
+  | .5 | .051 / .050 / .050 / .048 | .040 / .021 / .007 / 0 | .038 / .018 / .006 / 0 |
+  | .66 | .044 / .042 / .040 / .040 | .040 / .020 / .007 / 0 | .036 / .017 / .006 / 0 |
+
+  Under bpt, as under WTA, a correlated Minds bloc leaves one Persona almost no pivot; prop keeps a 1/8 slice at every correlation.
+
+**Users faction capture** (T4; Users population support .3, 9 random voters + k coordinated For). P(Users bloc casts For):
+| k (share of voters) | WTA | bpt .15 | bpt .5 | bpt .66 | prop share |
+|---|---|---|---|---|---|
+| 0 (0) | .10 | .80 | .10 | .03 | .30 |
+| 1 (.10) | .10 | .96 | .27 | .03 | .37 |
+| 2 (.18) | .27 | 1.00 | .27 | .03 | .43 |
+| 3 (.25) | .27 | 1.00 | .54 | .10 | .48 |
+| 6 (.40) | .81 | 1.00 | .81 | .27 | .58 |
+| 9 (.50) | .96 | 1.00 | 1.00 | .54 | .65 |
+| 12 (.57) | 1.00 | 1.00 | 1.00 | .80 | .70 |
+- At q=.15 the bloc casts For with no faction at all 80% of the time (population support .3 > .15); a 2-voter faction (18%) makes it certain. This confirms the coordinator's note: at .15, about a 15% faction captures the bloc's whole weight.
+- At .66 a faction needs roughly half the turnout to capture the bloc half the time.
+
+**Logrolling** (T5; 800 agendas, 6 motions):
+| seed | q | rule | P(>=1 trade) | mean welfare change | P(a non-trader loses) | P(a trader ends worse) |
+|---|---|---|---|---|---|---|
+| equal | .15 | WTA / bpt / prop .5 | .128 / .001 / .007 | +.56 / +.01 / +.05 | 0 / 0 / 0 | .007 / 0 / 0 |
+| equal | .5 | WTA = bpt / prop .5 | .589 / .451 | +.14 / -.43 | .376 / .316 | .231 / .146 |
+| equal | .66 | WTA / bpt / prop .5 | .614 / .367 / .245 | +.10 / +.60 / +.41 | .393 / .250 / .177 | .231 / .071 / .035 |
+| minds-heavy | .5 | WTA = bpt / prop .5 | .608 / .330 | -.05 / -.26 | .490 / .282 | .176 / .071 |
+| minds-heavy | .66 | WTA / bpt / prop .5 | .463 / .362 / .282 | +.17 / +.39 / +.37 | .375 / .289 / .206 | .095 / .031 / .043 |
+- At .15, almost nothing is left to trade under bpt: nearly everything passes.
+- At .66, bpt trades less than WTA, with higher mean welfare and less third-party harm. Most remaining trades build supermajorities for motions that a strongly-wanting minority of blocs care about.
+
+**Lone Minds, she absent** (T6). P(pass) at Minds ICC 0 / .44 / 1:
+| category | q | prop = bpt | WTA |
+|---|---|---|---|
+| Bugs | .15 | .77 / .65 / .50 | .45 / .47 / .50 |
+| Cosmetics | .30 | .66 / .59 / .50 | .45 / .47 / .50 |
+| Balance | .40 | .56 / .53 / .50 | .45 / .47 / .50 |
+| Features / NewContent | .50 | .56 / .53 / .50 | .45 / .47 / .50 |
+| FundamentalDesign | .66 | .34 / .42 / .50 | .45 / .47 / .50 |
+- A lone estate under bpt behaves exactly as under prop: the internal threshold is the binding one, so categories bind. Under WTA they are inert.
+
+**Present case** (T7; Minds 8 coin-flip, her alone, Users/Patrons empty). P(pass | she For / Against / home):
+| seed | q | prop | WTA | bpt |
+|---|---|---|---|---|
+| equal | .15 | 1 / .855 / .965 | 1 / .363 / .363 | 1 / .965 / .965 |
+| equal | .5 | 1 / .004 / .637 | 1 / .363 / .363 | 1 / .637 / .637 |
+| equal | .66 | .855 / 0 / .145 | .637 / 0 / .363 | .145 / 0 / .145 |
+| minds-heavy | .5 | .996 / .035 / .637 | .637 / .363 / .363 | .637 / .637 / .637 |
+| members-heavy | any | For always passes, Against always fails, under all three rules | | |
+- Under bpt with two equal live estates:
+  - At q <= .5 her For forces passage, and her Against has the same effect as staying home.
+  - At q=.66 her Against is a veto, and her For has the same effect as staying home.
+- Minds-heavy q=.5 under bpt: her vote is irrelevant (.637 in every column), and the Minds alone decide.
+
+**Operator's whole-tally pivot** (T8; coin voters, Users 10, Patrons 2 on log(1+d), her share of contribution S=.8). Values are prop / WTA / bpt:
+| seed | q | alone | n=5 k=3 | n=20 k=3 | n=20 one-each |
+|---|---|---|---|---|---|
+| equal | .15 | .012 / .199 / 0 | .002 / .175 / 0 | 0 / .136 / 0 | 0 / .035 / 0 |
+| equal | .5 | .723 / .429 / .300 | .308 / .376 / .263 | .159 / .293 / .206 | .042 / .076 / .053 |
+| equal | .66 | .373 / .433 / .086 | .150 / .377 / .053 | .074 / .294 / .021 | .019 / .076 / .004 |
+| members-heavy | .5 | 1 / .863 / .734 | .612 / .753 / .641 | .383 / .588 / .500 | .101 / .152 / .130 |
+| members-heavy | .66 | .806 / .630 / .092 | .237 / .549 / .058 | .079 / .428 / .023 | .021 / .111 / .004 |
+- At .15 under bpt, the coin-flip blocs almost always clear 15%, so no single voter matters, her included.
+- At .66, bpt gives her the smallest pivot of the three rules at every Members size, because she can block her bloc but rarely flips the council.
+
+**Strategic checks** (T9; exhaustive, renormalized, no quorum; sizes 8/1/0/0 and 3/3/2/2, all seeds and q): 0 profitable misreports, 0 profitable abstentions and 0 profitable estate stay-homes. bpt is monotone and participation-safe here, as prop and WTA were in sections 6 and N1.
+
+## 10. Capping the operator: weight share vs decisiveness
+Her words, relayed: "I would limit my influence by half, just so I'm not deciding everything". Code `estate-sims\cap.py` (out `cap.out.md`, full grid: 3 cases x 3 seeds x 3 q x 5 caps x 3 rules).
+- **Weight share x:** her internal share of Members x Members weight / live weight (renormalized).
+- **How the cap c works:** if she is the sole Member, the Members estate weight is cut to c/(1-c) x the other live weight. Otherwise her internal weight is cut until x = c.
+- **Decisiveness:** her pivot rate, measured twice. Coin voters (Banzhaf) and the motion model (Minds ICC .44) give different numbers for the same rule.
+- **Unilateral pass (U+):** her For passes with everyone else Against.
+- **Unilateral block (U-):** her Against fails with everyone else For.
+- Ties pass (>=).
+
+**Present case** (Minds 8, her alone, two live estates). Cells: pivot coin / pivot motion, with U+U- flags:
+| seed, q | cap (x) | prop | WTA | bpt |
+|---|---|---|---|---|
+| equal .15 | none = .5 (.50) | .14 / .42 YN | .64 / .53 YN | .03 / .35 YN |
+| equal .15 | .33 | .03 / .35 YN | .64 / .53 YN | .03 / .35 YN |
+| equal .5 | none = .5 (.50) | .996 / .73 YN | .64 / .53 YN | .36 / .47 YN |
+| equal .5 | .49 | .992 / .46 NN | .27 / .06 NN | 0 / 0 NN |
+| equal .5 | .33 | .71 / .17 NN | .27 / .06 NN | 0 / 0 NN |
+| equal .66 | none / .49 / .40 | .86 / .58 to .64 / .53 NY | .64 / .53 NY | .14 / .42 NY |
+| equal .66 | .33 | .64 / .25 NN | .27 / .06 NN | 0 / 0 NN |
+| members-heavy .5 | none (.69) | 1 / 1 YY | 1 / 1 YY | 1 / 1 YY |
+| members-heavy .5 | .5 / .49 | same as equal .5 at cap .5 / .49 | | |
+- **A 50% cap with ties passing does not take away her unilateral power.**
+  - In the two-estate case: at q <= .5 her For alone passes; at q > .5 her Against alone blocks.
+  - Generally: U+ holds iff x >= q, and U- holds iff x > 1-q. Removing both needs x < min(q, 1-q):
+    - q=.5: any cap below .5 (.49 works).
+    - q=.66: below .34 (.40 and .49 still leave her the block).
+    - q=.15: below .15 (no tested cap removes U+).
+- **Pivot at or below half, present case:**
+  - With cap .49 at q=.5: WTA .27 and bpt 0 on both measures (under bpt the Minds then decide alone).
+  - Prop stays at .99 on coin voters even at cap .49 (and .71 at .33). The motion model gives prop .46 at cap .49 and .17 at .33. One Persona For is enough to carry her 49% For past .5, and she loses only to a unanimous Against from the Minds.
+  - WTA at .15 stays at .64 / .53 under every cap. At .15, x >= .15 keeps U+, and the Minds estate casts all or nothing.
+
+**Growth path** (S=.8, k=3, Users 10, Patrons 2). Her weight share is already below every tested cap, so no cap binds:
+- x = .10 / .12 / .18 at n=5 for equal / minds-heavy / members-heavy.
+- x = .05 / .06 / .09 at n=20.
+
+Her decisiveness still exceeds half in some cells (coin / motion):
+| case | prop | WTA | bpt |
+|---|---|---|---|
+| n=5, members-heavy, q=.5 (x=.18) | .61 / .31 | .76 / .42 | .64 / .39 |
+| n=5, equal, q=.5 (x=.10) | .31 / .15 | .38 / .21 | .26 / .19 |
+| n=20, members-heavy, q=.5 (x=.09) | .38 / .14 | .59 / .15 | .50 / .15 |
+| n=5, members-heavy, q=.66 | .24 / .26 | .55 / .32 | .06 / .24 (U- under bpt) |
+- Under WTA and bpt, her pivot comes from steering a bloc that carries 45% of the weight, not from her own 9-18% share. A cap on her personal weight share therefore leaves this channel open.
+- Under bpt at .66 she gets a unilateral block at n=5 members-heavy with x=.18: her Against holds the Members internal For share under .66, so the whole 45% is cast Against.
+
+**Distinction, as measured:**
+- **Weight share is a rule parameter.** A cap on it is enforceable per tally (renormalized) and removes U+/U- only when x < min(q, 1-q) of the tally.
+- **Decisiveness (pivot rate) is not a rule parameter.** It is a function of the rule, the threshold, the bloc structure and how everyone else votes. The same cap gives .99 or .46 (prop, q=.5, cap .49) depending on the voter model. No weight cap tested bounds it under every model.
+- Holding her decisiveness at or below half under unitary rules (WTA, bpt) would need a cap on the weight of any bloc she can steer, or on her internal decisiveness in that bloc. A cap on her own share does not do it.
+- Present case, equal seed: rule and cap combinations whose pivot is at or below .5 on both voter models.
+  - q=.15: prop at every cap (.14 / .42 uncapped); bpt at every cap (.03 / .35). WTA at no cap (.64 / .53).
+  - q=.5: WTA and bpt at cap .49 or lower. Prop at no tested cap (coin .71 even at .33).
+  - q=.66: bpt at every cap (.14 / .42), but U- survives until the cap is below .34. WTA at cap .33. Prop at no tested cap (coin .64 at .33).

docs/research/2026-10-29-estate-tally-game-theory/sims/bounds.out.md

@@ -0,0 +1,11 @@
+| seed | q | prop min-pass / max-fail | wta min-pass / max-fail | bpt min-pass / max-fail |
+|---|---|---|---|---|
+| equal | 0.15 | 0.150 / <0.150 | 0.125 / 0.500 | 0.037 / 0.150 |
+| equal | 0.5 | 0.500 / <0.500 | 0.250 / 0.625 | 0.250 / 0.625 |
+| equal | 0.66 | 0.660 / <0.660 | 0.375 / 0.750 | 0.495 / 0.830 |
+| minds-heavy | 0.15 | 0.150 / <0.150 | 0.100 / 0.550 | 0.030 / 0.235 |
+| minds-heavy | 0.5 | 0.500 / <0.500 | 0.250 / 0.700 | 0.250 / 0.700 |
+| minds-heavy | 0.66 | 0.660 / <0.660 | 0.350 / 0.800 | 0.462 / 0.864 |
+| members-heavy | 0.15 | 0.150 / <0.150 | 0.075 / 0.500 | 0.022 / 0.150 |
+| members-heavy | 0.5 | 0.500 / <0.500 | 0.275 / 0.725 | 0.275 / 0.725 |
+| members-heavy | 0.66 | 0.660 / <0.660 | 0.400 / 0.825 | 0.528 / 0.881 |

docs/research/2026-10-29-estate-tally-game-theory/sims/bounds.py

@@ -0,0 +1,23 @@
+"""Aggregate-support bounds for each rule, all four estates live: lowest weighted For share that can pass,
+highest weighted For share that can fail (bloc shares free in [0,1]). Run: python -I bounds.py"""
+import itertools
+SEEDS = {"equal": [25, 25, 25, 25], "minds-heavy": [40, 30, 20, 10], "members-heavy": [20, 45, 20, 15]}
+eps = 1e-6
+print("| seed | q | prop min-pass / max-fail | wta min-pass / max-fail | bpt min-pass / max-fail |")
+print("|---|---|---|---|---|")
+for s, w in SEEDS.items():
+    W = sum(w)
+    for q in (0.15, 0.5, 0.66):
+        res = {}
+        for rule, t in (("wta", 0.5), ("bpt", q)):
+            mp, mf = 1.0, 0.0
+            for S in itertools.product((0, 1), repeat=4):   # S = blocs casting For
+                ws = sum(wi for wi, x in zip(w, S) if x)
+                passes = ws >= q * W - 1e-9
+                # For-blocs need share > t (wta) or >= t (bpt); Against-blocs share < t (wta) or < t (bpt)
+                lo = sum(wi * (t + (eps if rule == "wta" else 0)) for wi, x in zip(w, S) if x) / W
+                hi = (ws + sum(wi * (t - eps) for wi, x in zip(w, S) if not x)) / W
+                if passes: mp = min(mp, lo)
+                else: mf = max(mf, hi)
+            res[rule] = f"{mp:.3f} / {mf:.3f}"
+        print(f"| {s} | {q} | {q:.3f} / <{q:.3f} | {res['wta']} | {res['bpt']} |")

docs/research/2026-10-29-estate-tally-game-theory/sims/cap.out.md

@@ -0,0 +1,148 @@
+Cells: pivot coin / pivot motion / U+ U- (unilateral pass, unilateral block; Y/N). Her weight share shown as x.
+
+### present 8/1/0/0
+| seed | q | cap | her share x | prop | wta | bpt |
+|---|---|---|---|---|---|---|
+| equal | 0.15 | none | 0.500 | 0.143 / 0.416 / YN | 0.635 / 0.528 / YN | 0.034 / 0.354 / YN |
+| equal | 0.15 | 0.5 | 0.500 | 0.143 / 0.416 / YN | 0.635 / 0.528 / YN | 0.034 / 0.354 / YN |
+| equal | 0.15 | 0.49 | 0.490 | 0.143 / 0.416 / YN | 0.635 / 0.528 / YN | 0.034 / 0.354 / YN |
+| equal | 0.15 | 0.4 | 0.400 | 0.034 / 0.354 / YN | 0.635 / 0.528 / YN | 0.034 / 0.354 / YN |
+| equal | 0.15 | 0.33 | 0.330 | 0.034 / 0.354 / YN | 0.635 / 0.528 / YN | 0.034 / 0.354 / YN |
+| equal | 0.5 | none | 0.500 | 0.996 / 0.727 / YN | 0.635 / 0.528 / YN | 0.361 / 0.473 / YN |
+| equal | 0.5 | 0.5 | 0.500 | 0.996 / 0.727 / YN | 0.635 / 0.528 / YN | 0.361 / 0.473 / YN |
+| equal | 0.5 | 0.49 | 0.490 | 0.992 / 0.455 / NN | 0.274 / 0.055 / NN | 0.000 / 0.000 / NN |
+| equal | 0.5 | 0.4 | 0.400 | 0.931 / 0.293 / NN | 0.274 / 0.055 / NN | 0.000 / 0.000 / NN |
+| equal | 0.5 | 0.33 | 0.330 | 0.712 / 0.168 / NN | 0.274 / 0.055 / NN | 0.000 / 0.000 / NN |
+| equal | 0.66 | none | 0.500 | 0.857 / 0.584 / NY | 0.639 / 0.527 / NY | 0.144 / 0.416 / NY |
+| equal | 0.66 | 0.5 | 0.500 | 0.857 / 0.584 / NY | 0.639 / 0.527 / NY | 0.144 / 0.416 / NY |
+| equal | 0.66 | 0.49 | 0.490 | 0.857 / 0.584 / NY | 0.639 / 0.527 / NY | 0.144 / 0.416 / NY |
+| equal | 0.66 | 0.4 | 0.400 | 0.639 / 0.527 / NY | 0.639 / 0.527 / NY | 0.144 / 0.416 / NY |
+| equal | 0.66 | 0.33 | 0.330 | 0.635 / 0.254 / NN | 0.274 / 0.055 / NN | 0.000 / 0.000 / NN |
+| minds-heavy | 0.15 | none | 0.429 | 0.143 / 0.416 / YN | 0.635 / 0.528 / YN | 0.034 / 0.354 / YN |
+| minds-heavy | 0.15 | 0.5 | 0.429 | 0.143 / 0.416 / YN | 0.635 / 0.528 / YN | 0.034 / 0.354 / YN |
+| minds-heavy | 0.15 | 0.49 | 0.429 | 0.143 / 0.416 / YN | 0.635 / 0.528 / YN | 0.034 / 0.354 / YN |
+| minds-heavy | 0.15 | 0.4 | 0.400 | 0.034 / 0.354 / YN | 0.635 / 0.528 / YN | 0.034 / 0.354 / YN |
+| minds-heavy | 0.15 | 0.33 | 0.330 | 0.034 / 0.354 / YN | 0.635 / 0.528 / YN | 0.034 / 0.354 / YN |
+| minds-heavy | 0.5 | none | 0.429 | 0.961 / 0.374 / NN | 0.274 / 0.055 / NN | 0.000 / 0.000 / NN |
+| minds-heavy | 0.5 | 0.5 | 0.429 | 0.961 / 0.374 / NN | 0.274 / 0.055 / NN | 0.000 / 0.000 / NN |
+| minds-heavy | 0.5 | 0.49 | 0.429 | 0.961 / 0.374 / NN | 0.274 / 0.055 / NN | 0.000 / 0.000 / NN |
+| minds-heavy | 0.5 | 0.4 | 0.400 | 0.931 / 0.293 / NN | 0.274 / 0.055 / NN | 0.000 / 0.000 / NN |
+| minds-heavy | 0.5 | 0.33 | 0.330 | 0.712 / 0.168 / NN | 0.274 / 0.055 / NN | 0.000 / 0.000 / NN |
+| minds-heavy | 0.66 | none | 0.429 | 0.639 / 0.527 / NY | 0.639 / 0.527 / NY | 0.144 / 0.416 / NY |
+| minds-heavy | 0.66 | 0.5 | 0.429 | 0.639 / 0.527 / NY | 0.639 / 0.527 / NY | 0.144 / 0.416 / NY |
+| minds-heavy | 0.66 | 0.49 | 0.429 | 0.639 / 0.527 / NY | 0.639 / 0.527 / NY | 0.144 / 0.416 / NY |
+| minds-heavy | 0.66 | 0.4 | 0.400 | 0.639 / 0.527 / NY | 0.639 / 0.527 / NY | 0.144 / 0.416 / NY |
+| minds-heavy | 0.66 | 0.33 | 0.330 | 0.635 / 0.254 / NN | 0.274 / 0.055 / NN | 0.000 / 0.000 / NN |
+| members-heavy | 0.15 | none | 0.692 | 0.361 / 0.473 / YN | 0.635 / 0.528 / YN | 0.034 / 0.354 / YN |
+| members-heavy | 0.15 | 0.5 | 0.500 | 0.143 / 0.416 / YN | 0.635 / 0.528 / YN | 0.034 / 0.354 / YN |
+| members-heavy | 0.15 | 0.49 | 0.490 | 0.143 / 0.416 / YN | 0.635 / 0.528 / YN | 0.034 / 0.354 / YN |
+| members-heavy | 0.15 | 0.4 | 0.400 | 0.034 / 0.354 / YN | 0.635 / 0.528 / YN | 0.034 / 0.354 / YN |
+| members-heavy | 0.15 | 0.33 | 0.330 | 0.034 / 0.354 / YN | 0.635 / 0.528 / YN | 0.034 / 0.354 / YN |
+| members-heavy | 0.5 | none | 0.692 | 1.000 / 1.000 / YY | 1.000 / 1.000 / YY | 1.000 / 1.000 / YY |
+| members-heavy | 0.5 | 0.5 | 0.500 | 0.996 / 0.727 / YN | 0.635 / 0.528 / YN | 0.361 / 0.473 / YN |
+| members-heavy | 0.5 | 0.49 | 0.490 | 0.992 / 0.455 / NN | 0.274 / 0.055 / NN | 0.000 / 0.000 / NN |
+| members-heavy | 0.5 | 0.4 | 0.400 | 0.931 / 0.293 / NN | 0.274 / 0.055 / NN | 0.000 / 0.000 / NN |
+| members-heavy | 0.5 | 0.33 | 0.330 | 0.712 / 0.168 / NN | 0.274 / 0.055 / NN | 0.000 / 0.000 / NN |
+| members-heavy | 0.66 | none | 0.692 | 1.000 / 1.000 / YY | 1.000 / 1.000 / YY | 1.000 / 1.000 / YY |
+| members-heavy | 0.66 | 0.5 | 0.500 | 0.857 / 0.584 / NY | 0.639 / 0.527 / NY | 0.144 / 0.416 / NY |
+| members-heavy | 0.66 | 0.49 | 0.490 | 0.857 / 0.584 / NY | 0.639 / 0.527 / NY | 0.144 / 0.416 / NY |
+| members-heavy | 0.66 | 0.4 | 0.400 | 0.639 / 0.527 / NY | 0.639 / 0.527 / NY | 0.144 / 0.416 / NY |
+| members-heavy | 0.66 | 0.33 | 0.330 | 0.635 / 0.254 / NN | 0.274 / 0.055 / NN | 0.000 / 0.000 / NN |
+
+### growth n=5 k=3 S=.8 +U10 P2
+| seed | q | cap | her share x | prop | wta | bpt |
+|---|---|---|---|---|---|---|
+| equal | 0.15 | none | 0.098 | 0.001 / 0.065 / NN | 0.175 / 0.115 / NN | 0.000 / 0.027 / YN |
+| equal | 0.15 | 0.5 | 0.098 | 0.001 / 0.065 / NN | 0.175 / 0.115 / NN | 0.000 / 0.027 / YN |
+| equal | 0.15 | 0.49 | 0.098 | 0.001 / 0.065 / NN | 0.175 / 0.115 / NN | 0.000 / 0.027 / YN |
+| equal | 0.15 | 0.4 | 0.098 | 0.001 / 0.065 / NN | 0.175 / 0.115 / NN | 0.000 / 0.027 / YN |
+| equal | 0.15 | 0.33 | 0.098 | 0.001 / 0.065 / NN | 0.175 / 0.115 / NN | 0.000 / 0.027 / YN |
+| equal | 0.5 | none | 0.098 | 0.306 / 0.153 / NN | 0.376 / 0.205 / NN | 0.264 / 0.189 / NN |
+| equal | 0.5 | 0.5 | 0.098 | 0.306 / 0.153 / NN | 0.376 / 0.205 / NN | 0.264 / 0.189 / NN |
+| equal | 0.5 | 0.49 | 0.098 | 0.306 / 0.153 / NN | 0.376 / 0.205 / NN | 0.264 / 0.189 / NN |
+| equal | 0.5 | 0.4 | 0.098 | 0.306 / 0.153 / NN | 0.376 / 0.205 / NN | 0.264 / 0.189 / NN |
+| equal | 0.5 | 0.33 | 0.098 | 0.306 / 0.153 / NN | 0.376 / 0.205 / NN | 0.264 / 0.189 / NN |
+| equal | 0.66 | none | 0.098 | 0.150 / 0.133 / NN | 0.378 / 0.202 / NN | 0.054 / 0.164 / NN |
+| equal | 0.66 | 0.5 | 0.098 | 0.150 / 0.133 / NN | 0.378 / 0.202 / NN | 0.054 / 0.164 / NN |
+| equal | 0.66 | 0.49 | 0.098 | 0.150 / 0.133 / NN | 0.378 / 0.202 / NN | 0.054 / 0.164 / NN |
+| equal | 0.66 | 0.4 | 0.098 | 0.150 / 0.133 / NN | 0.378 / 0.202 / NN | 0.054 / 0.164 / NN |
+| equal | 0.66 | 0.33 | 0.098 | 0.150 / 0.133 / NN | 0.378 / 0.202 / NN | 0.054 / 0.164 / NN |
+| minds-heavy | 0.15 | none | 0.118 | 0.001 / 0.104 / NN | 0.274 / 0.186 / NN | 0.000 / 0.045 / YN |
+| minds-heavy | 0.15 | 0.5 | 0.118 | 0.001 / 0.104 / NN | 0.274 / 0.186 / NN | 0.000 / 0.045 / YN |
+| minds-heavy | 0.15 | 0.49 | 0.118 | 0.001 / 0.104 / NN | 0.274 / 0.186 / NN | 0.000 / 0.045 / YN |
+| minds-heavy | 0.15 | 0.4 | 0.118 | 0.001 / 0.104 / NN | 0.274 / 0.186 / NN | 0.000 / 0.045 / YN |
+| minds-heavy | 0.15 | 0.33 | 0.118 | 0.001 / 0.104 / NN | 0.274 / 0.186 / NN | 0.000 / 0.045 / YN |
+| minds-heavy | 0.5 | none | 0.118 | 0.452 / 0.152 / NN | 0.412 / 0.200 / NN | 0.303 / 0.197 / NN |
+| minds-heavy | 0.5 | 0.5 | 0.118 | 0.452 / 0.152 / NN | 0.412 / 0.200 / NN | 0.303 / 0.197 / NN |
+| minds-heavy | 0.5 | 0.49 | 0.118 | 0.452 / 0.152 / NN | 0.412 / 0.200 / NN | 0.303 / 0.197 / NN |
+| minds-heavy | 0.5 | 0.4 | 0.118 | 0.452 / 0.152 / NN | 0.412 / 0.200 / NN | 0.303 / 0.197 / NN |
+| minds-heavy | 0.5 | 0.33 | 0.118 | 0.452 / 0.152 / NN | 0.412 / 0.200 / NN | 0.303 / 0.197 / NN |
+| minds-heavy | 0.66 | none | 0.118 | 0.142 / 0.153 / NN | 0.453 / 0.215 / NN | 0.087 / 0.198 / NN |
+| minds-heavy | 0.66 | 0.5 | 0.118 | 0.142 / 0.153 / NN | 0.453 / 0.215 / NN | 0.087 / 0.198 / NN |
+| minds-heavy | 0.66 | 0.49 | 0.118 | 0.142 / 0.153 / NN | 0.453 / 0.215 / NN | 0.087 / 0.198 / NN |
+| minds-heavy | 0.66 | 0.4 | 0.118 | 0.142 / 0.153 / NN | 0.453 / 0.215 / NN | 0.087 / 0.198 / NN |
+| minds-heavy | 0.66 | 0.33 | 0.118 | 0.142 / 0.153 / NN | 0.453 / 0.215 / NN | 0.087 / 0.198 / NN |
+| members-heavy | 0.15 | none | 0.176 | 0.003 / 0.103 / YN | 0.175 / 0.115 / NN | 0.000 / 0.027 / YN |
+| members-heavy | 0.15 | 0.5 | 0.176 | 0.003 / 0.103 / YN | 0.175 / 0.115 / NN | 0.000 / 0.027 / YN |
+| members-heavy | 0.15 | 0.49 | 0.176 | 0.003 / 0.103 / YN | 0.175 / 0.115 / NN | 0.000 / 0.027 / YN |
+| members-heavy | 0.15 | 0.4 | 0.176 | 0.003 / 0.103 / YN | 0.175 / 0.115 / NN | 0.000 / 0.027 / YN |
+| members-heavy | 0.15 | 0.33 | 0.176 | 0.003 / 0.103 / YN | 0.175 / 0.115 / NN | 0.000 / 0.027 / YN |
+| members-heavy | 0.5 | none | 0.176 | 0.611 / 0.308 / NN | 0.755 / 0.415 / NN | 0.641 / 0.392 / NN |
+| members-heavy | 0.5 | 0.5 | 0.176 | 0.611 / 0.308 / NN | 0.755 / 0.415 / NN | 0.641 / 0.392 / NN |
+| members-heavy | 0.5 | 0.49 | 0.176 | 0.611 / 0.308 / NN | 0.755 / 0.415 / NN | 0.641 / 0.392 / NN |
+| members-heavy | 0.5 | 0.4 | 0.176 | 0.611 / 0.308 / NN | 0.755 / 0.415 / NN | 0.641 / 0.392 / NN |
+| members-heavy | 0.5 | 0.33 | 0.176 | 0.611 / 0.308 / NN | 0.755 / 0.415 / NN | 0.641 / 0.392 / NN |
+| members-heavy | 0.66 | none | 0.176 | 0.237 / 0.255 / NN | 0.552 / 0.317 / NN | 0.058 / 0.238 / NY |
+| members-heavy | 0.66 | 0.5 | 0.176 | 0.237 / 0.255 / NN | 0.552 / 0.317 / NN | 0.058 / 0.238 / NY |
+| members-heavy | 0.66 | 0.49 | 0.176 | 0.237 / 0.255 / NN | 0.552 / 0.317 / NN | 0.058 / 0.238 / NY |
+| members-heavy | 0.66 | 0.4 | 0.176 | 0.237 / 0.255 / NN | 0.552 / 0.317 / NN | 0.058 / 0.238 / NY |
+| members-heavy | 0.66 | 0.33 | 0.176 | 0.237 / 0.255 / NN | 0.552 / 0.317 / NN | 0.058 / 0.238 / NY |
+
+### growth n=20 k=3 S=.8 +U10 P2
+| seed | q | cap | her share x | prop | wta | bpt |
+|---|---|---|---|---|---|---|
+| equal | 0.15 | none | 0.048 | 0.000 / 0.034 / NN | 0.133 / 0.041 / NN | 0.000 / 0.022 / YN |
+| equal | 0.15 | 0.5 | 0.048 | 0.000 / 0.034 / NN | 0.133 / 0.041 / NN | 0.000 / 0.022 / YN |
+| equal | 0.15 | 0.49 | 0.048 | 0.000 / 0.034 / NN | 0.133 / 0.041 / NN | 0.000 / 0.022 / YN |
+| equal | 0.15 | 0.4 | 0.048 | 0.000 / 0.034 / NN | 0.133 / 0.041 / NN | 0.000 / 0.022 / YN |
+| equal | 0.15 | 0.33 | 0.048 | 0.000 / 0.034 / NN | 0.133 / 0.041 / NN | 0.000 / 0.022 / YN |
+| equal | 0.5 | none | 0.048 | 0.158 / 0.075 / NN | 0.294 / 0.076 / NN | 0.205 / 0.069 / NN |
+| equal | 0.5 | 0.5 | 0.048 | 0.158 / 0.075 / NN | 0.294 / 0.076 / NN | 0.205 / 0.069 / NN |
+| equal | 0.5 | 0.49 | 0.048 | 0.158 / 0.075 / NN | 0.294 / 0.076 / NN | 0.205 / 0.069 / NN |
+| equal | 0.5 | 0.4 | 0.048 | 0.158 / 0.075 / NN | 0.294 / 0.076 / NN | 0.205 / 0.069 / NN |
+| equal | 0.5 | 0.33 | 0.048 | 0.158 / 0.075 / NN | 0.294 / 0.076 / NN | 0.205 / 0.069 / NN |
+| equal | 0.66 | none | 0.048 | 0.074 / 0.064 / NN | 0.294 / 0.076 / NN | 0.022 / 0.064 / NN |
+| equal | 0.66 | 0.5 | 0.048 | 0.074 / 0.064 / NN | 0.294 / 0.076 / NN | 0.022 / 0.064 / NN |
+| equal | 0.66 | 0.49 | 0.048 | 0.074 / 0.064 / NN | 0.294 / 0.076 / NN | 0.022 / 0.064 / NN |
+| equal | 0.66 | 0.4 | 0.048 | 0.074 / 0.064 / NN | 0.294 / 0.076 / NN | 0.022 / 0.064 / NN |
+| equal | 0.66 | 0.33 | 0.048 | 0.074 / 0.064 / NN | 0.294 / 0.076 / NN | 0.022 / 0.064 / NN |
+| minds-heavy | 0.15 | none | 0.058 | 0.000 / 0.051 / NN | 0.209 / 0.067 / NN | 0.000 / 0.038 / YN |
+| minds-heavy | 0.15 | 0.5 | 0.058 | 0.000 / 0.051 / NN | 0.209 / 0.067 / NN | 0.000 / 0.038 / YN |
+| minds-heavy | 0.15 | 0.49 | 0.058 | 0.000 / 0.051 / NN | 0.209 / 0.067 / NN | 0.000 / 0.038 / YN |
+| minds-heavy | 0.15 | 0.4 | 0.058 | 0.000 / 0.051 / NN | 0.209 / 0.067 / NN | 0.000 / 0.038 / YN |
+| minds-heavy | 0.15 | 0.33 | 0.058 | 0.000 / 0.051 / NN | 0.209 / 0.067 / NN | 0.000 / 0.038 / YN |
+| minds-heavy | 0.5 | none | 0.058 | 0.248 / 0.074 / NN | 0.321 / 0.074 / NN | 0.236 / 0.073 / NN |
+| minds-heavy | 0.5 | 0.5 | 0.058 | 0.248 / 0.074 / NN | 0.321 / 0.074 / NN | 0.236 / 0.073 / NN |
+| minds-heavy | 0.5 | 0.49 | 0.058 | 0.248 / 0.074 / NN | 0.321 / 0.074 / NN | 0.236 / 0.073 / NN |
+| minds-heavy | 0.5 | 0.4 | 0.058 | 0.248 / 0.074 / NN | 0.321 / 0.074 / NN | 0.236 / 0.073 / NN |
+| minds-heavy | 0.5 | 0.33 | 0.058 | 0.248 / 0.074 / NN | 0.321 / 0.074 / NN | 0.236 / 0.073 / NN |
+| minds-heavy | 0.66 | none | 0.058 | 0.056 / 0.075 / NN | 0.353 / 0.079 / NN | 0.035 / 0.080 / NN |
+| minds-heavy | 0.66 | 0.5 | 0.058 | 0.056 / 0.075 / NN | 0.353 / 0.079 / NN | 0.035 / 0.080 / NN |
+| minds-heavy | 0.66 | 0.49 | 0.058 | 0.056 / 0.075 / NN | 0.353 / 0.079 / NN | 0.035 / 0.080 / NN |
+| minds-heavy | 0.66 | 0.4 | 0.058 | 0.056 / 0.075 / NN | 0.353 / 0.079 / NN | 0.035 / 0.080 / NN |
+| minds-heavy | 0.66 | 0.33 | 0.058 | 0.056 / 0.075 / NN | 0.353 / 0.079 / NN | 0.035 / 0.080 / NN |
+| members-heavy | 0.15 | none | 0.087 | 0.000 / 0.057 / NN | 0.133 / 0.041 / NN | 0.000 / 0.022 / YN |
+| members-heavy | 0.15 | 0.5 | 0.087 | 0.000 / 0.057 / NN | 0.133 / 0.041 / NN | 0.000 / 0.022 / YN |
+| members-heavy | 0.15 | 0.49 | 0.087 | 0.000 / 0.057 / NN | 0.133 / 0.041 / NN | 0.000 / 0.022 / YN |
+| members-heavy | 0.15 | 0.4 | 0.087 | 0.000 / 0.057 / NN | 0.133 / 0.041 / NN | 0.000 / 0.022 / YN |
+| members-heavy | 0.15 | 0.33 | 0.087 | 0.000 / 0.057 / NN | 0.133 / 0.041 / NN | 0.000 / 0.022 / YN |
+| members-heavy | 0.5 | none | 0.087 | 0.382 / 0.141 / NN | 0.586 / 0.153 / NN | 0.498 / 0.145 / NN |
+| members-heavy | 0.5 | 0.5 | 0.087 | 0.382 / 0.141 / NN | 0.586 / 0.153 / NN | 0.498 / 0.145 / NN |
+| members-heavy | 0.5 | 0.49 | 0.087 | 0.382 / 0.141 / NN | 0.586 / 0.153 / NN | 0.498 / 0.145 / NN |
+| members-heavy | 0.5 | 0.4 | 0.087 | 0.382 / 0.141 / NN | 0.586 / 0.153 / NN | 0.498 / 0.145 / NN |
+| members-heavy | 0.5 | 0.33 | 0.087 | 0.382 / 0.141 / NN | 0.586 / 0.153 / NN | 0.498 / 0.145 / NN |
+| members-heavy | 0.66 | none | 0.087 | 0.079 / 0.121 / NN | 0.428 / 0.116 / NN | 0.024 / 0.089 / NN |
+| members-heavy | 0.66 | 0.5 | 0.087 | 0.079 / 0.121 / NN | 0.428 / 0.116 / NN | 0.024 / 0.089 / NN |
+| members-heavy | 0.66 | 0.49 | 0.087 | 0.079 / 0.121 / NN | 0.428 / 0.116 / NN | 0.024 / 0.089 / NN |
+| members-heavy | 0.66 | 0.4 | 0.087 | 0.079 / 0.121 / NN | 0.428 / 0.116 / NN | 0.024 / 0.089 / NN |
+| members-heavy | 0.66 | 0.33 | 0.087 | 0.079 / 0.121 / NN | 0.428 / 0.116 / NN | 0.024 / 0.089 / NN |

docs/research/2026-10-29-estate-tally-game-theory/sims/cap.py

@@ -0,0 +1,75 @@
+"""Operator cap (her words: "I would limit my influence by half, just so I'm not deciding everything").
+Cap c on her WEIGHT SHARE of the renormalized tally: her share = (her internal share of Members) * W_Me / W_live.
+If she is the sole Member, the cap shrinks the Members estate weight to c/(1-c) * (other live weight);
+otherwise it shrinks her internal weight until her share = c. Then measure DECISIVENESS:
+pivot rate (coin voters; and motion model, Minds ICC .44), unilateral pass (her For passes with everyone else
+Against) and unilateral block (her Against fails with everyone else For). Ties pass (>=). Run: python -I cap.py
+"""
+import numpy as np
+SEEDS = {"equal": [25, 25, 25, 25], "minds-heavy": [40, 30, 20, 10], "members-heavy": [20, 45, 20, 15]}
+
+def tally(Wb, F, Tot, q, rule):
+    Wb = np.asarray(Wb, float); live = Tot > 0; sh = np.where(live, F / np.where(live, Tot, 1), 0)
+    if rule == "prop": f = (sh * Wb).sum(-1); den = (live * Wb).sum(-1)
+    elif rule == "wta":
+        st = np.where(live, np.sign(2 * F - Tot), 0); f = (st == 1) @ Wb; den = f + (st == -1) @ Wb
+    else: f = ((sh >= q - 1e-9) & live) @ Wb; den = live @ Wb
+    return (den > 0) & (f >= q * den - 1e-9)
+
+def mweights(n, S=.8, k=3):
+    if n == 1: return np.ones(1)
+    tail = np.array([i ** (-1 / 1.16) for i in range(1, n)]); tail = tail / tail.sum() * (1 - S)
+    return np.concatenate([[S], tail]) ** (1 / k)
+
+def apply_cap(Wb, wM, sizes, c):
+    Wb = np.array(Wb, float); wM = wM.copy(); live = np.array([s > 0 for s in sizes])
+    if c is None: return Wb, wM
+    L = (Wb * live).sum(); x = wM[0] / wM.sum()
+    if x * Wb[1] <= c * L + 1e-12: return Wb, wM
+    if len(wM) == 1:
+        Wb[1] = c / (1 - c) * (L - Wb[1])
+    else:
+        x_new = c * L / Wb[1]; o = wM[1:].sum(); wM[0] = x_new * o / (1 - x_new)
+    return Wb, wM
+
+def run(Wb, wM, sizes, q, rule, model, T=100_000, seed=9):
+    r = np.random.default_rng(seed)
+    ws = [np.ones(sizes[0]), wM, np.ones(sizes[2]), np.log1p(np.array([50, 500.0])[:sizes[3]])]
+    if model == "coin": p = np.full((T, 4), .5)
+    else:
+        m = r.standard_normal(T); p = 1 / (1 + np.exp(-1.7 * (0.6 * m[:, None] + 0.8 * r.standard_normal((T, 4)))))
+    F = np.zeros((T, 4)); Tot = np.zeros((T, 4)); her = None
+    for b, w in enumerate(ws):
+        if len(w) == 0: continue
+        pb = p[:, b:b + 1]
+        if b == 0 and model == "motion":
+            a = p[:, 0] * .56 / .44; cc = (1 - p[:, 0]) * .56 / .44; pb = r.beta(a, cc)[:, None]
+        v = r.random((T, len(w))) < pb
+        if b == 1: her = v[:, 0]
+        F[:, b] = v @ w; Tot[:, b] = w.sum()
+    G = F.copy(); G[:, 1] += np.where(her, -wM[0], wM[0])
+    return np.mean(tally(Wb, F, Tot, q, rule) != tally(Wb, G, Tot, q, rule))
+
+def unilateral(Wb, wM, sizes, q, rule):
+    ws = [np.ones(sizes[0]), wM, np.ones(sizes[2]), np.log1p(np.array([50, 500.0])[:sizes[3]])]
+    Tot = np.array([[w.sum() for w in ws]])
+    Fp = np.array([[0, wM[0], 0, 0]], float); Fb = np.array([[w.sum() for w in ws]], float); Fb[0, 1] -= wM[0]
+    return bool(tally(Wb, Fp, Tot, q, rule)[0]), not bool(tally(Wb, Fb, Tot, q, rule)[0])
+
+CAPS = (None, .5, .49, .4, .33)
+CASES = (("present 8/1/0/0", (8, 1, 0, 0)), ("growth n=5 k=3 S=.8 +U10 P2", (8, 5, 10, 2)), ("growth n=20 k=3 S=.8 +U10 P2", (8, 20, 10, 2)))
+print("Cells: pivot coin / pivot motion / U+ U- (unilateral pass, unilateral block; Y/N). Her weight share shown as x.")
+for cname, sizes in CASES:
+    print(f"\n### {cname}")
+    print("| seed | q | cap | her share x | prop | wta | bpt |"); print("|---|---|---|---|---|---|---|")
+    for s, W0 in SEEDS.items():
+        for q in (0.15, 0.5, 0.66):
+            for c in CAPS:
+                Wb, wM = apply_cap(W0, mweights(sizes[1]), sizes, c)
+                live = np.array([n > 0 for n in sizes]); x = wM[0] / wM.sum() * Wb[1] / (Wb * live).sum()
+                cells = []
+                for rule in ("prop", "wta", "bpt"):
+                    pc = run(Wb, wM, sizes, q, rule, "coin"); pm = run(Wb, wM, sizes, q, rule, "motion")
+                    up, ub = unilateral(Wb, wM, sizes, q, rule)
+                    cells.append(f"{pc:.3f} / {pm:.3f} / {'Y' if up else 'N'}{'Y' if ub else 'N'}")
+                print(f"| {s} | {q} | {c if c else 'none'} | {x:.3f} | " + " | ".join(cells) + " |")

docs/research/2026-10-29-estate-tally-game-theory/sims/growth.out.md

@@ -0,0 +1,110 @@
+## G1. Present case: Members = her alone, Minds 8 (fair coins; 'unan' = Minds fully correlated)
+Cells: P(her vote flips the motion) / P(outcome matches her vote), prop then WTA.
+| seed | q | Users, Patrons | Minds | prop pivot / match | WTA pivot / match |
+|---|---|---|---|---|---|
+| equal | 0.15 | 0U, 0P | indep | 0.145 / 0.570 | 0.636 / 0.817 |
+| equal | 0.15 | 0U, 0P | unan | 0.501 / 0.752 | 0.501 / 0.752 |
+| equal | 0.15 | 3U, 1P | indep | 0.066 / 0.530 | 0.159 / 0.578 |
+| equal | 0.15 | 3U, 1P | unan | 0.126 / 0.564 | 0.126 / 0.564 |
+| equal | 0.5 | 0U, 0P | indep | 0.996 / 0.998 | 0.636 / 0.817 |
+| equal | 0.5 | 0U, 0P | unan | 0.501 / 0.752 | 0.501 / 0.752 |
+| equal | 0.5 | 3U, 1P | indep | 0.500 / 0.750 | 0.410 / 0.705 |
+| equal | 0.5 | 3U, 1P | unan | 0.467 / 0.733 | 0.374 / 0.687 |
+| equal | 0.66 | 0U, 0P | indep | 0.855 / 0.928 | 0.635 / 0.818 |
+| equal | 0.66 | 0U, 0P | unan | 0.499 / 0.749 | 0.499 / 0.749 |
+| equal | 0.66 | 3U, 1P | indep | 0.420 / 0.712 | 0.407 / 0.705 |
+| equal | 0.66 | 3U, 1P | unan | 0.375 / 0.687 | 0.375 / 0.687 |
+| minds-heavy | 0.15 | 0U, 0P | indep | 0.145 / 0.570 | 0.636 / 0.817 |
+| minds-heavy | 0.15 | 0U, 0P | unan | 0.501 / 0.752 | 0.501 / 0.752 |
+| minds-heavy | 0.15 | 3U, 1P | indep | 0.017 / 0.506 | 0.251 / 0.624 |
+| minds-heavy | 0.15 | 3U, 1P | unan | 0.251 / 0.627 | 0.251 / 0.628 |
+| minds-heavy | 0.5 | 0U, 0P | indep | 0.961 / 0.980 | 0.271 / 0.636 |
+| minds-heavy | 0.5 | 0U, 0P | unan | 0.000 / 0.501 | 0.000 / 0.501 |
+| minds-heavy | 0.5 | 3U, 1P | indep | 0.857 / 0.929 | 0.477 / 0.739 |
+| minds-heavy | 0.5 | 3U, 1P | unan | 0.280 / 0.640 | 0.374 / 0.688 |
+| minds-heavy | 0.66 | 0U, 0P | indep | 0.635 / 0.818 | 0.635 / 0.818 |
+| minds-heavy | 0.66 | 0U, 0P | unan | 0.499 / 0.749 | 0.499 / 0.749 |
+| minds-heavy | 0.66 | 3U, 1P | indep | 0.484 / 0.744 | 0.475 / 0.739 |
+| minds-heavy | 0.66 | 3U, 1P | unan | 0.467 / 0.733 | 0.375 / 0.687 |
+| members-heavy | 0.15 | 0U, 0P | indep | 0.365 / 0.681 | 0.636 / 0.817 |
+| members-heavy | 0.15 | 0U, 0P | unan | 0.501 / 0.752 | 0.501 / 0.752 |
+| members-heavy | 0.15 | 3U, 1P | indep | 0.122 / 0.558 | 0.159 / 0.578 |
+| members-heavy | 0.15 | 3U, 1P | unan | 0.220 / 0.611 | 0.126 / 0.564 |
+| members-heavy | 0.5 | 0U, 0P | indep | 1.000 / 1.000 | 1.000 / 1.000 |
+| members-heavy | 0.5 | 0U, 0P | unan | 1.000 / 1.000 | 1.000 / 1.000 |
+| members-heavy | 0.5 | 3U, 1P | indep | 0.988 / 0.994 | 0.818 / 0.908 |
+| members-heavy | 0.5 | 3U, 1P | unan | 0.936 / 0.968 | 0.750 / 0.875 |
+| members-heavy | 0.66 | 0U, 0P | indep | 1.000 / 1.000 | 1.000 / 1.000 |
+| members-heavy | 0.66 | 0U, 0P | unan | 1.000 / 1.000 | 1.000 / 1.000 |
+| members-heavy | 0.66 | 3U, 1P | indep | 0.700 / 0.851 | 0.567 / 0.785 |
+| members-heavy | 0.66 | 3U, 1P | unan | 0.687 / 0.843 | 0.500 / 0.749 |
+
+## G2. Her weight share inside Members; WTA-internal she alone decides the bloc iff share > 0.5
+| n Members | S | one-each | k=1 | k=2 | k=3 | k=5 |
+|---|---|---|---|---|---|---|
+| 1 | 1.0 | 1.00* | 1.00* | 1.00* | 1.00* | 1.00* |
+| 2 | 0.5 | 0.50 | 0.50 | 0.50 | 0.50 | 0.50 |
+| 2 | 0.8 | 0.50 | 0.80* | 0.67* | 0.61* | 0.57* |
+| 2 | 0.95 | 0.50 | 0.95* | 0.81* | 0.73* | 0.64* |
+| 3 | 0.5 | 0.33 | 0.50 | 0.42 | 0.39 | 0.37 |
+| 3 | 0.8 | 0.33 | 0.80* | 0.59* | 0.50* | 0.43 |
+| 3 | 0.95 | 0.33 | 0.95* | 0.76* | 0.63* | 0.51* |
+| 5 | 0.5 | 0.20 | 0.50 | 0.34 | 0.29 | 0.25 |
+| 5 | 0.8 | 0.20 | 0.80* | 0.51* | 0.39 | 0.31 |
+| 5 | 0.95 | 0.20 | 0.95* | 0.69* | 0.52* | 0.38 |
+| 10 | 0.5 | 0.10 | 0.50* | 0.26 | 0.19 | 0.15 |
+| 10 | 0.8 | 0.10 | 0.80* | 0.41 | 0.28 | 0.19 |
+| 10 | 0.95 | 0.10 | 0.95* | 0.60* | 0.39 | 0.24 |
+| 20 | 0.5 | 0.05 | 0.50 | 0.20 | 0.13 | 0.09 |
+| 20 | 0.8 | 0.05 | 0.80* | 0.33 | 0.19 | 0.12 |
+| 20 | 0.95 | 0.05 | 0.95* | 0.52* | 0.29 | 0.15 |
+| 50 | 0.5 | 0.02 | 0.50* | 0.14 | 0.08 | 0.05 |
+| 50 | 0.8 | 0.02 | 0.80* | 0.24 | 0.12 | 0.06 |
+| 50 | 0.95 | 0.02 | 0.95* | 0.41 | 0.18 | 0.08 |
+(* = she alone decides the Members bloc under WTA/unitary internal majority)
+
+## G3. Growth path: her pivot over the whole tally (fair coins, Minds indep, Users 10, Patrons [50,500] log), q=0.5
+| seed | n Members | S | curve | prop pivot | WTA pivot |
+|---|---|---|---|---|---|
+| equal | 1 | 1.0 | alone | 0.723 | 0.429 |
+| equal | 5 | 0.5 | one-each | 0.152 | 0.161 |
+| equal | 5 | 0.5 | k=1 | 0.387 | 0.413 |
+| equal | 5 | 0.5 | k=2 | 0.259 | 0.269 |
+| equal | 5 | 0.5 | k=3 | 0.225 | 0.215 |
+| equal | 5 | 0.5 | k=5 | 0.195 | 0.161 |
+| equal | 5 | 0.8 | one-each | 0.152 | 0.161 |
+| equal | 5 | 0.8 | k=1 | 0.601 | 0.434 |
+| equal | 5 | 0.8 | k=2 | 0.392 | 0.434 |
+| equal | 5 | 0.8 | k=3 | 0.305 | 0.380 |
+| equal | 5 | 0.8 | k=5 | 0.237 | 0.215 |
+| equal | 20 | 0.5 | one-each | 0.040 | 0.076 |
+| equal | 20 | 0.5 | k=1 | 0.396 | 0.430 |
+| equal | 20 | 0.5 | k=2 | 0.161 | 0.290 |
+| equal | 20 | 0.5 | k=3 | 0.106 | 0.201 |
+| equal | 20 | 0.5 | k=5 | 0.074 | 0.144 |
+| equal | 20 | 0.8 | one-each | 0.040 | 0.076 |
+| equal | 20 | 0.8 | k=1 | 0.606 | 0.430 |
+| equal | 20 | 0.8 | k=2 | 0.267 | 0.411 |
+| equal | 20 | 0.8 | k=3 | 0.156 | 0.293 |
+| equal | 20 | 0.8 | k=5 | 0.095 | 0.179 |
+| members-heavy | 1 | 1.0 | alone | 1.000 | 0.862 |
+| members-heavy | 5 | 0.5 | one-each | 0.296 | 0.323 |
+| members-heavy | 5 | 0.5 | k=1 | 0.752 | 0.823 |
+| members-heavy | 5 | 0.5 | k=2 | 0.519 | 0.538 |
+| members-heavy | 5 | 0.5 | k=3 | 0.441 | 0.429 |
+| members-heavy | 5 | 0.5 | k=5 | 0.380 | 0.323 |
+| members-heavy | 5 | 0.8 | one-each | 0.296 | 0.323 |
+| members-heavy | 5 | 0.8 | k=1 | 0.987 | 0.862 |
+| members-heavy | 5 | 0.8 | k=2 | 0.779 | 0.862 |
+| members-heavy | 5 | 0.8 | k=3 | 0.613 | 0.755 |
+| members-heavy | 5 | 0.8 | k=5 | 0.475 | 0.429 |
+| members-heavy | 20 | 0.5 | one-each | 0.099 | 0.152 |
+| members-heavy | 20 | 0.5 | k=1 | 0.832 | 0.861 |
+| members-heavy | 20 | 0.5 | k=2 | 0.388 | 0.580 |
+| members-heavy | 20 | 0.5 | k=3 | 0.259 | 0.403 |
+| members-heavy | 20 | 0.5 | k=5 | 0.179 | 0.288 |
+| members-heavy | 20 | 0.8 | one-each | 0.099 | 0.152 |
+| members-heavy | 20 | 0.8 | k=1 | 0.991 | 0.861 |
+| members-heavy | 20 | 0.8 | k=2 | 0.627 | 0.824 |
+| members-heavy | 20 | 0.8 | k=3 | 0.380 | 0.586 |
+| members-heavy | 20 | 0.8 | k=5 | 0.231 | 0.359 |

docs/research/2026-10-29-estate-tally-game-theory/sims/growth.py

@@ -0,0 +1,73 @@
+"""Present case and growth path (operator 2026-10-29: "until we get more people in, I'm the only active member").
+Operator = Member 0. S = her share of total Member contribution; the other n-1 follow the Pareto(1.16) ladder.
+Empty blocs cast nothing and drop out of the denominator (abstentions excluded). Run: python -I growth.py
+"""
+import numpy as np
+SEEDS = {"equal": [25, 25, 25, 25], "minds-heavy": [40, 30, 20, 10], "members-heavy": [20, 45, 20, 15]}
+CURVES = {"one-each": None, "k=1": 1, "k=2": 2, "k=3": 3, "k=5": 5}
+
+def mweights(n, S, k):
+    if n == 1: return np.ones(1)
+    tail = np.array([i ** (-1 / 1.16) for i in range(1, n)]); tail = tail / tail.sum() * (1 - S)
+    c = np.concatenate([[S], tail]); return np.ones(n) if k is None else c ** (1 / k)
+
+def tally(Wb, F, Tot, q, rule):
+    Wb = np.array(Wb, float); live = Tot > 0
+    if rule == "prop":
+        sh = np.divide(F, Tot, out=np.zeros_like(F), where=live); f = (sh * Wb).sum(1); den = (live * Wb).sum(1)
+    else:
+        st = np.where(live, np.sign(2 * F - Tot), 0); f = (st == 1) @ Wb; den = f + (st == -1) @ Wb
+    return (den > 0) & (f >= q * den - 1e-9)
+
+def her_power(wM, Wb, q, users=0, patrons=(), minds_corr=False, T=200_000, seed=5):
+    r = np.random.default_rng(seed)
+    ws = [np.ones(8), wM, np.ones(users), np.log1p(np.array(patrons, float))]
+    F = np.zeros((T, 4)); Tot = np.zeros((T, 4)); her = None
+    for b, w in enumerate(ws):
+        if len(w) == 0: continue
+        if b == 0 and minds_corr: v = np.repeat(r.random((T, 1)) < .5, 8, 1)
+        else: v = r.random((T, len(w))) < .5
+        if b == 1: her = v[:, 0]
+        F[:, b] = v @ w; Tot[:, b] = w.sum()
+    res = {}
+    for rule in ("prop", "wta"):
+        G = F.copy(); G[:, 1] += np.where(her, -wM[0], wM[0])
+        o = tally(Wb, F, Tot, q, rule); o2 = tally(Wb, G, Tot, q, rule)
+        res[rule] = (np.mean(o != o2), np.mean(o == her))
+    return res
+
+if __name__ == "__main__":
+    print("## G1. Present case: Members = her alone, Minds 8 (fair coins; 'unan' = Minds fully correlated)")
+    print("Cells: P(her vote flips the motion) / P(outcome matches her vote), prop then WTA.")
+    print("| seed | q | Users, Patrons | Minds | prop pivot / match | WTA pivot / match |")
+    print("|---|---|---|---|---|---|")
+    for name, Wb in SEEDS.items():
+        for q in (0.15, 0.5, 0.66):
+            for users, pat in ((0, ()), (3, (100,))):
+                for mc in (False, True):
+                    r = her_power(np.ones(1), Wb, q, users, pat, mc, T=100_000)
+                    print(f"| {name} | {q} | {users}U, {len(pat)}P | {'unan' if mc else 'indep'} | {r['prop'][0]:.3f} / {r['prop'][1]:.3f} | {r['wta'][0]:.3f} / {r['wta'][1]:.3f} |")
+
+    print("\n## G2. Her weight share inside Members; WTA-internal she alone decides the bloc iff share > 0.5")
+    print("| n Members | S | one-each | k=1 | k=2 | k=3 | k=5 |")
+    print("|---|---|---|---|---|---|---|")
+    for n in (1, 2, 3, 5, 10, 20, 50):
+        for S in (0.5, 0.8, 0.95):
+            if n == 1 and S != 0.95: continue
+            cells = []
+            for kn, k in CURVES.items():
+                w = mweights(n, S if n > 1 else 1, k); sh = w[0] / w.sum()
+                cells.append(f"{sh:.2f}{'*' if sh > 0.5 else ''}")
+            print(f"| {n} | {S if n > 1 else 1.0} | " + " | ".join(cells) + " |")
+    print("(* = she alone decides the Members bloc under WTA/unitary internal majority)")
+
+    print("\n## G3. Growth path: her pivot over the whole tally (fair coins, Minds indep, Users 10, Patrons [50,500] log), q=0.5")
+    print("| seed | n Members | S | curve | prop pivot | WTA pivot |")
+    print("|---|---|---|---|---|---|")
+    for name in ("equal", "members-heavy"):
+        Wb = SEEDS[name]
+        for n in (1, 5, 20):
+            for S in ((1.0,) if n == 1 else (0.5, 0.8)):
+                for kn, k in (CURVES.items() if n > 1 else [("alone", None)]):
+                    r = her_power(mweights(n, S, k), Wb, .5, users=10, patrons=(50, 500), T=100_000)
+                    print(f"| {name} | {n} | {S} | {kn} | {r['prop'][0]:.3f} | {r['wta'][0]:.3f} |")

docs/research/2026-10-29-estate-tally-game-theory/sims/lone.out.md

@@ -0,0 +1,28 @@
+## L1. Quorum floors a lone Minds turnout (8 of 8) meets, she absent
+| floor type | Minds-alone value | equal | minds-heavy | members-heavy |
+|---|---|---|---|---|
+| headcount fraction of eligible (8 Minds + her) | 8/9 = 0.889 | same | same | same |
+| estate-weight fraction of live-eligible estates | w_M/(w_M+w_Me) | 0.500 | 0.571 | 0.308 |
+A floor above these values requires her turnout; at or below, Minds alone can decide.
+
+## L2. Lone Minds: Personas For needed and P(pass), motion model, by category
+| category | q | Personas needed prop | Personas needed WTA | P(pass) prop ICC 0 / .44 / 1 | P(pass) WTA ICC 0 / .44 / 1 |
+|---|---|---|---|---|---|
+| Bugs | 0.15 | 2 | 5 (any q) | 0.775 / 0.647 / 0.500 | 0.446 / 0.474 / 0.500 |
+| Cosmetics | 0.3 | 3 | 5 (any q) | 0.662 / 0.585 / 0.500 | 0.446 / 0.474 / 0.500 |
+| Balance | 0.4 | 4 | 5 (any q) | 0.554 / 0.528 / 0.500 | 0.446 / 0.474 / 0.500 |
+| Features | 0.5 | 4 | 5 (any q) | 0.554 / 0.528 / 0.500 | 0.446 / 0.474 / 0.500 |
+| NewContent | 0.5 | 4 | 5 (any q) | 0.554 / 0.528 / 0.500 | 0.446 / 0.474 / 0.500 |
+| FundamentalDesign | 0.66 | 6 | 5 (any q) | 0.337 / 0.418 / 0.500 | 0.446 / 0.474 / 0.500 |
+Under WTA a lone estate casts 100% For or 100% Against, so For/(For+Against) is 1 or 0 and category thresholds are inert.
+
+## L3. Delay-plus-cancel window: P(she is back before the decision takes effect), absence ~ Exponential(mean A)
+| delay D | A=1 day | A=3 days | A=7 days | A=14 days |
+|---|---|---|---|---|
+| 1 d | 0.63 | 0.28 | 0.13 | 0.07 |
+| 2 d | 0.86 | 0.49 | 0.25 | 0.13 |
+| 3 d | 0.95 | 0.63 | 0.35 | 0.19 |
+| 7 d | 1.00 | 0.90 | 0.63 | 0.39 |
+| 10 d | 1.00 | 0.96 | 0.76 | 0.51 |
+| 14 d | 1.00 | 0.99 | 0.86 | 0.63 |
+Memoryless assumption; real absences are not exponential. P = chance a cancel opportunity exists, not that it is used.

docs/research/2026-10-29-estate-tally-game-theory/sims/lone.py

@@ -0,0 +1,41 @@
+"""Lone estate bounds (operator 2026-10-29: "they totally should be able to make decisions without me if I'm not there to vote").
+Present case with her absent: Minds (8) are the only live estate; renormalization makes Minds the whole tally.
+L1 quorum floors that a lone Minds turnout meets; L2 category thresholds vs Personas needed and pass rates;
+L3 delay-plus-cancel window: P(she returns before effect) for exponential absence. Run: python -I lone.py
+"""
+import math
+import numpy as np
+CATS = {"Bugs": .15, "Cosmetics": .30, "Balance": .40, "Features": .50, "NewContent": .50, "FundamentalDesign": .66}
+
+print("## L1. Quorum floors a lone Minds turnout (8 of 8) meets, she absent")
+print("| floor type | Minds-alone value | equal | minds-heavy | members-heavy |")
+print("|---|---|---|---|---|")
+print("| headcount fraction of eligible (8 Minds + her) | 8/9 = 0.889 | same | same | same |")
+for lab in ("estate-weight fraction of live-eligible estates",):
+    vals = [wm_ / (wm_ + wme_) for wm_, wme_ in ((25, 25), (40, 30), (20, 45))]
+    print(f"| {lab} | w_M/(w_M+w_Me) | {vals[0]:.3f} | {vals[1]:.3f} | {vals[2]:.3f} |")
+print("A floor above these values requires her turnout; at or below, Minds alone can decide.")
+
+print("\n## L2. Lone Minds: Personas For needed and P(pass), motion model, by category")
+r = np.random.default_rng(11); T = 400_000
+m = r.standard_normal(T); p = 1 / (1 + np.exp(-1.7 * (0.6 * m + 0.8 * r.standard_normal(T))))
+def minds_for(icc):
+    if icc >= 1: return np.where(r.random(T) < p, 8, 0)
+    if icc <= 0: return r.binomial(8, p)
+    a = p * (1 - icc) / icc; b = (1 - p) * (1 - icc) / icc; return r.binomial(8, r.beta(a, b))
+print("| category | q | Personas needed prop | Personas needed WTA | P(pass) prop ICC 0 / .44 / 1 | P(pass) WTA ICC 0 / .44 / 1 |")
+print("|---|---|---|---|---|---|")
+draws = {icc: minds_for(icc) for icc in (0, .44, 1)}
+for c, q in CATS.items():
+    need = math.ceil(q * 8 - 1e-9)
+    pp = [np.mean(draws[i] / 8 >= q - 1e-9) for i in (0, .44, 1)]
+    pw = [np.mean(draws[i] >= 5) for i in (0, .44, 1)]
+    print(f"| {c} | {q} | {need} | 5 (any q) | " + " / ".join(f"{x:.3f}" for x in pp) + " | " + " / ".join(f"{x:.3f}" for x in pw) + " |")
+print("Under WTA a lone estate casts 100% For or 100% Against, so For/(For+Against) is 1 or 0 and category thresholds are inert.")
+
+print("\n## L3. Delay-plus-cancel window: P(she is back before the decision takes effect), absence ~ Exponential(mean A)")
+print("| delay D | A=1 day | A=3 days | A=7 days | A=14 days |")
+print("|---|---|---|---|---|")
+for D in (1, 2, 3, 7, 10, 14):
+    print(f"| {D} d | " + " | ".join(f"{1 - math.exp(-D / A):.2f}" for A in (1, 3, 7, 14)) + " |")
+print("Memoryless assumption; real absences are not exponential. P = chance a cancel opportunity exists, not that it is used.")

docs/research/2026-10-29-estate-tally-game-theory/sims/mc.out.md

@@ -0,0 +1,38 @@
+## A. P(outcome differs, prop vs WTA) and single-voter pivot rates (Minds ICC .44, humans 0, Users turnout 10% = 30 voters)
+| weights | q | P(pass) prop | P(pass) WTA | P(differ) | pivot prop M/Me/U/P | pivot WTA M/Me/U/P |
+|---|---|---|---|---|---|---|
+| equal | 0.15 | 0.934 | 0.838 | 0.098 | 0.0202/0.0118/0.0062/0.0424 | 0.0139/0.0135/0.0063/0.0406 |
+| equal | 0.5 | 0.501 | 0.594 | 0.119 | 0.0501/0.0262/0.0133/0.1004 | 0.0207/0.0227/0.0115/0.0756 |
+| equal | 0.66 | 0.265 | 0.404 | 0.148 | 0.0422/0.0228/0.0112/0.0870 | 0.0199/0.0219/0.0110/0.0762 |
+| minds-heavy | 0.15 | 0.913 | 0.796 | 0.122 | 0.0432/0.0180/0.0058/0.0236 | 0.0193/0.0188/0.0088/0.0037 |
+| minds-heavy | 0.5 | 0.500 | 0.537 | 0.118 | 0.0718/0.0258/0.0084/0.0330 | 0.0305/0.0233/0.0112/0.0276 |
+| minds-heavy | 0.66 | 0.299 | 0.357 | 0.091 | 0.0651/0.0256/0.0079/0.0323 | 0.0379/0.0206/0.0040/0.0248 |
+| members-heavy | 0.15 | 0.932 | 0.838 | 0.101 | 0.0184/0.0219/0.0050/0.0279 | 0.0139/0.0135/0.0063/0.0406 |
+| members-heavy | 0.5 | 0.500 | 0.500 | 0.111 | 0.0376/0.0463/0.0099/0.0566 | 0.0096/0.0466/0.0050/0.0480 |
+| members-heavy | 0.66 | 0.270 | 0.342 | 0.113 | 0.0343/0.0409/0.0088/0.0512 | 0.0125/0.0356/0.0068/0.0494 |
+
+## B. Minds within-bloc correlation (equal weights, q=0.5)
+| Minds ICC | Kish n_eff of 8 | P(differ) | Minds |share-0.5| mean | Minds pivot prop | Minds pivot WTA | P(Minds tie) |
+|---|---|---|---|---|---|---|
+| 0.0 | 8.00 | 0.115 | 0.280 | 0.0506 | 0.0403 | 0.107 |
+| 0.2 | 3.33 | 0.118 | 0.324 | 0.0513 | 0.0304 | 0.086 |
+| 0.44 | 1.96 | 0.119 | 0.379 | 0.0495 | 0.0199 | 0.054 |
+| 0.8 | 1.21 | 0.124 | 0.458 | 0.0487 | 0.0064 | 0.017 |
+| 1.0 | 1.00 | 0.126 | 0.500 | 0.0474 | 0.0000 | 0.000 |
+
+## C. Users turnout (equal weights, q=0.5, Users roll 300)
+| turnout | Users voters | P(Users WTA cast != population majority) | mean |prop share - p_U| | P(motion != full-turnout result) prop | same, WTA |
+|---|---|---|---|---|---|
+| 0.01 | 3 | 0.181 | 0.186 | 0.077 | 0.062 |
+| 0.03 | 9 | 0.117 | 0.106 | 0.044 | 0.040 |
+| 0.1 | 30 | 0.084 | 0.058 | 0.024 | 0.024 |
+| 0.3 | 90 | 0.044 | 0.033 | 0.014 | 0.014 |
+
+## D. Coordinated Users faction of k voters, Users population support p_U=0.3, turnout 3% (9 random voters + k)
+| k | P(Users bloc cast For) WTA | mean Users For share prop |
+|---|---|---|
+| 0 | 0.098 | 0.300 |
+| 3 | 0.270 | 0.475 |
+| 6 | 0.803 | 0.580 |
+| 9 | 0.961 | 0.650 |
+| 12 | 1.000 | 0.700 |

docs/research/2026-10-29-estate-tally-game-theory/sims/mc.py

@@ -0,0 +1,82 @@
+"""Monte Carlo: proportional vs winner-take-all estate tallies under a motion model.
+Motion model: common merit m~N(0,1), bloc taste e_b~N(0,1), bloc mean support p_b=logistic(1.7*(0.6m+0.8e_b)).
+Within-bloc correlation: individual propensities ~ Beta with mean p_b and ICC r_b (beta-binomial).
+Users: roll 300, a random sample of round(300*turnout) votes. Run: python -I mc.py
+"""
+import numpy as np
+rng = np.random.default_rng(20261029)
+BLOCS = ["Minds", "Members", "Users", "Patrons"]
+WEIGHTS = {"equal": [25, 25, 25, 25], "minds-heavy": [40, 30, 20, 10], "members-heavy": [20, 45, 20, 15]}
+T = 200_000
+
+def draw(minds_r=0.44, human_r=0.0, turnout=0.1, T=T):
+    sizes = [8, 15, max(1, round(300 * turnout)), 4]
+    rs = [minds_r, human_r, human_r, human_r]
+    m = rng.standard_normal(T)
+    p = 1 / (1 + np.exp(-1.7 * (0.6 * m[:, None] + 0.8 * rng.standard_normal((T, 4)))))
+    F = np.zeros((T, 4), int); first = np.zeros((T, 4), int)
+    for b, (n, r) in enumerate(zip(sizes, rs)):
+        if r <= 0: probs = np.repeat(p[:, b:b + 1], n, 1)
+        elif r >= 1: probs = np.repeat((rng.random((T, 1)) < p[:, b:b + 1]).astype(float), n, 1)
+        else:
+            a = p[:, b] * (1 - r) / r; c = (1 - p[:, b]) * (1 - r) / r
+            probs = np.repeat(rng.beta(a, c)[:, None], n, 1)  # one shared propensity per bloc-motion = beta-binomial ICC r
+        v = rng.random((T, n)) < probs
+        F[:, b] = v.sum(1); first[:, b] = v[:, 0]
+    return np.array(sizes), p, F, first
+
+def out_prop(ws, sizes, F, q):
+    s = (F / sizes) @ np.array(ws, float); return s >= q * sum(ws) - 1e-9
+
+def out_wta(ws, sizes, F, q):
+    ws = np.array(ws, float); st = np.sign(2 * F - sizes)  # +1 For, -1 Against, 0 tie casts nothing
+    f = (st == 1) @ ws; a = (st == -1) @ ws
+    return (f + a > 0) & (f >= q * (f + a) - 1e-9)
+
+def flip(F, first, b):
+    G = F.copy(); G[:, b] += np.where(first[:, b] == 1, -1, 1); return G
+
+def fmt(v): return " | ".join(f"{x:.3f}" for x in v)
+
+if __name__ == "__main__":
+    print("## A. P(outcome differs, prop vs WTA) and single-voter pivot rates (Minds ICC .44, humans 0, Users turnout 10% = 30 voters)")
+    sizes, p, F, first = draw()
+    print("| weights | q | P(pass) prop | P(pass) WTA | P(differ) | pivot prop M/Me/U/P | pivot WTA M/Me/U/P |")
+    print("|---|---|---|---|---|---|---|")
+    for name, ws in WEIGHTS.items():
+        for q in (0.15, 0.5, 0.66):
+            op, ow = out_prop(ws, sizes, F, q), out_wta(ws, sizes, F, q)
+            pp = [np.mean(op != out_prop(ws, sizes, flip(F, first, b), q)) for b in range(4)]
+            pw = [np.mean(ow != out_wta(ws, sizes, flip(F, first, b), q)) for b in range(4)]
+            print(f"| {name} | {q} | {op.mean():.3f} | {ow.mean():.3f} | {np.mean(op != ow):.3f} | "
+                  + "/".join(f"{x:.4f}" for x in pp) + " | " + "/".join(f"{x:.4f}" for x in pw) + " |")
+
+    print("\n## B. Minds within-bloc correlation (equal weights, q=0.5)")
+    print("| Minds ICC | Kish n_eff of 8 | P(differ) | Minds |share-0.5| mean | Minds pivot prop | Minds pivot WTA | P(Minds tie) |")
+    print("|---|---|---|---|---|---|---|")
+    for r in (0.0, 0.2, 0.44, 0.8, 1.0):
+        sizes, p, F, first = draw(minds_r=r, T=100_000); ws = WEIGHTS["equal"]
+        op, ow = out_prop(ws, sizes, F, .5), out_wta(ws, sizes, F, .5)
+        pp = np.mean(op != out_prop(ws, sizes, flip(F, first, 0), .5)); pw = np.mean(ow != out_wta(ws, sizes, flip(F, first, 0), .5))
+        print(f"| {r} | {8 / (1 + 7 * r):.2f} | {np.mean(op != ow):.3f} | {np.mean(abs(F[:, 0] / 8 - .5)):.3f} | {pp:.4f} | {pw:.4f} | {np.mean(2 * F[:, 0] == 8):.3f} |")
+
+    print("\n## C. Users turnout (equal weights, q=0.5, Users roll 300)")
+    print("| turnout | Users voters | P(Users WTA cast != population majority) | mean |prop share - p_U| | P(motion != full-turnout result) prop | same, WTA |")
+    print("|---|---|---|---|---|---|")
+    for t in (0.01, 0.03, 0.1, 0.3):
+        sizes, p, F, first = draw(turnout=t, T=100_000); ws = WEIGHTS["equal"]
+        st = np.sign(2 * F[:, 2] - sizes[2]); pop = np.sign(p[:, 2] - .5)
+        Ffull = F.astype(float).copy(); Ffull[:, 2] = p[:, 2] * sizes[2]
+        sfull = sizes.copy()
+        opf = out_prop(ws, sfull, Ffull, .5)
+        stf = np.sign(2 * F - sizes).astype(float); stf[:, 2] = pop
+        wsA = np.array(ws, float); owf = ((stf == 1) @ wsA) >= .5 * (((stf == 1) | (stf == -1)) @ wsA)
+        print(f"| {t} | {sizes[2]} | {np.mean(st != pop):.3f} | {np.mean(abs(F[:, 2] / sizes[2] - p[:, 2])):.3f} | "
+              f"{np.mean(out_prop(ws, sizes, F, .5) != opf):.3f} | {np.mean(out_wta(ws, sizes, F, .5) != owf):.3f} |")
+
+    print("\n## D. Coordinated Users faction of k voters, Users population support p_U=0.3, turnout 3% (9 random voters + k)")
+    print("| k | P(Users bloc cast For) WTA | mean Users For share prop |")
+    print("|---|---|---|")
+    for k in (0, 3, 6, 9, 12):
+        rnd = rng.random((100_000, 9)) < 0.3; f = rnd.sum(1) + k; n = 9 + k
+        print(f"| {k} | {np.mean(2 * f > n):.3f} | {np.mean(f / n):.3f} |")

docs/research/2026-10-29-estate-tally-game-theory/sims/noshow.out.md

@@ -0,0 +1,117 @@
+## N1. Profitable deviations (count of profile x actor cases where deviating gets the actor's sincere preference)
+Present case sizes Minds 8 / Members 1 (her) / Users 0 / Patrons 0; mixed case 3/1/2/1.
+| sizes | weights | q | rule | quorum | profiles | indiv profitable dev | of which hers | estate stay-home profitable |
+|---|---|---|---|---|---|---|---|---|
+| 8/1/0/0 | (25, 25, 25, 25) | 0.5 | prop | none | 512 | 0 | 0 | 0 |
+| 8/1/0/0 | (25, 25, 25, 25) | 0.5 | prop | head | 512 | 0 | 0 | 93 |
+| 8/1/0/0 | (25, 25, 25, 25) | 0.5 | prop | two | 512 | 1 | 1 | 94 |
+| 8/1/0/0 | (25, 25, 25, 25) | 0.5 | wta | none | 512 | 0 | 0 | 0 |
+| 8/1/0/0 | (25, 25, 25, 25) | 0.5 | wta | head | 512 | 0 | 0 | 93 |
+| 8/1/0/0 | (25, 25, 25, 25) | 0.5 | wta | two | 512 | 93 | 93 | 186 |
+| 8/1/0/0 | (25, 25, 25, 25) | 0.66 | prop | none | 512 | 0 | 0 | 0 |
+| 8/1/0/0 | (25, 25, 25, 25) | 0.66 | prop | head | 512 | 0 | 0 | 56 |
+| 8/1/0/0 | (25, 25, 25, 25) | 0.66 | prop | two | 512 | 0 | 0 | 56 |
+| 8/1/0/0 | (25, 25, 25, 25) | 0.66 | wta | none | 512 | 0 | 0 | 0 |
+| 8/1/0/0 | (25, 25, 25, 25) | 0.66 | wta | head | 512 | 0 | 0 | 0 |
+| 8/1/0/0 | (25, 25, 25, 25) | 0.66 | wta | two | 512 | 0 | 0 | 0 |
+| 8/1/0/0 | (40, 30, 20, 10) | 0.5 | prop | none | 512 | 0 | 0 | 0 |
+| 8/1/0/0 | (40, 30, 20, 10) | 0.5 | prop | head | 512 | 0 | 0 | 92 |
+| 8/1/0/0 | (40, 30, 20, 10) | 0.5 | prop | two | 512 | 9 | 9 | 101 |
+| 8/1/0/0 | (40, 30, 20, 10) | 0.5 | wta | none | 512 | 0 | 0 | 0 |
+| 8/1/0/0 | (40, 30, 20, 10) | 0.5 | wta | head | 512 | 0 | 0 | 0 |
+| 8/1/0/0 | (40, 30, 20, 10) | 0.5 | wta | two | 512 | 93 | 93 | 93 |
+| 8/1/0/0 | (40, 30, 20, 10) | 0.66 | prop | none | 512 | 0 | 0 | 0 |
+| 8/1/0/0 | (40, 30, 20, 10) | 0.66 | prop | head | 512 | 0 | 0 | 0 |
+| 8/1/0/0 | (40, 30, 20, 10) | 0.66 | prop | two | 512 | 0 | 0 | 0 |
+| 8/1/0/0 | (40, 30, 20, 10) | 0.66 | wta | none | 512 | 0 | 0 | 0 |
+| 8/1/0/0 | (40, 30, 20, 10) | 0.66 | wta | head | 512 | 0 | 0 | 0 |
+| 8/1/0/0 | (40, 30, 20, 10) | 0.66 | wta | two | 512 | 0 | 0 | 0 |
+| 8/1/0/0 | (20, 45, 20, 15) | 0.5 | prop | none | 512 | 0 | 0 | 0 |
+| 8/1/0/0 | (20, 45, 20, 15) | 0.5 | prop | head | 512 | 0 | 0 | 93 |
+| 8/1/0/0 | (20, 45, 20, 15) | 0.5 | prop | two | 512 | 0 | 0 | 93 |
+| 8/1/0/0 | (20, 45, 20, 15) | 0.5 | wta | none | 512 | 0 | 0 | 0 |
+| 8/1/0/0 | (20, 45, 20, 15) | 0.5 | wta | head | 512 | 0 | 0 | 93 |
+| 8/1/0/0 | (20, 45, 20, 15) | 0.5 | wta | two | 512 | 0 | 0 | 93 |
+| 8/1/0/0 | (20, 45, 20, 15) | 0.66 | prop | none | 512 | 0 | 0 | 0 |
+| 8/1/0/0 | (20, 45, 20, 15) | 0.66 | prop | head | 512 | 0 | 0 | 93 |
+| 8/1/0/0 | (20, 45, 20, 15) | 0.66 | prop | two | 512 | 0 | 0 | 93 |
+| 8/1/0/0 | (20, 45, 20, 15) | 0.66 | wta | none | 512 | 0 | 0 | 0 |
+| 8/1/0/0 | (20, 45, 20, 15) | 0.66 | wta | head | 512 | 0 | 0 | 93 |
+| 8/1/0/0 | (20, 45, 20, 15) | 0.66 | wta | two | 512 | 0 | 0 | 93 |
+| 3/1/2/1 | (25, 25, 25, 25) | 0.5 | prop | none | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (25, 25, 25, 25) | 0.5 | prop | head | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (25, 25, 25, 25) | 0.5 | prop | two | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (25, 25, 25, 25) | 0.5 | wta | none | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (25, 25, 25, 25) | 0.5 | wta | head | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (25, 25, 25, 25) | 0.5 | wta | two | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (25, 25, 25, 25) | 0.66 | prop | none | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (25, 25, 25, 25) | 0.66 | prop | head | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (25, 25, 25, 25) | 0.66 | prop | two | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (25, 25, 25, 25) | 0.66 | wta | none | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (25, 25, 25, 25) | 0.66 | wta | head | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (25, 25, 25, 25) | 0.66 | wta | two | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (40, 30, 20, 10) | 0.5 | prop | none | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (40, 30, 20, 10) | 0.5 | prop | head | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (40, 30, 20, 10) | 0.5 | prop | two | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (40, 30, 20, 10) | 0.5 | wta | none | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (40, 30, 20, 10) | 0.5 | wta | head | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (40, 30, 20, 10) | 0.5 | wta | two | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (40, 30, 20, 10) | 0.66 | prop | none | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (40, 30, 20, 10) | 0.66 | prop | head | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (40, 30, 20, 10) | 0.66 | prop | two | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (40, 30, 20, 10) | 0.66 | wta | none | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (40, 30, 20, 10) | 0.66 | wta | head | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (40, 30, 20, 10) | 0.66 | wta | two | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (20, 45, 20, 15) | 0.5 | prop | none | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (20, 45, 20, 15) | 0.5 | prop | head | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (20, 45, 20, 15) | 0.5 | prop | two | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (20, 45, 20, 15) | 0.5 | wta | none | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (20, 45, 20, 15) | 0.5 | wta | head | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (20, 45, 20, 15) | 0.5 | wta | two | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (20, 45, 20, 15) | 0.66 | prop | none | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (20, 45, 20, 15) | 0.66 | prop | head | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (20, 45, 20, 15) | 0.66 | prop | two | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (20, 45, 20, 15) | 0.66 | wta | none | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (20, 45, 20, 15) | 0.66 | wta | head | 128 | 0 | 0 | 0 |
+| 3/1/2/1 | (20, 45, 20, 15) | 0.66 | wta | two | 128 | 0 | 0 | 0 |
+
+## N2. Present case outcome map (Minds 8 independent fair coins, her vote fixed), renormalized
+P(pass | she votes For) / P(pass | she votes Against) / P(pass | she stays home)
+| weights | q | rule | quorum | For | Against | home |
+|---|---|---|---|---|---|---|
+| (25, 25) | 0.15 | prop | none | 1.000 | 0.855 | 0.965 |
+| (25, 25) | 0.15 | prop | two | 1.000 | 0.855 | 0.000 |
+| (25, 25) | 0.15 | wta | none | 1.000 | 0.363 | 0.363 |
+| (25, 25) | 0.15 | wta | two | 1.000 | 0.363 | 0.000 |
+| (25, 25) | 0.5 | prop | none | 1.000 | 0.004 | 0.637 |
+| (25, 25) | 0.5 | prop | two | 1.000 | 0.004 | 0.000 |
+| (25, 25) | 0.5 | wta | none | 1.000 | 0.363 | 0.363 |
+| (25, 25) | 0.5 | wta | two | 1.000 | 0.363 | 0.000 |
+| (25, 25) | 0.66 | prop | none | 0.855 | 0.000 | 0.145 |
+| (25, 25) | 0.66 | prop | two | 0.855 | 0.000 | 0.000 |
+| (25, 25) | 0.66 | wta | none | 0.637 | 0.000 | 0.363 |
+| (25, 25) | 0.66 | wta | two | 0.637 | 0.000 | 0.000 |
+| (40, 30) | 0.15 | prop | none | 1.000 | 0.855 | 0.965 |
+| (40, 30) | 0.15 | prop | two | 1.000 | 0.855 | 0.000 |
+| (40, 30) | 0.15 | wta | none | 1.000 | 0.363 | 0.363 |
+| (40, 30) | 0.15 | wta | two | 1.000 | 0.363 | 0.000 |
+| (40, 30) | 0.5 | prop | none | 0.996 | 0.035 | 0.637 |
+| (40, 30) | 0.5 | prop | two | 0.996 | 0.035 | 0.000 |
+| (40, 30) | 0.5 | wta | none | 0.637 | 0.363 | 0.363 |
+| (40, 30) | 0.5 | wta | two | 0.637 | 0.363 | 0.000 |
+| (40, 30) | 0.66 | prop | none | 0.637 | 0.000 | 0.145 |
+| (40, 30) | 0.66 | prop | two | 0.637 | 0.000 | 0.000 |
+| (40, 30) | 0.66 | wta | none | 0.637 | 0.000 | 0.363 |
+| (40, 30) | 0.66 | wta | two | 0.637 | 0.000 | 0.000 |
+| (20, 45) | 0.15 | prop | none | 1.000 | 0.637 | 0.965 |
+| (20, 45) | 0.15 | prop | two | 1.000 | 0.637 | 0.000 |
+| (20, 45) | 0.15 | wta | none | 1.000 | 0.363 | 0.363 |
+| (20, 45) | 0.15 | wta | two | 1.000 | 0.363 | 0.000 |
+| (20, 45) | 0.5 | prop | none | 1.000 | 0.000 | 0.637 |
+| (20, 45) | 0.5 | prop | two | 1.000 | 0.000 | 0.000 |
+| (20, 45) | 0.5 | wta | none | 1.000 | 0.000 | 0.363 |
+| (20, 45) | 0.5 | wta | two | 1.000 | 0.000 | 0.000 |
+| (20, 45) | 0.66 | prop | none | 1.000 | 0.000 | 0.145 |
+| (20, 45) | 0.66 | prop | two | 1.000 | 0.000 | 0.000 |
+| (20, 45) | 0.66 | wta | none | 1.000 | 0.000 | 0.363 |
+| (20, 45) | 0.66 | wta | two | 1.000 | 0.000 | 0.000 |

docs/research/2026-10-29-estate-tally-game-theory/sims/noshow.py

@@ -0,0 +1,70 @@
+"""No-show incentives under the renormalization ruling (operator 2026-10-29: "normalize it by who actually voted").
+Estate weights renormalize over estates where at least one For/Against ballot was cast; WTA tie casts nothing.
+A motion failing its quorum fails (status quo). Exhaustive over sincere For/Against profiles.
+Deviations: one voter switches or abstains; or a whole estate stays home (estate as unitary actor).
+Quorum floors: none | head = cast ballots >= half of eligible individuals | two = at least two estates voting.
+Run: python -I noshow.py
+"""
+import itertools
+
+def tally(ws, sizes, ballots, q, rule, quorum):
+    F = [0] * 4; A = [0] * 4; idx = 0
+    for b, n in enumerate(sizes):
+        for v in ballots[idx:idx + n]:
+            F[b] += v == 1; A[b] += v == -1
+        idx += n
+    live = [b for b in range(4) if F[b] + A[b] > 0]
+    if quorum == "head" and sum(F) + sum(A) < sum(sizes) / 2: return False
+    if quorum == "two" and len(live) < 2: return False
+    f = a = 0.0
+    for b in live:
+        if rule == "prop": f += ws[b] * F[b] / (F[b] + A[b]); a += ws[b] * A[b] / (F[b] + A[b])
+        elif F[b] > A[b]: f += ws[b]
+        elif A[b] > F[b]: a += ws[b]
+    return f + a > 0 and f >= q * (f + a) - 1e-9
+
+def probe(ws, sizes, q, rule, quorum):
+    N = sum(sizes); starts = [sum(sizes[:b]) for b in range(4)]
+    ind = est = her = 0; prof = 0
+    for bal in itertools.product((1, -1), repeat=N):
+        prof += 1; o = tally(ws, sizes, bal, q, rule, quorum)
+        for i, v in enumerate(bal):
+            want = v == 1
+            if o != want and any(tally(ws, sizes, bal[:i] + (d,) + bal[i + 1:], q, rule, quorum) == want for d in (-v, 0)):
+                ind += 1
+                if sizes[1] == 1 and i == starts[1]: her += 1
+        for b in range(4):
+            if sizes[b] == 0: continue
+            seg = bal[starts[b]:starts[b] + sizes[b]]; pos = sum(seg) > 0 if 2 * sum(x == 1 for x in seg) != len(seg) else None
+            if pos is None or o == pos: continue
+            home = bal[:starts[b]] + (0,) * sizes[b] + bal[starts[b] + sizes[b]:]
+            est += tally(ws, sizes, home, q, rule, quorum) == pos
+    return prof, ind, her, est
+
+if __name__ == "__main__":
+    print("## N1. Profitable deviations (count of profile x actor cases where deviating gets the actor's sincere preference)")
+    print("Present case sizes Minds 8 / Members 1 (her) / Users 0 / Patrons 0; mixed case 3/1/2/1.")
+    print("| sizes | weights | q | rule | quorum | profiles | indiv profitable dev | of which hers | estate stay-home profitable |")
+    print("|---|---|---|---|---|---|---|---|---|")
+    for sizes in ((8, 1, 0, 0), (3, 1, 2, 1)):
+        for ws in ((25, 25, 25, 25), (40, 30, 20, 10), (20, 45, 20, 15)):
+            for q in (0.5, 0.66):
+                for rule in ("prop", "wta"):
+                    for quorum in ("none", "head", "two"):
+                        p, i, h, e = probe(ws, sizes, q, rule, quorum)
+                        print(f"| {'/'.join(map(str, sizes))} | {ws} | {q} | {rule} | {quorum} | {p} | {i} | {h} | {e} |")
+
+    print("\n## N2. Present case outcome map (Minds 8 independent fair coins, her vote fixed), renormalized")
+    print("P(pass | she votes For) / P(pass | she votes Against) / P(pass | she stays home)")
+    print("| weights | q | rule | quorum | For | Against | home |")
+    print("|---|---|---|---|---|---|---|")
+    from math import comb
+    for ws in ((25, 25, 25, 25), (40, 30, 20, 10), (20, 45, 20, 15)):
+        for q in (0.15, 0.5, 0.66):
+            for rule in ("prop", "wta"):
+                for quorum in ("none", "two"):
+                    row = []
+                    for hv in (1, -1, 0):
+                        pp = sum(comb(8, k) / 256 * tally(ws, (8, 1, 0, 0), (1,) * k + (-1,) * (8 - k) + (hv,), q, rule, quorum) for k in range(9))
+                        row.append(f"{pp:.3f}")
+                    print(f"| {ws[:2]} | {q} | {rule} | {quorum} | " + " | ".join(row) + " |")

docs/research/2026-10-29-estate-tally-game-theory/sims/power.out.md

@@ -0,0 +1,41 @@
+## Unitary blocs: normalized Banzhaf / Shapley-Shubik, veto blocs
+| weights | q | Banzhaf M/Me/U/P | Shapley M/Me/U/P | veto blocs |
+|---|---|---|---|---|
+| equal [25, 25, 25, 25] | 0.15 | 0.25/0.25/0.25/0.25 | 0.25/0.25/0.25/0.25 | none |
+| equal [25, 25, 25, 25] | 0.5 | 0.25/0.25/0.25/0.25 | 0.25/0.25/0.25/0.25 | none |
+| equal [25, 25, 25, 25] | 0.66 | 0.25/0.25/0.25/0.25 | 0.25/0.25/0.25/0.25 | none |
+| minds-heavy [40, 30, 20, 10] | 0.15 | 0.33/0.33/0.33/0.00 | 0.33/0.33/0.33/0.00 | none |
+| minds-heavy [40, 30, 20, 10] | 0.5 | 0.42/0.25/0.25/0.08 | 0.42/0.25/0.25/0.08 | none |
+| minds-heavy [40, 30, 20, 10] | 0.66 | 0.50/0.30/0.10/0.10 | 0.58/0.25/0.08/0.08 | Minds |
+| members-heavy [20, 45, 20, 15] | 0.15 | 0.25/0.25/0.25/0.25 | 0.25/0.25/0.25/0.25 | none |
+| members-heavy [20, 45, 20, 15] | 0.5 | 0.17/0.50/0.17/0.17 | 0.17/0.50/0.17/0.17 | none |
+| members-heavy [20, 45, 20, 15] | 0.66 | 0.20/0.40/0.20/0.20 | 0.17/0.50/0.17/0.17 | Members |
+
+## Individual power (P one voter flips the motion), sizes {'Minds': 8, 'Members': 15, 'Users': 30, 'Patrons': 4}
+| weights | q | rule | Minds | Members | Users | Patrons | max/min |
+|---|---|---|---|---|---|---|---|
+| equal | 0.15 | WTA | 0.0538 | 0.0525 | 0.0316 | 0.0683 | 2.2 |
+| equal | 0.15 | prop | 0.0000 | 0.0000 | 0.0000 | 0.0000 | 2.7 |
+| equal | 0.5 | WTA | 0.1184 | 0.0961 | 0.0640 | 0.1584 | 2.5 |
+| equal | 0.5 | prop | 0.1426 | 0.0770 | 0.0384 | 0.2956 | 7.7 |
+| equal | 0.66 | WTA | 0.1184 | 0.0961 | 0.0640 | 0.1584 | 2.5 |
+| equal | 0.66 | prop | 0.0262 | 0.0145 | 0.0073 | 0.0474 | 6.5 |
+| minds-heavy | 0.15 | WTA | 0.0782 | 0.0661 | 0.0398 | 0.0293 | 2.7 |
+| minds-heavy | 0.15 | prop | 0.0000 | 0.0000 | 0.0000 | 0.0000 | 3.9 |
+| minds-heavy | 0.5 | WTA | 0.1686 | 0.1080 | 0.0505 | 0.0609 | 3.3 |
+| minds-heavy | 0.5 | prop | 0.2343 | 0.0909 | 0.0302 | 0.1146 | 7.8 |
+| minds-heavy | 0.66 | WTA | 0.1769 | 0.0942 | 0.0316 | 0.0511 | 5.6 |
+| minds-heavy | 0.66 | prop | 0.0407 | 0.0172 | 0.0058 | 0.0215 | 7.0 |
+| members-heavy | 0.15 | WTA | 0.0538 | 0.0525 | 0.0316 | 0.0683 | 2.2 |
+| members-heavy | 0.15 | prop | 0.0000 | 0.0000 | 0.0000 | 0.0000 | 3.7 |
+| members-heavy | 0.5 | WTA | 0.0366 | 0.1891 | 0.0164 | 0.0583 | 11.5 |
+| members-heavy | 0.5 | prop | 0.1246 | 0.1509 | 0.0327 | 0.1888 | 5.8 |
+| members-heavy | 0.66 | WTA | 0.0647 | 0.1455 | 0.0324 | 0.0900 | 4.5 |
+| members-heavy | 0.66 | prop | 0.0167 | 0.0200 | 0.0045 | 0.0243 | 5.4 |
+
+## Penrose square-root weights (WTA individual-power equalizer, independent voters)
+sqrt(n) shares: [19.9, 27.3, 38.6, 14.1]
+with Minds n_eff=8/(1+7*0.44)=1.96: [11.0, 30.4, 43.0, 15.7]
+headcount shares (prop equalizer): [14.0, 26.3, 52.6, 7.0]
+sqrt weights q=0.5: WTA indiv [0.0928, 0.0835, 0.096, 0.1218]  prop indiv [0.1414, 0.1027, 0.0722, 0.2034]
+headcount weights q=0.5: WTA indiv [0.0, 0.0303, 0.1445, 0.0]  prop indiv [0.1061, 0.1061, 0.1061, 0.1061]

docs/research/2026-10-29-estate-tally-game-theory/sims/power.py

@@ -0,0 +1,110 @@
+"""A priori power of estate blocs and of individuals inside them.
+Pass rule (Bifrost MotionGovernanceService): For / (For + Against) >= q, abstain excluded.
+Blocs: Minds, Members, Users, Patrons. Run: python -I power.py
+"""
+import itertools, math
+from math import comb
+
+BLOCS = ["Minds", "Members", "Users", "Patrons"]
+WEIGHTS = {"equal": [25, 25, 25, 25], "minds-heavy": [40, 30, 20, 10], "members-heavy": [20, 45, 20, 15]}
+QS = [0.15, 0.5, 0.66]
+SIZES = [8, 15, 30, 4]  # voting individuals (Users = active turnout, not roll)
+
+def wins(ws, S, q):
+    return sum(ws[i] for i in S) >= q * sum(ws) - 1e-12
+
+def banzhaf(ws, q):
+    n = len(ws); sw = [0] * n
+    for i in range(n):
+        others = [j for j in range(n) if j != i]
+        for r in range(len(others) + 1):
+            for S in itertools.combinations(others, r):
+                if not wins(ws, S, q) and wins(ws, S + (i,), q):
+                    sw[i] += 1
+    t = sum(sw); return [s / t for s in sw], sw
+
+def shapley(ws, q):
+    n = len(ws); piv = [0] * n
+    for perm in itertools.permutations(range(n)):
+        acc = 0
+        for i in perm:
+            acc += ws[i]
+            if acc >= q * sum(ws) - 1e-12:
+                piv[i] += 1; break
+    t = sum(piv); return [p / t for p in piv]
+
+def veto(ws, q):
+    W = sum(ws); return [BLOCS[i] for i in range(len(ws)) if W - ws[i] < q * W - 1e-12]
+
+def binom(n):  # P(k For among n coin-flip voters)
+    return [comb(n, k) / 2 ** n for k in range(n + 1)]
+
+def wta_state(k, n):  # +1 For, -1 Against, 0 tie casts nothing
+    return 1 if 2 * k > n else (-1 if 2 * k < n else 0)
+
+def outcome_wta(ws, states, q):
+    f = sum(w for w, s in zip(ws, states) if s == 1); a = sum(w for w, s in zip(ws, states) if s == -1)
+    return f + a > 0 and f / (f + a) >= q - 1e-12
+
+def bloc_state_dist(n):
+    d = {1: 0.0, -1: 0.0, 0: 0.0}
+    for k, p in enumerate(binom(n)): d[wta_state(k, n)] += p
+    return d
+
+def indiv_power_wta(ws, q, sizes, b):
+    """P(one voter in bloc b changes the motion outcome), others independent fair coins."""
+    others = [j for j in range(len(ws)) if j != b]
+    dists = [bloc_state_dist(sizes[j]) for j in others]
+    tot = 0.0
+    for k, pk in enumerate(binom(sizes[b] - 1)):
+        sF, sA = wta_state(k + 1, sizes[b]), wta_state(k, sizes[b])
+        if sF == sA: continue
+        for combo in itertools.product([1, -1, 0], repeat=len(others)):
+            p = pk
+            for d, s in zip(dists, combo): p *= d[s]
+            if p == 0: continue
+            st = [0] * len(ws)
+            for j, s in zip(others, combo): st[j] = s
+            stF = st[:]; stF[b] = sF; stA = st[:]; stA[b] = sA
+            if outcome_wta(ws, stF, q) != outcome_wta(ws, stA, q): tot += p
+    return tot
+
+def indiv_power_prop(ws, q, sizes, b):
+    others = [j for j in range(len(ws)) if j != b]
+    W = sum(ws); tot = 0.0
+    dists = [binom(sizes[j]) for j in others]
+    for ks in itertools.product(*[range(sizes[j] + 1) for j in others]):
+        p = 1.0; base = 0.0
+        for j, k, d in zip(others, ks, dists): p *= d[k]; base += ws[j] * k / sizes[j]
+        for k, pk in enumerate(binom(sizes[b] - 1)):
+            vF = base + ws[b] * (k + 1) / sizes[b]; vA = base + ws[b] * k / sizes[b]
+            if (vF >= q * W - 1e-12) != (vA >= q * W - 1e-12): tot += p * pk
+    return tot
+
+if __name__ == "__main__":
+    print("## Unitary blocs: normalized Banzhaf / Shapley-Shubik, veto blocs")
+    print("| weights | q | Banzhaf M/Me/U/P | Shapley M/Me/U/P | veto blocs |")
+    print("|---|---|---|---|---|")
+    for name, ws in WEIGHTS.items():
+        for q in QS:
+            bz, _ = banzhaf(ws, q); ss = shapley(ws, q)
+            f = lambda v: "/".join(f"{x:.2f}" for x in v)
+            print(f"| {name} {ws} | {q} | {f(bz)} | {f(ss)} | {', '.join(veto(ws, q)) or 'none'} |")
+    print("\n## Individual power (P one voter flips the motion), sizes", dict(zip(BLOCS, SIZES)))
+    print("| weights | q | rule | Minds | Members | Users | Patrons | max/min |")
+    print("|---|---|---|---|---|---|---|---|")
+    for name, ws in WEIGHTS.items():
+        for q in QS:
+            for rule, fn in (("WTA", indiv_power_wta), ("prop", indiv_power_prop)):
+                v = [fn(ws, q, SIZES, b) for b in range(4)]
+                r = max(v) / min(v) if min(v) > 0 else float("inf")
+                print(f"| {name} | {q} | {rule} | " + " | ".join(f"{x:.4f}" for x in v) + f" | {r:.1f} |")
+    print("\n## Penrose square-root weights (WTA individual-power equalizer, independent voters)")
+    sq = [math.sqrt(n) for n in SIZES]; print("sqrt(n) shares:", [round(100 * s / sum(sq), 1) for s in sq])
+    neff = [8 / (1 + 7 * 0.44)] + SIZES[1:]
+    sq2 = [math.sqrt(n) for n in neff]; print("with Minds n_eff=8/(1+7*0.44)=%.2f:" % neff[0], [round(100 * s / sum(sq2), 1) for s in sq2])
+    pr = [100 * n / sum(SIZES) for n in SIZES]; print("headcount shares (prop equalizer):", [round(x, 1) for x in pr])
+    for ws, lab in ((sq, "sqrt"), (SIZES, "headcount")):
+        for q in (0.5,):
+            v = [indiv_power_wta(ws, q, SIZES, b) for b in range(4)]; u = [indiv_power_prop(ws, q, SIZES, b) for b in range(4)]
+            print(f"{lab} weights q={q}: WTA indiv", [round(x, 4) for x in v], " prop indiv", [round(x, 4) for x in u])

docs/research/2026-10-29-estate-tally-game-theory/sims/strat.out.md

@@ -0,0 +1,43 @@
+## S1. Profitable misreport/abstention on a single binary motion (sizes 3/3/2/2, exhaustive)
+| weights | q | quorum | rule | profiles x voters | profitable deviations | of which abstention |
+|---|---|---|---|---|---|---|
+| [25, 25, 25, 25] | 0.15 | 0.0 | prop | 10240 | 0 | 0 |
+| [25, 25, 25, 25] | 0.15 | 0.0 | wta | 10240 | 0 | 0 |
+| [25, 25, 25, 25] | 0.15 | 0.5 | prop | 10240 | 0 | 0 |
+| [25, 25, 25, 25] | 0.15 | 0.5 | wta | 10240 | 192 | 192 |
+| [25, 25, 25, 25] | 0.5 | 0.0 | prop | 10240 | 0 | 0 |
+| [25, 25, 25, 25] | 0.5 | 0.0 | wta | 10240 | 0 | 0 |
+| [25, 25, 25, 25] | 0.5 | 0.5 | prop | 10240 | 0 | 0 |
+| [25, 25, 25, 25] | 0.5 | 0.5 | wta | 10240 | 192 | 192 |
+| [25, 25, 25, 25] | 0.66 | 0.0 | prop | 10240 | 0 | 0 |
+| [25, 25, 25, 25] | 0.66 | 0.0 | wta | 10240 | 0 | 0 |
+| [25, 25, 25, 25] | 0.66 | 0.5 | prop | 10240 | 0 | 0 |
+| [25, 25, 25, 25] | 0.66 | 0.5 | wta | 10240 | 0 | 0 |
+| [40, 30, 20, 10] | 0.15 | 0.0 | prop | 10240 | 0 | 0 |
+| [40, 30, 20, 10] | 0.15 | 0.0 | wta | 10240 | 0 | 0 |
+| [40, 30, 20, 10] | 0.15 | 0.5 | prop | 10240 | 0 | 0 |
+| [40, 30, 20, 10] | 0.15 | 0.5 | wta | 10240 | 288 | 288 |
+| [40, 30, 20, 10] | 0.5 | 0.0 | prop | 10240 | 0 | 0 |
+| [40, 30, 20, 10] | 0.5 | 0.0 | wta | 10240 | 0 | 0 |
+| [40, 30, 20, 10] | 0.5 | 0.5 | prop | 10240 | 0 | 0 |
+| [40, 30, 20, 10] | 0.5 | 0.5 | wta | 10240 | 144 | 144 |
+| [40, 30, 20, 10] | 0.66 | 0.0 | prop | 10240 | 0 | 0 |
+| [40, 30, 20, 10] | 0.66 | 0.0 | wta | 10240 | 0 | 0 |
+| [40, 30, 20, 10] | 0.66 | 0.5 | prop | 10240 | 0 | 0 |
+| [40, 30, 20, 10] | 0.66 | 0.5 | wta | 10240 | 0 | 0 |
+
+## S2. Logrolling (greedy best mutually profitable pairwise trade, repeated, max 6 trades)
+
+### weights [25, 25, 25, 25], q=0.5, 6 motions, 1500 agendas; bloc utility u[b,m]~N(0,1) per motion passed
+| bloc type | delta | P(>=1 trade) | mean trades | mean welfare change (sum u) | P(welfare falls) | P(a non-trader loses) | P(a trader ends worse than sincere) |
+|---|---|---|---|---|---|---|---|
+| unitary | 1.0 | 0.615 | 1.04 | +0.168 | 0.245 | 0.397 | 0.234 |
+| proportional | 0.5 | 0.430 | 0.66 | -0.396 | 0.338 | 0.305 | 0.127 |
+| proportional | 0.2 | 0.127 | 0.17 | -0.027 | 0.071 | 0.093 | 0.017 |
+
+### weights [40, 30, 20, 10], q=0.5, 6 motions, 1500 agendas; bloc utility u[b,m]~N(0,1) per motion passed
+| bloc type | delta | P(>=1 trade) | mean trades | mean welfare change (sum u) | P(welfare falls) | P(a non-trader loses) | P(a trader ends worse than sincere) |
+|---|---|---|---|---|---|---|---|
+| unitary | 1.0 | 0.615 | 0.90 | +0.016 | 0.302 | 0.484 | 0.184 |
+| proportional | 0.5 | 0.324 | 0.44 | -0.306 | 0.230 | 0.261 | 0.076 |
+| proportional | 0.2 | 0.110 | 0.13 | -0.075 | 0.070 | 0.099 | 0.013 |

docs/research/2026-10-29-estate-tally-game-theory/sims/strat.py

@@ -0,0 +1,86 @@
+"""Strategic probes. Run: python -I strat.py
+S1 exhaustive: can any voter gain by misreporting or abstaining on one binary motion? (with and without a quorum)
+S2 logrolling among 4 blocs over a 6-motion agenda: unitary blocs (whole weight deliverable) vs
+   proportional blocs whose leadership can move only a fraction delta of the bloc's share.
+"""
+import itertools
+import numpy as np
+
+def tally(ws, blocs, ballots, q, rule, quorum=0.0):
+    """ballots: tuple of +1 For, -1 Against, 0 abstain, one per voter; blocs: bloc index per voter."""
+    F = [0] * len(ws); A = [0] * len(ws)
+    for b, v in zip(blocs, ballots):
+        if v == 1: F[b] += 1
+        elif v == -1: A[b] += 1
+    f = a = 0.0
+    for b, w in enumerate(ws):
+        if F[b] + A[b] == 0: continue
+        if rule == "prop": f += w * F[b] / (F[b] + A[b]); a += w * A[b] / (F[b] + A[b])
+        elif F[b] > A[b]: f += w
+        elif A[b] > F[b]: a += w
+    if f + a < quorum * sum(ws) - 1e-9 or f + a == 0: return False
+    return f >= q * (f + a) - 1e-9
+
+def s1():
+    blocs = [0, 0, 0, 1, 1, 1, 2, 2, 3, 3]
+    print("| weights | q | quorum | rule | profiles x voters | profitable deviations | of which abstention |")
+    print("|---|---|---|---|---|---|---|")
+    for ws in ([25, 25, 25, 25], [40, 30, 20, 10]):
+        for q in (0.15, 0.5, 0.66):
+            for quorum in (0.0, 0.5):
+                for rule in ("prop", "wta"):
+                    cache = {}
+                    def out(bal):
+                        if bal not in cache: cache[bal] = tally(ws, blocs, bal, q, rule, quorum)
+                        return cache[bal]
+                    gain = gab = n = 0
+                    for bal in itertools.product((1, -1), repeat=10):  # sincere profiles, no sincere abstainers
+                        o = out(bal)
+                        for i, v in enumerate(bal):
+                            n += 1; want = v == 1
+                            if o == want: continue
+                            for d in (-v, 0):
+                                b2 = bal[:i] + (d,) + bal[i + 1:]
+                                if out(b2) == want: gain += 1; gab += d == 0; break
+                    print(f"| {ws} | {q} | {quorum} | {rule} | {n} | {gain} | {gab} |")
+
+def s2(ws=(25, 25, 25, 25), q=0.5, M=6, T=1_500, seed=3):
+    rng = np.random.default_rng(seed); W = np.array(ws, float)
+    print(f"\n### weights {list(ws)}, q={q}, {M} motions, {T} agendas; bloc utility u[b,m]~N(0,1) per motion passed")
+    print("| bloc type | delta | P(>=1 trade) | mean trades | mean welfare change (sum u) | P(welfare falls) | P(a non-trader loses) | P(a trader ends worse than sincere) |")
+    print("|---|---|---|---|---|---|---|---|")
+    for kind, delta in (("unitary", 1.0), ("proportional", 0.5), ("proportional", 0.2)):
+        stats = np.zeros(6)
+        for t in range(T):
+            u = rng.standard_normal((4, M))
+            share0 = 1 / (1 + np.exp(-2 * u)) if kind == "proportional" else (u > 0).astype(float)
+            dev = np.zeros((4, M))  # signed share shift each bloc has committed to
+            def outcome(dv):
+                s = np.clip(share0 + dv, 0, 1); return (W @ s) >= q * W.sum() - 1e-9
+            def util(o): return u @ o
+            o_s = outcome(dev); U_s = util(o_s); cur = U_s.copy(); trades = 0; traders = set()
+            while True:
+                best = None
+                for A, B in itertools.permutations(range(4), 2):
+                    if A > B: continue
+                    for x in range(M):
+                        if dev[A, x] != 0: continue
+                        for y in range(M):
+                            if y == x or dev[B, y] != 0: continue
+                            d2 = dev.copy(); d2[A, x] = -np.sign(u[A, x]) * delta; d2[B, y] = -np.sign(u[B, y]) * delta
+                            Un = util(outcome(d2)); g = Un - cur
+                            if g[A] > 1e-9 and g[B] > 1e-9 and (best is None or g[A] + g[B] > best[0]):
+                                best = (g[A] + g[B], d2, Un, A, B)
+                if best is None or trades >= 6: break
+                _, dev, cur, A, B = best; trades += 1; traders |= {A, B}
+            dW = cur.sum() - U_s.sum(); non = [b for b in range(4) if b not in traders]
+            stats += [trades > 0, trades, dW, dW < -1e-9, any(cur[b] < U_s[b] - 1e-9 for b in non),
+                      any(cur[b] < U_s[b] - 1e-9 for b in traders)]
+        s = stats / T
+        print(f"| {kind} | {delta} | {s[0]:.3f} | {s[1]:.2f} | {s[2]:+.3f} | {s[3]:.3f} | {s[4]:.3f} | {s[5]:.3f} |")
+
+if __name__ == "__main__":
+    print("## S1. Profitable misreport/abstention on a single binary motion (sizes 3/3/2/2, exhaustive)")
+    s1()
+    print("\n## S2. Logrolling (greedy best mutually profitable pairwise trade, repeated, max 6 trades)")
+    s2(); s2(ws=(40, 30, 20, 10))

docs/research/2026-10-29-estate-tally-game-theory/sims/third.out.md

@@ -0,0 +1,146 @@
+## T1. Motion model (Minds ICC .44; 8/15/30/4): P(pass) and pairwise P(outcomes differ)
+| seed | q | P(pass) prop/wta/bpt | differ bpt-prop | differ bpt-wta | differ prop-wta |
+|---|---|---|---|---|---|
+| equal | 0.15 | 0.934/0.838/0.985 | 0.050 | 0.147 | 0.098 |
+| equal | 0.5 | 0.502/0.594/0.676 | 0.179 | 0.082 | 0.119 |
+| equal | 0.66 | 0.265/0.405/0.233 | 0.080 | 0.171 | 0.148 |
+| minds-heavy | 0.15 | 0.913/0.796/0.966 | 0.056 | 0.170 | 0.122 |
+| minds-heavy | 0.5 | 0.502/0.537/0.575 | 0.126 | 0.038 | 0.117 |
+| minds-heavy | 0.66 | 0.298/0.357/0.236 | 0.091 | 0.121 | 0.092 |
+| members-heavy | 0.15 | 0.932/0.838/0.985 | 0.053 | 0.147 | 0.100 |
+| members-heavy | 0.5 | 0.500/0.499/0.528 | 0.106 | 0.029 | 0.111 |
+| members-heavy | 0.66 | 0.271/0.343/0.194 | 0.099 | 0.149 | 0.113 |
+
+## T2. Single-voter pivot M/Me/U/P (same draws), equal seed
+| q | prop | wta | bpt |
+|---|---|---|---|
+| 0.15 | 0.0200/0.0118/0.0062/0.0425 | 0.0136/0.0136/0.0066/0.0402 | 0.0022/0.0041/0.0021/0.0173 |
+| 0.5 | 0.0502/0.0259/0.0135/0.1016 | 0.0201/0.0226/0.0114/0.0760 | 0.0184/0.0193/0.0096/0.0816 |
+| 0.66 | 0.0426/0.0227/0.0110/0.0873 | 0.0205/0.0225/0.0112/0.0755 | 0.0175/0.0182/0.0095/0.0676 |
+
+## T3. Single-Persona pivot vs Minds ICC (equal seed)
+| ICC | q=.15 prop/wta/bpt | q=.5 prop/wta/bpt | q=.66 prop/wta/bpt |
+|---|---|---|---|
+| 0 | 0.0198/0.0241/0.0057 | 0.0509/0.0397/0.0376 | 0.0443/0.0399/0.0361 |
+| 0.44 | 0.0202/0.0143/0.0024 | 0.0502/0.0211/0.0181 | 0.0422/0.0204/0.0172 |
+| 0.8 | 0.0206/0.0042/0.0008 | 0.0495/0.0065/0.0061 | 0.0403/0.0067/0.0061 |
+| 1 | 0.0211/0.0000/0.0000 | 0.0481/0.0000/0.0000 | 0.0400/0.0000/0.0000 |
+
+## T4. Users faction capture: population support .3, 9 random voters + k coordinated For
+P(Users bloc casts For), wta vs bpt; prop share in brackets
+| k | faction share of voters | wta | bpt q=.15 | bpt q=.5 | bpt q=.66 | prop share |
+|---|---|---|---|---|---|---|
+| 0 | 0.00 | 0.097 | 0.803 | 0.097 | 0.026 | 0.300 |
+| 1 | 0.10 | 0.099 | 0.960 | 0.271 | 0.025 | 0.370 |
+| 2 | 0.18 | 0.272 | 1.000 | 0.272 | 0.026 | 0.428 |
+| 3 | 0.25 | 0.269 | 1.000 | 0.536 | 0.097 | 0.475 |
+| 6 | 0.40 | 0.805 | 1.000 | 0.805 | 0.270 | 0.580 |
+| 9 | 0.50 | 0.960 | 1.000 | 1.000 | 0.541 | 0.650 |
+| 12 | 0.57 | 1.000 | 1.000 | 1.000 | 0.804 | 0.700 |
+| 18 | 0.67 | 1.000 | 1.000 | 1.000 | 1.000 | 0.766 |
+
+## T5. Logrolling (6 motions, 800 agendas, greedy mutually profitable pairwise trades, max 6)
+| seed | q | rule | P(>=1 trade) | mean trades | mean welfare change | P(non-trader loses) | P(trader ends worse) |
+|---|---|---|---|---|---|---|---|
+| equal | 0.15 | wta | 0.128 | 0.14 | +0.559 | 0.000 | 0.007 |
+| equal | 0.15 | bpt | 0.001 | 0.00 | +0.007 | 0.000 | 0.000 |
+| equal | 0.15 | prop delta .5 | 0.007 | 0.01 | +0.047 | 0.000 | 0.000 |
+| equal | 0.5 | wta | 0.589 | 0.99 | +0.143 | 0.376 | 0.231 |
+| equal | 0.5 | bpt | 0.589 | 0.99 | +0.143 | 0.376 | 0.231 |
+| equal | 0.5 | prop delta .5 | 0.451 | 0.72 | -0.432 | 0.316 | 0.146 |
+| equal | 0.66 | wta | 0.614 | 1.03 | +0.097 | 0.393 | 0.231 |
+| equal | 0.66 | bpt | 0.367 | 0.50 | +0.601 | 0.250 | 0.071 |
+| equal | 0.66 | prop delta .5 | 0.245 | 0.30 | +0.414 | 0.177 | 0.035 |
+| minds-heavy | 0.15 | wta | 0.249 | 0.27 | +0.730 | 0.130 | 0.013 |
+| minds-heavy | 0.15 | bpt | 0.014 | 0.01 | +0.064 | 0.004 | 0.000 |
+| minds-heavy | 0.15 | prop delta .5 | 0.010 | 0.01 | +0.064 | 0.000 | 0.000 |
+| minds-heavy | 0.5 | wta | 0.608 | 0.87 | -0.052 | 0.490 | 0.176 |
+| minds-heavy | 0.5 | bpt | 0.608 | 0.87 | -0.052 | 0.490 | 0.176 |
+| minds-heavy | 0.5 | prop delta .5 | 0.330 | 0.43 | -0.263 | 0.282 | 0.071 |
+| minds-heavy | 0.66 | wta | 0.463 | 0.61 | +0.166 | 0.375 | 0.095 |
+| minds-heavy | 0.66 | bpt | 0.362 | 0.42 | +0.392 | 0.289 | 0.031 |
+| minds-heavy | 0.66 | prop delta .5 | 0.282 | 0.35 | +0.374 | 0.206 | 0.043 |
+
+## T6. Lone Minds (she absent) by category: P(pass), motion model, ICC 0/.44/1
+| category | q | prop | wta | bpt |
+|---|---|---|---|---|
+| Bugs | 0.15 | 0.774/0.646/0.502 | 0.448/0.473/0.502 | 0.774/0.646/0.502 |
+| Cosmetics | 0.3 | 0.663/0.585/0.502 | 0.448/0.473/0.502 | 0.663/0.585/0.502 |
+| Balance | 0.4 | 0.556/0.528/0.502 | 0.448/0.473/0.502 | 0.556/0.528/0.502 |
+| Features/NewContent | 0.5 | 0.556/0.528/0.502 | 0.448/0.473/0.502 | 0.556/0.528/0.502 |
+| FundamentalDesign | 0.66 | 0.341/0.417/0.502 | 0.448/0.473/0.502 | 0.341/0.417/0.502 |
+
+## T7. Present case (Minds 8 coin-flip, her alone in Members, Users/Patrons empty): P(pass | she For / Against / home)
+| seed | q | prop | wta | bpt |
+|---|---|---|---|---|
+| equal | 0.15 | 1.000/0.855/0.965 | 1.000/0.363/0.363 | 1.000/0.965/0.965 |
+| equal | 0.5 | 1.000/0.004/0.637 | 1.000/0.363/0.363 | 1.000/0.637/0.637 |
+| equal | 0.66 | 0.855/0.000/0.145 | 0.637/0.000/0.363 | 0.145/0.000/0.145 |
+| minds-heavy | 0.15 | 1.000/0.855/0.965 | 1.000/0.363/0.363 | 1.000/0.965/0.965 |
+| minds-heavy | 0.5 | 0.996/0.035/0.637 | 0.637/0.363/0.363 | 0.637/0.637/0.637 |
+| minds-heavy | 0.66 | 0.637/0.000/0.145 | 0.637/0.000/0.363 | 0.145/0.000/0.145 |
+| members-heavy | 0.15 | 1.000/0.637/0.965 | 1.000/0.363/0.363 | 1.000/0.965/0.965 |
+| members-heavy | 0.5 | 1.000/0.000/0.637 | 1.000/0.000/0.363 | 1.000/0.000/0.637 |
+| members-heavy | 0.66 | 1.000/0.000/0.145 | 1.000/0.000/0.363 | 1.000/0.000/0.145 |
+
+## T8. Operator pivot over the whole tally (coin voters, Users 10, Patrons [50,500] log), S=.8
+| seed | q | n | curve | prop | wta | bpt |
+|---|---|---|---|---|---|---|
+| equal | 0.15 | 1 | alone | 0.012 | 0.199 | 0.000 |
+| equal | 0.15 | 5 | one-each | 0.001 | 0.075 | 0.000 |
+| equal | 0.15 | 5 | k=3 | 0.002 | 0.175 | 0.000 |
+| equal | 0.15 | 20 | one-each | 0.000 | 0.035 | 0.000 |
+| equal | 0.15 | 20 | k=3 | 0.000 | 0.136 | 0.000 |
+| equal | 0.15 | 20 | k=5 | 0.000 | 0.082 | 0.000 |
+| equal | 0.5 | 1 | alone | 0.723 | 0.429 | 0.300 |
+| equal | 0.5 | 5 | one-each | 0.154 | 0.162 | 0.113 |
+| equal | 0.5 | 5 | k=3 | 0.308 | 0.376 | 0.263 |
+| equal | 0.5 | 20 | one-each | 0.042 | 0.076 | 0.053 |
+| equal | 0.5 | 20 | k=3 | 0.159 | 0.293 | 0.206 |
+| equal | 0.5 | 20 | k=5 | 0.097 | 0.180 | 0.126 |
+| equal | 0.66 | 1 | alone | 0.373 | 0.433 | 0.086 |
+| equal | 0.66 | 5 | one-each | 0.075 | 0.162 | 0.021 |
+| equal | 0.66 | 5 | k=3 | 0.150 | 0.377 | 0.053 |
+| equal | 0.66 | 20 | one-each | 0.019 | 0.076 | 0.004 |
+| equal | 0.66 | 20 | k=3 | 0.074 | 0.294 | 0.021 |
+| equal | 0.66 | 20 | k=5 | 0.044 | 0.180 | 0.012 |
+| members-heavy | 0.15 | 1 | alone | 0.035 | 0.199 | 0.000 |
+| members-heavy | 0.15 | 5 | one-each | 0.002 | 0.075 | 0.000 |
+| members-heavy | 0.15 | 5 | k=3 | 0.003 | 0.175 | 0.000 |
+| members-heavy | 0.15 | 20 | one-each | 0.000 | 0.035 | 0.000 |
+| members-heavy | 0.15 | 20 | k=3 | 0.000 | 0.136 | 0.000 |
+| members-heavy | 0.15 | 20 | k=5 | 0.000 | 0.082 | 0.000 |
+| members-heavy | 0.5 | 1 | alone | 1.000 | 0.863 | 0.734 |
+| members-heavy | 0.5 | 5 | one-each | 0.294 | 0.325 | 0.276 |
+| members-heavy | 0.5 | 5 | k=3 | 0.612 | 0.753 | 0.641 |
+| members-heavy | 0.5 | 20 | one-each | 0.101 | 0.152 | 0.130 |
+| members-heavy | 0.5 | 20 | k=3 | 0.383 | 0.588 | 0.500 |
+| members-heavy | 0.5 | 20 | k=5 | 0.235 | 0.360 | 0.306 |
+| members-heavy | 0.66 | 1 | alone | 0.806 | 0.630 | 0.092 |
+| members-heavy | 0.66 | 5 | one-each | 0.128 | 0.237 | 0.023 |
+| members-heavy | 0.66 | 5 | k=3 | 0.237 | 0.549 | 0.058 |
+| members-heavy | 0.66 | 20 | one-each | 0.021 | 0.111 | 0.004 |
+| members-heavy | 0.66 | 20 | k=3 | 0.079 | 0.428 | 0.023 |
+| members-heavy | 0.66 | 20 | k=5 | 0.046 | 0.262 | 0.013 |
+
+## T9. Exhaustive profitable misreport/abstention/stay-home under bpt (renormalized, no quorum)
+| sizes | seed | q | profiles | profitable indiv deviations | estate stay-home profitable |
+|---|---|---|---|---|---|
+| 8/1/0/0 | equal | 0.15 | 512 | 0 | 0 |
+| 8/1/0/0 | equal | 0.5 | 512 | 0 | 0 |
+| 8/1/0/0 | equal | 0.66 | 512 | 0 | 0 |
+| 8/1/0/0 | minds-heavy | 0.15 | 512 | 0 | 0 |
+| 8/1/0/0 | minds-heavy | 0.5 | 512 | 0 | 0 |
+| 8/1/0/0 | minds-heavy | 0.66 | 512 | 0 | 0 |
+| 8/1/0/0 | members-heavy | 0.15 | 512 | 0 | 0 |
+| 8/1/0/0 | members-heavy | 0.5 | 512 | 0 | 0 |
+| 8/1/0/0 | members-heavy | 0.66 | 512 | 0 | 0 |
+| 3/3/2/2 | equal | 0.15 | 1024 | 0 | 0 |
+| 3/3/2/2 | equal | 0.5 | 1024 | 0 | 0 |
+| 3/3/2/2 | equal | 0.66 | 1024 | 0 | 0 |
+| 3/3/2/2 | minds-heavy | 0.15 | 1024 | 0 | 0 |
+| 3/3/2/2 | minds-heavy | 0.5 | 1024 | 0 | 0 |
+| 3/3/2/2 | minds-heavy | 0.66 | 1024 | 0 | 0 |
+| 3/3/2/2 | members-heavy | 0.15 | 1024 | 0 | 0 |
+| 3/3/2/2 | members-heavy | 0.5 | 1024 | 0 | 0 |
+| 3/3/2/2 | members-heavy | 0.66 | 1024 | 0 | 0 |

docs/research/2026-10-29-estate-tally-game-theory/sims/third.py

@@ -0,0 +1,153 @@
+"""Third rule `bpt` (bloc-parliament-at-threshold): a live bloc casts its whole weight For iff its internal
+weighted For share (abstain excluded) >= q, else Against. Council: For weight / live weight >= q (renormalized).
+Compared with prop and wta (wta: internal majority, tie casts nothing). Run: python -I third.py
+"""
+import itertools, math
+import numpy as np
+SEEDS = {"equal": [25, 25, 25, 25], "minds-heavy": [40, 30, 20, 10], "members-heavy": [20, 45, 20, 15]}
+QS = (0.15, 0.5, 0.66)
+
+def tally(Wb, F, Tot, q, rule):
+    Wb = np.array(Wb, float); live = Tot > 0; sh = np.divide(F, np.where(live, Tot, 1)); sh = np.where(live, sh, 0)
+    if rule == "prop": f = (sh * Wb).sum(-1); den = (live * Wb).sum(-1)
+    elif rule == "wta":
+        st = np.where(live, np.sign(2 * F - Tot), 0); f = (st == 1) @ Wb; den = f + (st == -1) @ Wb
+    else: f = ((sh >= q - 1e-9) & live) @ Wb; den = live @ Wb
+    return (den > 0) & (f >= q * den - 1e-9)
+
+def motion(T, sizes, minds_r, seed, coin=False, wvec=None):
+    r = np.random.default_rng(seed)
+    if coin: p = np.full((T, 4), .5)
+    else:
+        m = r.standard_normal(T); p = 1 / (1 + np.exp(-1.7 * (0.6 * m[:, None] + 0.8 * r.standard_normal((T, 4)))))
+    ws = wvec or [np.ones(n) for n in sizes]; F = np.zeros((T, 4)); Tot = np.zeros((T, 4)); V = []
+    for b, w in enumerate(ws):
+        if len(w) == 0: V.append(np.zeros((T, 0), bool)); continue
+        pb = p[:, b:b + 1]
+        if b == 0 and minds_r >= 1: pb = (r.random((T, 1)) < pb).astype(float)
+        elif b == 0 and minds_r > 0:
+            a = p[:, 0] * (1 - minds_r) / minds_r; c = (1 - p[:, 0]) * (1 - minds_r) / minds_r; pb = r.beta(a, c)[:, None]
+        v = r.random((T, len(w))) < pb; V.append(v); F[:, b] = v @ w; Tot[:, b] = w.sum()
+    return ws, V, F, Tot
+
+def piv(ws, V, F, Tot, b, Wb, q, rule):
+    G = F.copy(); G[:, b] += np.where(V[b][:, 0], -ws[b][0], ws[b][0])
+    return np.mean(tally(Wb, F, Tot, q, rule) != tally(Wb, G, Tot, q, rule))
+
+R = ("prop", "wta", "bpt")
+print("## T1. Motion model (Minds ICC .44; 8/15/30/4): P(pass) and pairwise P(outcomes differ)")
+print("| seed | q | P(pass) prop/wta/bpt | differ bpt-prop | differ bpt-wta | differ prop-wta |")
+print("|---|---|---|---|---|---|")
+ws, V, F, Tot = motion(200_000, (8, 15, 30, 4), .44, 1)
+for s, Wb in SEEDS.items():
+    for q in QS:
+        o = {r: tally(Wb, F, Tot, q, r) for r in R}
+        print(f"| {s} | {q} | " + "/".join(f"{o[r].mean():.3f}" for r in R) +
+              f" | {np.mean(o['bpt'] != o['prop']):.3f} | {np.mean(o['bpt'] != o['wta']):.3f} | {np.mean(o['prop'] != o['wta']):.3f} |")
+
+print("\n## T2. Single-voter pivot M/Me/U/P (same draws), equal seed")
+print("| q | prop | wta | bpt |"); print("|---|---|---|---|")
+for q in QS:
+    print(f"| {q} | " + " | ".join("/".join(f"{piv(ws, V, F, Tot, b, SEEDS['equal'], q, r):.4f}" for b in range(4)) for r in R) + " |")
+
+print("\n## T3. Single-Persona pivot vs Minds ICC (equal seed)")
+print("| ICC | q=.15 prop/wta/bpt | q=.5 prop/wta/bpt | q=.66 prop/wta/bpt |"); print("|---|---|---|---|")
+for icc in (0, .44, .8, 1):
+    w2, V2, F2, T2 = motion(100_000, (8, 15, 30, 4), icc, 2)
+    print(f"| {icc} | " + " | ".join("/".join(f"{piv(w2, V2, F2, T2, 0, SEEDS['equal'], q, r):.4f}" for r in R) for q in QS) + " |")
+
+print("\n## T4. Users faction capture: population support .3, 9 random voters + k coordinated For")
+print("P(Users bloc casts For), wta vs bpt; prop share in brackets")
+print("| k | faction share of voters | wta | bpt q=.15 | bpt q=.5 | bpt q=.66 | prop share |"); print("|---|---|---|---|---|---|---|")
+rr = np.random.default_rng(4)
+for k in (0, 1, 2, 3, 6, 9, 12, 18):
+    f = (rr.random((100_000, 9)) < .3).sum(1) + k; n = 9 + k; sh = f / n
+    print(f"| {k} | {k / n:.2f} | {np.mean(2 * f > n):.3f} | " + " | ".join(f"{np.mean(sh >= q - 1e-9):.3f}" for q in QS) + f" | {sh.mean():.3f} |")
+
+print("\n## T5. Logrolling (6 motions, 800 agendas, greedy mutually profitable pairwise trades, max 6)")
+print("| seed | q | rule | P(>=1 trade) | mean trades | mean welfare change | P(non-trader loses) | P(trader ends worse) |")
+print("|---|---|---|---|---|---|---|---|")
+def logroll(Wb, q, kind, T=800, M=6, seed=3):
+    rng = np.random.default_rng(seed); W = np.array(Wb, float); st = np.zeros(5)
+    for _ in range(T):
+        u = rng.standard_normal((4, M)); share = 1 / (1 + np.exp(-2 * u))
+        base = {"wta": (u > 0).astype(float), "bpt": (share >= q).astype(float), "prop": share}[kind]
+        cast = base.copy()
+        def out(c): return (W @ c) >= q * W.sum() - 1e-9
+        U0 = u @ out(cast); cur = U0.copy(); used = set(); n = 0; traders = set()
+        while n < 6:
+            best = None
+            for A, B in itertools.combinations(range(4), 2):
+                for x, y in itertools.permutations(range(M), 2):
+                    if (A, x) in used or (B, y) in used: continue
+                    c2 = cast.copy()
+                    for b, mm in ((A, x), (B, y)):
+                        c2[b, mm] = (0.0 if u[b, mm] > 0 else 1.0) if kind != "prop" else np.clip(base[b, mm] - np.sign(u[b, mm]) * .5, 0, 1)
+                    g = u @ out(c2) - cur
+                    if g[A] > 1e-9 and g[B] > 1e-9 and (best is None or g[A] + g[B] > best[0]): best = (g[A] + g[B], c2, A, B, x, y)
+            if best is None: break
+            _, cast, A, B, x, y = best; used |= {(A, x), (B, y)}; traders |= {A, B}; n += 1; cur = u @ out(cast)
+        non = [b for b in range(4) if b not in traders]
+        st += [n > 0, n, cur.sum() - U0.sum(), any(cur[b] < U0[b] - 1e-9 for b in non), any(cur[b] < U0[b] - 1e-9 for b in traders)]
+    return st / T
+for s in ("equal", "minds-heavy"):
+    for q in (0.15, 0.5, 0.66):
+        for kind in ("wta", "bpt", "prop"):
+            v = logroll(SEEDS[s], q, kind)
+            print(f"| {s} | {q} | {kind if kind != 'prop' else 'prop delta .5'} | {v[0]:.3f} | {v[1]:.2f} | {v[2]:+.3f} | {v[3]:.3f} | {v[4]:.3f} |")
+
+print("\n## T6. Lone Minds (she absent) by category: P(pass), motion model, ICC 0/.44/1")
+print("| category | q | prop | wta | bpt |"); print("|---|---|---|---|---|")
+lone = {icc: motion(200_000, (8, 0, 0, 0), icc, 5) for icc in (0, .44, 1)}
+for c, q in {"Bugs": .15, "Cosmetics": .30, "Balance": .40, "Features/NewContent": .50, "FundamentalDesign": .66}.items():
+    print(f"| {c} | {q} | " + " | ".join("/".join(f"{tally(SEEDS['equal'], lone[i][2], lone[i][3], q, r).mean():.3f}" for i in (0, .44, 1)) for r in R) + " |")
+
+print("\n## T7. Present case (Minds 8 coin-flip, her alone in Members, Users/Patrons empty): P(pass | she For / Against / home)")
+print("| seed | q | prop | wta | bpt |"); print("|---|---|---|---|---|")
+from math import comb
+for s, Wb in SEEDS.items():
+    for q in QS:
+        cells = []
+        for r in R:
+            vals = []
+            for hv in (1, -1, 0):
+                F_ = np.array([[k, 1.0 if hv == 1 else 0, 0, 0] for k in range(9)]); T_ = np.array([[8, 1.0 if hv else 0, 0, 0]] * 9)
+                pk = np.array([comb(8, k) / 256 for k in range(9)]); vals.append(float(pk @ tally(Wb, F_, T_, q, r)))
+            cells.append("/".join(f"{x:.3f}" for x in vals))
+        print(f"| {s} | {q} | " + " | ".join(cells) + " |")
+
+print("\n## T8. Operator pivot over the whole tally (coin voters, Users 10, Patrons [50,500] log), S=.8")
+def mweights(n, S, k):
+    if n == 1: return np.ones(1)
+    tail = np.array([i ** (-1 / 1.16) for i in range(1, n)]); tail = tail / tail.sum() * (1 - S)
+    c = np.concatenate([[S], tail]); return np.ones(n) if k is None else c ** (1 / k)
+print("| seed | q | n | curve | prop | wta | bpt |"); print("|---|---|---|---|---|---|---|")
+for s in ("equal", "members-heavy"):
+    for q in QS:
+        for n, kn, k in ((1, "alone", None), (5, "one-each", None), (5, "k=3", 3), (20, "one-each", None), (20, "k=3", 3), (20, "k=5", 5)):
+            wv = [np.ones(8), mweights(n, .8, k), np.ones(10), np.log1p(np.array([50, 500.0]))]
+            w8, V8, F8, T8 = motion(100_000, None, 0, 6, coin=True, wvec=wv)
+            print(f"| {s} | {q} | {n} | {kn} | " + " | ".join(f"{piv(w8, V8, F8, T8, 1, SEEDS[s], q, r):.3f}" for r in R) + " |")
+
+print("\n## T9. Exhaustive profitable misreport/abstention/stay-home under bpt (renormalized, no quorum)")
+def tl(ws_, sizes, bal, q):
+    F = [0] * 4; A = [0] * 4; i = 0
+    for b, n in enumerate(sizes):
+        for v in bal[i:i + n]: F[b] += v == 1; A[b] += v == -1
+        i += n
+    live = [b for b in range(4) if F[b] + A[b]]; f = sum(ws_[b] for b in live if F[b] / (F[b] + A[b]) >= q - 1e-9)
+    den = sum(ws_[b] for b in live); return den > 0 and f >= q * den - 1e-9
+print("| sizes | seed | q | profiles | profitable indiv deviations | estate stay-home profitable |"); print("|---|---|---|---|---|---|")
+for sizes in ((8, 1, 0, 0), (3, 3, 2, 2)):
+    for s, Wb in SEEDS.items():
+        for q in QS:
+            st = [sum(sizes[:b]) for b in range(4)]; ind = est = n = 0
+            for bal in itertools.product((1, -1), repeat=sum(sizes)):
+                n += 1; o = tl(Wb, sizes, bal, q)
+                for i, v in enumerate(bal):
+                    if o != (v == 1) and any(tl(Wb, sizes, bal[:i] + (d,) + bal[i + 1:], q) == (v == 1) for d in (-v, 0)): ind += 1
+                for b in range(4):
+                    if not sizes[b]: continue
+                    seg = bal[st[b]:st[b] + sizes[b]]; pref = seg.count(1) / len(seg) >= q  # bloc's own position under bpt
+                    if o != pref and tl(Wb, sizes, bal[:st[b]] + (0,) * sizes[b] + bal[st[b] + sizes[b]:], q) == pref: est += 1
+            print(f"| {'/'.join(map(str, sizes))} | {s} | {q} | {n} | {ind} | {est} |")

docs/research/2026-10-29-estate-tally-game-theory/sims/weights.out.md

@@ -0,0 +1,76 @@
+## W1. Effective voters (Kish = inverse Herfindahl) and top share
+| bloc | curve | operator S | Kish n_eff | top voter share | internal Banzhaf of top (WTA bloc) |
+|---|---|---|---|---|---|
+| Members (15) | one-each | 0.5 | 15.00 | 0.067 | 0.209 |
+| Members (15) | k=1 | 0.5 | 3.55 | 0.500 | 1.000 |
+| Members (15) | k=2 | 0.5 | 10.13 | 0.222 | 0.672 |
+| Members (15) | k=3 | 0.5 | 12.85 | 0.154 | 0.481 |
+| Members (15) | k=5 | 0.5 | 14.30 | 0.112 | 0.333 |
+| Members (15) | one-each | 0.8 | 15.00 | 0.067 | 0.209 |
+| Members (15) | k=1 | 0.8 | 1.55 | 0.800 | 1.000 |
+| Members (15) | k=2 | 0.8 | 6.05 | 0.364 | 0.958 |
+| Members (15) | k=3 | 0.8 | 10.44 | 0.225 | 0.700 |
+| Members (15) | k=5 | 0.8 | 13.54 | 0.143 | 0.470 |
+| Patrons (4) | one-each | - | 4.00 | 0.250 | 0.750 |
+| Patrons (4) | k=1 | - | 1.10 | 0.951 | 1.000 |
+| Patrons (4) | log(1+d) | - | 3.33 | 0.423 | 0.750 |
+| Patrons (4) | k=3 | - | 2.40 | 0.594 | 1.000 |
+| Patrons (4) | k=5 | - | 3.22 | 0.452 | 0.750 |
+| Patrons (4) | k=10 | - | 3.78 | 0.346 | 0.750 |
+
+## W2. Operator's power over the whole tally (two-tier Banzhaf, all voters fair coins, 200k draws)
+Comparators: a one-each Member; a Mind (8); a User (30); top Patron under log(1+d).
+| bloc weights | q | Members curve | S | op pivot prop | op pivot WTA | one-each Member prop/WTA | Mind prop/WTA | User prop/WTA |
+|---|---|---|---|---|---|---|---|---|
+| equal | 0.5 | one-each (baseline) | - | 0.0688 | 0.0887 | - | 0.1335/0.1066 | 0.0341/0.0588 |
+| equal | 0.5 | k=1 | 0.5 | 0.5037 | 0.4220 | - | 0.1117/0.1067 | 0.0294/0.0591 |
+| equal | 0.5 | k=2 | 0.5 | 0.2321 | 0.2855 | - | 0.1286/0.1064 | 0.0338/0.0588 |
+| equal | 0.5 | k=3 | 0.5 | 0.1611 | 0.2046 | - | 0.1301/0.1066 | 0.0348/0.0586 |
+| equal | 0.5 | k=5 | 0.5 | 0.1175 | 0.1412 | - | 0.1312/0.1065 | 0.0345/0.0588 |
+| equal | 0.5 | k=1 | 0.8 | 0.7458 | 0.4220 | - | 0.0791/0.1067 | 0.0217/0.0591 |
+| equal | 0.5 | k=2 | 0.8 | 0.3764 | 0.4044 | - | 0.1214/0.1067 | 0.0323/0.0591 |
+| equal | 0.5 | k=3 | 0.8 | 0.2353 | 0.2966 | - | 0.1288/0.1064 | 0.0343/0.0588 |
+| equal | 0.5 | k=5 | 0.8 | 0.1492 | 0.1998 | - | 0.1309/0.1065 | 0.0349/0.0587 |
+| equal | 0.66 | one-each (baseline) | - | 0.0167 | 0.0885 | - | 0.0305/0.1084 | 0.0083/0.0595 |
+| equal | 0.66 | k=1 | 0.5 | 0.1367 | 0.4227 | - | 0.0425/0.1083 | 0.0118/0.0591 |
+| equal | 0.66 | k=2 | 0.5 | 0.0563 | 0.2849 | - | 0.0325/0.1087 | 0.0089/0.0590 |
+| equal | 0.66 | k=3 | 0.5 | 0.0391 | 0.2041 | - | 0.0315/0.1089 | 0.0086/0.0596 |
+| equal | 0.66 | k=5 | 0.5 | 0.0281 | 0.1402 | - | 0.0310/0.1087 | 0.0081/0.0598 |
+| equal | 0.66 | k=1 | 0.8 | 0.2524 | 0.4227 | - | 0.0573/0.1083 | 0.0150/0.0591 |
+| equal | 0.66 | k=2 | 0.8 | 0.0940 | 0.4051 | - | 0.0368/0.1083 | 0.0101/0.0592 |
+| equal | 0.66 | k=3 | 0.8 | 0.0566 | 0.2959 | - | 0.0324/0.1088 | 0.0090/0.0591 |
+| equal | 0.66 | k=5 | 0.8 | 0.0358 | 0.1994 | - | 0.0313/0.1088 | 0.0083/0.0597 |
+| members-heavy | 0.5 | one-each (baseline) | - | 0.1462 | 0.1769 | - | 0.1208/0.0588 | 0.0317/0.0256 |
+| members-heavy | 0.5 | k=1 | 0.5 | 0.8932 | 0.8447 | - | 0.0399/0.0585 | 0.0108/0.0257 |
+| members-heavy | 0.5 | k=2 | 0.5 | 0.4826 | 0.5700 | - | 0.1052/0.0585 | 0.0276/0.0256 |
+| members-heavy | 0.5 | k=3 | 0.5 | 0.3413 | 0.4083 | - | 0.1153/0.0587 | 0.0314/0.0257 |
+| members-heavy | 0.5 | k=5 | 0.5 | 0.2489 | 0.2814 | - | 0.1196/0.0586 | 0.0312/0.0257 |
+| members-heavy | 0.5 | k=1 | 0.8 | 0.9990 | 0.8447 | - | 0.0009/0.0584 | 0.0003/0.0256 |
+| members-heavy | 0.5 | k=2 | 0.8 | 0.7504 | 0.8096 | - | 0.0734/0.0583 | 0.0198/0.0257 |
+| members-heavy | 0.5 | k=3 | 0.8 | 0.4956 | 0.5928 | - | 0.1058/0.0584 | 0.0284/0.0257 |
+| members-heavy | 0.5 | k=5 | 0.8 | 0.3181 | 0.3986 | - | 0.1178/0.0586 | 0.0312/0.0256 |
+| members-heavy | 0.66 | one-each (baseline) | - | 0.0218 | 0.1263 | - | 0.0176/0.0688 | 0.0047/0.0366 |
+| members-heavy | 0.66 | k=1 | 0.5 | 0.2538 | 0.6046 | - | 0.0570/0.0688 | 0.0151/0.0364 |
+| members-heavy | 0.66 | k=2 | 0.5 | 0.0727 | 0.4074 | - | 0.0248/0.0691 | 0.0066/0.0365 |
+| members-heavy | 0.66 | k=3 | 0.5 | 0.0487 | 0.2919 | - | 0.0198/0.0692 | 0.0056/0.0365 |
+| members-heavy | 0.66 | k=5 | 0.5 | 0.0347 | 0.2011 | - | 0.0181/0.0688 | 0.0052/0.0366 |
+| members-heavy | 0.66 | k=1 | 0.8 | 0.6287 | 0.6046 | - | 0.0785/0.0688 | 0.0205/0.0364 |
+| members-heavy | 0.66 | k=2 | 0.8 | 0.1359 | 0.5793 | - | 0.0392/0.0688 | 0.0104/0.0364 |
+| members-heavy | 0.66 | k=3 | 0.8 | 0.0708 | 0.4232 | - | 0.0243/0.0691 | 0.0065/0.0365 |
+| members-heavy | 0.66 | k=5 | 0.8 | 0.0439 | 0.2851 | - | 0.0190/0.0692 | 0.0055/0.0366 |
+
+## W3. Exponent sensitivity under the motion model (Minds ICC .44, equal bloc weights, q=0.5, S=0.5)
+P(motion outcome differs) between Members curve k and k=3 baseline, Patron curve log(1+d); and Patron curve vs log(1+d) with Members k=3.
+| varied | curve | P(differ) prop | P(differ) WTA | operator pivot prop | operator pivot WTA |
+|---|---|---|---|---|---|
+| Members | one-each | 0.014 | 0.014 | 0.0254 | 0.0217 |
+| Members | k=1 | 0.051 | 0.061 | 0.2080 | 0.2962 |
+| Members | k=2 | 0.010 | 0.012 | 0.0889 | 0.0856 |
+| Members | k=3 | 0.000 | 0.000 | 0.0609 | 0.0545 |
+| Members | k=5 | 0.007 | 0.008 | 0.0436 | 0.0361 |
+| Patrons | one-each | 0.027 | 0.032 | - | - |
+| Patrons | k=1 | 0.080 | 0.033 | - | - |
+| Patrons | log(1+d) | 0.000 | 0.000 | - | - |
+| Patrons | k=3 | 0.026 | 0.033 | - | - |
+| Patrons | k=5 | 0.006 | 0.000 | - | - |
+| Patrons | k=10 | 0.013 | 0.000 | - | - |

docs/research/2026-10-29-estate-tally-game-theory/sims/weights.py

@@ -0,0 +1,99 @@
+"""Within-bloc vote-power curves (operator addition 2026-10-29).
+Members: w = contribution^(1/k). Patrons: w = log(1+d) or d^(1/k). Minds, Users: one each.
+Assumptions (stated, not data): 15 Members; operator (member 0) holds share S of all contribution
+(S=0.5 or 0.8); the other 14 follow a Pareto(alpha=1.16, "80/20") quantile ladder c_i = i^(-1/1.16).
+4 Patrons with donations [10, 50, 200, 5000]. Run: python -I weights.py
+"""
+import itertools, math
+import numpy as np
+rng = np.random.default_rng(29)
+
+def members(S):
+    tail = np.array([i ** (-1 / 1.16) for i in range(1, 15)]); tail /= tail.sum()
+    return np.concatenate([[S / (1 - S)], tail])  # operator / tail-sum = S/(1-S)
+
+PATRON_D = np.array([10, 50, 200, 5000.0])
+CURVES_M = {"one-each": lambda c: np.ones_like(c), "k=1": lambda c: c, "k=2": np.sqrt,
+            "k=3": lambda c: c ** (1 / 3), "k=5": lambda c: c ** 0.2}
+CURVES_P = {"one-each": lambda d: np.ones_like(d), "k=1": lambda d: d, "log(1+d)": np.log1p,
+            "k=3": lambda d: d ** (1 / 3), "k=5": lambda d: d ** 0.2, "k=10": lambda d: d ** 0.1}
+
+def kish(w): return w.sum() ** 2 / (w ** 2).sum()
+
+def internal_banzhaf(w, i=0):
+    """P(voter i decides the weighted bloc majority), others fair coins; tie casts nothing (counts as change)."""
+    others = np.delete(w, i); n = len(others); tot = 0
+    for bits in itertools.product([0, 1], repeat=n):
+        f = np.dot(bits, others); a = others.sum() - f
+        sF = np.sign(f + w[i] - a); sA = np.sign(f - a - w[i])
+        tot += sF != sA
+    return tot / 2 ** n
+
+def tally(Wb, F, Tot, q, rule):
+    """F, Tot: (T,4) weighted For and cast weight per bloc."""
+    Wb = np.array(Wb, float)
+    if rule == "prop":
+        return (F / Tot) @ Wb >= q * Wb.sum() - 1e-9
+    st = np.sign(2 * F - Tot); f = (st == 1) @ Wb; a = (st == -1) @ Wb
+    return (f + a > 0) & (f >= q * (f + a) - 1e-9)
+
+def sim(wM, wP, Wb=(25, 25, 25, 25), q=0.5, T=200_000, model="coin", minds_r=0.44, seed=1):
+    r = np.random.default_rng(seed)
+    if model == "coin": p = np.full((T, 4), .5)
+    else:
+        m = r.standard_normal(T); p = 1 / (1 + np.exp(-1.7 * (0.6 * m[:, None] + 0.8 * r.standard_normal((T, 4)))))
+    ws = [np.ones(8), wM, np.ones(30), wP]; F = np.zeros((T, 4)); Tot = np.zeros((T, 4)); V = []
+    for b, w in enumerate(ws):
+        pb = p[:, b:b + 1]
+        if b == 0 and model != "coin" and minds_r > 0:
+            a = p[:, 0] * (1 - minds_r) / minds_r; c = (1 - p[:, 0]) * (1 - minds_r) / minds_r
+            pb = r.beta(a, c)[:, None]
+        v = r.random((T, len(w))) < pb; V.append(v)
+        F[:, b] = v @ w; Tot[:, b] = w.sum()
+    return ws, V, F, Tot
+
+def pivot(ws, V, F, Tot, b, i, Wb, q, rule):
+    G = F.copy(); G[:, b] += np.where(V[b][:, i], -ws[b][i], ws[b][i])
+    return np.mean(tally(Wb, F, Tot, q, rule) != tally(Wb, G, Tot, q, rule))
+
+if __name__ == "__main__":
+    print("## W1. Effective voters (Kish = inverse Herfindahl) and top share")
+    print("| bloc | curve | operator S | Kish n_eff | top voter share | internal Banzhaf of top (WTA bloc) |")
+    print("|---|---|---|---|---|---|")
+    for S in (0.5, 0.8):
+        for name, fn in CURVES_M.items():
+            w = fn(members(S)); print(f"| Members (15) | {name} | {S} | {kish(w):.2f} | {w[0] / w.sum():.3f} | {internal_banzhaf(w):.3f} |")
+    for name, fn in CURVES_P.items():
+        w = fn(PATRON_D); print(f"| Patrons (4) | {name} | - | {kish(w):.2f} | {w.max() / w.sum():.3f} | {internal_banzhaf(w, int(np.argmax(w))):.3f} |")
+
+    print("\n## W2. Operator's power over the whole tally (two-tier Banzhaf, all voters fair coins, 200k draws)")
+    print("Comparators: a one-each Member; a Mind (8); a User (30); top Patron under log(1+d).")
+    print("| bloc weights | q | Members curve | S | op pivot prop | op pivot WTA | one-each Member prop/WTA | Mind prop/WTA | User prop/WTA |")
+    print("|---|---|---|---|---|---|---|---|---|")
+    wP = np.log1p(PATRON_D)
+    for Wb, lab in (((25, 25, 25, 25), "equal"), ((20, 45, 20, 15), "members-heavy")):
+        for q in (0.5, 0.66):
+            for S in (0.5, 0.8):
+                for name in ("one-each", "k=1", "k=2", "k=3", "k=5"):
+                    if name == "one-each" and S == 0.8: continue
+                    wM = CURVES_M[name](members(S)); ws, V, F, Tot = sim(wM, wP, Wb, q)
+                    pr = [pivot(ws, V, F, Tot, b, i, Wb, q, "prop") for b, i in ((1, 0), (0, 0), (2, 0))]
+                    pw = [pivot(ws, V, F, Tot, b, i, Wb, q, "wta") for b, i in ((1, 0), (0, 0), (2, 0))]
+                    base = "" if name != "one-each" else " (baseline)"
+                    print(f"| {lab} | {q} | {name}{base} | {S if name != 'one-each' else '-'} | {pr[0]:.4f} | {pw[0]:.4f} | - | {pr[1]:.4f}/{pw[1]:.4f} | {pr[2]:.4f}/{pw[2]:.4f} |")
+
+    print("\n## W3. Exponent sensitivity under the motion model (Minds ICC .44, equal bloc weights, q=0.5, S=0.5)")
+    print("P(motion outcome differs) between Members curve k and k=3 baseline, Patron curve log(1+d); and Patron curve vs log(1+d) with Members k=3.")
+    print("| varied | curve | P(differ) prop | P(differ) WTA | operator pivot prop | operator pivot WTA |")
+    print("|---|---|---|---|---|---|")
+    Wb = (25, 25, 25, 25); q = .5
+    def outcomes(wM, wP):
+        ws, V, F, Tot = sim(wM, wP, Wb, q, T=200_000, model="motion", seed=7)
+        return ws, V, F, Tot, tally(Wb, F, Tot, q, "prop"), tally(Wb, F, Tot, q, "wta")
+    *_, bp, bw = outcomes(CURVES_M["k=3"](members(.5)), wP)
+    for name in ("one-each", "k=1", "k=2", "k=3", "k=5"):
+        ws, V, F, Tot, op, ow = outcomes(CURVES_M[name](members(.5)), wP)
+        print(f"| Members | {name} | {np.mean(op != bp):.3f} | {np.mean(ow != bw):.3f} | {pivot(ws, V, F, Tot, 1, 0, Wb, q, 'prop'):.4f} | {pivot(ws, V, F, Tot, 1, 0, Wb, q, 'wta'):.4f} |")
+    for name in ("one-each", "k=1", "log(1+d)", "k=3", "k=5", "k=10"):
+        ws, V, F, Tot, op, ow = outcomes(CURVES_M["k=3"](members(.5)), CURVES_P[name](PATRON_D))
+        print(f"| Patrons | {name} | {np.mean(op != bp):.3f} | {np.mean(ow != bw):.3f} | - | - |")

docs/research/2026-10-29-swarm-governance-prior-art.md

@@ -0,0 +1,119 @@
+# Swarm governance on Bifrost: readiness and prior art (2026-10-29)
+
+Serves follow-up `eureka-body:follow_up:swarm-governance-on-bifrost` and ruling `eureka-body:ruling:self-run-result-to-classifier` (classifier tuning by swarm vote). Two Eyes passes, facts only. Part 1 reads Bifrost at 7b63031; part 2 is prior art from the web, with confidence tags.
+
+## Part 1: Bifrost governance readiness
+
+Motions (Postgres/EF, Razor + Eve surface): Domain/BifrostModels.cs:665-721 (Motion, Vote), enums :86-115; Features/Motions/MotionGovernanceService.cs (create :13, vote :47, close :95-131); MotionCategoryPolicy.cs thresholds Bugs .15, Cosmetics .30, Balance .40, Features .50, NewContent .50, FundamentalDesign .66.
+Pass rule: For weight / (For+Against weight) >= ApprovalThreshold; Abstain excluded; no quorum field or code anywhere (grep "quorum" empty). Close is manual by creator or CanModerateMotions (:105); ResolveStatusLabel also derives Passed/Failed display after ClosesAtUtc.
+Weight: Membership.EffectiveVotingWeight = 0 unless Status Active, else max(1, sum current TierSnapshot weights) (BifrostModels.cs:357-361). TierSnapshotKind Patron|Contributor.
+Membership: MembershipStatus Authenticated|PendingApproval|Active|Suspended; MemberRole StandardMember|Producer|Maintainer|LedgerReviewer|PlatformAdmin (RoleAssignment); flags IsPlatformAdmin, CanManageProjects, CanManageLedger, CanModerateMotions. Activation: bootstrap admin, admin approval (Pages/App/Members), Heimdall member claim. Native registration POST /auth/bifrost/register is anonymous, yields Authenticated only. /App is ActiveMember-gated (Program.cs:57).
+Personas: no Persona account/voter class. BridgeActorKind Member|Agent|Persona|Service exists for bridge actions only (BifrostModels.cs:178). A Persona can only vote if it holds a UserAccount with Active membership (nothing in code makes one). Persona identity names are "reserved in Bifrost's identity namespace" per gamecult-ops/docs/gamecult-chat-target.md:84,179: Persona Matrix user "Registered by the mouth when Bifrost governance approves the Persona" -- documented; no code for that approval found.
+Typed-document exposure: motions/votes are Postgres rows, not CultCache docs. GET /eve/governance/surface (Program.cs:513, ActiveMember-gated) returns Eve JSON surface (Eve is deprecated per F:\Projects\CLAUDE.md). MotionEveSurfaceService names cultmesh://asgard.starfire.bifrost/commands/motion and motion.create/vote/close commands; no handler for that route found in code (grep). verse-service-contract.md:60,185-196 documents schema gamecult.bifrost.governance and the command route; schema ids for motion/vote listed as todo (:256).
+Governance topics/comments: tools/governance-threads.mjs, CultCache file .bifrost/governance-threads.cc, types bifrost.governance.topic / topic-comment; statuses open->consensus_ready->approved->dispatched->closed; support/objection are comment stances, not votes; the web app never reads it (docs/concept-mill-votes-target.md facts 1-5). Eyes pass 2026-10-10 found no such store on Yggdrasil. Web keeps only GovernanceActivityReceipt rows.
+Concept Mill votes (the one different vote system): ConceptVoteModels.cs, Features/ConceptVotes/*, Pages/Mill/Vote; VoterClass Anonymous|Account|Member; public tally export /public/concepts with CORS (ConceptTallyExport.cs). Per-subject appraisals, not motions; deployed in 67072b2 lineage.
+Chat integration: persona-matrix-mouth.mjs (Persona Matrix speech, main 7b63031), OIDC issuer + back-channel logout on membership leave (main 1894f65); persona feedback ingress/delivery as signed CultCache docs (docs/bridge.md:195-217). No motion/vote surface in chat found. Discord/Reddit voting prompts documented as future (full-implementation-strategy.md:78-79).
+UI: Razor /App/Motions (Pages/App/Motions/Index.cshtml[.cs]), /App/Members; no tally history page beyond list.
+Docs: docs/verse-service-contract.md, full-implementation-strategy.md (Phase 3 governance and revenue share), bridge.md, agent-transport.md, concept-mill-votes-target.md, jurisdiction-map.md.
+Ruling read: eureka-body:ruling:self-run-result-to-classifier (InForce, Operator, 2026-10-29): "tuning authority belongs to a swarm decision process, pending that process existing."
+Not read: Bifrost tests, jurisdiction-map.md, live DB contents (motion count unknown), campaign rulings beyond the one above.
+
+## Part 2: Prior art
+
+## 1. Quorum and close timing
+
+Apache (https://www.apache.org/foundation/voting.html) [P]
+- Votes should generally run at least 72 hours so all time zones can take part.
+- Lazy consensus = silence gives assent; not usable for code changes under review-then-commit unless declared at vote start.
+- Types: procedural = simple majority (more +1 than -1); code modification = consensus approval (3 +1, no -1) unless lazy consensus declared; release = majority approval (3 binding +1, more +1 than -1).
+- Veto only on code modifications: a -1 needs technical justification, else invalid; it blocks until withdrawn. Releases cannot be vetoed.
+- Binding votes: PMC members; others advisory. Only explicit votes count.
+- Page does not define "lazy majority" or "2/3 majority" (those terms are in other ASF docs, not checked).
+
+IETF rough consensus, RFC 7282 (https://www.rfc-editor.org/rfc/rfc7282.html) [P]
+- Explicitly not voting; the chair judges whether every technical objection was considered and answered; call is appealable.
+- Named failure modes: capitulation (objector gives up unanswered), horse-trading, vote stuffing (recruiting voices to swamp objections), polls treated as decisions, ignored objections.
+
+Loomio (https://www.loomio.com/docs/en/user_manual/polls/vote_share_requirements, https://help.loomio.com/en/user_manual/polls/quorum) [P/S]
+- Quorum is optional, a percentage of eligible voters; set per poll or per poll template.
+- Vote-share requirements are separate: threshold measured against eligible voters or votes cast; weighted voting uses weight instead of headcount; a Block option with "no more than 0%" lets one block vote prevent passage.
+- Docs example: 5 eligible, 75% agreement of eligible plus 60% quorum; 2 agreeing votes (40% of eligible) fail.
+- Closing: deadline can be extended or proposal closed early; no built-in minimum open period found; group-written rules vary (one group: >=50% of reps participate, open two weeks) (https://www.loomio.com/d/tmaQYcM5/proposed-changes-to-the-loomio-voting-process-for-e-nable-proposals) [S].
+
+Debian constitution (https://www.debian.org/devel/constitution) [P]
+- GR: discussion period min 2 weeks, max 3 (App. A.1.1); voting period 2 weeks, Leader may vary by 1 week (4.2.3); quorum 3Q where Q = half sqrt(number of Developers); casting vote for Leader; default option "None of the above" (4.2.4); ranked ballot, Condorcet/Schwartz-set counting (App. A.5).
+- Sponsorship needed to propose a GR: K = min(Q, 5) (4.2.1, 4.2.7). 2K sponsors can put a Leader/Delegate decision on hold (4.2.2).
+- Supermajorities: 3:1 for constitutional amendments and foundation documents (4.1.2, 4.1.5.3); 2:1 to override a Technical Committee decision (4.1.4).
+
+Robert's Rules small boards [S]
+- Default quorum is a majority of the membership unless bylaws say otherwise (https://www.dummies.com/article/business-careers-money/business/general-business/roberts-rules-for-defining-a-quorum-189712, https://mtas.tennessee.edu/system/files/mrln/mknowledge/main/Quorum_Hodge_2018_public_legop.pdf).
+- "Small board" relaxed procedure applies to bodies of about 12 or fewer (https://www.wv-wmd.org/polity/smallboards.html). The search did not confirm any finer threshold.
+
+Decidim (https://docs.decidim.org/en/develop/admin/components/proposals) [S]
+- Proposals component settings include per-participant vote cap, minimum votes per user (below it votes do not count), acceptance threshold per proposal, and an option to keep collecting votes after threshold. Version-dependent. Decidim's closing/quorum semantics for formal decisions were not found.
+
+Low-turnout evidence (DAOs, large N, not small groups):
+- Average DAO participation 6.3% (review, source study unnamed) and ~17% of voting tokens delegated, clustered on popular delegates, across 18 Ethereum DAOs (https://www.frontiersin.org/journals/blockchain/articles/10.3389/fbloc.2025.1598283/epub, https://arxiv.org/pdf/2510.05830) [S].
+- Feichtinger, Fritsch, Vonlanthen, Wattenhofer, "The Hidden Shortcomings of (D)AOs", 21 DAOs: high voting-right concentration (https://arxiv.org/pdf/2302.12125v2.pdf) [S].
+- Compound Proposal 289 (July 2024) passed 682,191 to 633,636 with <7% of COMP supply; an earlier proposal 279 failed with 88% against; reported as an alleged governance attack, resolved by a negotiated cancellation (https://thedefiant.io/news/defi/compound-governance-attack-reveals-inherent-vulnerabilities-of-daos, https://www.theblock.co/post/307943/24-million-compound-finance-proposal-passed-by-whale-over-dao-objections, https://coindesk.com/business/2024/07/30/comp-token-rises-as-whale-backs-down-on-supposed-governance-attack-on-compound) [S].
+- No source located that specifically studies stalled/quorum-busting motions in groups of ~10-20. Not found, not proven absent.
+
+## 2. Vote weighting; mixed human/AI voting
+
+One-member-one-vote vs weighted:
+- Beanstalk (Apr 2022): flash-loaned voting power passed BIP-18/19 and drained ~$76M actually stolen (headline $182M); causes cited: no flash-loan-resistant vote measurement, no execution delay (https://www.bleepingcomputer.com/news/security/beanstalk-defi-platform-loses-182-million-in-flash-loan-attack/, https://rekt.news/beanstalk-rekt, https://www.merklescience.com/blog/hack-track-analysis-of-beanstalk-flash-loan-attack) [S].
+- OpenZeppelin Governor: voting power read from a past snapshot (ERC20Votes checkpoints), voting delay lets members exit before the snapshot matters; quorum as a fraction of supply at snapshot, only For+Abstain count (https://docs.openzeppelin.com/contracts/5.x/governance) [P].
+
+Quadratic voting:
+- Lalley and Weyl, "Quadratic Voting: How Mechanism Design Can Radicalize Democracy" (https://papers.ssrn.com; also https://bfi.uchicago.edu/wp-content/uploads/2016-14-1.pdf); Posner and Weyl 2017 survey (https://www.Gwern.net/doc/economics/mechanism-design/quadratic-voting/2017-posner.pdf) [S].
+- Weyl argues collusion/fraud is deterred except at very large scale (https://www.microsoft.com/en-us/research/?p=893088) [S]; Rivest's note argues QV is inherently susceptible to collusion [S].
+- Sybil/wallet splitting defeats the quadratic cost without proof of personhood (https://www.spark.money/glossary/quadratic-voting) [S].
+- "Concave is the New Linear: The Impossibility of Anti-Plutocratic DAO Governance" (https://arxiv.org/pdf/2605.18990) [A, 2026]: title states an impossibility claim; body not read.
+
+AI agents in governance (2025-2026):
+- DAO-AI, arXiv 2510.21117 (https://arxiv.org/html/2510.21117v2) [A]: multi-agent analysis of proposals/forum/voting; reports interpretable, auditable signals; agentic AI as decision-maker study.
+- QOC DAO, arXiv 2511.08641 (https://arxiv.org/html/2511.08641v1) [A]: roadmap human-only -> agents simulate stakeholders with humans holding final authority -> AI-driven DAO.
+- "Who Controls the Collective AI Vote? Real-World Evidence and Adversarial Testing of Multi-Agent Delegation in DAO Governance" (https://neurips.cc/virtual/2026/165281) [A]: several visible agents may share one actor controlling instructions, evidence, software, signing or reversal; combines analytical model, public-record audit of three deployed systems, tests of three voting rules, open-model replay; reports separating untrusted proposal text from governing instructions cut targeted vote changes in one fixed model; controller separation reduced common-input attacks but not direct compromise of one agent; layered safeguards lowered all four channels.
+- Blockful ENS AI Delegate experiment: agents on own servers vote from bias prompt + DAO constitution + proposal (https://blockful.notion.site/AI-Delegate-8296ff74623a4078b1ab7e7536adfabf) [S].
+- Arbitrum RFC on "Agentic Governance Pivot": community asked for how agents work and a public vote-history dashboard (https://forum.arbitrum.foundation/t/rfc-proposal-to-adjust-the-voting-power-of-the-arbitrum-community-pool-ratifying-the-agentic-governance-pivot/29280/11) [S].
+- Epistemic delegation paper mentions a possible block of AI "Condorcet agents" as imagination-stage (https://arxiv.org/pdf/2505.04136) [S].
+- Trustless Autonomy, arXiv 2505.09757: interview study, governance dilemma of unreliable agents (https://www.arxiv.org/pdf/2505.09757) [S].
+- No study found of small mixed human/AI-agent boards voting on operational settings of their own system.
+
+## 3. Sybil and correlated voters
+
+- Kohli, "Nine Judges, Two Effective Votes: Correlated Errors Undermine LLM Evaluation Panels", arXiv 2605.29800 (https://arxiv.org/abs/2605.29800; Apple ML research page https://machinelearning.apple.com/research/correlated-llm-evaluation-panels) [P abstract]: 9 frontier LLMs from 7 families on three NLI datasets carry ~2 independent votes (Kish n_eff); panel accuracy 8-22 points below independent-voting expectation; best single judge matches or beats panel; aggregation methods close at most 11% of the gap; holds across prompts, temperature, CoT, a pairwise-preference task. Abstract does not split same-family vs cross-family; narrow task domain; preprint, review status unverified.
+- STRIVE, arXiv 2608.04567 (https://arxiv.org/pdf/2608.04567) [S]: failing-group jury 33% vs best member 47%; some items missed by every configuration.
+- Theory: Condorcet jury theorem assumes independent voters; Austen-Smith and Banks (1996) showed independence is necessary for the aggregation benefit (cited in Kohli) [S]. Explainer: https://towardsdatascience.com/your-six-ai-models-are-really-two-the-math-of-correlated-mistakes/ [S].
+- Controller concentration across visible agents: the NeurIPS "Who Controls..." abstract above [A].
+- IETF names vote stuffing as a failure mode of voting-style consensus (RFC 7282, above).
+- Compound 289: delegated voting power concentrated in one delegate authored successive proposals (sources in section 1) [S].
+- Not found: any study of one operator running several personas on the same base model as voters specifically (closest: Kohli, NeurIPS abstract).
+
+## 4. Delegated or tiered authority
+
+Apache (voting.html above) [P]: PMC binding; non-PMC advisory; decision type determines threshold; code vetoes need technical justification.
+
+Rust:
+- RFC 1068 governance (https://github.com/rust-lang/rfcs/blob/master/text/1068-rust-governance.md) [P via summary]: subteams own RFCs in their area (shepherd, accept/reject, policy on what needs an RFC); core team sets direction, creates/shuts subteams; consensus is the norm; for minor disputes shepherd or leader decides; deep disagreement: leader decides after consulting core team; final comment period one week in that RFC text; new technical arguments raised in FCP trigger another comment period; each subteam sets its own rules for when an RFC is required.
+- Compiler FCP page (https://forge.rust-lang.org/compiler/proposals-and-stabilization.html) [P]: FCP needs team sign-off, then a ten-day wait; outstanding concerns block completion (`@rustbot concern` / `resolve`), countdown restarts when concerns resolve; FCP can be skipped for easily reversed MCPs. The page did not describe the disposition (merge/close/postpone) or majority-of-team checkbox mechanism; those were not verified.
+
+Debian (constitution above) [P]:
+- Individual developers decide their own work (3); Leader delegates (5.1.1, 8); delegation irrevocable once a specific decision is made (5.1.1); Leader cannot override a Delegate's made decision (8.2); GR can override Leader/Delegate (4.1.3) and TC (2:1, 4.1.4); TC decides last-resort, overrule Developer by 3:1 (6.1.4, 6.3.5); Secretary runs votes and interprets (7.1).
+
+Kubernetes KEP (https://www.k8s.dev/resources/keps/5241/, https://kubernetes.io/blog/2020/08/21/moving-forward-from-beta/) [S]: owning-SIG approvers move a KEP provisional -> implementable; significant later changes need every approver; graduation criteria are written into the KEP; stages alpha (off by default), beta (usually on, can be disabled), GA (always on).
+
+Loomio: block option as per-option veto (above).
+
+## 5. Binding a decision to a parameter change
+
+- Compound Governor (https://docs.compound.finance/v2/governance/, https://wiki.tally.xyz/docs/compound-governor) [S]: passed proposal queued in a Timelock, executable after 2 days; voting delay and period are themselves parameters changeable through governance; a Pause Guardian can act without a vote; Olympus's Bravo deployment adds a veto guardian who may veto any time before execution (https://docs.olympusdao.finance/main/contracts/docs/src/external/governance/GovernorBravoDelegate.sol/contract.GovernorBravoDelegate) [S].
+- OpenZeppelin Governor + TimelockController [P]: delay "allows users to exit the system if they disagree with a decision before it is executed"; roles proposer (the Governor only), executor (may be anyone), canceller, admin (to be renounced after setup); extra proposers/cancellers flagged as a risk of bypassing or blocking governance; optional proposal threshold limits who can propose. Guardian extension lets a guardian cancel at any stage (https://docs.openzeppelin.com/contracts/api/governance) [S].
+- Beanstalk had no execution delay (section 2 sources) [S].
+- MakerDAO Governance Security Module delay and executive-vs-poll split: fetch redirected to https://developers.skyeco.com/ and was not read; not verified here.
+- Compound 290 plan: team multisig deploying a new Governor to strip a delegate's power (reported intent, later cancelled) (sources in section 1) [S].
+- Kubernetes: parameters change via feature gates whose default flips at KEP graduation stages, decided by SIG approvers, not vote (section 4) [S].
+- Feature-flag change-control (LaunchDarkly approvals, etc.): not searched.
+
+## Not covered or unverified
+- Maker GSM, ASF "lazy majority"/2:3 definitions, Rust FCP disposition and majority-checkbox rule, Decidim formal-decision close semantics, feature-flag approval workflows, full text of every [A] paper, same-family LLM correlation numbers, anything on stalled-motion rates in small boards.

docs/research/anonymous-vote-stuffing-prior-art.md

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+# Anonymous vote stuffing: prior art
+
+Serves the fork: concept-mill-votes Cut 4, anti-stuffing defence; campaign concept-mill-votes; 2026-10-10.
+Subject text: "Anti-stuffing defence" in `F:\Projects\Bifrost\docs\concept-mill-votes-target.md` (lines ~106-130).
+Gathered by Eyes. Facts with pointers; no recommendation. Items marked (secondary) were not read at the primary source. Search-engine summaries were not verified against the pages unless stated.
+
+Gaps: (a) a query for residential-proxy and CAPTCHA-farm pricing was refused by the search tool, so no measured cost of a headless/proxy farm is here; (b) StrawPoll's own duplicate-check docs were not found; (c) Friendly Captcha's own licence/docs pages were not read; (d) ALTCHA's server-verification and PoW doc pages returned 404/empty; (e) national ePrivacy guidance beyond CNIL and ICO was not searched.
+
+## 1. Anonymous and low-friction voting in established systems
+
+- Poll software generally: duplicate checks are IP locking, cookie, or sign-in. Vendor docs say IP checks block shared networks (offices, schools), cookie checks are beaten by clearing cookies or switching browsers, and sign-in is strongest but still needs multi-account safeguards. Kentico: https://docs.kentico.com/k8/securing-websites/designing-secure-websites/securing-and-protecting-the-system/preventing-duplicate-poll-voting-and-content-rating . Academic restatement ("IP locking, cookie-based methods"): https://www.scitepress.org/PublishedPapers/2004/14026/14026.pdf (2004). WordPress poll-plugin thread reporting repeat votes despite "cookie and ip" logging: https://wordpress.org/support/?p=1278907
+- StrawPoll: its own option documentation was not found; the design doc's StrawPoll statement is not confirmed by this pass.
+- Reddit: "vote fuzzing" described by staff only via press (Daily Dot, https://dailydot.com/news/reddit-vote-count-percent-like/ , undated): displayed totals altered as an anti-spam measure. Mechanics (offsetting detected bot votes, paired fake votes) come from user/moderator posts only; no official algorithm page found (secondary).
+- Hacker News: a "voting ring detector" demotes rather than kills (dang, 2014, https://news.ycombinator.com/item?id=7542985 ; community list https://github.com/minimaxir/hacker-news-undocumented ). Moderators have publicly rolled back a ring penalty as a false positive (https://hn.svelte.dev/item/47457689 ). Internals unpublished.
+- Stack Exchange: help page "serial voting reversed" (https://stackoverflowteams.com/help/serial-voting-reversed): one user voting on many of another user's posts in a short window is judged invalid and removed; some removal by a daily automated process, some by staff after investigation. Thresholds not public. The page says a "voting corrected" event does not imply wrongdoing.
+- Product Hunt: staff reply in https://www.producthunt.com/p/producthunt/vote-selling-on-product-hunt says they will not reveal vote weights or all signals; a zero-point rule for voters with no history was under consideration. Weighting by account age/activity is asserted only by third-party guides (secondary).
+- Academic, Sybil resistance:
+  - Douceur, "The Sybil Attack" (IPTPS 2002): absent a logically centralized authority, Sybil attacks can always be mounted barring unrealistic resource parity. https://courses.csail.mit.edu/6.895/fall02/papers/Douceur/iptps02-douceur.pdf . Identifying nodes by hash of IP address (CFS) is noted as implicitly relying on an authority.
+  - SybilGuard/SybilLimit (Yu, Gibbons, Kaminsky, Xiao, 2008): bound accepted Sybil nodes using social-network structure (fast mixing). https://www.comp.nus.edu.sg/~yuhf/sybillimit-tr.pdf
+  - SumUp (Tran, Min, Li, Subramanian, NSDI 2009): content-vote aggregation capping adversary votes at the number of attack edges in a trust graph, plus feedback-based reduction of misbehaving voters; applied to a Digg vote trace, found strong evidence of attack on many "popular" articles. https://static.usenix.org/events/nsdi09/tech/full_papers/tran/tran.pdf
+  - All three need a social/trust graph or authority; none targets graph-less anonymous visitors.
+
+## 2. Proof-of-work challenges
+
+| Project | Licence | Self-host | .NET | Pointers |
+|---|---|---|---|---|
+| ALTCHA | MIT (widget README) | Yes | Official server list: TS, Dart, PHP, Go, Python, Java, Ruby, Elixir, Rust, C++ (no C#). Community: Ixnas.AltchaNet (0.4.x; SHA-256; replay store interface; bundled in-memory store "for testing only") and unofficial Altcha.Net 1.2.0 (replay store interface; in-memory not advised multi-server) | https://raw.githubusercontent.com/altcha-org/altcha/main/README.md ; https://www.nuget.org/packages/Altcha.Net ; https://www.nuget.org/packages/Ixnas.AltchaNet (via search, not opened) |
+| mCaptcha | AGPL-3.0 | Yes, Docker Compose; separate Rust service | None found | https://github.com/mCaptcha/mCaptcha ; README: "active development", no releases listed, SHA-256 PoW, difficulty scales with load (about 2 s under attack), proof configs expire after 30 s and are single-use, cookie-free, IP-independent |
+| Cap | Apache-2.0 | Yes, Docker/workers | None stated | https://github.com/tiagozip/cap ; README claims "gpu-resistant" PoW plus instrumentation challenges; no algorithm parameters; size claims are marketing |
+| Friendly Captcha | Third-party listings: front end MPL-2.0 (unconfirmed); back end hosted commercial, a "lite" self-host server mentioned (unconfirmed) | Hosted service | Not checked | https://friendlycaptcha.com/insights/open-source-captcha/ ; https://openalternative.co/friendly-captcha (secondary) |
+| Anubis | MIT, Go | Yes, reverse-proxy sidecar | n/a | https://github.com/TecharoHQ/anubis ; aimed at scrapers; README calls itself "a bit of a nuclear response" and notes it can block good bots |
+
+- ALTCHA widget: PBKDF2/SHA variants bundled; Argon2id and Scrypt (memory-bound, "harder to accelerate on ASICs or GPUs") are separate imports; `minDuration` default 500 ms; `timeout` default 90 s; `humanInteractionSignature` on by default (mechanism not documented in the README). Ixnas.AltchaNet defaults: complexity 50000-100000, expiry 120 s (search summary).
+- Argued or measured attacker cost:
+  - Laurie and Clayton, "Proof-of-Work Proves Not to Work" (WEIS 2004): difficulty high enough to stop spam would stop significant numbers of legitimate senders, since attackers use hijacked machines and run continuously. https://www.cl.cam.ac.uk/~rnc1/proofwork2.pdf . Rebuttal, Liu and Camp, "Proof of Work can Work" (2006): works if work is weighted by a reputation function. https://sites.cs.ucsb.edu/~rich/class/cs293b-cloud/papers/lui-pow.pdf
+  - Anubis: its author acknowledges PoW works best against crawlers that cannot run JavaScript; an operator with a solver keeps the authorization cookie and continues (LWN, https://lwn.net/Articles/1028558 ). A July 2026 CLI client (anubis-fetch) automates the challenge (secondary: https://runtimewire.com/article/anubis-bypass-proof-of-work-bot-wall-limits ).
+  - No numbers (seconds per solve on commodity vs GPU hardware, attacker cost per 1000 votes) found for ALTCHA, mCaptcha or Cap.
+- Reuse shape: mCaptcha tokens are single-use and short-lived; Anubis issues a cookie that covers later requests.
+
+## 3. ASP.NET Core rate limiting and forwarded headers
+
+Docs read: https://learn.microsoft.com/en-us/aspnet/core/performance/rate-limit (ms.date 2026-09-03; covers 7.0-12.0) and https://learn.microsoft.com/en-us/aspnet/core/host-and-deploy/proxy-load-balancer (ms.date 2026-04-23).
+
+- Rate limiter: `AddRateLimiter`, `GlobalLimiter` or named policies, `PartitionedRateLimiter.Create<HttpContext,string>`, `RateLimitPartition.GetFixedWindowLimiter` etc. The doc's "By IP address" sample keys on `Connection.RemoteIpAddress?.ToString() ?? "unknown"`. The page contains no IPv6 prefix guidance.
+- Doc warnings: partitioning on user-controlled input can exhaust memory (each distinct key creates and caches a limiter); "if you create partitions by using client IP addresses, your app becomes vulnerable to Denial of Service attacks that use IP Source Address Spoofing" (cites BCP 38).
+- `UseRateLimiter` must come after `UseRouting` when endpoint-specific policies/attributes are used; global-only may precede it.
+- Time-based limiters do not refund a permit already taken when a later chained limiter rejects.
+- `OnRejected`/`RejectionStatusCode` are needed for 429; the doc shows setting Retry-After manually or from lease metadata.
+- Forwarded headers:
+  - Middleware "should run before other middleware" (before `UseHsts`; may follow diagnostics/error handling). Anything reading `RemoteIpAddress`, including the rate limiter, must come after it to see the forwarded address.
+  - Default `KnownNetworks` is a single loopback entry (`IPNetwork(IPAddress.Loopback, 8)`), and `KnownProxies` likewise loopback-only. Forwarded values are accepted only if the immediate peer matches one of the lists.
+  - Default `ForwardLimit` is 1: only the rightmost `X-Forwarded-For` entry is processed (right to left). Null is advised only with known proxies/networks configured.
+  - Doc: "Only allow trusted proxies and networks to forward headers. Otherwise, IP spoofing attacks are possible."
+  - Dual-mode sockets: IPv4 entries must be given in IPv4-mapped IPv6 form; check `RemoteIpAddress` to see which applies.
+  - `ASPNETCORE_FORWARDEDHEADERS_ENABLED=true` uses cloud-style settings and "doesn't enable features such as the KnownProxies option".
+  - Unverified: whether newer .NET renames `KnownNetworks`; the page read lists `KnownNetworks` with `IPNetwork`.
+- IPv6 prefix practice (practitioner sources only; no standard or vendor guidance found):
+  - RFC 8981 privacy extensions rotate the interface id inside one /64 (preferred lifetime 1 day, valid 2 days, up to 3 concurrent). https://www.rfc-editor.org/rfc/rfc8981.html
+  - A residential customer can obtain /56 or /48 via DHCPv6-PD, so per-/64 buckets can be spread across by one household. v6ops https://psg.com/lists/v6ops/v6ops.2010/msg00152.html ; NANOG https://mailman.nanog.org/pipermail/nanog/2015-October/079735.html
+  - One ISP policy quoted: /56 broadband, /48 business, /64 mobile; aggregating too high can block tens of thousands of mobile users. Suggested escalating aggregation /64 to /48 to /40 to /36 to /32 on observed abuse. Nextcloud thread weighing /56 default: https://help.nextcloud.com/t/is-bruteforce-protection-ipv6-ready/215084
+  - No source found for a /24 IPv4 partition choice.
+
+## 4. Device/cookie identifiers
+
+- Data Protection (https://learn.microsoft.com/en-us/aspnet/core/security/data-protection/configuration/default-settings ; `.../configuration/overview`):
+  - Default key storage: Azure Apps `%HOME%`, else user profile (`%LOCALAPPDATA%`, DPAPI on Windows), else IIS registry; "If none of these conditions match, keys aren't persisted outside of the current process. When the process shuts down, all generated keys are lost."
+  - Docker: persist keys to a volume or external store. `SetApplicationName` must match across deployments (default discriminator is content-root path).
+  - Default key lifetime 90 days with auto-roll; retired keys still decrypt while kept. "Deleting a key makes its protected data permanently inaccessible"; docs recommend not deleting.
+  - A custom key repository disables automatic encryption of keys at rest.
+  - Payload algorithms: AES-256-CBC + HMACSHA256 (encrypted and authenticated, not only signed).
+- SameSite: Chrome treats cookies without a SameSite attribute as Lax from v80 (https://web.dev/articles/samesite-cookies-explained ). Chrome kept third-party cookies; Privacy Sandbox APIs retired Oct 2025 (secondary: https://engadget.com/cybersecurity/google-has-killed-privacy-sandbox-130029899.html ). Safari blocks third-party cookies by default, Firefox blocks known trackers (secondary, 2019). A same-origin vote page is first-party throughout.
+- Safari ITP: 7-day cap applies to cookies written via `document.cookie`; WebKit's Wilander stated Secure HttpOnly server-set cookies are not affected (https://simoahava.com/privacy/first-party-cookies-webkit-revisited/ ; WebKit bugs 237350, 237474). Sources disagree on later script-cookie handling; none found capping server-set cookies.
+- Private/incognito windows discard the cookie jar on close (browser behaviour; no primary source fetched).
+- Regulators:
+  - ICO, "What are the exceptions" (https://ico.org.uk/for-organisations/direct-marketing-and-privacy-and-electronic-communications/guidance-on-the-use-of-storage-and-access-technologies/what-are-the-exceptions/ ): PECR examples include "ensuring the security of terminal equipment" and "preventing or detecting fraud"; necessity is assessed "from the point of view of the subscriber or user, not your own"; a second purpose voids the exception; advertising never qualifies, including click-fraud detection.
+  - CNIL cookies FAQ (https://www.cnil.fr/fr/cookies-et-autres-traceurs/regles/cookies/FAQ), Q16: fraud-prevention trackers are in general not exempt, but may be in particular cases such as securing a user authentication mechanism. Q17 (CAPTCHA): no consent if the sole purpose is securing the site or an authentication mechanism for the user's benefit; consent if data is reused for the provider's own ends (reCAPTCHA named) or purposes unspecified; where consent is required, refusal bypasses the protection.
+  - EDPB Guidelines 2/2023 on Art. 5(3) ePrivacy (v2.0, 7 Oct 2024): applies to any storage/access on terminal equipment, technology-neutral, including identifiers other than cookies; lists "tracking based on IP only" as a use case. https://www.edpb.europa.eu/documents/guideline/guidelines-22023-on-technical-scope-of-art-53-of-eprivacy-directive_en . Its exemption text on identifiers was not read.
+  - GDPR status of an HMAC'd network tag stored per row was not searched.
+
+## 5. Known failure modes per layer
+
+- Device token: cleared cookies, private windows and fresh profiles reset it (poll vendors, Kentico); a scripted client omits or discards it. Unpersisted Data Protection keys invalidate every issued token on each restart; deleted keys invalidate tokens signed with them.
+- IP/prefix limits:
+  - Shared NAT: poll vendors report schools and offices tripping IP checks. CGN measurement: Livadariu et al. infer 4.1K ASes deploy CGN (2014-2016 data); Mandalari et al. found CGN in 10% of 60+ tested ISPs; Richter et al. https://arxiv.org/abs/1605.05606 ; CAIDA https://www-old.caida.org/publications/papers/2018/inferring_carrier_grade_nat/ . Blocklists and address reuse: https://steel.isi.edu/members/sivaram/papers/blocklisting_impact.pdf . No CGN false-positive rate for voting found.
+  - Mobile IPv6: carriers commonly assign a /64 per device (forum, secondary); whether a named carrier changes the prefix per session was not found. RFC 8981 rotates addresses within the /64.
+  - Delegated prefixes larger than /64 span many buckets (v6ops/NANOG above).
+  - Header trust: forged `X-Forwarded-For` is accepted only when the immediate peer is in KnownProxies/Networks; without `UseForwardedHeaders`, `RemoteIpAddress` is the proxy for every client (one bucket). IP-keyed partitions carry the doc's DoS/memory warning.
+- Audit-and-purge: HN and Stack Exchange both reverse or demote by pattern and both document false positives (above); neither publishes thresholds.
+- PoW: Laurie/Clayton and Anubis (above): attackers with solvers or botnets pay CPU; legitimate low-end devices pay too; a reusable cookie spreads one solve over many requests. .NET libraries require a replay store; in-memory stores are test-only/single-instance. Headless-farm cost: not gathered.
+- Third-party challenge: CNIL Q17 names reCAPTCHA as requiring consent where the provider reuses data.
+
+## Where the current design's assumptions are contradicted by evidence
+
+1. The design lists proof-of-work as slowing scripts yet barely touching determined attackers; the cited literature agrees, but the design also says ALTCHA "needs no third party" and is "ALTCHA-style library served from Bifrost": ALTCHA has no official C# server library, only community packages that need a custom replay store for production.
+2. Data Protection default key persistence is process-lifetime unless a profile/registry/volume exists; default key lifetime is 90 days, not one year. The one-year device cookie depends on retired keys being kept and `DataProtection__KeysPath` set (the doc's fact 22 flags the path; the doc does not state the key-loss consequence for tokens).
+3. The design's /64 partition for IPv6 is described by practitioner sources as bypassable by one household holding a /56 or /48 and by privacy-extension rotation inside a /64; the opposite risk (aggregating above /64 on mobile) is documented as collateral damage. No evidence was found for the /24 IPv4 choice.
+4. The design treats the device cookie as needing no consent notice; ICO and CNIL exempt security cookies only where security is the sole purpose and from the user's side, CNIL calls fraud-prevention trackers generally non-exempt (exception: securing an authentication mechanism), and ICO says users should still be informed. A vote-integrity cookie is not an authentication mechanism and was not addressed by either text found.
+5. The design says large sites "rely on after-the-fact detection ... then discount or purge": confirmed for HN, Stack Exchange and (secondary) Reddit, but those systems also publish no thresholds, keep false-positive reversals, and Reddit/Product Hunt add vote fuzzing or voter-history weighting, which the design does not include.

docs/research/customer-onboarding-body-facts.md

@@ -0,0 +1,105 @@
+# Customer onboarding: body facts at 2026-10-30
+
+Served: the same forks. Eyes pass over Bifrost origin/main, Heimdall, StreamPixels state/map.yaml, gamecult-ops inventory and the eureka mind. Facts only.
+
+# Eyes: customer onboarding, what the body can do today (2026-10-30)
+
+Read via `git show origin/main:` after `git fetch` in each repo. Bifrost origin/main = cc76f0f; Heimdall = 5146c72; StreamPixels = 9a113d3; gamecult-ops = c03e03c. Facts only. Not read: Bifrost tests, live DB contents, jurisdiction-map.md, bifrost-mvp-plan.md body, Heimdall implementation (src/app.ts), StreamPixels docs/joystick-integration-map.md, Yggdrasil live state (no ssh).
+
+## 0. The trigger (mind)
+- `eureka-body:ruling:customers-get-voting-power-onboarding-owed` (Operator, 2026-10-30, InForce). Quote: "Funny coincidence, then, that our first customer, and likely the largest for a while, is a fox themed vtuber, with 1,500€ of work contracted, and therefore voting power. We need a workflow to onboard customers on our platform since we're giving them voting power". Ruling text: "Prior-art and body passes come first; estate placement, weighting and related-party handling are forks for the operator." `precedents: []`.
+
+## 1. Bifrost (F:\Projects\Bifrost; ASP.NET Core 8 Razor Pages, PostgreSQL/EF Core)
+
+### 1a. Member and identity model (code at origin/main)
+- `UserAccount` (src/Bifrost.Web/Domain/BifrostModels.cs ~l.213): Id (Guid; per docs/context.md "UserAccount.Id is the subject" of the OIDC issuer), BifrostIdentity, optional GitHubUserId/GitHubLogin, HeimdallAccountId, DisplayName, AvatarUrl; 1:1 `MemberProfile` (nickname, headline, portfolio, skills, availability, notes) and 1:1 `Membership`.
+- `Membership` (l.~330): `MembershipStatus` Authenticated | PendingApproval | Active | Suspended (l.5-10); flags IsPlatformAdmin, CanManageProjects, CanManageLedger, CanModerateMotions; `RoleAssignment` roles StandardMember | Producer | Maintainer | LedgerReviewer | PlatformAdmin; `TierSnapshot` (Kind Patron|Contributor, Label, Weight, IsCurrent).
+- Stored in PostgreSQL via EF migrations (Data/Migrations, 15 migrations 2026-04 to 2026-10-22). Not CultCache. CultCache is used only for the bridge/receipt/governance-thread/persona-feedback stores (`.bifrost/*.cc`; README, docs/bridge.md).
+- Sign-in paths (Program.cs): GET `/auth/sign-in` (GitHub OAuth, l.314); POST `/auth/bifrost/register` anonymous (l.342) takes `identity`, optional displayName, returnUrl; signs in as Authenticated, no password/credential visible in the handler (BifrostIdentityService.RegisterNativeAsync, Features/Membership/BifrostIdentityService.cs:15); GET `/auth/heimdall/{provider}` (l.374) with AllowedProviders discord, patreon (HeimdallAuthService.cs:37-40); Heimdall complete page l.530-537.
+
+### 1b. Estates
+- No "estate" concept exists in Bifrost code. `git grep -w estate(s)` in src/ and README returns nothing; hits are only in docs/research/2026-10-29-estate-tally-game-theory/ (research, with Python sims) and the swarm-governance research note. Minds / Members / Users / Patrons blocks exist only as rulings (section 5).
+- Closest code analogues: `MembershipStatus` (Authenticated ~ Users, Active ~ Members), `TierSnapshotKind.Patron`. No Persona/Mind account class; `BridgeActorKind` Member|Agent|Persona|Service (BifrostModels.cs:178) is for bridge actions only (research note Part 1).
+
+### 1c. How a person joins today
+- Invite-only alpha (README "Alpha Scope"). `MembershipInvitation` (BifrostModels.cs:406) keyed on normalized GitHub login (MembershipSynchronizationService.cs: invitation lookup by NormalizedGitHubLogin). Admin invites at Pages/App/Members `OnPostInviteAsync` (Index.cshtml.cs:34); invited GitHub sign-in becomes PendingApproval; admin `OnPostApproveAsync` (l.92) sets Active, ApprovedAtUtc, StandardMember role. Also OnPostToggleRoleAsync (l.127), OnPostSetTierAsync (l.184), OnPostUpdateProfileAsync (l.240).
+- Un-invited GitHub or native sign-in stays Authenticated. Bootstrap admins by GitHub login via `Bootstrap:AdminGitHubLogins` become Active admin automatically.
+- Heimdall path: Discord role (KTLST guild role) or Patreon tier title (`Inner Sanctum`) entitlement grants Active (HeimdallAuthService.cs ~l.296-324; docs/app-profiles/bifrost.md in Heimdall).
+- /App is ActiveMember-gated (Program.cs:57 per research note).
+- No application form, no customer/client type, no contract record, no related-party flag, no email invite (invitations are GitHub-login keyed), no self-service for a person without GitHub, Discord-guild role, or Patreon tier.
+
+### 1d. Vote weighting in code (not the ruled design)
+- `Membership.EffectiveVotingWeight` = 0 unless Active, else `Math.Max(1, sum of current TierSnapshot weights)` (BifrostModels.cs:357-361).
+- Patron tiers (Features/Patronage/PatronTierPolicy.cs): Bronze 10 pts w1, Silver 100 w2, Gold 1,000 w3, Platinum 10,000 w4, Unobtanium 100,000 w5. Points from `PatronSupportEvent` amounts; one-time donations: full for 30 days, then 50% decayed 1%/week; recurring snapshots count while current; adjustments added (GetHistoricalDonationPoints). `PatronSupportEvent` carries ProjectId, provider (Manual|Patreon|PayPal|Stripe), currency code, amount.
+- Contributor points: `PointTransaction` (BifrostModels.cs:773; types ManualAdjustment, ApprovedWork, ContinuousRoleCredit, PatronSupport, Decay). Contribution-to-vote scaling: no code found that scales vote weight by contribution beyond TierSnapshot kind Contributor set by admin (OnPostSetTierAsync).
+- No log or exponent curve anywhere in src (grep Math.Log/Sqrt empty). Rulings `governance-vote-power-scaling` (log patrons, lower exponent members) are not implemented.
+
+### 1e. Motions, brake, timelock (code)
+- `Motion`/`Vote` Postgres rows (BifrostModels.cs:665, 702). MotionGovernanceService.cs: CreateMotionAsync (:13), CastVoteAsync (:47; weight copied from actor at cast time), CloseMotionAsync (:95; manual, by creator or CanModerateMotions). Pass = For/(For+Against) >= ApprovalThreshold, abstain excluded; no quorum.
+- Thresholds (MotionCategoryPolicy.cs; research note): Bugs .15, Cosmetics .30, Balance .40, Features .50, NewContent .50, FundamentalDesign .66.
+- Brake and timelock: absent. `git grep -i -E 'timelock|brake|quorum'` in src/ returns nothing. They exist only as rulings. `motion.create/vote/close` command names appear in MotionEveSurfaceService with no handler (research note Part 1). Only machine surface: GET `/eve/governance/surface` (Program.cs:513), deprecated Eve JSON. Motions are not typed CultMesh state.
+- Docs: docs/verse-service-contract.md lists schema `gamecult.bifrost.governance`; motion/vote schema ids marked todo (:256 per research note).
+
+### 1f. Other Bifrost surfaces relevant to a customer
+- Stripe: `StripeOptions` (Configuration/StripeOptions.cs; EnableCheckout, SecretKey, WebhookSecret, GeneralPatronageGitHubLogin, Success/Cancel URLs default to velvet.gamecult.org); routes GET `/patronage/{project}/checkout` (Program.cs:431) and POST `/patronage/stripe/webhook` (:489); Webhook records a `PatronSupportEvent` against the configured GeneralPatronageGitHubLogin account.
+- PayPal/Patreon: docs/paypal-patronage.md: Heimdall POSTs HMAC-signed support facts to `/heimdall/patron-support/events` (Program.cs:408). "PayPal owns money movement... Bifrost owns patronage meaning".
+- Ledger (`LedgerEntry` types PatronCredit, ContributionCredit, NominalCompensation, Adjustment; payout proposal batches). README: "no real payout execution in v1"; "internal ledgers only".
+- OIDC issuer for Matrix chat (docs/oidc-issuer.md; main 1894f65/83daabe): Bifrost is the identity issuer; back-channel logout reconciler ends sessions of non-Active subjects (OidcLogoutReconciler). Remaining scar: Heimdall still mints its own account id.
+- Concept Mill votes (ConceptVotes/*, VoterClass Anonymous|Account|Member): per-subject appraisals, not motions.
+
+### 1g. Documented gaps
+- Swarm research note (docs/research/2026-10-29-swarm-governance-prior-art.md Part 1) and follow-up `eureka-body:follow_up:swarm-governance-on-bifrost` item text: no quorum; manual close only; Personas cannot be Active members or vote; motions/votes are Postgres rows not typed CultMesh state; only machine surface is deprecated Eve JSON; motion.* commands without handler; no Matrix surface; Yggdrasil behind main.
+- README "Next Build Target" and docs/full-implementation-strategy.md l.11: "not an internet-facing alpha"; payout proposals, revenue-share automation, decay automation, GitHub App guidance are future. No single "gaps list" file found.
+
+## 2. Heimdall (F:\Projects\Heimdall; TypeScript/Fastify; in-memory + Postgres stores)
+- Providers (src/contracts.ts:1): discord, patreon, github, twitch, youtube, spotify, joystick.
+- App profiles (src/app-profiles.ts): repixelizer (identity discord, patreon); streampixels (identity twitch, youtube; managed connection twitch, youtube, joystick; allowedReturnOrigins streampixels.gamecult.org); bifrost (identity+entitlement discord, patreon; l.138-143); ghostlight (discord). Built-in app slugs are "seed data, not the set of permissible apps" (contracts.ts comment).
+- Bifrost integration (docs/app-profiles/bifrost.md): Bifrost starts Discord or Patreon OAuth with a server-owned entitlement policy over `backend_callback`; Heimdall delivers to `https://bifrost.gamecult.org/auth/heimdall/callback`; Bifrost creates/updates UserAccount, activates standard membership, issues its own cookie. Patron sync: POST `/v1/apps/bifrost/patron-support/sync` -> signed RecurringSupportSnapshot to Bifrost. Heimdall does not own ledgers, points, votes.
+- Bifrost's own AllowedProviders is discord, patreon only (HeimdallAuthService.cs:37-40). Twitch/YouTube are not Bifrost sign-in providers; Heimdall's bifrost profile does not list them. GitHub is signed in by Bifrost directly, not through Heimdall.
+- Non-technical external person today: could sign into Bifrost with a Discord account holding the KTLST role in the GameCult guild (Active at once), or a Patreon account with an active `Inner Sanctum` tier (Active at once), or GitHub if invited by login, or native register (identity string, lands Authenticated, no vote). No email/password/magic-link sign-in exists in Heimdall's provider list. Whether the live Heimdall has Discord/Patreon creds configured: runbooks/heimdall-discord-launch.md and bifrost-alpha-deploy.md say configured (inventory.md:1019 "Heimdall-mediated Discord/Patreon access and Patreon support intake env are configured"); live check not done.
+- Heimdall state map (state/map.yaml l.62-63, 129-130): live release d51fa6b (hand-deployed 2026-10-19) includes Joystick H1; remaining: human canaries, refresh/revocation, admin surfaces.
+- Joystick consent work (open): `joystick:follow_up:h1-joystick-consent-round-trip` (the streamer completes a Joystick connect consent through a creator-bound streampixels connect start on live Heimdall d51fa6b; verify a joystick linked identity keyed by channel_id). StreamPixels map.yaml open_operator_decisions: "Joystick S0/S1: the streamer's consent click is still owed before the connector goes live". Joystick is a managed creator connection only, not a viewer sign-in (docs/app-profiles/streampixels.md; `joystick:ruling:signin-waits-for-public-bot`). Other Joystick follow-ups in docs/architecture.md:442-457: cross-process-failed-refresh-marker, connect-start-needs-app-auth, heimdall-idunn-onboarding, joystick-viewer-signin-public-bot.
+- Open High finding relevant to identity linking: `gamecult-chat:follow_up:streampixels-link-target-takeover` (InForce): an unauthenticated Heimdall link start for streampixels can name any profile id; StreamPixels redeem links with no session check; Plausible High, unconfirmed.
+
+## 3. StreamPixels (F:\Projects\StreamPixels, state/map.yaml, state/evidence.jsonl)
+- Engagement (map.yaml l.17-70): the StreamPixels client; `budget_eur: 1500`; split even, EUR 500 per milestone (operator 2026-09-14; currency corrected from USD by operator 2026-10-25); milestones M1 "whole system running end to end on her stream" (September), M2 committed 2026-09-15: GPU fixed-capacity particle pool and AquaSynth impact audio (October), M3 TBD sold by proposal (November). Cadence: "The operator needs one milestone paid per month to survive." evidence.jsonl l.16 records the engagement (written as "$1,500" on 2026-09-14).
+- Recorded money status: map.yaml has no field recording a milestone as invoiced or paid; no invoice/payment/received hits in map.yaml or evidence.jsonl (grep). Milestone completion state: M1 still in progress per `focus: milestone-1-unity-repair` and active_subgoals (A3b, C1 remaining, l.153); the map.yaml read ended before the full active_subgoals/next_action sections.
+- Consent: map.yaml `consent`: "Her channel is not a marketing asset. Publicly associating her with the overlay requires asking her."
+- Business context l.60-66: "She has explicitly ruled out microtransactions".
+- Heimdall/Bifrost identity for the client: no Bifrost or Heimdall account, user id or invitation naming the client or her streamer handle found. Searched Bifrost and Heimdall for the client's and streamer's handles: no account or invitation found. Her Heimdall identity, if any, lives in live DB (not checked). StreamPixels has creator memberships and linked identities in its own store (apps/service/src/app.ts ~l.698, 1491-1602) via Twitch/YouTube/Joystick; live contents not checked.
+- StreamPixels forks stay in chat, no Kiko desk: `web-customize:ruling:sp-forks-in-chat-until-thing2` (2026-10-26).
+
+## 4. Payment / invoicing / money received
+- Recorded payment-receiving surfaces: Bifrost Stripe checkout+webhook (patronage; runbooks/bifrost-alpha-deploy.md:84-98 lists `Stripe__EnableCheckout`, `Stripe__SecretKey`, `Stripe__WebhookSecret`, `Stripe__GeneralPatronageGitHubLogin`; whether live-enabled unknown, inventory.md has no Stripe flag); Heimdall-signed Patreon and PayPal support facts (docs/paypal-patronage.md); StreamPixels donation source Ko-fi webhook (map.yaml settled decision, for streamer donations, not for the operator's fees).
+- No invoicing surface found: grep of gamecult-ops (excluding repo-census docs) for invoice returns nothing; Bifrost has no invoice entity (LedgerEntry/Payout are internal, "no real payout execution", "internal ledgers only"). `PatronSupportEvent` is the nearest "money received" record (amount, currency, provider, externalSupportId, ProjectId) and drives patron voting points; there is no contract/engagement/client-payment event kind (kinds: OneTimeDonation, RecurringSupportSnapshot, SupportAdjustment; providers Manual, Patreon, PayPal, Stripe). A Manual provider event can be admin-entered.
+- Treasury: `eureka-body:follow_up:swarm-treasury-and-revenue` (InForce): typed runway document (balance, committed costs, expected income) "The operator enters figures; no bank credentials are ever handled by agents"; not built. Owner repo GameCult/gamecult-ops. Source ruling `eureka-body:ruling:operator-legal-vehicle-shared-solvency` (operator is GameCult's legal and financial vehicle; her bank account pays for server and tokens).
+- Operator's bank/payment record for the EUR 1,500: not recorded in any file read.
+
+## 5. The mind (ids)
+Follow-ups (all InForce, campaign eureka-body):
+- `eureka-body:follow_up:swarm-governance-on-bifrost` (admitted 2026-10-29T20:45Z).
+- `eureka-body:follow_up:co-op-charter` (2026-10-29T21:13Z): one typed charter document in Bifrost with every governed parameter (estates and weights, within-estate curves and exponents, operator influence cap, bloc position rule, quorum, category thresholds, close timing, decision delay and cancel); amended by motion, higher threshold for charter amendments (Debian 3:1 cited). Gathers rulings governance-estate-blocks, governance-vote-power-scaling, estate-weights-normalize-by-turnout, swarm-decides-without-operator, operator-influence-below-half, swarm-governance-in-bifrost, desk questions 37, 38, 40, 41. Not on bring-up path; operator holds the seat until Bifrost governance is live.
+- `eureka-body:follow_up:swarm-treasury-and-revenue` (2026-10-29T21:24Z): treasury runway doc plus a revenue-map Eyes pass.
+Rulings (Operator, InForce):
+- `eureka-body:ruling:governance-estate-blocks` (10-29): four blocks Minds (Personas), Members (Active members), Users (authenticated accounts), Patrons (patron tiers); each block's internal vote gives its position; block weights are governed settings changed by motion. The ruling lists no Customers estate.
+- `eureka-body:ruling:estate-every-estate-equal-seed` (10-29, answers `estate-overlap-and-seed`): a person votes in every estate they belong to; estates start at equal weight.
+- `eureka-body:ruling:estate-bloc-parliament-at-threshold` (answers `estate-bloc-position`): each estate casts whole weight For only if its internal For share meets the category threshold; known cost: low categories rescaled before go-live (0.15 passes on 3.7% overall support).
+- `eureka-body:ruling:estate-weights-normalize-by-turnout` (10-29): only estates where someone voted count; weights renormalized to sum 1; empty estate drops out.
+- `eureka-body:ruling:governance-vote-power-scaling` (10-29): patrons by strongly flattened log of donation total; members by contribution with a lower exponent; curves and exponents governed; exact functions "a sketch to be calibrated by simulation (her numbers are feel, not gates)"; replaces `max(1, tier weight)` when the governance cut lands.
+- `eureka-body:ruling:operator-influence-below-half` (10-29; supersedes `operator-influence-capped-at-half`): strictly less than half; mechanism and number from simulation; a governed parameter. Research: Bifrost docs/research/2026-10-29-estate-tally-game-theory (18bbe6c adds bloc-parliament-at-threshold and operator influence cap; present case Members = her alone, Minds 8, Users/Patrons empty, README l.84).
+- `eureka-body:ruling:swarm-decides-without-operator` (10-29): no quorum rule may require her vote; rules out at-least-two-estates floor.
+- `eureka-body:ruling:motion-deadline-quorum-autoclose` (10-29, answers `motion-quorum-and-close`): default 72h window; Bifrost auto-closes; quorum is a majority of eligible voters.
+- `eureka-body:ruling:brake-to-bifrost` (10-29; quote: "hand the brake to bifrost") and `eureka-body:ruling:brake-anyone-pulls-motion-releases` (answers `brake-engage-release`): any Mind or human member engages the brake at once, every pull published with reason; releasing takes a motion (short window, e.g. 24h, majority); until Bifrost governance is live the brake stays in the root-owned swarm control store (`eureka-body:ruling:brake-dial-root-store-now`, 2026-10-02).
+- `eureka-body:ruling:decision-timelock-owner-applies` (answers `decision-applies-how`): passed motion published as typed CultMesh state with an effective time (e.g. 24h); the owning service applies it then; cancellable until then; who may cancel follows brake-to-bifrost and the charter (operator holds no private cancel).
+- `eureka-body:ruling:swarm-governance-in-bifrost` (2026-10-10); `swarm-shares-log-bound`; `swarm-membership-operator-rules` (operator rules births/retirements/transfers; any mind proposes; a mind may leave).
+- `eureka-body:ruling:operator-legal-vehicle-shared-solvency` (10-29); `eureka-body:ruling:customers-get-voting-power-onboarding-owed` (10-30).
+- Withdrawn question `eureka-body:question:persona-vote-weight` (replaced by estate blocks); withdrawn `estate-internal-tally` (restated as `estate-bloc-position`).
+- "Kiko rulings": the 2026-10-29T21:41:40Z batch (ordinal 4430) answering desk questions: estate-overlap-and-seed, estate-bloc-position, brake-engage-release, decision-applies-how, motion-quorum-and-close. No separate document labeled Kiko beyond these and `web-customize:ruling:sp-forks-in-chat-until-thing2`.
+- No ruling or follow-up found on: a Customers estate, related-party/conflict-of-interest handling for a customer who is a related party, customer vote weight from contract value, a customer onboarding workflow (other than the 10-30 ruling), or a co-op charter document existing yet (semantic query top hits showed none).
+- Joystick: `joystick:campaign:self`, `joystick:follow_up:h1-joystick-consent-round-trip`.
+
+## 6. What Yggdrasil runs for Bifrost
+- gamecult-ops inventory.md:1021: live release `/srv/bifrost/app/releases/20261010043032-67072b2`, revision `67072b28923017f93f484d901c7a6d31e3678d88`, deployed 2026-10-10; app user `bifrost`, root `/srv/bifrost/app`, env `/srv/bifrost/env`, bound `127.0.0.1:5080` via `bifrost.service` behind nginx (`bifrost.gamecult.org`, TLS issued 2026-06-10), local PostgreSQL 16. Heimdall-mediated Discord/Patreon access and Patreon intake env configured (l.1019).
+- Distance: `git rev-list --count 67072b2..origin/main` = 94 today (follow-up text says 89 at 2026-10-29). Commits since 67072b2 touching src/: OIDC issuer for Matrix chat (83daabe, 404dafd), Heimdall sign-in cookie ring and signed callback (15f96c4, b7e3bdf, b2110f5), Mill votes sign-in offer (cf74019), NuGet pins/lockfiles, mouth-all-personas (cc76f0f, tools/). So OIDC issuer and the newest Heimdall sign-in hardening are not live.
+- Also on Yggdrasil from Bifrost: `bifrost-persona-feedback.service`, `bifrost-persona-mouth.service`, `bifrost-watchdog-notice` timer (inventory.md:710-729; Persona delivery via Discord per that inventory text; main now moves Persona speech to Matrix per docs/bridge.md:199). Whether the Stripe/Heimdall env flags are live was not verified (no ssh).
+- Deployment authority is Idunn for managed workloads; Bifrost deploy is by `scripts/deploy-bifrost-alpha.sh` / runbooks/bifrost-alpha-deploy.md per inventory (interim); not confirmed which path produced 67072b2.

docs/research/customer-onboarding-prior-art.md

@@ -0,0 +1,56 @@
+# Customer-member onboarding: prior art
+
+Served: eureka-body:ruling:customers-get-voting-power-onboarding-owed (2026-10-30), the forks on customer estate, weight, decay, related parties and join flow. Eyes pass, facts only; [U] marks unverified.
+
+# Eyes facts: customer onboarding and voice in multi-stakeholder / platform co-ops (2026-10-30)
+
+Method: web search result summaries plus two WebFetch attempts. Most facts come from search-result summaries, not full-page reads. "[V]" means the source was returned by search and the claim is stated there; "[U]" means unverified, conflicting, or not found. No primary statutory text was retrieved (both wetten.overheid.nl fetches returned only tables of contents / metadata).
+
+## Q1. Admission and classes in multi-stakeholder and platform co-ops
+
+- Stocksy United [V]: three classes. A = advisors on board, capped at 5, may buy up to 200 shares (one support page). B = staff, may buy one extra B share a year. C = contributing artists, max one $1 share. Class C cap of 1,000 was removed by member resolution (support docs date it 2018). Patronage for A and C is not tied to share count. Members can submit resolutions. Sources: https://stocksy.com/legal/rules ; https://support.stocksy.com/hc/en-us/articles/201658696 ; https://support.stocksy.com/hc/en-us/articles/201659716-Is-there-a-limit-on-the-number-of-Co-op-members ; https://geo.coop/content/stocksy-united-removes-its-membership-cap ; https://support.stocksy.com/hc/en-us/articles/201808247-Can-members-purchase-more-shares-in-the-Co-op
+- Stocksy: the 1,000 cap led to regular review and removal of inactive members (company announcement via https://gdusa.com/stocksy-member-owners-open-door-to-new-contributors/) [V, secondary].
+- Fairbnb [V, partly planned]: intends to admit hosts, guests, local businesses, neighbours; per a 2020-era description workers and advisors are members, local partners/users/hosts "in the foreseeable future"; funders' voting power is statutorily limited to one third of assembly votes. Another source says it currently operates as a worker co-op without hosts. Italian and Spanish co-op law reportedly makes multi-stakeholder creation from scratch hard. Sources: https://www.thenews.coop/can-fairbnb-become-a-platform-for-community-powered-tourism/ ; https://wiki.p2pfoundation.net/FairBnB . Current composition [U]; one source is a promotional travel blog.
+- Resonate [V, one interview, other figures conflict]: three voting classes, Music-Makers 45%, Fans 35%, Collaborators 20% (Peter Harris interview), plus a Founder class with early board-appointment say. Listener membership 5 EUR/yr (Billboard). Source: https://www.resilience.org/stories/2018-06-15/resonation-an-interview-with-peter-harris/ ; https://geo.coop/content/own-music-you-stream-resonate . Whether percentages are voting or profit share is conflated across sources [U]; check resonate.is.
+- Eva (Montreal) [V, self-reported]: three categories, driver members, rider members, worker members. Fees and requirements not found. Sources: https://en.wikipedia.org/wiki/Eva_(coop%C3%A9rative) ; https://wiki.p2pfoundation.net/Eva_Coop . Up & Go: described as worker-owned cleaners' co-op in NYC; no membership-class details found [U].
+- Open Food Network [V]: governance as collective of affiliates under a "global pledge"; Open Food Foundation oversees governance and finance; UK arm "co-op of co-ops" with food hubs, farmers, shoppers as members, sociocratic circles. Sources: https://www.openfoodnetwork.org/about-us/ ; https://www.uk.coop/blog/open-food-network-making-food-systems-fair-and-sustainable-unfound . No customer admission steps found [U].
+- Eroski/Mondragon [V]: worker-members and consumer-members; General Assembly of 500 delegates, 250 worker and 250 consumer; 1.3M+ consumer members (2022). Surplus: 40% to worker-members, 50% reserves, 10% COFIP (2026 assembly). Consumer-member fee (~$75/yr) from older source [U]; per-member consumer vote weight not found [U]. Sources: https://corporativo.eroski.es/wp-content/uploads/20260528_PR_General-Assembly-2026.pdf ; https://archive.grocer.coop/node/7142 ; https://eurocoop.coop/news/184-Eroskis-growing-membership-putting-members-at-the-heart-of-co-op.html
+- REI [V, secondary]: lifetime membership $30 one-time (older $15/$20); dividend now "Co-op Member Reward" (patronage dividend and/or promotional reward, decided annually); historically ~10% of regular-price spend; ballot for board election sent with dividend notice. Older rule: active member = paid fee and bought >= $10 in a calendar year [U for current]. Sources: https://www.rei.com/membership ; https://www.rei.com/membership/join ; https://www.nbcnews.com/select/amp/rcna172651
+- Quebec solidarity co-ops [V]: classes user members, worker members, supporting members (1997 amendment). Required share count may differ by class; rebates to users by business done, to workers by work volume; supporting members get no rebate. Voting formula not found; set in by-laws [U]. Sources: https://www.publicationsduquebec.gouv.qc.ca/fileadmin/Fichiers_client/lois_et_reglements/LoisAnnuelles/en/1997/1997C17A.PDF ; https://cdn-contenu.quebec.ca/cdn-contenu/adm/min/economie/contenu/cooperatives/modeles_reglement/MO_reglements_generaux_solidarite.pdf (model by-laws, not opened) ; https://www.co-oplaw.org/?p=8947
+- Italian social co-ops, Law 381/1991 [V]: volunteer members (soci volontari) unpaid, capped at 50% of membership (art. 2); user members (soci fruitori) are service beneficiaries or relatives, reimbursed documented expenses only; investor members (soci sovventori) permitted; type B requires >= 30% disadvantaged workers, who should become members where possible. Voting caps for sovventori not retrieved; civil code art. 2526 not read [U]. Sources: https://www.bosettiegatti.eu/info/norme/statali/1991_0381.htm ; https://base.socioeco.org/docs/l_381_91.pdf ; https://www.fpcu.it/App_Common/Files/FilesEventi/346348/Slide%20videoconferenza%2014_12_2018.pdf
+- Platform Cooperativism Consortium / Exit to Community [V, thin]: E2C (Schneider, Mannan; "Exit to Community: Strategies for Multi-Stakeholder Ownership in the Platform Economy") describes transfer of ownership to users, workers, stakeholders. No findings on customer admission mechanics [U]. Source: https://wiki.p2pfoundation.net/Nathan_Schneider_on_Exit_to_Community_and_Community_Ownership_Through_Platform_Coops
+- Not found: Fairbnb/Resonate/Eva application-and-approval steps and member agreement text [U].
+
+## Q2. Purchase-based voice, plutocracy, dominant customer, related parties
+
+- Ag co-ops (US) [V, 1990s-2003 sources]: 93% of direct-membership co-ops used one-member-one-vote, 7% proportional (patronage-based extra votes) per a 1997 USDA report. Capper-Volstead exemption described as conditioned on one-vote-per-member or an 8% dividend cap (secondary summary; Texas AG opinion reads its state version as flat one-vote). State statutes largely determine which is allowed. Arguments: proportional voting for those with more equity at risk; one-member-one-vote as cooperative democratic principle, which IRS has generally endorsed. Statute text not retrieved [U]. Sources: https://www.rd.usda.gov/sites/default/files/rr156.pdf ; https://aglawjournal.wp.drake.edu/wp-content/uploads/sites/66/2016/09/agVol01No2-Matthews.pdf ; https://nationalaglawcenter.org/wp-content/uploads/assets/bibarticles/royer_principles.pdf ; https://le.utah.gov/~2003/bills/sbillenr/SB0142.htm
+- Patronage dividends vs voice: Stocksy A/C and REI/Quebec rebates tie money to patronage while voting stays per-member or per-class (see Q1 entries). Quebec supporting members get no rebate.
+- Multi-stakeholder co-ops [V]: typically one-member-one-vote within a class, fixed board seats per class; minimum and maximum vote shares per class suggested to harmonise interests; allocation of governance rights between classes is a key drafting decision; a customer member may have less "skin in the game"; boards should adopt conflict-of-interest policies. Sources: https://www.co-oplaw.org/?p=8947 ; https://ccednet-rcdec.ca/resource/multi-stakeholder-co-ops/ ; https://resources.uwcc.wisc.edu/CaseStudies/MSC-Training-Needs.pdf
+- Fairbnb's funder cap (one third of assembly votes) is a class-level vote ceiling (Q1 source).
+- Concave weighting and plutocracy [V, preprints]: arXiv 2605.18990 "Concave is the New Linear: The Impossibility of Anti-Plutocratic DAO Governance" argues quadratic or any concave mechanism cannot withstand a Sybil adversary on permissionless chains (power grows at least linearly in holdings). Not fully read, from snippet. https://arxiv.org/pdf/2605.18990 ; https://arxiv.org/pdf/2602.09608
+- Related parties / family member as customer: no source found addressing related-party voting in co-ops [U]. Only the generic conflict-of-interest policy recommendation above.
+- Dominant single customer in a class: no source found [U], other than class-level caps above.
+
+## Q3. Digital governance tooling
+
+- Decidim [V]: census authorization by admin CSV import; participants self-initiate verification from profile; authorization handlers are pluggable (SMS code, postal-letter code); CVE-2026-45415 let a limited participant-manager alter census records (fixed in 0.30.9 / 0.31.5 / 0.32.0). Sources: https://docs.decidim.org/en/admin/participants/authorizations/census ; https://docs.decidim.org/en/admin/participants/authorizations/code_postal_letter ; https://www.wiz.io/ja-jp/vulnerability-database/cve/cve-2026-45415 . Ephemeral verifications page exists (https://docs.decidim.org/en/v0.31/admin/participants/authorizations/ephemeral_verifications), not read. Revocation behaviour not retrieved [U].
+- Loomio [V]: email invite with single-use link; join requests need coordinator approval depending on privacy; reusable link bypasses approval. Source: https://help.loomio.com/en/user_manual/groups/inviting_people/index.html . No weighted voting or expiry found [U].
+- Snapshot / token DAOs [V]: quadratic voting relies on proof-of-personhood; whales split across wallets; fewer than 20 delegates reportedly hold >50% of power in major DAOs; vote-escrow aligns long-term incentives but is illiquid. Sources: https://blog.tally.xyz/a-simple-guide-to-quadratic-voting ; https://www.spark.money/glossary/quadratic-voting ; https://blockeden.xyz/forum/t/1-of-token-holders-control-90-of-voting-power-across-major-daos-quadratic-voting-delegation-incentives-and-conviction-voting-havent-fixed-the-plutocracy-problem/541 (forum, low rigor).
+- Decay / expiry [V]: EIP-7787 draft proposes token voting-power decay over a fixed 90-day period (draft, not deployed). Colony described as decaying reputation unless members keep contributing. Sources: https://eips.ethereum.org/EIPS/eip-7787 ; https://blog.colony.io/8-essential-voting-mechanisms-in-daos/ . A forum post describes log-decayed power for large holdings (10x holdings ~ 4x power).
+- DAOstack [V]: non-transferable reputation earned by contribution; peer-reviewed retrospective "The rise and fall of DAOstack": https://peerj.com/articles/cs-3320 . Decay specifics unconfirmed [U]. Aragon: non-transferable reputation templates; claims about Aragon dissolution and ANT voting removal from a single low-quality source [U].
+- Open Collective: nothing retrieved on backer voting rights or governance [U].
+
+## Q4. Contract-funded versus donation-funded voice
+
+- No literature found distinguishing a paying client class from a patron/donor class [U].
+- Adjacent facts: Dutch sample statutes with donors (donateurs) lacking general-meeting votes (Q5); Quebec supporting members as a non-voting-benefit, no-rebate class (Q1); investor/funder classes as non-user classes with separate caps (Fairbnb, UK rulebook example: https://files.uniteddiversity.coop/Cooperatives/Multi-Stakeholder_Co-ops/go!_rules_v3.0.pdf , from search listing, not opened); Stocksy and REI tie money flows to patronage not votes; Resonate has listener class at 5 EUR/yr.
+
+## Q5. EU / Netherlands legal and consent points
+
+- BW 2:53: coöperatie is an association founded by notarial deed, at least two members at founding, no max (https://wetboekplus.nl/burgerlijk-wetboek-boek-2-artikel-53-oprichting-cooperatie-en-onderlinge-waarborgmaatschappij/ , https://www.viajuridica.nl/informatiesoorten/wetstoelichtingen/oprichting-cooperatie-art-2-53-2-54-bw) [V]. Articles on voting (2:38 etc.), 2:53a, member rights: text not retrieved; official page fetches gave metadata only [U].
+- Admission in sample statutes [V]: board decides unless statutes assign it to the general meeting; general meeting can override a refusal; one set requires unanimity of a fully present meeting; one gives board six weeks to answer in writing. Register of members kept by the board, inspectable by members; board may record additional data beyond the list. Voting: one set denies donors votes; another lets non-qualifying members vote on certain proposals. Sources: https://www.glastuinbouwnederland.nl/content/user_upload/Komkommer_Concept_statuten_gewasco%C3%B6peratie_komkommerUA__3_.pdf ; https://rhoon.herenboeren.nl/wp-content/uploads/2024/05/Huishoudelijk-Reglement-Herenboeren-Rhoon.pdf ; https://www.kennisnetgeboortezorg.nl/wp-content/uploads/2019/05/Statuten-coo%CC%88peratie-IGO-Geboortehart.pdf ; https://raad.ridderkerk.nl/Documenten/bijlage/Bijlage-8-ledenovereenkomst.pdf (ledenovereenkomst example, not opened).
+- GDPR/AVG for member registers [V, secondary]: common lawful basis cited is Art. 6(1)(b) (performance of membership agreement), sometimes plus consent for extra data; GDPR sets no fixed retention (AP position quoted), Dutch practice often keeps accounting data 7 years, rest deleted after termination; processing register practically required. Sources: https://www.kvk.nl/wetten-en-regels/ga-als-vereniging-goed-om-met-privacy-en-avg/ ; https://www.legiscope.com/blog/avg-verenigingen-stichtingen.html ; https://www.moore-drv.nl/avg-hoe-lang-mag-u-persoonsgegevens-bewaren/ . Direct Autoriteit Persoonsgegevens guidance not retrieved [U].
+- Not found: coöperatie U.A. member-agreement requirements beyond statutes; relationship between customer contract and membership [U].
+
+## Gaps (not retrieved)
+Open Collective governance; Up & Go structure; Eva/Fairbnb/Resonate application steps; Capper-Volstead statute text; Italian civil code art. 2526; Quebec voting formula; Dutch BW 2:38/2:53a text; AP guidance; any source on related-party or dominant-customer voting; paid-client vs donor estates.

docs/research/email-mouth-prior-art.md

@@ -0,0 +1,55 @@
+# Bifrost email mouth: prior art
+
+Served: eureka-body:ruling:payment-mints-invite-bifrost-ledger-email-mouth and the fork on outbound mail (self-hosted SMTP vs transactional provider). Eyes pass, facts only; [U] marks unverified. Gaps not researched: provider suspension behaviour for new senders, DPAs, .NET SDKs, IP warm-up and blocklists, invite/recovery token lifetimes across platforms.
+
+# Eyes: email mouth prior art (2026-10-30)
+[U] = unverified / secondary source only. Web facts came via WebFetch summaries (small-model extraction), not raw page reads.
+
+## Q4 The body (read first, local)
+- Yggdrasil provider: Netcup KVM, 16 vCPU, 62 GiB, Debian 13, ufw active, public ports 22/80/443 only. F:\Projects\gamecult-ops\inventory.md:605,619,629; docs\research\2026-10-22-matrix-stand-up-facts.md:73. Netcup SCP is the console fallback (inventory.md:626).
+- DNS: gamecult.org zone on Hetzner DNS (NS hydrogen/oxygen/helium.ns.hetzner.com); agents hold no Hetzner DNS credential, DNS edits are operator-done; no wildcard, no CAA. gamecult-ops\docs\gamecult-chat-map.md:23; inventory.md:1075,1090; runbooks\forgejo-eureka-yggdrasil.md:24.
+- Other domains: erycina.org exists (runbooks\erycina-org-site-deploy.md, forgejo-erycina-yggdrasil.md); its DNS host not checked [U]. gamecult.com/.net/.dev: no hit in inventory.md.
+- Existing mail setup / MX / SPF / DKIM / DMARC records: grep of gamecult-ops inventory.md, runbooks, docs for MX|SPF|DKIM|DMARC|smtp|postfix|mailgun|postmark|"port 25" found none documented. Only mail mention: runbooks\forgejo-erycina-yggdrasil.md:104 "Mailer - no notifications configured. Enabling it means owning deliverability and an SMTP credential." Live DNS not queried (no dig/DoH run) [U].
+- Port 25 on Yggdrasil: not documented in gamecult-ops; ufw lists inbound ports only. Not tested (no ssh by constraint).
+- Bifrost (origin/main): no Smtp, MailKit, MimeKit, IEmailSender, SendGrid hit in src/*.cs, *.csproj, *.cshtml. Only "email" hit in code: src/Bifrost.Web/Program.cs:187 (GitHub OAuth scope "user:email"). Checkout is Stripe: src/Bifrost.Web/Features/Patronage/StripeCheckoutService.cs, StripeWebhookService.cs, Configuration/StripeOptions.cs; HttpClient to https://api.stripe.com/ (Program.cs:135); route /patronage/{project}/checkout (Program.cs:431).
+- Bifrost UserAccount (src/Bifrost.Web/Domain/BifrostModels.cs:243): fields Id, BifrostIdentity, NormalizedBifrostIdentity, GitHubUserId, HeimdallAccountId, GitHubLogin, NormalizedGitHubLogin, DisplayName, AvatarUrl, CreatedAtUtc, LastSeenAtUtc + nav props (read to ~line 275). No Email field seen. Bifrost currently stores no email per account.
+- docs/research/customer-onboarding-body-facts.md (Bifrost origin/main) :29 "no email invite (invitations are GitHub-login keyed)"; :59 no email/password/magic-link sign-in in Heimdall's provider list; sign-in is Discord role, Patreon tier, GitHub, or native register.
+- Heimdall (F:\Projects\Heimdall, HEAD): carries optional `primaryEmail` from OAuth identity into account create/update: src/app.ts:381,1048,1052,1078; src/backend-handoff.ts:8; src/oauth.ts:27; src/store/in-memory.ts:81. No SMTP/mailer found in the grep (head -8 only, not exhaustive) [U].
+- Forgejo on Yggdrasil: mailer disabled (see above).
+
+## Q1 Self-hosted outbound
+- Gmail sender guidelines (https://support.google.com/a/answer/81126), all senders: SPF or DKIM; valid forward+reverse DNS (PTR) on sending IPs; TLS; spam rate <0.3% (recommend <0.10%); RFC 5322. Bulk (>5,000/day): both SPF and DKIM, DMARC published (p=none ok), From aligned with SPF or DKIM domain, one-click unsubscribe (List-Unsubscribe + List-Unsubscribe-Post) for marketing/subscribed mail only. DKIM key >=1024, 2048 recommended. Volume here (tens-hundreds/month) is far below the 5,000/day bulk line, so only the all-senders rules apply by the page's wording.
+- Gmail rejection codes 4.7.29-4.7.31 for non-compliance [U] (secondary summary of the Google page).
+- Outlook.com high-volume sender requirements (5,000/day, SPF/DKIM/DMARC, reject action): fetch failed to return body; only title/keywords seen [U]. https://techcommunity.microsoft.com/blog/microsoftdefenderforoffice365blog/strengthening-email-ecosystem-outlook%E2%80%99s-new-requirements-for-high%E2%80%90volume-senders/4399730
+- Yahoo: not fetched; secondary sources say same 2024 requirements as Google [U] (https://help.close.com/docs/requirements-for-bulk-email-senders).
+- Netcup port 25: conflicting sources, no official Netcup page retrieved. serverkueche.de tutorial says new servers ship with SCP firewall policy "netcup Mail block" blocking outbound 25, 465, 587 (silent timeout), removable in SCP by deactivating the template (https://serverkueche.de/en/tutorials/netcup-firewall-setup/); netcup community forum thread (Aug 2026 per search summary) agrees default firewall blocks mail ports (https://forum.netcup.de/thread/22247-netcup-firewall-blockiert-smtp-ports-warum/); netcup.discount (third party) claims port 25 open by default (https://www.netcup.discount/en/guides/port-25-unblock). All [U]. Note this SCP firewall is separate from Yggdrasil's ufw.
+- PTR/rDNS on Netcup is set in SCP (per netcup.discount guide) [U].
+- IP reputation/warm-up/blocklists for VPS ranges: not researched beyond Mox README: "Large or cheap cloud providers often don't maintain good reputations or may block all outgoing SMTP"; new machines may have SMTP blocked initially, opened after cool-down or support contact (https://github.com/mjl-/mox).
+- Stacks:
+  - Mox (Go, MIT, Mechiel Lukkien, NLnet/EU funded; SMTP in/out, IMAP, webmail, SPF/DKIM/DMARC, DANE, MTA-STS, TLSRPT, ACME; `mox quickstart` prints DNS records; README recommends dedicated machine + DNSSEC resolver; smarthost via Transport in mox.conf + Routes in domains.conf; if smarthost add its IPs to SPF) https://github.com/mjl-/mox . 1,105 commits, 196 open issues at fetch.
+  - Stalwart (Rust, AGPL-3.0 + Enterprise SELv2, ~85% features AGPL; SMTP/IMAP/JMAP/CalDAV; DMARC/DKIM/SPF/ARC/DANE/MTA-STS; queues, routing rules; weekly community releases; only vouched contributors, bugfix/translation PRs) https://github.com/stalwartlabs/stalwart
+  - Maddy (Go, GPL-3.0; replaces Postfix+Dovecot+OpenDKIM etc.; IMAP "beta"; commit/release recency not shown in fetch; smarthost support not stated on page) https://github.com/foxcpp/maddy
+  - Postfix+OpenDKIM, Chasquid: not researched.
+- Unattended-operation failure modes: not found in sourced material beyond Mox README note on IP reputation. Stalwart fetch at stalw.art/docs redirected without content.
+
+## Q2 Transactional providers (pricing fetched from vendor pages 2026-10-30)
+- Postmark: Free 100 emails/mo, no overages, no expiry; no tier between 100 and 10,000/mo; Basic $15/mo for 10,000; inbound on Pro $16.50 and Platform $18 only; data residency not stated on pricing page; new accounts start on free plan, no approval text on page. https://postmarkapp.com/pricing
+- Amazon SES: $0.10/1,000 outbound + $0.12/GB attachments; no permanent free email quota on page (new-AWS-customer credits up to $200, 6 months); inbound $0.10/1,000 + $0.09/1,000 chunks; dedicated IP $24.95/mo. Sandbox/production-access text not on page [U]. https://aws.amazon.com/ses/pricing/ . EU regions exist (eu-west-1 etc.) [U not fetched].
+- Mailgun: Free $0, 100 emails/day, 1 domain, 1 inbound route, 1-day log retention; Basic $15/mo for 10,000, 5 inbound routes; "send through the US or the EU from a single account". https://www.mailgun.com/pricing/
+- Resend: Free 3,000/mo with 100/day cap, 3 domains; Pro $20/mo for 50,000; multi-region sending on all plans (EU not named on page); inbound on all plans via webhooks, counts toward quota. https://resend.com/pricing
+- Mailjet: Free 6,000/mo, 200/day; Starter $9/mo 8,000; EU hosting not stated on page; GDPR/DPA link present; inbound = "Parse API", limits not stated. https://www.mailjet.com/pricing/
+- Brevo: pricing page fetch gave no numbers. Search summaries: free 300/day, SMTP relay smtp-relay.brevo.com:587, Brevo branding on free plan mails, French company with EU data centres, paid tiers conflicting ($9/$25) [U]. https://www.brevo.com/en/bulk-email-service/ ; inbound parsing mentioned on page, details not seen.
+- Scaleway TEM (search summary of scaleway.com docs/pricing; direct fetch 403): EUR 0.25/1,000 pay-as-you-go, free 300/mo, billed per recipient; Scale plan 100K emails + dedicated IP ~EUR 80/mo (French site) [U]. Pages: https://scaleway.com/en/pricing/managed-services , https://www.scaleway.com/en/docs/transactional-email/reference-content/tem-capabilities-and-limits/ . Inbound: not found [U]. Scaleway is French (EU residency) [U].
+- Account suspension/approval behaviour for new senders, .NET SDK vs SMTP relay per provider, DPAs: not retrieved for any provider (all of these offer SMTP relay and REST API per general knowledge [U]).
+
+## Q3 Hybrid (self-hosted inbound + provider smarthost)
+- Mox documents the pattern directly (Transport/Routes smarthost, SPF include of relay IPs, caveat: relay may rewrite Message-ID or reject multiple DKIM signatures). https://github.com/mjl-/mox
+- Frequency of the pattern in practice: only generic search hits on "Smart host" (https://en.wikipedia.org/wiki/Smart_host); no prevalence data found.
+
+## Q5 Account-security prior art
+- OWASP Forgot Password Cheat Sheet (https://cheatsheetseries.owasp.org/cheatsheets/Forgot_Password_Cheat_Sheet.html): tokens from CSPRNG; single use and expire after an appropriate period (no number given); invalidate outstanding links after success; tie token to user; rate-limit requests per account; identical response and timing whether or not account exists; do not build URLs from Host header; HTTPS; Referrer-Policy no-referrer on the reset page; do not auto-login after reset; do not lock account on forgot attempts; page refers to Password Storage cheat sheet for storage (hashing not mandated on page).
+- Not researched: GitHub/Slack/Discord/Notion invite and recovery lifetimes, email as recovery factor for OAuth-only accounts, OWASP magic-link-specific guidance, NIST 800-63B out-of-band authenticator (10-minute lifetime is my recollection) [U].
+- Related local prior art: Loomio single-use email invite link, no expiry found [U] (Bifrost docs/research/customer-onboarding-prior-art.md:37).
+
+## Gaps
+Live DNS (MX/SPF/DMARC) not queried; Yggdrasil port 25 untested; Outlook/Yahoo primary pages not read; provider suspension policies, DPAs, .NET SDKs, EU-hosted extras (e.g. Mailjet/Brevo/Scaleway residency confirmation), account-security prior art mostly unresearched (tool budget).

docs/research/matrix-roles-prior-art.md

@@ -0,0 +1,59 @@
+# Discord-like roles on Matrix: prior art
+
+Served: the operator question whether Discord-like roles need a Matrix fork (2026-10-30), eureka-body:follow_up:matrix-roles-from-bifrost-estates, and the chat-client fork. Eyes pass, facts only; [U] marks unverified.
+
+# Eyes: Matrix roles prior art (2026-10-30). Facts only. [U] = unverified.
+Statuses read via `gh api repos/matrix-org/matrix-spec-proposals/pulls/N` (state, merged, labels), 2026-10-30.
+
+## Q1 Spec
+MSCs (all github.com/matrix-org/matrix-spec-proposals/pull/N):
+- 2812 [WIP] Role-based power/permissions (turt2live): OPEN, unmerged, last update 2025-08-12, labels needs-implementation, requires-room-version.
+- 4056 Role-Based Access Control (mk II) (turt2live, created 2023-09-15): OPEN, last update 2025-04-12. PR body is only a rendered link (branch travis/msc/rbac-pl); text not read [U].
+- 3949 Power Level Tags (ajbura): OPEN, update 2026-10-11, needs-implementation. Defines state event `m.room.power_level_tags`, state_key "", content = map of power-level integer -> {name, color (hex), icon{key emoji|mxc, info}}; its text says tags would show in timeline and member list. Implementation listed: Cinny. Text: raw.githubusercontent.com/ajbura/matrix-spec-proposals/power-level-tag/proposals/3949-power-level-tag.md
+- 4522 Username colors (nushea, created 2026-07-28): OPEN. `m.color_preference` {on_dark,on_light}: per-account in extended profile (MSC4133), per-room in `m.room.member` content, per-message in `m.per_message_profile`. Implementation: Sable PR 1526 (setting + rendering).
+- 4527 State event power levels (created 2026-08-09): OPEN. Impl links: complement#940, ruma#2640, Continuwuity PR 2393.
+- 3915 Owner power level (0-150): CLOSED unmerged 2026-01-18, label finished-final-comment-period.
+- 4289 Privilege creators: MERGED (closed 2025-07-22; labels merged, disposition-merge, A-Room Spec).
+- 3991 Power level up!: OPEN, last update 2023-04-14.
+- 3219 [WIP] Space Flair (turt2live): OPEN, last update 2022-10-21.
+- 4121 m.role.moderator in /.well-known/matrix/support: OPEN; homeserver support records, not room roles.
+- 2212 Third party user power levels: OPEN (2022).
+
+Space-wide power levels:
+- 2962 Managing power levels via Spaces (ara4n): OPEN, last update 2022-05-05. Template power_levels in parent space inherited by children (per search summary of its text [U]).
+- 3216 Synchronized access control for Spaces (joepie91): OPEN, 2022-05-05. Adds `m.space.power_levels`; comment: a non-spaces-aware client's edits get overwritten on next inherited change [U, search summary].
+- No merged MSC found giving space-wide power levels. Both are OPEN.
+
+Custom state events:
+- Spec: complete event MUST NOT exceed 65536 bytes (spec.matrix.org/latest/client-server-api/).
+- Per-event-type send level via `m.room.power_levels` `events` map, else `state_default` [spec knowledge, not re-fetched, U].
+- State arrives via /sync as room state; whether a client reads an unknown type is client-specific. Cinny reads `m.room.power_level_tags` (Q3).
+
+## Q2 Element Web
+- Releases: v1.12.33 (2026-10-27), v1.12.32 (2026-10-16), v1.12.31 (2026-10-13), with rc builds in between (gh api repos/element-hq/element-web/releases). Repo is a pnpm/nx monorepo: packages/{module-api, shared-components, shared-types, shared-utils, ...}, modules/{banner, restricted-guests, widget-lifecycle, widget-toggles}.
+- License: AGPL-3.0 (GitHub spdx); repo also contains LICENSE-GPL-3.0 and LICENSE-COMMERCIAL ("Licensees holding a valid commercial license with Element may use this software in accordance with the terms contained in a written agreement").
+- AGPL duties for a hosted modified fork: not sourced this pass [U]. (General knowledge: section 13 network-use source offer.)
+- config.json (docs/config.md): `default_theme`, custom themes, `branding`, `embedded_pages`, `setting_defaults`, `features` (labs), UI-feature toggles, and `modules` (array of URLs/paths dynamically imported at startup, ~lines 597-609). Doc: "doesn't support complete re-branding/private labeling".
+- Module API: `@element-hq/element-web-module-api` 2.3.0 (packages/module-api/package.json). Module = class with static `moduleApiVersion` semver and `load()`. Surfaces in packages/module-api/src/api/: auth, builtins, client, composer, config, custom-components, customisations, dialog, extras, i18n, navigation, profile, settings, stores, urlpreview, widget, widget-lifecycle, x509.
+  - custom-components.ts (@alpha, "Subject to change"): custom message renderers with render hints, including a hint documented as "Should the sender's profile be rendered for this event" (default true); room preview bar renderer. Overriding render means editing is unavailable.
+  - customisations.ts: `registerShouldShowComponent` only shows/hides listed UI components (invite, create room/space, directory, widgets, explore, room options).
+  - extras.ts (@alpha): space-panel item, room-header buttons.
+  - profile.ts: read-only profile of the logged-in user.
+  - No sender-name decorator or member-list hook found in the file listing; stores.ts, builtins.ts, client.ts not read in detail [U].
+- Theme details (custom theme JSON/CSS variables): not read [U].
+- Maintained-fork cost (merge pain, cadence of known forks): not gathered [U].
+
+## Q3 Other clients and prior art
+- Cinny (AGPL-3.0, pushed 2026-10-28): src/app/hooks/usePowerLevelTags.ts has DEFAULT_TAGS {9001 Goku, 150 Manager, 101 Founder, 100 Admin, 50 Moderator, 0 Member}, each with name+color; reads a state event (type in src/types/matrix/room.ts); src/app/hooks/useMemberPowerTag.ts resolves a member's tag from power level, with a room-creators tag, and applies `accessibleColor` per ThemeKind. This is the MSC3949 implementation.
+- Sable (AGPL-3.0; repo now "Sable-Legacy", v2 at git.sable.moe): implements MSC4522 colours (SableClient/Sable#1526, per MSC text).
+- Commet (AGPL-3.0, pushed 2026-10-29): room permissions settings page defines `MatrixRoomRoleEntry` {name, powerlevel} (commet/lib/ui/pages/settings/categories/room/permissions/matrix/matrix_room_permissions_page.dart). Timeline colour/badge display not checked [U].
+- FluffyChat, Nheko, SchildiChat: issue searches returned nothing; no evidence either way [U].
+- Rocket.Chat-on-Matrix, Conduit/Continuwuity communities, Polycule: not researched [U]. Continuwuity has an MSC4527 implementation PR (forgejo.ellis.link/continuwuation/continuwuity/pulls/2393).
+- mautrix-discord (github.com/mautrix/discord): stores Discord roles in a DB `role` table (dc_guild_id, dcid, name, icon, mentionable, managed, hoist, color, position, permissions), synced from GuildRoleCreate/Update/Delete (user.go:684-688, 978+; database/role.go). ROADMAP.md lists "Power level" and "Role permissions" unchecked. portal.go:1734-1739 uses room power levels only to gate @room mentions. No evidence found of writing Discord roles into Matrix state or power levels.
+
+## Q4 Body
+- Chat map: F:\Projects\gamecult-ops\docs\gamecult-chat-map.md. Element Web at chat.gamecult.org is static `root /srv/element-web/current` (symlink to /srv/element-web/releases/<version>), 404 until campaign cut C5 (lines 71, 101); runbooks/gamecult-chat-host-yggdrasil.md:6 says Element Web's release belongs to C5. No deployed Element release found in the docs. Homeserver matrix.gamecult.org -> Synapse 127.0.0.1:8834; federation and admin paths 404; apex /.well-known/matrix/client base_url https://matrix.gamecult.org (lines 93-102).
+- Synapse: ygg-verify probe ran matrixdotorg/synapse 1.163.0 on postgres:16 (chat map line 27, P5). Upstream latest Synapse v1.164.1 (2026-10-28), MAS v1.28.0 (2026-10-27). Deployed versions on Yggdrasil not checked (no ssh) [U].
+- Idunn targets `synapse`, `matrix-auth`; C3 `synapse-mas-under-idunn` packages them.
+- Bifrost origin/main docs/oidc-issuer.md: OpenIddict 7.7.1; scopes `openid profile`; claims only `sub`, `preferred_username` (never changes), `name`; "No e-mail, no Heimdall id, no GitHub id, and no membership detail leaves Bifrost". MAS is the OIDC client.
+- Bifrost role code: only membership roles in its own DB (`MemberRole` StandardMember|Producer|Maintainer|LedgerReviewer|PlatformAdmin, RoleAssignment; src/Bifrost.Web/Data/BifrostDbContext.cs:113-114; docs/research/customer-onboarding-body-facts.md:16). Grep of origin/main docs and src for power_level / m.room.power found nothing. docs/bridge.md:199: Personas speak through `tools/persona-matrix-mouth.mjs` with per-persona Matrix access tokens (the only Matrix writer found).

docs/watchdog-notice.md

@@ -22,6 +22,15 @@ node tools/watchdog-notice.mjs status --journal-store J
 - `BIFROST_DISCORD_BOT_TOKEN` in the environment, read only by
   `bifrost-bridge.mjs`, which the reader spawns.
 
+## Retry
+
+A notice whose send failed (bridge exit 75) is never dropped. It is eligible
+again once `min(2^(attempts-1), 60)` minutes have passed since its last attempt
+in the journal: 1, 2, 4, 8, 16, 32, then every 60 minutes. A run that finds it
+inside its delay skips it without spawning the bridge. An entry stamped ahead of the clock (a host clock stepped forward, then corrected) is eligible now, and its next attempt rewrites the stamp. Every attempt carries the
+same nonce, so a Discord outage of any length costs a late notice, not a lost
+one, and a retry that succeeds is the one post.
+
 ## Behaviour
 
 - P is Idunn's `idunn.operator_incident.v1` store. The reader reads it without a
@@ -31,7 +40,7 @@ node tools/watchdog-notice.mjs status --journal-store J
 - J is Bifrost's journal, `bifrost.watchdog_notice_execution.v1`, keyed
   `<incident_key>#opened` or `<incident_key>#closed`. A `running` entry found at
   start becomes `unknown` and is never sent again. A `failed` entry is retried on
-  later runs with the same nonce, up to five attempts. The journal is never
+  later runs with the same nonce, never given up on (see Retry). The journal is never
   pruned: what Bifrost has sent is Bifrost's memory, whatever P holds.
 - The bridge (`bifrost-bridge.mjs discord-dm`) exits 75 for argument or token
   errors, a failure opening the DM channel, or any non-2xx answer to the message
@@ -43,9 +52,11 @@ node tools/watchdog-notice.mjs status --journal-store J
   `failed` for exit 75 only. Any other non-success without a message id (another exit code,
   a signal, the spawn timeout, unreadable output) is `unknown`: never sent again,
   counted by the exit status.
-- The exit status is non-zero while any entry is `unknown` or out of attempts, or
-  while P holds a record of this schema that breaks its contract. systemd shows
-  that; `status` lists the entries.
+- The exit status is non-zero while any entry is `unknown` or has failed three or
+  more times, or while P holds a record of this schema that breaks its contract.
+  systemd shows that; `status` lists the entries, with `attempts` and, for a
+  `failed` entry, `nextEligibleAt`. The non-zero status is the signal only: the
+  entry keeps being retried.
 - Notice text is built from `condition`, `subject` and ISO UTC times only. The
   subject follows Idunn's `require_id` (1-256 bytes of `[A-Za-z0-9-_.:/]`) and
   is placed in inline code. A time outside the ECMAScript Date range refuses the

src/Bifrost.Web/Bifrost.Web.csproj

@@ -11,7 +11,14 @@
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
+    <PackageReference Include="BouncyCastle.Cryptography" Version="2.4.0" />
     <PackageReference Include="Npgsql.EntityFrameworkCore.PostgreSQL" Version="8.0.0" />
+    <!-- Direct pins lift transitive packages past their advisories; the lockfile holds the result. -->
+    <PackageReference Include="Npgsql" Version="8.0.3" />
+    <PackageReference Include="System.Text.Json" Version="8.0.5" />
+    <PackageReference Include="Microsoft.Extensions.Caching.Memory" Version="8.0.1" />
+    <PackageReference Include="OpenIddict.Server.AspNetCore" Version="7.7.1" />
+    <PackageReference Include="OpenIddict.EntityFrameworkCore" Version="7.7.1" />
   </ItemGroup>
 
 </Project>

src/Bifrost.Web/Configuration/ConceptVoteOptions.cs

@@ -0,0 +1,53 @@
+namespace Bifrost.Web.Configuration;
+
+public sealed class ConceptVoteOptions
+{
+    public const string SectionName = "ConceptVotes";
+
+    // HMAC-SHA256 output is 32 bytes (RFC 2104 advises a key at least as long as the hash output), so a shorter
+    // secret makes the tag brute-forceable over the IPv4 space if the table leaks.
+    public const int MinNetworkTagSecretLength = 32;
+
+    // Keys the network tag. Required outside Development and Testing, at least MinNetworkTagSecretLength
+    // characters (StartupConfigurationValidator).
+    public string NetworkTagSecret { get; init; } = string.Empty;
+
+    // The research note (docs/research/anonymous-vote-stuffing-prior-art.md:57-61) finds no source for a
+    // coarser IPv4 partition than the address itself, so the default is the exact address.
+    public int IPv4PrefixLength { get; init; } = 32;
+
+    // /64 is bypassed by RFC 8981 privacy rotation and households can hold a /56 or /48; /56 is the practitioner
+    // default weighed in the note, not a standard. Tune on observed abuse.
+    public int IPv6PrefixLength { get; init; } = 56;
+
+    // Vote budgets (Features/ConceptVotes/ConceptVoteRateLimits). The research note
+    // (docs/research/anonymous-vote-stuffing-prior-art.md section 3) gives no numbers, so these are first values to tune on
+    // observed abuse. Cast: one visitor reading through the Mill can vote on a few dozen concepts in a sitting, so 30 per
+    // 10 minutes per account or network prefix does not trouble a person and caps a script at 180 an hour.
+    public int CastPermits { get; init; } = 30;
+
+    public TimeSpan CastWindow { get; init; } = TimeSpan.FromMinutes(10);
+
+    // Mint: a new device cookie is a new voter identity, the cheapest stuffing lever. Anonymous visitors share an
+    // address behind carrier, school and office NAT (the research note records it), so 30 new devices per hour per
+    // address (operator ruling concept-mill-votes:ruling:mint-budget-30-per-hour); per-device and per-prefix cast
+    // limits still bound stuffing.
+    public int MintPermits { get; init; } = 30;
+
+    public TimeSpan MintWindow { get; init; } = TimeSpan.FromHours(1);
+
+    // The most partitions each budget table holds at once (cast by account, cast by network prefix, mint). At the cap a
+    // partition not yet held evicts the least recently used one that still has permits left; a partition that has
+    // spent its permits is never evicted, so rotating sources can at most win back a forgotten partition's partial
+    // budget. 100000 partitions is a few tens of MB; a real audience is far below it.
+    public int MaxTrackedKeys { get; init; } = 100_000;
+
+    // The origins whose pages may read the public tally export from a browser (CORS). Each entry is exactly
+    // https://host[:non-default-port], lower case, no path; empty allows none. StartupConfigurationValidator
+    // refuses anything else outside Development and Testing, because "*" would allow every origin.
+    public string[] AllowedOrigins { get; init; } = [];
+
+    // The Mill page the vote page links back to; the concept's key is appended as the anchor. Production is the
+    // Aetheria site's page, so a deploy overrides nothing unless the page moves (ConceptVotes__MillPageUrl).
+    public string MillPageUrl { get; init; } = "https://aetheria.gamecult.org/Game-Design/Concept-Mill";
+}

src/Bifrost.Web/Configuration/HeimdallOptions.cs

@@ -14,6 +14,8 @@ public sealed class HeimdallOptions
 
     public string PatreonTierTitle { get; init; } = "Inner Sanctum";
 
+    public string AppSecret { get; init; } = string.Empty;
+
     public string PatronSupportIntakeSecret { get; init; } = string.Empty;
 
     public bool EnablePatronSupportIntake { get; init; } = true;
@@ -24,11 +26,13 @@ public sealed class HeimdallOptions
 
     public bool IsDiscordConfigured =>
         IsConfigured &&
+        !string.IsNullOrWhiteSpace(AppSecret) &&
         !string.IsNullOrWhiteSpace(DiscordGuildId) &&
         DiscordAllowedRoleIds.Length > 0;
 
     public bool IsPatreonConfigured =>
         IsConfigured &&
+        !string.IsNullOrWhiteSpace(AppSecret) &&
         !string.IsNullOrWhiteSpace(PatreonTierTitle);
 
     public bool IsPatronSupportIntakeConfigured =>

src/Bifrost.Web/Configuration/OidcIssuerOptions.cs

@@ -0,0 +1,44 @@
+namespace Bifrost.Web.Configuration;
+
+/// <summary>
+/// The OIDC provider surface (section <c>Bifrost:Oidc</c>). An absent section means the provider is not mapped at
+/// all; a present section is complete or startup fails. Keys and the client secret are named by file path, never inlined.
+/// </summary>
+public sealed class OidcIssuerOptions
+{
+    public const string SectionName = "Bifrost:Oidc";
+
+    /// <summary>PEM file holding the EC P-256 private key that signs tokens (ES256).</summary>
+    public string SigningKeyPath { get; init; } = string.Empty;
+
+    /// <summary>File holding the 32-byte symmetric token-encryption key as base64.</summary>
+    public string EncryptionKeyPath { get; init; } = string.Empty;
+
+    public OidcClientsOptions Clients { get; init; } = new();
+
+    /// <summary>Null when the section is absent.</summary>
+    public static OidcIssuerOptions? FromConfiguration(IConfiguration configuration)
+    {
+        var section = configuration.GetSection(SectionName);
+        return section.Exists() ? section.Get<OidcIssuerOptions>() ?? new OidcIssuerOptions() : null;
+    }
+}
+
+public sealed class OidcClientsOptions
+{
+    /// <summary>Matrix Authentication Service, the one client of this provider.</summary>
+    public OidcClientOptions Mas { get; init; } = new();
+}
+
+public sealed class OidcClientOptions
+{
+    public string ClientId { get; init; } = string.Empty;
+
+    /// <summary>File holding the client secret.</summary>
+    public string ClientSecretPath { get; init; } = string.Empty;
+
+    public string RedirectUri { get; init; } = string.Empty;
+
+    /// <summary>MAS's back-channel logout URL for this provider. Empty: no logout is sent and no session is ended.</summary>
+    public string BackchannelLogoutUri { get; init; } = string.Empty;
+}

src/Bifrost.Web/Data/BifrostDbContext.cs

@@ -5,6 +5,10 @@ namespace Bifrost.Web.Data;
 
 public sealed class BifrostDbContext(DbContextOptions<BifrostDbContext> options) : DbContext(options)
 {
+    // The OpenIddict tables are part of this model for every way a context is built: the host, the concepts
+    // command, tests and the design-time factory that generates migrations.
+    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder) => optionsBuilder.UseOpenIddict();
+
     public DbSet<UserAccount> UserAccounts => Set<UserAccount>();
 
     public DbSet<MemberProfile> MemberProfiles => Set<MemberProfile>();
@@ -63,6 +67,10 @@ public sealed class BifrostDbContext(DbContextOptions<BifrostDbContext> options)
 
     public DbSet<AuditEvent> AuditEvents => Set<AuditEvent>();
 
+    public DbSet<ConceptSubject> ConceptSubjects => Set<ConceptSubject>();
+
+    public DbSet<ConceptAppraisal> ConceptAppraisals => Set<ConceptAppraisal>();
+
     protected override void OnModelCreating(ModelBuilder modelBuilder)
     {
         modelBuilder.Entity<UserAccount>(entity =>
@@ -523,5 +531,31 @@ public sealed class BifrostDbContext(DbContextOptions<BifrostDbContext> options)
                 .HasForeignKey(x => x.ActorUserAccountId)
                 .OnDelete(DeleteBehavior.SetNull);
         });
+
+        modelBuilder.Entity<ConceptSubject>(entity =>
+        {
+            entity.Property(x => x.Collection).HasMaxLength(80);
+            entity.Property(x => x.Key).HasMaxLength(80);
+            entity.Property(x => x.Title).HasMaxLength(240);
+            entity.HasIndex(x => new { x.Collection, x.Key }).IsUnique();
+        });
+
+        modelBuilder.Entity<ConceptAppraisal>(entity =>
+        {
+            entity.Property(x => x.VoterKey).HasMaxLength(120);
+            entity.Property(x => x.NetworkTag).HasMaxLength(64);
+            entity.Property(x => x.Stance).HasConversion<string>().HasMaxLength(16);
+            entity.Property(x => x.VoterClass).HasConversion<string>().HasMaxLength(16);
+            entity.HasIndex(x => new { x.SubjectId, x.VoterKey }).IsUnique();
+            entity.HasIndex(x => new { x.NetworkTag, x.CastAtUtc });
+            entity.HasOne(x => x.Subject)
+                .WithMany()
+                .HasForeignKey(x => x.SubjectId)
+                .OnDelete(DeleteBehavior.Restrict);
+            entity.HasOne<UserAccount>()
+                .WithMany()
+                .HasForeignKey(x => x.UserAccountId)
+                .OnDelete(DeleteBehavior.SetNull);
+        });
     }
 }

src/Bifrost.Web/Data/Migrations/20260608210000_AddHeimdallUserIdentity.cs

@@ -1,3 +1,4 @@
+using Microsoft.EntityFrameworkCore.Infrastructure;
 using Microsoft.EntityFrameworkCore.Migrations;
 
 #nullable disable
@@ -5,6 +6,7 @@ using Microsoft.EntityFrameworkCore.Migrations;
 namespace Bifrost.Web.Data.Migrations
 {
     /// <inheritdoc />
+    [DbContext(typeof(BifrostDbContext))]
     [Migration("20260608210000_AddHeimdallUserIdentity")]
     public partial class AddHeimdallUserIdentity : Migration
     {

src/Bifrost.Web/Data/Migrations/20260609143000_AddPatronSupportDerivation.cs

@@ -1,3 +1,4 @@
+using Microsoft.EntityFrameworkCore.Infrastructure;
 using Microsoft.EntityFrameworkCore.Migrations;
 
 #nullable disable
@@ -5,6 +6,7 @@ using Microsoft.EntityFrameworkCore.Migrations;
 namespace Bifrost.Web.Data.Migrations
 {
     /// <inheritdoc />
+    [DbContext(typeof(BifrostDbContext))]
     [Migration("20260609143000_AddPatronSupportDerivation")]
     public partial class AddPatronSupportDerivation : Migration
     {

src/Bifrost.Web/Data/Migrations/20260609160000_AddExternalPatronProviderIntake.cs

@@ -1,10 +1,12 @@
 using Bifrost.Web.Domain;
+using Microsoft.EntityFrameworkCore.Infrastructure;
 using Microsoft.EntityFrameworkCore.Migrations;
 
 #nullable disable
 
 namespace Bifrost.Web.Data.Migrations
 {
+    [DbContext(typeof(BifrostDbContext))]
     [Migration("20260609160000_AddExternalPatronProviderIntake")]
     public partial class AddExternalPatronProviderIntake : Migration
     {

src/Bifrost.Web/Data/Migrations/20260622142000_AddBridgeActionIdentityProvenance.cs

@@ -1,3 +1,4 @@
+using Microsoft.EntityFrameworkCore.Infrastructure;
 using Microsoft.EntityFrameworkCore.Migrations;
 
 #nullable disable
@@ -5,6 +6,8 @@ using Microsoft.EntityFrameworkCore.Migrations;
 namespace Bifrost.Web.Data.Migrations
 {
     /// <inheritdoc />
+    [DbContext(typeof(BifrostDbContext))]
+    [Migration("20260622142000_AddBridgeActionIdentityProvenance")]
     public partial class AddBridgeActionIdentityProvenance : Migration
     {
         /// <inheritdoc />

src/Bifrost.Web/Data/Migrations/20260622165000_AddBifrostNativeIdentity.cs

@@ -1,3 +1,4 @@
+using Microsoft.EntityFrameworkCore.Infrastructure;
 using Microsoft.EntityFrameworkCore.Migrations;
 
 #nullable disable
@@ -5,6 +6,7 @@ using Microsoft.EntityFrameworkCore.Migrations;
 namespace Bifrost.Web.Data.Migrations
 {
     /// <inheritdoc />
+    [DbContext(typeof(BifrostDbContext))]
     [Migration("20260622165000_AddBifrostNativeIdentity")]
     public partial class AddBifrostNativeIdentity : Migration
     {

src/Bifrost.Web/Data/Migrations/20260622202000_AddBridgeActionTargetSurfaceName.cs

@@ -1,3 +1,4 @@
+using Microsoft.EntityFrameworkCore.Infrastructure;
 using Microsoft.EntityFrameworkCore.Migrations;
 
 #nullable disable
@@ -5,6 +6,8 @@ using Microsoft.EntityFrameworkCore.Migrations;
 namespace Bifrost.Web.Data.Migrations
 {
     /// <inheritdoc />
+    [DbContext(typeof(BifrostDbContext))]
+    [Migration("20260622202000_AddBridgeActionTargetSurfaceName")]
     public partial class AddBridgeActionTargetSurfaceName : Migration
     {
         /// <inheritdoc />

src/Bifrost.Web/Data/Migrations/20260705190000_AddPatronSupportProjectAttribution.cs

@@ -1,4 +1,5 @@
 using System;
+using Microsoft.EntityFrameworkCore.Infrastructure;
 using Microsoft.EntityFrameworkCore.Migrations;
 
 #nullable disable
@@ -6,6 +7,8 @@ using Microsoft.EntityFrameworkCore.Migrations;
 namespace Bifrost.Web.Data.Migrations
 {
     /// <inheritdoc />
+    [DbContext(typeof(BifrostDbContext))]
+    [Migration("20260705190000_AddPatronSupportProjectAttribution")]
     public partial class AddPatronSupportProjectAttribution : Migration
     {
         /// <inheritdoc />

src/Bifrost.Web/Data/Migrations/20261010043937_AddConceptVotes.cs

@@ -0,0 +1,93 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace Bifrost.Web.Data.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddConceptVotes : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateTable(
+                name: "ConceptSubjects",
+                columns: table => new
+                {
+                    Id = table.Column<Guid>(type: "uuid", nullable: false),
+                    Collection = table.Column<string>(type: "character varying(80)", maxLength: 80, nullable: false),
+                    Key = table.Column<string>(type: "character varying(80)", maxLength: 80, nullable: false),
+                    Title = table.Column<string>(type: "character varying(240)", maxLength: 240, nullable: false),
+                    RegisteredAtUtc = table.Column<DateTimeOffset>(type: "timestamp with time zone", nullable: false),
+                    RetiredAtUtc = table.Column<DateTimeOffset>(type: "timestamp with time zone", nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_ConceptSubjects", x => x.Id);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "ConceptAppraisals",
+                columns: table => new
+                {
+                    Id = table.Column<Guid>(type: "uuid", nullable: false),
+                    SubjectId = table.Column<Guid>(type: "uuid", nullable: false),
+                    VoterKey = table.Column<string>(type: "character varying(120)", maxLength: 120, nullable: false),
+                    Stance = table.Column<string>(type: "character varying(16)", maxLength: 16, nullable: false),
+                    VoterClass = table.Column<string>(type: "character varying(16)", maxLength: 16, nullable: false),
+                    UserAccountId = table.Column<Guid>(type: "uuid", nullable: true),
+                    NetworkTag = table.Column<string>(type: "character varying(64)", maxLength: 64, nullable: false),
+                    CastAtUtc = table.Column<DateTimeOffset>(type: "timestamp with time zone", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_ConceptAppraisals", x => x.Id);
+                    table.ForeignKey(
+                        name: "FK_ConceptAppraisals_ConceptSubjects_SubjectId",
+                        column: x => x.SubjectId,
+                        principalTable: "ConceptSubjects",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.Restrict);
+                    table.ForeignKey(
+                        name: "FK_ConceptAppraisals_UserAccounts_UserAccountId",
+                        column: x => x.UserAccountId,
+                        principalTable: "UserAccounts",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.SetNull);
+                });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_ConceptAppraisals_NetworkTag_CastAtUtc",
+                table: "ConceptAppraisals",
+                columns: new[] { "NetworkTag", "CastAtUtc" });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_ConceptAppraisals_SubjectId_VoterKey",
+                table: "ConceptAppraisals",
+                columns: new[] { "SubjectId", "VoterKey" },
+                unique: true);
+
+            migrationBuilder.CreateIndex(
+                name: "IX_ConceptAppraisals_UserAccountId",
+                table: "ConceptAppraisals",
+                column: "UserAccountId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_ConceptSubjects_Collection_Key",
+                table: "ConceptSubjects",
+                columns: new[] { "Collection", "Key" },
+                unique: true);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "ConceptAppraisals");
+
+            migrationBuilder.DropTable(
+                name: "ConceptSubjects");
+        }
+    }
+}

src/Bifrost.Web/Data/Migrations/20261022163159_AddOpenIddict.cs

@@ -0,0 +1,166 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace Bifrost.Web.Data.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddOpenIddict : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateTable(
+                name: "OpenIddictApplications",
+                columns: table => new
+                {
+                    Id = table.Column<string>(type: "text", nullable: false),
+                    ApplicationType = table.Column<string>(type: "character varying(50)", maxLength: 50, nullable: true),
+                    ClientId = table.Column<string>(type: "character varying(100)", maxLength: 100, nullable: true),
+                    ClientSecret = table.Column<string>(type: "text", nullable: true),
+                    ClientType = table.Column<string>(type: "character varying(50)", maxLength: 50, nullable: true),
+                    ConcurrencyToken = table.Column<string>(type: "character varying(50)", maxLength: 50, nullable: true),
+                    ConsentType = table.Column<string>(type: "character varying(50)", maxLength: 50, nullable: true),
+                    DisplayName = table.Column<string>(type: "text", nullable: true),
+                    DisplayNames = table.Column<string>(type: "text", nullable: true),
+                    JsonWebKeySet = table.Column<string>(type: "text", nullable: true),
+                    Permissions = table.Column<string>(type: "text", nullable: true),
+                    PostLogoutRedirectUris = table.Column<string>(type: "text", nullable: true),
+                    Properties = table.Column<string>(type: "text", nullable: true),
+                    RedirectUris = table.Column<string>(type: "text", nullable: true),
+                    Requirements = table.Column<string>(type: "text", nullable: true),
+                    Settings = table.Column<string>(type: "text", nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_OpenIddictApplications", x => x.Id);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "OpenIddictScopes",
+                columns: table => new
+                {
+                    Id = table.Column<string>(type: "text", nullable: false),
+                    ConcurrencyToken = table.Column<string>(type: "character varying(50)", maxLength: 50, nullable: true),
+                    Description = table.Column<string>(type: "text", nullable: true),
+                    Descriptions = table.Column<string>(type: "text", nullable: true),
+                    DisplayName = table.Column<string>(type: "text", nullable: true),
+                    DisplayNames = table.Column<string>(type: "text", nullable: true),
+                    Name = table.Column<string>(type: "character varying(200)", maxLength: 200, nullable: true),
+                    Properties = table.Column<string>(type: "text", nullable: true),
+                    Resources = table.Column<string>(type: "text", nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_OpenIddictScopes", x => x.Id);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "OpenIddictAuthorizations",
+                columns: table => new
+                {
+                    Id = table.Column<string>(type: "text", nullable: false),
+                    ApplicationId = table.Column<string>(type: "text", nullable: true),
+                    ConcurrencyToken = table.Column<string>(type: "character varying(50)", maxLength: 50, nullable: true),
+                    CreationDate = table.Column<DateTime>(type: "timestamp with time zone", nullable: true),
+                    Properties = table.Column<string>(type: "text", nullable: true),
+                    Scopes = table.Column<string>(type: "text", nullable: true),
+                    Status = table.Column<string>(type: "character varying(50)", maxLength: 50, nullable: true),
+                    Subject = table.Column<string>(type: "character varying(400)", maxLength: 400, nullable: true),
+                    Type = table.Column<string>(type: "character varying(50)", maxLength: 50, nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_OpenIddictAuthorizations", x => x.Id);
+                    table.ForeignKey(
+                        name: "FK_OpenIddictAuthorizations_OpenIddictApplications_Application~",
+                        column: x => x.ApplicationId,
+                        principalTable: "OpenIddictApplications",
+                        principalColumn: "Id");
+                });
+
+            migrationBuilder.CreateTable(
+                name: "OpenIddictTokens",
+                columns: table => new
+                {
+                    Id = table.Column<string>(type: "text", nullable: false),
+                    ApplicationId = table.Column<string>(type: "text", nullable: true),
+                    AuthorizationId = table.Column<string>(type: "text", nullable: true),
+                    ConcurrencyToken = table.Column<string>(type: "character varying(50)", maxLength: 50, nullable: true),
+                    CreationDate = table.Column<DateTime>(type: "timestamp with time zone", nullable: true),
+                    ExpirationDate = table.Column<DateTime>(type: "timestamp with time zone", nullable: true),
+                    Payload = table.Column<string>(type: "text", nullable: true),
+                    Properties = table.Column<string>(type: "text", nullable: true),
+                    RedemptionDate = table.Column<DateTime>(type: "timestamp with time zone", nullable: true),
+                    ReferenceId = table.Column<string>(type: "character varying(100)", maxLength: 100, nullable: true),
+                    Status = table.Column<string>(type: "character varying(50)", maxLength: 50, nullable: true),
+                    Subject = table.Column<string>(type: "character varying(400)", maxLength: 400, nullable: true),
+                    Type = table.Column<string>(type: "character varying(150)", maxLength: 150, nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_OpenIddictTokens", x => x.Id);
+                    table.ForeignKey(
+                        name: "FK_OpenIddictTokens_OpenIddictApplications_ApplicationId",
+                        column: x => x.ApplicationId,
+                        principalTable: "OpenIddictApplications",
+                        principalColumn: "Id");
+                    table.ForeignKey(
+                        name: "FK_OpenIddictTokens_OpenIddictAuthorizations_AuthorizationId",
+                        column: x => x.AuthorizationId,
+                        principalTable: "OpenIddictAuthorizations",
+                        principalColumn: "Id");
+                });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_OpenIddictApplications_ClientId",
+                table: "OpenIddictApplications",
+                column: "ClientId",
+                unique: true);
+
+            migrationBuilder.CreateIndex(
+                name: "IX_OpenIddictAuthorizations_ApplicationId_Status_Subject_Type",
+                table: "OpenIddictAuthorizations",
+                columns: new[] { "ApplicationId", "Status", "Subject", "Type" });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_OpenIddictScopes_Name",
+                table: "OpenIddictScopes",
+                column: "Name",
+                unique: true);
+
+            migrationBuilder.CreateIndex(
+                name: "IX_OpenIddictTokens_ApplicationId_Status_Subject_Type",
+                table: "OpenIddictTokens",
+                columns: new[] { "ApplicationId", "Status", "Subject", "Type" });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_OpenIddictTokens_AuthorizationId",
+                table: "OpenIddictTokens",
+                column: "AuthorizationId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_OpenIddictTokens_ReferenceId",
+                table: "OpenIddictTokens",
+                column: "ReferenceId",
+                unique: true);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "OpenIddictScopes");
+
+            migrationBuilder.DropTable(
+                name: "OpenIddictTokens");
+
+            migrationBuilder.DropTable(
+                name: "OpenIddictAuthorizations");
+
+            migrationBuilder.DropTable(
+                name: "OpenIddictApplications");
+        }
+    }
+}

src/Bifrost.Web/Data/Migrations/BifrostDbContextModelSnapshot.cs

@@ -17,7 +17,7 @@ namespace Bifrost.Web.Data.Migrations
         {
 #pragma warning disable 612, 618
             modelBuilder
-                .HasAnnotation("ProductVersion", "8.0.0")
+                .HasAnnotation("ProductVersion", "8.0.30")
                 .HasAnnotation("Relational:MaxIdentifierLength", 63);
 
             NpgsqlModelBuilderExtensions.UseIdentityByDefaultColumns(modelBuilder);
@@ -367,15 +367,15 @@ namespace Bifrost.Web.Data.Migrations
                         .HasMaxLength(240)
                         .HasColumnType("character varying(240)");
 
+                    b.Property<string>("TargetSurface")
+                        .IsRequired()
+                        .HasColumnType("text");
+
                     b.Property<string>("TargetSurfaceName")
                         .IsRequired()
                         .HasMaxLength(120)
                         .HasColumnType("character varying(120)");
 
-                    b.Property<string>("TargetSurface")
-                        .IsRequired()
-                        .HasColumnType("text");
-
                     b.Property<string>("Title")
                         .IsRequired()
                         .HasMaxLength(240)
@@ -412,6 +412,88 @@ namespace Bifrost.Web.Data.Migrations
                     b.ToTable("BridgeActions");
                 });
 
+            modelBuilder.Entity("Bifrost.Web.Domain.ConceptAppraisal", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<DateTimeOffset>("CastAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("NetworkTag")
+                        .IsRequired()
+                        .HasMaxLength(64)
+                        .HasColumnType("character varying(64)");
+
+                    b.Property<string>("Stance")
+                        .IsRequired()
+                        .HasMaxLength(16)
+                        .HasColumnType("character varying(16)");
+
+                    b.Property<Guid>("SubjectId")
+                        .HasColumnType("uuid");
+
+                    b.Property<Guid?>("UserAccountId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("VoterClass")
+                        .IsRequired()
+                        .HasMaxLength(16)
+                        .HasColumnType("character varying(16)");
+
+                    b.Property<string>("VoterKey")
+                        .IsRequired()
+                        .HasMaxLength(120)
+                        .HasColumnType("character varying(120)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("UserAccountId");
+
+                    b.HasIndex("NetworkTag", "CastAtUtc");
+
+                    b.HasIndex("SubjectId", "VoterKey")
+                        .IsUnique();
+
+                    b.ToTable("ConceptAppraisals");
+                });
+
+            modelBuilder.Entity("Bifrost.Web.Domain.ConceptSubject", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("Collection")
+                        .IsRequired()
+                        .HasMaxLength(80)
+                        .HasColumnType("character varying(80)");
+
+                    b.Property<string>("Key")
+                        .IsRequired()
+                        .HasMaxLength(80)
+                        .HasColumnType("character varying(80)");
+
+                    b.Property<DateTimeOffset>("RegisteredAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<DateTimeOffset?>("RetiredAtUtc")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("Title")
+                        .IsRequired()
+                        .HasMaxLength(240)
+                        .HasColumnType("character varying(240)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Collection", "Key")
+                        .IsUnique();
+
+                    b.ToTable("ConceptSubjects");
+                });
+
             modelBuilder.Entity("Bifrost.Web.Domain.DecayRun", b =>
                 {
                     b.Property<Guid>("Id")
@@ -889,6 +971,9 @@ namespace Bifrost.Web.Data.Migrations
                         .IsRequired()
                         .HasColumnType("text");
 
+                    b.Property<Guid?>("ProjectId")
+                        .HasColumnType("uuid");
+
                     b.Property<string>("Provider")
                         .IsRequired()
                         .HasColumnType("text");
@@ -908,9 +993,6 @@ namespace Bifrost.Web.Data.Migrations
                         .HasMaxLength(240)
                         .HasColumnType("character varying(240)");
 
-                    b.Property<Guid?>("ProjectId")
-                        .HasColumnType("uuid");
-
                     b.Property<DateTimeOffset>("RecordedAtUtc")
                         .HasColumnType("timestamp with time zone");
 
@@ -922,12 +1004,12 @@ namespace Bifrost.Web.Data.Migrations
 
                     b.HasKey("Id");
 
+                    b.HasIndex("ProjectId");
+
                     b.HasIndex("Provider", "ProviderEventId")
                         .IsUnique()
                         .HasFilter("\"ProviderEventId\" <> ''");
 
-                    b.HasIndex("ProjectId");
-
                     b.HasIndex("UserAccountId", "Kind", "IsCurrentRecurringSupport");
 
                     b.ToTable("PatronSupportEvents");
@@ -1534,6 +1616,214 @@ namespace Bifrost.Web.Data.Migrations
                     b.ToTable("WorkReviews");
                 });
 
+            modelBuilder.Entity("OpenIddict.EntityFrameworkCore.Models.OpenIddictEntityFrameworkCoreApplication", b =>
+                {
+                    b.Property<string>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("text");
+
+                    b.Property<string>("ApplicationType")
+                        .HasMaxLength(50)
+                        .HasColumnType("character varying(50)");
+
+                    b.Property<string>("ClientId")
+                        .HasMaxLength(100)
+                        .HasColumnType("character varying(100)");
+
+                    b.Property<string>("ClientSecret")
+                        .HasColumnType("text");
+
+                    b.Property<string>("ClientType")
+                        .HasMaxLength(50)
+                        .HasColumnType("character varying(50)");
+
+                    b.Property<string>("ConcurrencyToken")
+                        .IsConcurrencyToken()
+                        .HasMaxLength(50)
+                        .HasColumnType("character varying(50)");
+
+                    b.Property<string>("ConsentType")
+                        .HasMaxLength(50)
+                        .HasColumnType("character varying(50)");
+
+                    b.Property<string>("DisplayName")
+                        .HasColumnType("text");
+
+                    b.Property<string>("DisplayNames")
+                        .HasColumnType("text");
+
+                    b.Property<string>("JsonWebKeySet")
+                        .HasColumnType("text");
+
+                    b.Property<string>("Permissions")
+                        .HasColumnType("text");
+
+                    b.Property<string>("PostLogoutRedirectUris")
+                        .HasColumnType("text");
+
+                    b.Property<string>("Properties")
+                        .HasColumnType("text");
+
+                    b.Property<string>("RedirectUris")
+                        .HasColumnType("text");
+
+                    b.Property<string>("Requirements")
+                        .HasColumnType("text");
+
+                    b.Property<string>("Settings")
+                        .HasColumnType("text");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("ClientId")
+                        .IsUnique();
+
+                    b.ToTable("OpenIddictApplications", (string)null);
+                });
+
+            modelBuilder.Entity("OpenIddict.EntityFrameworkCore.Models.OpenIddictEntityFrameworkCoreAuthorization", b =>
+                {
+                    b.Property<string>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("text");
+
+                    b.Property<string>("ApplicationId")
+                        .HasColumnType("text");
+
+                    b.Property<string>("ConcurrencyToken")
+                        .IsConcurrencyToken()
+                        .HasMaxLength(50)
+                        .HasColumnType("character varying(50)");
+
+                    b.Property<DateTime?>("CreationDate")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("Properties")
+                        .HasColumnType("text");
+
+                    b.Property<string>("Scopes")
+                        .HasColumnType("text");
+
+                    b.Property<string>("Status")
+                        .HasMaxLength(50)
+                        .HasColumnType("character varying(50)");
+
+                    b.Property<string>("Subject")
+                        .HasMaxLength(400)
+                        .HasColumnType("character varying(400)");
+
+                    b.Property<string>("Type")
+                        .HasMaxLength(50)
+                        .HasColumnType("character varying(50)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("ApplicationId", "Status", "Subject", "Type");
+
+                    b.ToTable("OpenIddictAuthorizations", (string)null);
+                });
+
+            modelBuilder.Entity("OpenIddict.EntityFrameworkCore.Models.OpenIddictEntityFrameworkCoreScope", b =>
+                {
+                    b.Property<string>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("text");
+
+                    b.Property<string>("ConcurrencyToken")
+                        .IsConcurrencyToken()
+                        .HasMaxLength(50)
+                        .HasColumnType("character varying(50)");
+
+                    b.Property<string>("Description")
+                        .HasColumnType("text");
+
+                    b.Property<string>("Descriptions")
+                        .HasColumnType("text");
+
+                    b.Property<string>("DisplayName")
+                        .HasColumnType("text");
+
+                    b.Property<string>("DisplayNames")
+                        .HasColumnType("text");
+
+                    b.Property<string>("Name")
+                        .HasMaxLength(200)
+                        .HasColumnType("character varying(200)");
+
+                    b.Property<string>("Properties")
+                        .HasColumnType("text");
+
+                    b.Property<string>("Resources")
+                        .HasColumnType("text");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("Name")
+                        .IsUnique();
+
+                    b.ToTable("OpenIddictScopes", (string)null);
+                });
+
+            modelBuilder.Entity("OpenIddict.EntityFrameworkCore.Models.OpenIddictEntityFrameworkCoreToken", b =>
+                {
+                    b.Property<string>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("text");
+
+                    b.Property<string>("ApplicationId")
+                        .HasColumnType("text");
+
+                    b.Property<string>("AuthorizationId")
+                        .HasColumnType("text");
+
+                    b.Property<string>("ConcurrencyToken")
+                        .IsConcurrencyToken()
+                        .HasMaxLength(50)
+                        .HasColumnType("character varying(50)");
+
+                    b.Property<DateTime?>("CreationDate")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<DateTime?>("ExpirationDate")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("Payload")
+                        .HasColumnType("text");
+
+                    b.Property<string>("Properties")
+                        .HasColumnType("text");
+
+                    b.Property<DateTime?>("RedemptionDate")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("ReferenceId")
+                        .HasMaxLength(100)
+                        .HasColumnType("character varying(100)");
+
+                    b.Property<string>("Status")
+                        .HasMaxLength(50)
+                        .HasColumnType("character varying(50)");
+
+                    b.Property<string>("Subject")
+                        .HasMaxLength(400)
+                        .HasColumnType("character varying(400)");
+
+                    b.Property<string>("Type")
+                        .HasMaxLength(150)
+                        .HasColumnType("character varying(150)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("AuthorizationId");
+
+                    b.HasIndex("ReferenceId")
+                        .IsUnique();
+
+                    b.HasIndex("ApplicationId", "Status", "Subject", "Type");
+
+                    b.ToTable("OpenIddictTokens", (string)null);
+                });
+
             modelBuilder.Entity("Bifrost.Web.Domain.AgentDispatchRun", b =>
                 {
                     b.HasOne("Bifrost.Web.Domain.UserAccount", "StartedByUserAccount")
@@ -1615,6 +1905,22 @@ namespace Bifrost.Web.Data.Migrations
                     b.Navigation("WorkItem");
                 });
 
+            modelBuilder.Entity("Bifrost.Web.Domain.ConceptAppraisal", b =>
+                {
+                    b.HasOne("Bifrost.Web.Domain.ConceptSubject", "Subject")
+                        .WithMany()
+                        .HasForeignKey("SubjectId")
+                        .OnDelete(DeleteBehavior.Restrict)
+                        .IsRequired();
+
+                    b.HasOne("Bifrost.Web.Domain.UserAccount", null)
+                        .WithMany()
+                        .HasForeignKey("UserAccountId")
+                        .OnDelete(DeleteBehavior.SetNull);
+
+                    b.Navigation("Subject");
+                });
+
             modelBuilder.Entity("Bifrost.Web.Domain.GitHubIssueLink", b =>
                 {
                     b.HasOne("Bifrost.Web.Domain.WorkItem", "WorkItem")
@@ -1992,6 +2298,30 @@ namespace Bifrost.Web.Data.Migrations
                     b.Navigation("WorkItem");
                 });
 
+            modelBuilder.Entity("OpenIddict.EntityFrameworkCore.Models.OpenIddictEntityFrameworkCoreAuthorization", b =>
+                {
+                    b.HasOne("OpenIddict.EntityFrameworkCore.Models.OpenIddictEntityFrameworkCoreApplication", "Application")
+                        .WithMany("Authorizations")
+                        .HasForeignKey("ApplicationId");
+
+                    b.Navigation("Application");
+                });
+
+            modelBuilder.Entity("OpenIddict.EntityFrameworkCore.Models.OpenIddictEntityFrameworkCoreToken", b =>
+                {
+                    b.HasOne("OpenIddict.EntityFrameworkCore.Models.OpenIddictEntityFrameworkCoreApplication", "Application")
+                        .WithMany("Tokens")
+                        .HasForeignKey("ApplicationId");
+
+                    b.HasOne("OpenIddict.EntityFrameworkCore.Models.OpenIddictEntityFrameworkCoreAuthorization", "Authorization")
+                        .WithMany("Tokens")
+                        .HasForeignKey("AuthorizationId");
+
+                    b.Navigation("Application");
+
+                    b.Navigation("Authorization");
+                });
+
             modelBuilder.Entity("Bifrost.Web.Domain.Membership", b =>
                 {
                     b.Navigation("RoleAssignments");
@@ -2090,6 +2420,18 @@ namespace Bifrost.Web.Data.Migrations
 
                     b.Navigation("WorkReviews");
                 });
+
+            modelBuilder.Entity("OpenIddict.EntityFrameworkCore.Models.OpenIddictEntityFrameworkCoreApplication", b =>
+                {
+                    b.Navigation("Authorizations");
+
+                    b.Navigation("Tokens");
+                });
+
+            modelBuilder.Entity("OpenIddict.EntityFrameworkCore.Models.OpenIddictEntityFrameworkCoreAuthorization", b =>
+                {
+                    b.Navigation("Tokens");
+                });
 #pragma warning restore 612, 618
         }
     }

src/Bifrost.Web/Domain/ConceptVoteModels.cs

@@ -0,0 +1,50 @@
+namespace Bifrost.Web.Domain;
+
+public enum ConceptStance
+{
+    Up,
+    Down
+}
+
+public enum VoterClass
+{
+    Anonymous,
+    Account,
+    Member
+}
+
+public sealed class ConceptSubject
+{
+    public Guid Id { get; set; } = Guid.NewGuid();
+
+    public string Collection { get; set; } = string.Empty;
+
+    public string Key { get; set; } = string.Empty;
+
+    public string Title { get; set; } = string.Empty;
+
+    public DateTimeOffset RegisteredAtUtc { get; set; }
+
+    public DateTimeOffset? RetiredAtUtc { get; set; }
+}
+
+public sealed class ConceptAppraisal
+{
+    public Guid Id { get; set; } = Guid.NewGuid();
+
+    public Guid SubjectId { get; set; }
+
+    public string VoterKey { get; set; } = string.Empty;
+
+    public ConceptStance Stance { get; set; }
+
+    public VoterClass VoterClass { get; set; }
+
+    public Guid? UserAccountId { get; set; }
+
+    public string NetworkTag { get; set; } = string.Empty;
+
+    public DateTimeOffset CastAtUtc { get; set; }
+
+    public ConceptSubject? Subject { get; set; }
+}

src/Bifrost.Web/Features/ConceptVotes/CastRequestGuard.cs

@@ -0,0 +1,29 @@
+using Bifrost.Web.Configuration;
+using Microsoft.AspNetCore.Http;
+
+namespace Bifrost.Web.Features.ConceptVotes;
+
+// The one place that decides whether a state-changing request to the vote page came from the site itself. The anonymous
+// vote flow carries no antiforgery token and no antiforgery cookie, so a cross-site form post is refused here instead
+// (OWASP Fetch Metadata): the Origin header must equal the configured site origin byte for byte, or, when the browser
+// sent no Origin, Sec-Fetch-Site must be exactly same-origin. Same-site, cross-site, none, absent and a repeated header
+// are all refused. Header values are compared, never echoed.
+public static class CastRequestGuard
+{
+    public static bool Allows(HttpRequest request, BifrostHostOptions host)
+    {
+        if (!Uri.TryCreate(host.PublicBaseUrl, UriKind.Absolute, out var site))
+        {
+            return false;
+        }
+
+        var origin = request.Headers.Origin;
+        if (request.Headers.ContainsKey("Origin"))
+        {
+            return origin.Count == 1 && string.Equals(origin[0], site.GetLeftPart(UriPartial.Authority), StringComparison.Ordinal);
+        }
+
+        var fetchSite = request.Headers["Sec-Fetch-Site"];
+        return fetchSite.Count == 1 && string.Equals(fetchSite[0], "same-origin", StringComparison.Ordinal);
+    }
+}

src/Bifrost.Web/Features/ConceptVotes/ConceptAppraisalService.cs

@@ -0,0 +1,268 @@
+using System.Net;
+using Bifrost.Web.Configuration;
+using Bifrost.Web.Data;
+using Bifrost.Web.Domain;
+using Bifrost.Web.Features.Shared;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Options;
+using Npgsql;
+
+namespace Bifrost.Web.Features.ConceptVotes;
+
+public enum CastResult
+{
+    Recorded,
+    Changed,
+    Unchanged,
+    UnknownSubject,
+    RetiredSubject,
+    NoVoter
+}
+
+public sealed record StanceCounts(int Up, int Down);
+
+public sealed record ConceptTally(int Up, int Down, StanceCounts Members);
+
+public sealed record ConceptSubjectView(
+    string Collection,
+    string Key,
+    string Title,
+    ConceptTally Tally,
+    ConceptStance? YourStance);
+
+// The only writer of ConceptAppraisal rows. Tallies are derived from rows on every read.
+public sealed class ConceptAppraisalService(
+    BifrostDbContext dbContext,
+    AuditTrailService auditTrail,
+    TimeProvider timeProvider,
+    IOptions<ConceptVoteOptions> options)
+{
+    private const string UniqueViolation = "23505";
+
+    public async Task<CastResult> CastAsync(
+        string collection,
+        string key,
+        VoterIdentity? voter,
+        ConceptStance stance,
+        IPAddress? client,
+        CancellationToken cancellationToken)
+    {
+        if (voter is null)
+        {
+            return CastResult.NoVoter;
+        }
+
+        var subject = await FindSubjectAsync(collection, key, cancellationToken);
+        if (subject is null)
+        {
+            return CastResult.UnknownSubject;
+        }
+
+        if (subject.RetiredAtUtc is not null)
+        {
+            return CastResult.RetiredSubject;
+        }
+
+        var opts = options.Value;
+        var tag = client is null
+            ? string.Empty
+            : NetworkPrefix.Tag(client, opts.IPv4PrefixLength, opts.IPv6PrefixLength, opts.NetworkTagSecret);
+
+        var existing = await FindAppraisalAsync(subject.Id, voter.Key, cancellationToken);
+        if (existing is not null)
+        {
+            return await ApplyStanceAsync(existing, stance, tag, cancellationToken);
+        }
+
+        var row = new ConceptAppraisal
+        {
+            SubjectId = subject.Id,
+            VoterKey = voter.Key,
+            Stance = stance,
+            VoterClass = voter.Class,
+            UserAccountId = voter.UserAccountId,
+            NetworkTag = tag,
+            CastAtUtc = timeProvider.GetUtcNow()
+        };
+        dbContext.ConceptAppraisals.Add(row);
+
+        try
+        {
+            await dbContext.SaveChangesAsync(cancellationToken);
+            return CastResult.Recorded;
+        }
+        catch (DbUpdateException ex) when (ex.InnerException is PostgresException { SqlState: UniqueViolation })
+        {
+            // A concurrent cast by the same voter won the insert: apply this stance to their row, once.
+            dbContext.Entry(row).State = EntityState.Detached;
+            var winner = await FindAppraisalAsync(subject.Id, voter.Key, cancellationToken);
+            if (winner is null)
+            {
+                throw;
+            }
+
+            return await ApplyStanceAsync(winner, stance, tag, cancellationToken);
+        }
+    }
+
+    public async Task<bool> RetractAsync(
+        string collection,
+        string key,
+        VoterIdentity? voter,
+        CancellationToken cancellationToken)
+    {
+        if (voter is null)
+        {
+            return false;
+        }
+
+        var subject = await FindSubjectAsync(collection, key, cancellationToken);
+        if (subject is null)
+        {
+            return false;
+        }
+
+        var row = await FindAppraisalAsync(subject.Id, voter.Key, cancellationToken);
+        if (row is null)
+        {
+            return false;
+        }
+
+        dbContext.ConceptAppraisals.Remove(row);
+        await dbContext.SaveChangesAsync(cancellationToken);
+        return true;
+    }
+
+    public async Task<int> PurgeAsync(
+        CurrentBifrostActor actor,
+        string networkTag,
+        DateTimeOffset fromUtc,
+        DateTimeOffset toUtc,
+        CancellationToken cancellationToken)
+    {
+        if (!actor.CanManageMembership || actor.UserAccount is null)
+        {
+            throw new UnauthorizedAccessException("Only a platform administrator can purge appraisals.");
+        }
+
+        if (string.IsNullOrEmpty(networkTag))
+        {
+            return 0;
+        }
+
+        var rows = await dbContext.ConceptAppraisals
+            .Where(x => x.NetworkTag == networkTag && x.CastAtUtc >= fromUtc && x.CastAtUtc < toUtc)
+            .ToListAsync(cancellationToken);
+        dbContext.ConceptAppraisals.RemoveRange(rows);
+
+        // The audit write saves the removals in the same SaveChanges. The member dashboard renders Detail, so it
+        // carries the window and count only: no network tag and no voter keys. The actor and window audit the purge.
+        await auditTrail.RecordAsync(
+            actor.UserAccount.Id,
+            nameof(ConceptAppraisal),
+            Guid.Empty,
+            "Purge",
+            $"from={fromUtc:O} to={toUtc:O} count={rows.Count}",
+            cancellationToken);
+        return rows.Count;
+    }
+
+    public async Task<IReadOnlyDictionary<string, ConceptTally>> GetTalliesAsync(
+        string collection,
+        CancellationToken cancellationToken)
+    {
+        var live = await dbContext.ConceptSubjects.AsNoTracking()
+            .Where(x => x.Collection == collection && x.RetiredAtUtc == null)
+            .Select(x => new { x.Id, x.Key })
+            .ToListAsync(cancellationToken);
+        var ids = live.Select(x => x.Id).ToList();
+
+        var groups = await dbContext.ConceptAppraisals.AsNoTracking()
+            .Where(x => ids.Contains(x.SubjectId))
+            .GroupBy(x => new { x.SubjectId, x.Stance, IsMember = x.VoterClass == VoterClass.Member })
+            .Select(g => new { g.Key.SubjectId, g.Key.Stance, g.Key.IsMember, Count = g.Count() })
+            .ToListAsync(cancellationToken);
+
+        return live.ToDictionary(
+            s => s.Key,
+            s => Tally(groups.Where(g => g.SubjectId == s.Id).Select(g => (g.Stance, g.IsMember, g.Count))),
+            StringComparer.Ordinal);
+    }
+
+    public async Task<ConceptSubjectView?> GetSubjectAsync(
+        string collection,
+        string key,
+        VoterIdentity? voter,
+        CancellationToken cancellationToken)
+    {
+        var subject = await FindSubjectAsync(collection, key, cancellationToken);
+        if (subject is null || subject.RetiredAtUtc is not null)
+        {
+            return null;
+        }
+
+        var groups = await dbContext.ConceptAppraisals.AsNoTracking()
+            .Where(x => x.SubjectId == subject.Id)
+            .GroupBy(x => new { x.Stance, IsMember = x.VoterClass == VoterClass.Member })
+            .Select(g => new { g.Key.Stance, g.Key.IsMember, Count = g.Count() })
+            .ToListAsync(cancellationToken);
+        var yours = voter is null
+            ? null
+            : (await FindAppraisalAsync(subject.Id, voter.Key, cancellationToken))?.Stance;
+
+        return new ConceptSubjectView(
+            subject.Collection,
+            subject.Key,
+            subject.Title,
+            Tally(groups.Select(g => (g.Stance, g.IsMember, g.Count))),
+            yours);
+    }
+
+    private static ConceptTally Tally(IEnumerable<(ConceptStance Stance, bool IsMember, int Count)> groups)
+    {
+        int up = 0, down = 0, memberUp = 0, memberDown = 0;
+        foreach (var (stance, isMember, count) in groups)
+        {
+            if (stance == ConceptStance.Up)
+            {
+                up += count;
+                memberUp += isMember ? count : 0;
+            }
+            else
+            {
+                down += count;
+                memberDown += isMember ? count : 0;
+            }
+        }
+
+        return new ConceptTally(up, down, new StanceCounts(memberUp, memberDown));
+    }
+
+    private async Task<CastResult> ApplyStanceAsync(
+        ConceptAppraisal row,
+        ConceptStance stance,
+        string tag,
+        CancellationToken cancellationToken)
+    {
+        if (row.Stance == stance)
+        {
+            return CastResult.Unchanged;
+        }
+
+        row.Stance = stance;
+        row.NetworkTag = tag;
+        row.CastAtUtc = timeProvider.GetUtcNow();
+        await dbContext.SaveChangesAsync(cancellationToken);
+        return CastResult.Changed;
+    }
+
+    private Task<ConceptSubject?> FindSubjectAsync(string collection, string key, CancellationToken cancellationToken) =>
+        ConceptKey.IsValid(collection) && ConceptKey.IsValid(key)
+            ? dbContext.ConceptSubjects
+                .SingleOrDefaultAsync(x => x.Collection == collection && x.Key == key, cancellationToken)
+            : Task.FromResult<ConceptSubject?>(null);
+
+    private Task<ConceptAppraisal?> FindAppraisalAsync(Guid subjectId, string voterKey, CancellationToken cancellationToken) =>
+        dbContext.ConceptAppraisals
+            .SingleOrDefaultAsync(x => x.SubjectId == subjectId && x.VoterKey == voterKey, cancellationToken);
+}

src/Bifrost.Web/Features/ConceptVotes/ConceptCommand.cs

@@ -0,0 +1,70 @@
+using Microsoft.Extensions.DependencyInjection;
+
+namespace Bifrost.Web.Features.ConceptVotes;
+
+// Host command: Bifrost.Web.dll concepts plan|apply <collection> <manifest.json> [--retire k1,k2]
+public static class ConceptCommand
+{
+    public const int Ok = 0;
+    public const int Refused = 1;
+    public const int Usage = 2;
+
+    // args are the words after "concepts".
+    public static async Task<int> RunAsync(string[] args, IServiceProvider services, TextWriter output)
+    {
+        var known = args.Length > 0 && args[0] is "plan" or "apply";
+        var hasRetire = args.Length == 5 && args[3] == "--retire";
+        if (!known || !(args.Length == 3 || hasRetire))
+        {
+            await output.WriteLineAsync("usage: concepts plan|apply <collection> <manifest.json> [--retire k1,k2]");
+            return Usage;
+        }
+
+        string[] retire = hasRetire ? args[4].Split(',', StringSplitOptions.RemoveEmptyEntries) : [];
+        try
+        {
+            var ships = ConceptSubjectRegistry.ParseManifest(await ReadManifestAsync(args[2]));
+            await using var scope = services.CreateAsyncScope();
+            var registry = scope.ServiceProvider.GetRequiredService<ConceptSubjectRegistry>();
+            var plan = args[0] == "apply"
+                ? await registry.ApplyAsync(args[1], ships, retire, default)
+                : await registry.PlanAsync(args[1], ships, retire, default);
+
+            foreach (var entry in plan.Entries)
+            {
+                await output.WriteLineAsync($"{entry.Change.ToString().ToLowerInvariant()} {entry.Key}");
+            }
+
+            return Ok;
+        }
+        catch (ManifestRefusedException ex)
+        {
+            await output.WriteLineAsync($"refused {ex.Field} {ex.Code}");
+            return Refused;
+        }
+    }
+
+    // Reads at most one byte past the bound, so a wrong file is never read whole.
+    private static async Task<byte[]> ReadManifestAsync(string path)
+    {
+        try
+        {
+            await using var stream = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.Read, 1, true);
+            var buffer = new byte[ConceptSubjectRegistry.MaxManifestBytes + 1];
+            var length = 0;
+            int read;
+            while (length < buffer.Length && (read = await stream.ReadAsync(buffer.AsMemory(length))) > 0)
+            {
+                length += read;
+            }
+
+            return buffer[..length];
+        }
+        // An empty or NUL path is an ArgumentException; a path the platform cannot name is NotSupported.
+        catch (Exception ex) when (ex is IOException or UnauthorizedAccessException or ArgumentException
+                                       or NotSupportedException or System.Security.SecurityException)
+        {
+            throw new ManifestRefusedException("manifest", "Unreadable");
+        }
+    }
+}

src/Bifrost.Web/Features/ConceptVotes/ConceptKey.cs

@@ -0,0 +1,13 @@
+using System.Text.RegularExpressions;
+
+namespace Bifrost.Web.Features.ConceptVotes;
+
+// The one grammar for a concept collection or key. \z, not $: $ admits a trailing line feed.
+public static class ConceptKey
+{
+    public const int MaxLength = 80;
+
+    private static readonly Regex Shape = new(@"^[a-z0-9-]{1,80}\z", RegexOptions.CultureInvariant);
+
+    public static bool IsValid(string? value) => value is not null && Shape.IsMatch(value);
+}

src/Bifrost.Web/Features/ConceptVotes/ConceptSubjectRegistry.cs

@@ -0,0 +1,352 @@
+using System.Globalization;
+using System.Text;
+using System.Text.Json;
+using Bifrost.Web.Data;
+using Bifrost.Web.Domain;
+using Bifrost.Web.Features.Shared;
+using Microsoft.EntityFrameworkCore;
+
+namespace Bifrost.Web.Features.ConceptVotes;
+
+public enum SubjectChange
+{
+    Add,
+    Rename,
+    Unchanged,
+    Revive,
+    Absent,
+    Retire,
+    Retired
+}
+
+public sealed record ManifestShip(string Key, string Title);
+
+public sealed record SubjectPlanEntry(SubjectChange Change, string Key, string Title);
+
+public sealed record SubjectPlan(string Collection, IReadOnlyList<SubjectPlanEntry> Entries);
+
+// A refusal names the field and a code, never the offending value.
+public sealed class ManifestRefusedException(string field, string code)
+    : Exception($"{field}: {code}")
+{
+    public string Field { get; } = field;
+
+    public string Code { get; } = code;
+}
+
+// The only writer of ConceptSubject: decides which concept keys exist, their titles and their retirement.
+public sealed class ConceptSubjectRegistry(
+    BifrostDbContext dbContext,
+    AuditTrailService auditTrail,
+    TimeProvider timeProvider)
+{
+    public const int MaxTitleLength = 240;
+
+    // Defaulted bounds (a Mill manifest is tens of ships): the whole file is refused above either.
+    public const int MaxManifestBytes = 1024 * 1024;
+
+    public const int MaxShips = 1000;
+
+    private static readonly UTF8Encoding StrictUtf8 = new(false, true);
+
+    // The Mill manifest is JSON from outside the Verse. Only ships[].id and ships[].name are read.
+    // This is the one input boundary: every malformed input leaves as a ManifestRefusedException.
+    public static IReadOnlyList<ManifestShip> ParseManifest(ReadOnlyMemory<byte> utf8)
+    {
+        using var document = ParseDocument(utf8);
+        var ships = ShipsOf(document.RootElement);
+        if (ships.ValueKind != JsonValueKind.Array)
+        {
+            throw new ManifestRefusedException("ships", "Missing");
+        }
+
+        if (ships.GetArrayLength() > MaxShips)
+        {
+            throw new ManifestRefusedException("ships", "TooMany");
+        }
+
+        var result = new List<ManifestShip>();
+        var seen = new HashSet<string>(StringComparer.Ordinal);
+        foreach (var ship in ships.EnumerateArray())
+        {
+            var at = $"ships[{result.Count}]";
+            var key = ReadString(ship, "id", at);
+            var title = ReadString(ship, "name", at);
+            if (!ConceptKey.IsValid(key))
+            {
+                throw new ManifestRefusedException($"{at}.id", "InvalidKey");
+            }
+
+            if (!seen.Add(key))
+            {
+                throw new ManifestRefusedException($"{at}.id", "Duplicate");
+            }
+
+            if (!IsValidTitle(title))
+            {
+                throw new ManifestRefusedException($"{at}.name", "InvalidTitle");
+            }
+
+            if (title.Length > MaxTitleLength)
+            {
+                throw new ManifestRefusedException($"{at}.name", "TooLong");
+            }
+
+            result.Add(new ManifestShip(key, title));
+        }
+
+        return result;
+    }
+
+    private static JsonElement ShipsOf(JsonElement root)
+    {
+        if (root.ValueKind != JsonValueKind.Object)
+        {
+            return default;
+        }
+
+        return root.TryGetProperty("ships", out var ships) ? ships : default;
+    }
+
+    // A displayed title: no control, format (bidi, zero-width, BOM), line or paragraph separator
+    // character, no leading or trailing whitespace, and at least one letter or digit. This is the
+    // character-class rule of the mind schema's Title type, kept here as the one copy in Bifrost.
+    private static bool IsValidTitle(string title)
+    {
+        if (title.Length == 0 || title != title.Trim())
+        {
+            return false;
+        }
+
+        var hasLetterOrDigit = false;
+        foreach (var rune in title.EnumerateRunes())
+        {
+            if (Rune.GetUnicodeCategory(rune) is UnicodeCategory.Control or UnicodeCategory.Format
+                or UnicodeCategory.LineSeparator or UnicodeCategory.ParagraphSeparator)
+            {
+                return false;
+            }
+
+            hasLetterOrDigit |= Rune.IsLetterOrDigit(rune);
+        }
+
+        return hasLetterOrDigit;
+    }
+
+    private static JsonDocument ParseDocument(ReadOnlyMemory<byte> utf8)
+    {
+        if (utf8.Length > MaxManifestBytes)
+        {
+            throw new ManifestRefusedException("manifest", "TooLarge");
+        }
+
+        try
+        {
+            StrictUtf8.GetCharCount(utf8.Span);
+        }
+        catch (DecoderFallbackException)
+        {
+            throw new ManifestRefusedException("manifest", "NotUtf8");
+        }
+
+        try
+        {
+            RejectDuplicateProperties(utf8.Span);
+            return JsonDocument.Parse(utf8);
+        }
+        catch (JsonException)
+        {
+            throw new ManifestRefusedException("manifest", "NotJson");
+        }
+        catch (InvalidOperationException)
+        {
+            // A property name holding a lone surrogate escape: not text.
+            throw new ManifestRefusedException("manifest", "BadText");
+        }
+    }
+
+    // System.Text.Json (net8.0) keeps the last of two equal property names; a manifest that says
+    // one thing twice is refused instead.
+    private static void RejectDuplicateProperties(ReadOnlySpan<byte> utf8)
+    {
+        var reader = new Utf8JsonReader(utf8);
+        var scopes = new Stack<HashSet<string>?>();
+        while (reader.Read())
+        {
+            switch (reader.TokenType)
+            {
+                case JsonTokenType.StartObject:
+                    scopes.Push(new HashSet<string>(StringComparer.Ordinal));
+                    break;
+                case JsonTokenType.StartArray:
+                    scopes.Push(null);
+                    break;
+                case JsonTokenType.EndObject:
+                case JsonTokenType.EndArray:
+                    scopes.Pop();
+                    break;
+                case JsonTokenType.PropertyName:
+                    if (!scopes.Peek()!.Add(reader.GetString()!))
+                    {
+                        throw new ManifestRefusedException("manifest", "DuplicateProperty");
+                    }
+
+                    break;
+            }
+        }
+    }
+
+    public async Task<SubjectPlan> PlanAsync(
+        string collection,
+        IReadOnlyList<ManifestShip> ships,
+        IReadOnlyCollection<string> retire,
+        CancellationToken cancellationToken)
+    {
+        if (!ConceptKey.IsValid(collection))
+        {
+            throw new ManifestRefusedException("collection", "InvalidKey");
+        }
+
+        var named = new HashSet<string>(StringComparer.Ordinal);
+        foreach (var key in retire)
+        {
+            if (!ConceptKey.IsValid(key))
+            {
+                throw new ManifestRefusedException("retire", "InvalidKey");
+            }
+
+            named.Add(key);
+        }
+
+        var registered = await dbContext.ConceptSubjects.AsNoTracking()
+            .Where(x => x.Collection == collection)
+            .ToDictionaryAsync(x => x.Key, StringComparer.Ordinal, cancellationToken);
+
+        var entries = new List<SubjectPlanEntry>();
+        foreach (var ship in ships)
+        {
+            var change = !registered.TryGetValue(ship.Key, out var row)
+                ? SubjectChange.Add
+                : row.RetiredAtUtc is not null
+                    ? SubjectChange.Revive
+                    : row.Title != ship.Title ? SubjectChange.Rename : SubjectChange.Unchanged;
+            entries.Add(new SubjectPlanEntry(change, ship.Key, ship.Title));
+        }
+
+        var inManifest = ships.Select(x => x.Key).ToHashSet(StringComparer.Ordinal);
+        var absent = registered.Values
+            .Where(x => x.RetiredAtUtc is null && !inManifest.Contains(x.Key))
+            .OrderBy(x => x.Key, StringComparer.Ordinal)
+            .ToList();
+        foreach (var subject in absent)
+        {
+            entries.Add(new SubjectPlanEntry(
+                named.Remove(subject.Key) ? SubjectChange.Retire : SubjectChange.Absent,
+                subject.Key,
+                subject.Title));
+        }
+
+        // A named key that an earlier run already retired is done: a rerun converges.
+        foreach (var key in named.OrderBy(x => x, StringComparer.Ordinal).ToList())
+        {
+            if (registered.TryGetValue(key, out var done) && done.RetiredAtUtc is not null && !inManifest.Contains(key))
+            {
+                entries.Add(new SubjectPlanEntry(SubjectChange.Retired, key, done.Title));
+                named.Remove(key);
+            }
+        }
+
+        // Whatever is still named is not a registered key missing from the manifest.
+        if (named.Count > 0)
+        {
+            throw new ManifestRefusedException("retire", "NotAbsent");
+        }
+
+        return new SubjectPlan(collection, entries);
+    }
+
+    public async Task<SubjectPlan> ApplyAsync(
+        string collection,
+        IReadOnlyList<ManifestShip> ships,
+        IReadOnlyCollection<string> retire,
+        CancellationToken cancellationToken)
+    {
+        var plan = await PlanAsync(collection, ships, retire, cancellationToken);
+        var rows = await dbContext.ConceptSubjects
+            .Where(x => x.Collection == collection)
+            .ToDictionaryAsync(x => x.Key, StringComparer.Ordinal, cancellationToken);
+
+        foreach (var entry in plan.Entries)
+        {
+            if (entry.Change is SubjectChange.Unchanged or SubjectChange.Absent or SubjectChange.Retired)
+            {
+                continue;
+            }
+
+            ConceptSubject subject;
+            if (entry.Change == SubjectChange.Add)
+            {
+                subject = new ConceptSubject
+                {
+                    Collection = collection,
+                    Key = entry.Key,
+                    Title = entry.Title,
+                    RegisteredAtUtc = timeProvider.GetUtcNow()
+                };
+                dbContext.ConceptSubjects.Add(subject);
+            }
+            else
+            {
+                subject = rows[entry.Key];
+                if (entry.Change == SubjectChange.Retire)
+                {
+                    subject.RetiredAtUtc = timeProvider.GetUtcNow();
+                }
+                else
+                {
+                    subject.Title = entry.Title;
+                    subject.RetiredAtUtc = null;
+                }
+            }
+
+            // The audit write saves the subject change in the same SaveChanges.
+            await auditTrail.RecordAsync(
+                null,
+                nameof(ConceptSubject),
+                subject.Id,
+                entry.Change.ToString(),
+                $"actor=host-command collection={collection} key={entry.Key}",
+                cancellationToken);
+        }
+
+        return plan;
+    }
+
+    private static string ReadString(JsonElement ship, string name, string at)
+    {
+        if (ship.ValueKind != JsonValueKind.Object)
+        {
+            throw new ManifestRefusedException($"{at}.{name}", "Missing");
+        }
+
+        if (!ship.TryGetProperty(name, out var value))
+        {
+            throw new ManifestRefusedException($"{at}.{name}", "Missing");
+        }
+
+        if (value.ValueKind != JsonValueKind.String)
+        {
+            throw new ManifestRefusedException($"{at}.{name}", "NotString");
+        }
+
+        try
+        {
+            return value.GetString()!;
+        }
+        catch (InvalidOperationException)
+        {
+            // A lone surrogate escape: not text.
+            throw new ManifestRefusedException($"{at}.{name}", "BadText");
+        }
+    }
+}

src/Bifrost.Web/Features/ConceptVotes/ConceptTallyExport.cs

@@ -0,0 +1,68 @@
+using Bifrost.Web.Configuration;
+using Microsoft.AspNetCore.Cors.Infrastructure;
+using Microsoft.Extensions.Options;
+using Microsoft.Net.Http.Headers;
+
+namespace Bifrost.Web.Features.ConceptVotes;
+
+// The public tally export and the one cross-origin policy in Bifrost. It owns nothing: counts are derived by
+// ConceptAppraisalService, origins come from ConceptVoteOptions.
+public static class ConceptTallyExport
+{
+    public const string CorsPolicy = "ConceptTallies";
+    private const string RoutePrefix = "/public/concepts";
+
+    // GET only, no credentials, and required by the export route alone: every other route carries no CORS
+    // metadata and gets no CORS headers.
+    public static IServiceCollection AddConceptTallyCors(this IServiceCollection services)
+    {
+        services.AddCors();
+        services
+            .AddOptions<CorsOptions>()
+            .Configure<IOptions<ConceptVoteOptions>>((cors, conceptVotes) =>
+                cors.AddPolicy(
+                    CorsPolicy,
+                    policy => policy.WithOrigins(conceptVotes.Value.AllowedOrigins).WithMethods("GET")));
+        return services;
+    }
+
+    // Replaces app.UseCors(): the one place the origin decision is made. Every response under the export route
+    // (200, 404, 304, preflight, refusal) varies by Origin, appended to any Vary already present, because the CORS
+    // headers differ by request Origin and a URL-keyed cache must not serve one variant to another. ASP.NET Core
+    // adds Vary: Origin itself only for policies of more than one origin; this policy has one, and a repeated token is harmless.
+    public static IApplicationBuilder UseConceptTallyCors(this IApplicationBuilder app)
+    {
+        app.Use((context, next) =>
+        {
+            if (context.Request.Path.StartsWithSegments(RoutePrefix))
+            {
+                context.Response.OnStarting(() =>
+                {
+                    context.Response.Headers.Append(HeaderNames.Vary, "Origin");
+                    return Task.CompletedTask;
+                });
+            }
+
+            return next(context);
+        });
+        return app.UseCors();
+    }
+
+    // Counts only, per live subject: ConceptTally carries no voter key, account id or network tag.
+    public static IEndpointConventionBuilder MapConceptTallyExport(this IEndpointRouteBuilder app) =>
+        app.MapGet(RoutePrefix + "/{collection}/tallies", async (
+            string collection,
+            ConceptAppraisalService appraisals,
+            HttpResponse response,
+            CancellationToken cancellationToken) =>
+        {
+            var tallies = await appraisals.GetTalliesAsync(collection, cancellationToken);
+            if (tallies.Count == 0)
+            {
+                return Results.NotFound();
+            }
+
+            response.Headers.CacheControl = "public, max-age=60";
+            return Results.Json(tallies);
+        }).AllowAnonymous().RequireCors(CorsPolicy);
+}

src/Bifrost.Web/Features/ConceptVotes/ConceptVoteRateLimits.cs

@@ -0,0 +1,29 @@
+using System.Net;
+using Bifrost.Web.Configuration;
+using Bifrost.Web.Features.Shared;
+using Microsoft.Extensions.Options;
+
+namespace Bifrost.Web.Features.ConceptVotes;
+
+// The one owner of the vote budgets. Cast is spent by every cast and retract; mint is spent additionally by a cast that
+// is about to mint a device cookie. A denial says why and how long to wait, and writes nothing. The partition is the
+// account when the voter is signed in, otherwise the network prefix (NetworkPrefix.Of) of the address the
+// forwarded-headers middleware left on the connection. No header and no client input ever becomes a key. Accounts
+// have a table of their own, so a flood of anonymous sources cannot crowd a signed-in voter out of it.
+public sealed class ConceptVoteRateLimits(IOptions<ConceptVoteOptions> options, TimeProvider clock)
+{
+    private readonly ConceptVoteOptions opts = options.Value;
+    private readonly FixedWindowBudget castAccounts = new(options.Value.CastPermits, options.Value.CastWindow, options.Value.MaxTrackedKeys, clock);
+    private readonly FixedWindowBudget castNetworks = new(options.Value.CastPermits, options.Value.CastWindow, options.Value.MaxTrackedKeys, clock);
+    private readonly FixedWindowBudget mint = new(options.Value.MintPermits, options.Value.MintWindow, options.Value.MaxTrackedKeys, clock);
+
+    public BudgetDenial? DenyCast(IPAddress? client, VoterIdentity? known) =>
+        known?.UserAccountId is { } account
+            ? castAccounts.Spend(account.ToString("N"))
+            : castNetworks.Spend(NetKey(client));
+
+    public BudgetDenial? DenyMint(IPAddress? client) => mint.Spend(NetKey(client));
+
+    private string NetKey(IPAddress? client) =>
+        client is null ? "unknown" : NetworkPrefix.Of(client, opts.IPv4PrefixLength, opts.IPv6PrefixLength);
+}

src/Bifrost.Web/Features/ConceptVotes/NetworkPrefix.cs

@@ -0,0 +1,45 @@
+using System.Net;
+using System.Security.Cryptography;
+using System.Text;
+
+namespace Bifrost.Web.Features.ConceptVotes;
+
+public static class NetworkPrefix
+{
+    public const int IPv4Bits = 32;
+    public const int IPv6Bits = 128;
+
+    public static bool IsValidLength(int length, int addressBits) => length >= 0 && length <= addressBits;
+
+    // The only prefix computation: IPv4-mapped IPv6 folds to IPv4, then the address is masked. Returns CIDR text.
+    public static string Of(IPAddress address, int ipv4Length, int ipv6Length)
+    {
+        if (address.IsIPv4MappedToIPv6)
+        {
+            address = address.MapToIPv4();
+        }
+
+        var bytes = address.GetAddressBytes();
+        var length = bytes.Length == 4 ? ipv4Length : ipv6Length;
+        if (!IsValidLength(length, bytes.Length * 8))
+        {
+            throw new ArgumentOutOfRangeException(nameof(ipv4Length), "Prefix length is outside the address family.");
+        }
+
+        for (var i = 0; i < bytes.Length; i++)
+        {
+            var kept = Math.Clamp(length - i * 8, 0, 8);
+            bytes[i] &= (byte)(0xFF << (8 - kept));
+        }
+
+        return new IPAddress(bytes) + "/" + length;
+    }
+
+    // Lowercase hex HMAC-SHA256 over the prefix text. Never reversible to an address; audit and purge only.
+    public static string Tag(IPAddress address, int ipv4Length, int ipv6Length, string secret)
+    {
+        var prefix = Of(address, ipv4Length, ipv6Length);
+        var mac = HMACSHA256.HashData(Encoding.UTF8.GetBytes(secret), Encoding.UTF8.GetBytes(prefix));
+        return Convert.ToHexString(mac).ToLowerInvariant();
+    }
+}

src/Bifrost.Web/Features/ConceptVotes/VoterIdentity.cs

@@ -0,0 +1,28 @@
+using System.Text.RegularExpressions;
+using Bifrost.Web.Domain;
+using Bifrost.Web.Features.Shared;
+
+namespace Bifrost.Web.Features.ConceptVotes;
+
+public sealed record VoterIdentity(string Key, VoterClass Class, Guid? UserAccountId)
+{
+    public const int MaxKeyLength = 120;
+
+    private static readonly Regex DeviceIdShape = new(@"^[A-Za-z0-9_-]{1,100}\z", RegexOptions.CultureInvariant);
+
+    // The one place a voter key and class are decided. Never reads vote weight.
+    public static VoterIdentity? For(CurrentBifrostActor actor, string? deviceId)
+    {
+        if (actor.IsAuthenticated && actor.UserAccount is { } account)
+        {
+            return new VoterIdentity(
+                "account:" + account.Id.ToString("N"),
+                actor.IsActiveMember ? VoterClass.Member : VoterClass.Account,
+                account.Id);
+        }
+
+        return deviceId is not null && DeviceIdShape.IsMatch(deviceId)
+            ? new VoterIdentity("device:" + deviceId, VoterClass.Anonymous, null)
+            : null;
+    }
+}

src/Bifrost.Web/Features/ConceptVotes/VoterKeyResolver.cs

@@ -0,0 +1,55 @@
+using System.Security.Cryptography;
+using Microsoft.AspNetCore.DataProtection;
+
+namespace Bifrost.Web.Features.ConceptVotes;
+
+// The only reader and writer of the bifrost_voter cookie. It supplies a device id and nothing else: VoterIdentity.For
+// decides the voter key and class. The cookie holds a protected random id, never a count, class or account.
+public sealed class VoterKeyResolver(IDataProtectionProvider dataProtection)
+{
+    public const string CookieName = "bifrost_voter";
+    public const string CookiePath = "/mill";
+    public static readonly TimeSpan CookieLifetime = TimeSpan.FromDays(365);
+
+    private const string Purpose = "Bifrost.ConceptVotes.DeviceToken.v1";
+
+    private readonly IDataProtector protector = dataProtection.CreateProtector(Purpose);
+
+    // The device id, or null when there is no cookie or it does not unprotect under this key ring and purpose
+    // (tampered, truncated, a bare id, or minted elsewhere). Nothing about a refused value is kept or reported.
+    public string? TryRead(HttpContext context)
+    {
+        if (!context.Request.Cookies.TryGetValue(CookieName, out var token) || string.IsNullOrEmpty(token))
+        {
+            return null;
+        }
+
+        try
+        {
+            return protector.Unprotect(token);
+        }
+        catch (CryptographicException)
+        {
+            return null;
+        }
+    }
+
+    // Sets a fresh device cookie on this response and returns its device id. Called only from a cast.
+    public string Mint(HttpContext context)
+    {
+        var deviceId = Guid.NewGuid().ToString("N");
+        context.Response.Cookies.Append(
+            CookieName,
+            protector.Protect(deviceId),
+            new CookieOptions
+            {
+                HttpOnly = true,
+                Secure = true,
+                SameSite = SameSiteMode.Lax,
+                Path = CookiePath,
+                MaxAge = CookieLifetime,
+                IsEssential = true
+            });
+        return deviceId;
+    }
+}

src/Bifrost.Web/Features/Heimdall/HeimdallAuthService.cs

@@ -1,27 +1,39 @@
+using System.Net;
 using System.Net.Http.Json;
-using System.Collections.Concurrent;
 using System.Security.Claims;
+using System.Security.Cryptography;
+using System.Text.Json;
 using System.Text.Json.Serialization;
 using Bifrost.Web.Configuration;
 using Bifrost.Web.Data;
 using Bifrost.Web.Domain;
 using Bifrost.Web.Features.Membership;
 using Bifrost.Web.Features.Shared;
-using Microsoft.AspNetCore.Authentication;
-using Microsoft.AspNetCore.Authentication.Cookies;
+using Microsoft.AspNetCore.DataProtection;
+using Microsoft.AspNetCore.WebUtilities;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Options;
 
 namespace Bifrost.Web.Features.Heimdall;
 
+/// <summary>
+/// Heimdall sign-in. Start issues an attempt that lives only in a Data Protection-protected cookie in the
+/// browser that began it. The browser that Heimdall authenticated presents the completion code from its
+/// URL fragment; Bifrost redeems it at Heimdall itself and signs in only when that browser holds the
+/// attempt's cookie and the redeemed return target names the same attempt.
+/// </summary>
 public sealed class HeimdallAuthService(
     HttpClient httpClient,
-    HeimdallAuthAttemptStore attemptStore,
+    HeimdallTokenVerifier tokenVerifier,
     BifrostDbContext dbContext,
     BifrostIdentityService bifrostIdentityService,
     IOptions<HeimdallOptions> heimdallOptions,
+    IDataProtectionProvider dataProtectionProvider,
     TimeProvider timeProvider)
 {
+    public const string ErrorRedirect = "/?auth=heimdall-error";
+    public const string AppSecretHeader = "x-heimdall-app-secret";
+
     private static readonly HashSet<string> AllowedProviders = new(StringComparer.OrdinalIgnoreCase)
     {
         "discord",
@@ -29,16 +41,29 @@ public sealed class HeimdallAuthService(
         "twitch"
     };
 
+    private readonly IDataProtector _protector = dataProtectionProvider.CreateProtector("Bifrost.Heimdall.Attempt.v1");
+
+    /// <summary>Points the client at Heimdall and, when the app has a secret, identifies Bifrost as the app.</summary>
+    public static void ConfigureClient(HttpClient client, HeimdallOptions options)
+    {
+        client.BaseAddress = new Uri(options.BaseUrl.TrimEnd('/'));
+        if (!string.IsNullOrWhiteSpace(options.AppSecret))
+        {
+            client.DefaultRequestHeaders.Add(AppSecretHeader, options.AppSecret);
+        }
+    }
+
     public async Task<HeimdallAuthStartResult> StartAsync(
         string provider,
         string callbackBaseUrl,
-        string returnUrl,
+        LocalReturnPath returnPath,
         bool requireMemberAccess,
+        IEnumerable<KeyValuePair<string, string>> requestCookies,
         CancellationToken cancellationToken)
     {
         if (!AllowedProviders.Contains(provider))
         {
-            throw new HeimdallAuthException($"Unsupported Heimdall provider '{provider}'.");
+            throw new HeimdallAuthException("Unsupported Heimdall provider.");
         }
 
         var options = heimdallOptions.Value;
@@ -50,14 +75,13 @@ public sealed class HeimdallAuthService(
         var entitlementPolicy = requireMemberAccess
             ? BuildMemberAccessPolicy(provider, options)
             : null;
-        var attemptId = Guid.NewGuid().ToString("N");
-        var callbackUrl = new Uri(new Uri(callbackBaseUrl.TrimEnd('/') + "/", UriKind.Absolute), "auth/heimdall/callback");
+        var nonce = WebEncoders.Base64UrlEncode(RandomNumberGenerator.GetBytes(32));
 
         var request = new HeimdallStartRequest(
             options.AppSlug,
             "sign_in",
-            ToAttemptReturnUrl(callbackBaseUrl, attemptId, returnUrl),
-            new HeimdallHandoff("backend_callback", attemptId, callbackUrl.ToString()),
+            ToAttemptReturnUrl(callbackBaseUrl, nonce),
+            new HeimdallHandoff("browser_completion"),
             entitlementPolicy);
 
         var response = await httpClient.PostAsJsonAsync(
@@ -67,8 +91,7 @@ public sealed class HeimdallAuthService(
 
         if (!response.IsSuccessStatusCode)
         {
-            var detail = await response.Content.ReadAsStringAsync(cancellationToken);
-            throw new HeimdallAuthException($"Heimdall rejected {provider} auth start: {detail}");
+            throw new HeimdallAuthException("Heimdall rejected the auth start.");
         }
 
         var payload = await response.Content.ReadFromJsonAsync<HeimdallStartResponse>(cancellationToken);
@@ -77,59 +100,174 @@ public sealed class HeimdallAuthService(
             throw new HeimdallAuthException("Heimdall auth start returned no authorization URL.");
         }
 
-        attemptStore.Create(attemptId, returnUrl);
-        attemptStore.SetRequiresMemberAccess(attemptId, requireMemberAccess);
-        return new HeimdallAuthStartResult(new Uri(payload.AuthorizationUrl, UriKind.Absolute), attemptId);
+        var attempt = new HeimdallAttempt(
+            nonce,
+            provider,
+            requireMemberAccess,
+            returnPath,
+            timeProvider.GetUtcNow() + HeimdallAttemptCookie.Lifetime);
+        return new HeimdallAuthStartResult(
+            new Uri(payload.AuthorizationUrl, UriKind.Absolute), ChooseSlot(requestCookies), Protect(attempt));
     }
 
-    public void StoreBackendCallback(HeimdallBackendCallbackPayload payload)
+    /// <summary>
+    /// The slot the new attempt's cookie takes: the first slot that holds no live attempt, else the one whose
+    /// attempt expires first. Parallel starts carry the same request cookies, so they choose the same slot and
+    /// overwrite each other; the Cookie header holds at most <see cref="HeimdallAttemptCookie.SlotNames"/> attempt
+    /// cookies however many starts a browser makes.
+    /// </summary>
+    private string ChooseSlot(IEnumerable<KeyValuePair<string, string>> requestCookies)
     {
-        if (!string.Equals(payload.AppSlug, heimdallOptions.Value.AppSlug, StringComparison.OrdinalIgnoreCase))
+        var cookies = requestCookies.ToLookup(x => x.Key, x => x.Value, StringComparer.Ordinal);
+        string? oldest = null;
+        var oldestExpiry = DateTimeOffset.MaxValue;
+        foreach (var name in HeimdallAttemptCookie.SlotNames)
         {
-            throw new HeimdallAuthException("Heimdall callback targeted a different app.");
+            var live = Read(cookies[name].FirstOrDefault());
+            if (live is null)
+            {
+                return name;
+            }
+
+            if (live.ExpiresAt < oldestExpiry)
+            {
+                oldest = name;
+                oldestExpiry = live.ExpiresAt;
+            }
         }
 
-        if (string.IsNullOrWhiteSpace(payload.AttemptId))
-        {
-            throw new HeimdallAuthException("Heimdall callback omitted attempt id.");
-        }
-
-        attemptStore.Complete(payload.AttemptId, payload);
+        return oldest!;
     }
 
-    public async Task<HeimdallCompletedSignIn> CompleteAttemptAsync(
-        string attemptId,
+    /// <summary>
+    /// The slot cookie that holds the attempt for this nonce: its name and value, or null when the browser holds
+    /// none (never started here, expired, or overwritten by a later start).
+    /// </summary>
+    public (string Name, string Value)? FindAttemptCookie(IEnumerable<KeyValuePair<string, string>> requestCookies, string? nonce)
+    {
+        foreach (var (name, value) in requestCookies)
+        {
+            if (HeimdallAttemptCookie.SlotNames.Contains(name) && Unprotect(value, nonce) is not null)
+            {
+                return (name, value);
+            }
+        }
+
+        return null;
+    }
+
+    public async Task<HeimdallCompletedSignIn> CompleteAsync(
+        string callbackBaseUrl,
+        string? nonce,
+        string? cookieValue,
+        string? code,
         CancellationToken cancellationToken)
     {
-        var attempt = attemptStore.TryTake(attemptId)
-            ?? throw new HeimdallAuthPendingException("Heimdall has not delivered this auth attempt yet.");
-        var payload = attempt.Payload
-            ?? throw new HeimdallAuthPendingException("Heimdall has not delivered this auth attempt yet.");
-
-        if (!payload.IsSuccessful)
+        var attempt = Unprotect(cookieValue, nonce)
+            ?? throw new HeimdallAuthException("Heimdall completion has no attempt for this browser.");
+        if (string.IsNullOrWhiteSpace(code))
         {
-            throw new HeimdallAuthException(payload.ErrorDescription ?? payload.Error ?? "Heimdall auth did not succeed.");
+            throw new HeimdallAuthException("Heimdall completion carried no code.");
         }
 
-        if (attempt.RequiresMemberAccess && !payload.HasMemberAccess)
+        var redeemed = await RedeemAsync(code, cancellationToken);
+        if (!string.Equals(redeemed.ReturnTo, ToAttemptReturnUrl(callbackBaseUrl, attempt.Nonce), StringComparison.Ordinal))
+        {
+            throw new HeimdallAuthException("Heimdall completion belongs to another attempt.");
+        }
+
+        if (string.IsNullOrWhiteSpace(redeemed.AccessToken))
+        {
+            throw new HeimdallAuthException("Heimdall completion carried no access token.");
+        }
+
+        var identity = await tokenVerifier.VerifyAsync(redeemed.AccessToken, redeemed.Account?.Id, cancellationToken);
+        if (attempt.RequiresMemberAccess && !identity.HasMemberAccess)
         {
             throw new HeimdallAuthException("Heimdall did not grant Bifrost member access.");
         }
 
-        var userAccount = await UpsertUserAccountAsync(payload, attempt.RequiresMemberAccess, cancellationToken);
+        var userAccount = await UpsertUserAccountAsync(
+            identity,
+            attempt.Provider,
+            attempt.RequiresMemberAccess,
+            cancellationToken);
         return new HeimdallCompletedSignIn(
-            bifrostIdentityService.BuildPrincipal(userAccount, payload.Provider ?? "heimdall"),
-            string.IsNullOrWhiteSpace(attempt.ReturnUrl) ? "/App" : attempt.ReturnUrl);
+            bifrostIdentityService.BuildPrincipal(userAccount, attempt.Provider),
+            attempt.ReturnPath);
     }
 
+    private async Task<HeimdallRedeemResponse> RedeemAsync(string code, CancellationToken cancellationToken)
+    {
+        try
+        {
+            using var response = await httpClient.PostAsJsonAsync(
+                $"/v1/apps/{Uri.EscapeDataString(heimdallOptions.Value.AppSlug)}/auth-completions/redeem",
+                new HeimdallRedeemRequest(code),
+                cancellationToken);
+            if (response.StatusCode != HttpStatusCode.Created)
+            {
+                throw new HeimdallAuthException("Heimdall did not redeem the completion code.");
+            }
+
+            return await response.Content.ReadFromJsonAsync<HeimdallRedeemResponse>(cancellationToken)
+                ?? throw new HeimdallAuthException("Heimdall redeem returned no body.");
+        }
+        catch (Exception error) when (error is not HeimdallAuthException && !cancellationToken.IsCancellationRequested)
+        {
+            throw new HeimdallAuthException("Heimdall redeem could not be read.");
+        }
+    }
+
+    private string Protect(HeimdallAttempt attempt) =>
+        _protector.Protect(JsonSerializer.Serialize(new AttemptWire(
+            attempt.Nonce, attempt.Provider, attempt.RequiresMemberAccess, attempt.ReturnPath.Value, attempt.ExpiresAt)));
+
+    /// <summary>The live attempt a cookie value protects when it belongs to this nonce, else null.</summary>
+    private HeimdallAttempt? Unprotect(string? cookieValue, string? nonce) =>
+        Read(cookieValue) is { } attempt && string.Equals(attempt.Nonce, nonce, StringComparison.Ordinal) ? attempt : null;
+
+    /// <summary>The live attempt a cookie value protects, else null.</summary>
+    private HeimdallAttempt? Read(string? cookieValue)
+    {
+        if (string.IsNullOrEmpty(cookieValue))
+        {
+            return null;
+        }
+
+        try
+        {
+            var wire = JsonSerializer.Deserialize<AttemptWire>(_protector.Unprotect(cookieValue));
+            if (wire is null || wire.ExpiresAt <= timeProvider.GetUtcNow())
+            {
+                return null;
+            }
+
+            return new HeimdallAttempt(
+                wire.Nonce, wire.Provider, wire.RequiresMemberAccess, LocalReturnPath.Parse(wire.ReturnPath), wire.ExpiresAt);
+        }
+        catch (Exception error) when (error is CryptographicException or JsonException or FormatException)
+        {
+            return null;
+        }
+    }
+
+    private sealed record AttemptWire(
+        string Nonce,
+        string Provider,
+        bool RequiresMemberAccess,
+        string ReturnPath,
+        DateTimeOffset ExpiresAt);
+
     private async Task<UserAccount> UpsertUserAccountAsync(
-        HeimdallBackendCallbackPayload payload,
+        HeimdallVerifiedIdentity identity,
+        string provider,
         bool grantMemberAccess,
         CancellationToken cancellationToken)
     {
         var now = timeProvider.GetUtcNow();
-        var accountId = payload.Account?.Id ?? throw new HeimdallAuthException("Heimdall response omitted account id.");
-        var displayName = payload.Account.DisplayName ?? accountId;
+        var accountId = identity.AccountId;
+        var displayName = identity.DisplayName ?? accountId;
 
         var userAccount = await dbContext.UserAccounts
             .Include(x => x.MemberProfile)
@@ -150,7 +288,7 @@ public sealed class HeimdallAuthService(
                 MemberProfile = new MemberProfile
                 {
                     Nickname = displayName,
-                    Headline = $"Verified through Heimdall {payload.Provider}",
+                    Headline = $"Verified through Heimdall {provider}",
                     UpdatedAtUtc = now
                 },
                 Membership = new Bifrost.Web.Domain.Membership
@@ -160,7 +298,7 @@ public sealed class HeimdallAuthService(
                     ApprovedAtUtc = grantMemberAccess ? now : null,
                     Notes = grantMemberAccess
                         ? "Activated by Heimdall member access claim"
-                        : $"Identity verified through Heimdall {payload.Provider}"
+                        : $"Identity verified through Heimdall {provider}"
                 }
             };
             dbContext.UserAccounts.Add(userAccount);
@@ -173,7 +311,7 @@ public sealed class HeimdallAuthService(
             {
                 UserAccountId = userAccount.Id,
                 Nickname = displayName,
-                Headline = $"Verified through Heimdall {payload.Provider}",
+                Headline = $"Verified through Heimdall {provider}",
                 UpdatedAtUtc = now
             };
             userAccount.Membership ??= new Bifrost.Web.Domain.Membership
@@ -248,61 +386,29 @@ public sealed class HeimdallAuthService(
             return BuildPatreonPolicy(options);
         }
 
-        throw new HeimdallAuthException($"Heimdall provider '{provider}' does not support Bifrost member access.");
+        throw new HeimdallAuthException("Heimdall provider does not support Bifrost member access.");
     }
 
-    private static string ToAttemptReturnUrl(string callbackBaseUrl, string attemptId, string returnUrl)
+    private static string ToAttemptReturnUrl(string callbackBaseUrl, string nonce)
     {
         var baseUri = new Uri(callbackBaseUrl.TrimEnd('/') + "/", UriKind.Absolute);
-        var target = string.IsNullOrWhiteSpace(returnUrl) ? "/App" : returnUrl;
-        var waitUri = new Uri(baseUri, "auth/heimdall/wait");
-        return $"{waitUri}?attemptId={Uri.EscapeDataString(attemptId)}&returnTo={Uri.EscapeDataString(target)}";
+        return $"{new Uri(baseUri, "auth/heimdall/complete")}?attempt={Uri.EscapeDataString(nonce)}";
     }
 }
 
 public class HeimdallAuthException(string message) : InvalidOperationException(message);
 
-public sealed class HeimdallAuthPendingException(string message) : HeimdallAuthException(message);
+public sealed record HeimdallAuthStartResult(Uri AuthorizationUrl, string CookieName, string CookieValue);
 
-public sealed record HeimdallAuthStartResult(Uri AuthorizationUrl, string AttemptId);
+public sealed record HeimdallCompletedSignIn(ClaimsPrincipal Principal, LocalReturnPath ReturnPath);
 
-public sealed record HeimdallCompletedSignIn(ClaimsPrincipal Principal, string RedirectUri);
-
-public sealed class HeimdallAuthAttemptStore
-{
-    private readonly ConcurrentDictionary<string, HeimdallAuthAttempt> _attempts = new(StringComparer.Ordinal);
-
-    public void Create(string attemptId, string returnUrl)
-    {
-        _attempts[attemptId] = new HeimdallAuthAttempt(returnUrl, null);
-    }
-
-    public void SetRequiresMemberAccess(string attemptId, bool requiresMemberAccess)
-    {
-        _attempts.AddOrUpdate(
-            attemptId,
-            _ => new HeimdallAuthAttempt("/App", null, requiresMemberAccess),
-            (_, existing) => existing with { RequiresMemberAccess = requiresMemberAccess });
-    }
-
-    public void Complete(string attemptId, HeimdallBackendCallbackPayload payload)
-    {
-        _attempts.AddOrUpdate(
-            attemptId,
-            _ => new HeimdallAuthAttempt(payload.ReturnTo ?? "/App", payload),
-            (_, existing) => existing with { Payload = payload });
-    }
-
-    public HeimdallAuthAttempt? TryTake(string attemptId)
-    {
-        return _attempts.TryRemove(attemptId, out var attempt) ? attempt : null;
-    }
-}
-
-public sealed record HeimdallAuthAttempt(
-    string ReturnUrl,
-    HeimdallBackendCallbackPayload? Payload,
-    bool RequiresMemberAccess = false);
+/// <summary>An attempt Start issued. It exists only inside its protected cookie.</summary>
+public sealed record HeimdallAttempt(
+    string Nonce,
+    string Provider,
+    bool RequiresMemberAccess,
+    LocalReturnPath ReturnPath,
+    DateTimeOffset ExpiresAt);
 
 public sealed record HeimdallStartRequest(
     [property: JsonPropertyName("appSlug")] string AppSlug,
@@ -313,11 +419,7 @@ public sealed record HeimdallStartRequest(
     [property: JsonPropertyName("entitlementPolicy")] HeimdallEntitlementPolicy? EntitlementPolicy);
 
 public sealed record HeimdallHandoff(
-    [property: JsonPropertyName("kind")] string Kind,
-    [property: JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
-    [property: JsonPropertyName("attemptId")] string? AttemptId = null,
-    [property: JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]
-    [property: JsonPropertyName("callbackUrl")] string? CallbackUrl = null);
+    [property: JsonPropertyName("kind")] string Kind);
 
 public sealed record HeimdallEntitlementPolicy(
     [property: JsonPropertyName("kind")] string Kind,
@@ -331,31 +433,45 @@ public sealed record HeimdallEntitlementPolicy(
 public sealed record HeimdallStartResponse(
     [property: JsonPropertyName("authorizationUrl")] string AuthorizationUrl);
 
-public sealed record HeimdallBackendCallbackPayload(
-    [property: JsonPropertyName("attemptId")] string AttemptId,
-    [property: JsonPropertyName("appSlug")] string? AppSlug,
-    [property: JsonPropertyName("status")] string? Status,
-    [property: JsonPropertyName("provider")] string? Provider,
-    [property: JsonPropertyName("returnTo")] string? ReturnTo,
-    [property: JsonPropertyName("error")] string? Error,
-    [property: JsonPropertyName("errorDescription")] string? ErrorDescription,
-    [property: JsonPropertyName("account")] HeimdallAccount? Account,
-    [property: JsonPropertyName("sharedCapabilities")] string[]? SharedCapabilities,
-    [property: JsonPropertyName("entitlements")] HeimdallEntitlements? Entitlements)
-{
-    public bool IsSuccessful => string.Equals(Status, "success", StringComparison.OrdinalIgnoreCase);
+public sealed record HeimdallRedeemRequest(
+    [property: JsonPropertyName("completionCode")] string CompletionCode);
 
-    public bool HasMemberAccess =>
-        SharedCapabilities?.Any(capability =>
-            string.Equals(capability, "member_access", StringComparison.OrdinalIgnoreCase) ||
-            string.Equals(capability, "app_access", StringComparison.OrdinalIgnoreCase)) == true ||
-        Entitlements?.Facts?.Any(fact =>
-            string.Equals(fact, "entitlement.app_access", StringComparison.OrdinalIgnoreCase)) == true;
-}
+public sealed record HeimdallRedeemResponse(
+    [property: JsonPropertyName("returnTo")] string? ReturnTo,
+    [property: JsonPropertyName("accessToken")] string? AccessToken,
+    [property: JsonPropertyName("account")] HeimdallAccount? Account);
 
 public sealed record HeimdallAccount(
-    [property: JsonPropertyName("id")] string Id,
-    [property: JsonPropertyName("displayName")] string? DisplayName);
+    [property: JsonPropertyName("id")] string Id);
 
-public sealed record HeimdallEntitlements(
-    [property: JsonPropertyName("facts")] string[]? Facts);
+/// <summary>
+/// The attempt cookies: a ring of <see cref="SlotNames"/> fixed names, so the Cookie header a browser sends to
+/// /auth/heimdall is bounded by construction (a worst-case attempt is about 2.4 KB; nginx's line limit is 8 KB).
+/// A start takes a free slot or overwrites the one expiring first; an overwritten attempt finds no cookie and
+/// is refused. The attempt's nonce lives inside the protected value, never in the cookie name.
+/// </summary>
+public static class HeimdallAttemptCookie
+{
+    public const string Prefix = "bifrost_heimdall_";
+    public const int SlotCount = 2;
+
+    public static readonly TimeSpan Lifetime = TimeSpan.FromMinutes(10);
+
+    public static readonly IReadOnlyList<string> SlotNames =
+        Enumerable.Range(0, SlotCount).Select(x => Prefix + x).ToArray();
+
+    public static CookieOptions Options() => new()
+    {
+        HttpOnly = true,
+        Secure = true,
+        SameSite = SameSiteMode.Lax,
+        Path = "/auth/heimdall",
+        MaxAge = Lifetime
+    };
+
+    /// <summary>
+    /// The options a deletion carries: only the attempt cookie's Path, which a cookie is matched on. It carries no
+    /// Max-Age, which would take precedence over the expiry Delete writes and leave the emptied cookie alive.
+    /// </summary>
+    public static CookieOptions DeleteOptions() => new() { Path = "/auth/heimdall" };
+}

src/Bifrost.Web/Features/Heimdall/HeimdallCompletePage.cs

@@ -0,0 +1,46 @@
+namespace Bifrost.Web.Features.Heimdall;
+
+/// <summary>
+/// The page Heimdall's "Return to the app" lands on. The completion code arrives in the URL fragment, which
+/// the server never sees, so the page's script reads it, drops it from the address bar, and posts it with
+/// the attempt to the same path. The page is static: it never contains a code.
+/// </summary>
+public static class HeimdallCompletePage
+{
+    public const string Html = """
+        <!doctype html>
+        <html lang="en">
+          <head>
+            <meta charset="utf-8" />
+            <meta name="viewport" content="width=device-width, initial-scale=1" />
+            <meta name="referrer" content="no-referrer" />
+            <title>Signing in - Bifrost</title>
+          </head>
+          <body>
+            <p>Finishing sign-in...</p>
+            <noscript><p>JavaScript is needed to finish sign-in.</p></noscript>
+            <form id="complete" method="post" action="/auth/heimdall/complete">
+              <input type="hidden" name="attempt" />
+              <input type="hidden" name="code" />
+            </form>
+            <script>
+              (function () {
+                var fragment = new URLSearchParams(location.hash.slice(1));
+                var attempt = new URLSearchParams(location.search).get("attempt");
+                var code = fragment.get("heimdall_completion_code");
+                var failed = fragment.get("heimdall_status") === "error";
+                history.replaceState(null, "", location.pathname + location.search);
+                if (failed || !code || !attempt) {
+                  location.replace("/?auth=heimdall-error");
+                  return;
+                }
+                var form = document.getElementById("complete");
+                form.elements.attempt.value = attempt;
+                form.elements.code.value = code;
+                form.submit();
+              })();
+            </script>
+          </body>
+        </html>
+        """;
+}

src/Bifrost.Web/Features/Heimdall/HeimdallTokenVerifier.cs

@@ -0,0 +1,284 @@
+using System.Text.Json;
+using Bifrost.Web.Configuration;
+using Microsoft.AspNetCore.WebUtilities;
+using Microsoft.Extensions.Options;
+using Org.BouncyCastle.Math.EC.Rfc8032;
+
+namespace Bifrost.Web.Features.Heimdall;
+
+/// <summary>
+/// The identity a Heimdall-signed access token asserts. Everything here comes from verified claims.
+/// </summary>
+public sealed record HeimdallVerifiedIdentity(string AccountId, string? DisplayName, bool HasMemberAccess);
+
+/// <summary>
+/// Verifies Heimdall's access tokens (EdDSA) against Heimdall's published JWKS. Heimdall is the issuer
+/// at <see cref="HeimdallOptions.BaseUrl"/>; the audience is this app's slug. Failures name a rule and
+/// never echo the token or any of its contents. One instance serves the process: it owns the key cache.
+/// </summary>
+public sealed class HeimdallTokenVerifier(
+    IHttpClientFactory httpClientFactory,
+    IOptions<HeimdallOptions> heimdallOptions,
+    TimeProvider timeProvider)
+{
+    public const string TokenType = "heimdall_access";
+    public const string ClientName = "heimdall-jwks";
+
+    internal static readonly TimeSpan ClockSkew = TimeSpan.FromSeconds(60);
+    internal static readonly TimeSpan KeyRefreshInterval = TimeSpan.FromSeconds(30);
+    internal static readonly TimeSpan KeyMaxAge = TimeSpan.FromHours(1);
+
+    private static readonly string[] MemberCapabilities = ["member_access", "app_access"];
+
+    private readonly SemaphoreSlim _fetchGate = new(1, 1);
+    private volatile KeySnapshot _keys = new(new Dictionary<string, byte[]>(StringComparer.Ordinal), DateTimeOffset.MinValue);
+    private DateTimeOffset _attemptedAt = DateTimeOffset.MinValue;
+
+    public async Task<HeimdallVerifiedIdentity> VerifyAsync(
+        string token,
+        string? payloadAccountId,
+        CancellationToken cancellationToken)
+    {
+        var parts = token.Split('.');
+        if (parts.Length != 3)
+        {
+            throw Refuse("token is not a compact JWS");
+        }
+
+        var headerBytes = Decode(parts[0]);
+        var payloadBytes = Decode(parts[1]);
+        var signature = Decode(parts[2]);
+
+        using var header = ParseJson(headerBytes, "token header is not JSON");
+        var kid = ReadKeyId(header.RootElement);
+        var publicKey = await FindKeyAsync(kid, cancellationToken);
+        if (publicKey is null)
+        {
+            throw Refuse("token key is not published");
+        }
+
+        var signingInput = System.Text.Encoding.ASCII.GetBytes($"{parts[0]}.{parts[1]}");
+        if (signature.Length != Ed25519.SignatureSize ||
+            !Ed25519.Verify(signature, 0, publicKey, 0, signingInput, 0, signingInput.Length))
+        {
+            throw Refuse("token signature is invalid");
+        }
+
+        using var payload = ParseJson(payloadBytes, "token payload is not JSON");
+        return CheckClaims(payload.RootElement, heimdallOptions.Value, payloadAccountId);
+    }
+
+    private sealed record KeySnapshot(Dictionary<string, byte[]> Keys, DateTimeOffset FetchedAt);
+
+    private static byte[] Decode(string segment)
+    {
+        try
+        {
+            return WebEncoders.Base64UrlDecode(segment);
+        }
+        catch (FormatException)
+        {
+            throw Refuse("token is not base64url");
+        }
+    }
+
+    private static JsonDocument ParseJson(byte[] bytes, string rule)
+    {
+        try
+        {
+            return JsonDocument.Parse(bytes);
+        }
+        catch (JsonException)
+        {
+            throw Refuse(rule);
+        }
+    }
+
+    private static string ReadKeyId(JsonElement header)
+    {
+        if (header.ValueKind != JsonValueKind.Object || StringClaim(header, "alg") != "EdDSA")
+        {
+            throw Refuse("token algorithm is not EdDSA");
+        }
+
+        var kid = StringClaim(header, "kid");
+        if (string.IsNullOrEmpty(kid))
+        {
+            throw Refuse("token has no key id");
+        }
+
+        return kid;
+    }
+
+    private HeimdallVerifiedIdentity CheckClaims(JsonElement claims, HeimdallOptions options, string? payloadAccountId)
+    {
+        if (claims.ValueKind != JsonValueKind.Object)
+        {
+            throw Refuse("token payload is not an object");
+        }
+
+        if (StringClaim(claims, "iss") != options.BaseUrl.TrimEnd('/'))
+        {
+            throw Refuse("token issuer is not Heimdall");
+        }
+
+        if (StringClaim(claims, "aud") != options.AppSlug)
+        {
+            throw Refuse("token audience is not this app");
+        }
+
+        if (StringClaim(claims, "typ") != TokenType)
+        {
+            throw Refuse("token type is not an access token");
+        }
+
+        if (!claims.TryGetProperty("app", out var app) ||
+            app.ValueKind != JsonValueKind.Object ||
+            StringClaim(app, "slug") != options.AppSlug)
+        {
+            throw Refuse("token app is not this app");
+        }
+
+        var now = timeProvider.GetUtcNow();
+        if (NumericDate(claims, "nbf") is not { } notBefore || now < notBefore - ClockSkew)
+        {
+            throw Refuse("token is not yet valid");
+        }
+
+        if (NumericDate(claims, "exp") is not { } expires || now - ClockSkew >= expires)
+        {
+            throw Refuse("token has expired");
+        }
+
+        var subject = StringClaim(claims, "sub");
+        if (string.IsNullOrEmpty(subject) ||
+            subject != StringClaim(claims, "account_id") ||
+            subject != payloadAccountId)
+        {
+            throw Refuse("token subject does not match the account");
+        }
+
+        var capabilities = new List<string>();
+        if (claims.TryGetProperty("capabilities", out var list) && list.ValueKind == JsonValueKind.Array)
+        {
+            foreach (var capability in list.EnumerateArray())
+            {
+                if (capability.ValueKind == JsonValueKind.String)
+                {
+                    capabilities.Add(capability.GetString()!);
+                }
+            }
+        }
+
+        return new HeimdallVerifiedIdentity(
+            subject,
+            StringClaim(claims, "display_name"),
+            capabilities.Any(capability => MemberCapabilities.Contains(capability, StringComparer.OrdinalIgnoreCase)));
+    }
+
+    /// <summary>The JWKS client waits a short, bounded time: a slow fetch must not hold sign-ins for long.</summary>
+    public static void ConfigureClient(HttpClient client, HeimdallOptions options)
+    {
+        client.BaseAddress = new Uri(options.BaseUrl.TrimEnd('/'));
+        client.Timeout = TimeSpan.FromSeconds(10);
+    }
+
+    private async Task<byte[]?> FindKeyAsync(string kid, CancellationToken cancellationToken)
+    {
+        if (TryFreshKey(kid, out var cached))
+        {
+            return cached;
+        }
+
+        await _fetchGate.WaitAsync(cancellationToken);
+        try
+        {
+            var now = timeProvider.GetUtcNow();
+            if (now - _attemptedAt >= KeyRefreshInterval)
+            {
+                _attemptedAt = now;
+                _keys = new KeySnapshot(await FetchKeysAsync(cancellationToken), now);
+            }
+
+            return _keys.Keys.GetValueOrDefault(kid);
+        }
+        finally
+        {
+            _fetchGate.Release();
+        }
+    }
+
+    private bool TryFreshKey(string kid, out byte[]? key)
+    {
+        var snapshot = _keys;
+        key = null;
+        return timeProvider.GetUtcNow() - snapshot.FetchedAt < KeyMaxAge && snapshot.Keys.TryGetValue(kid, out key);
+    }
+
+    private async Task<Dictionary<string, byte[]>> FetchKeysAsync(CancellationToken cancellationToken)
+    {
+        try
+        {
+            return await ReadKeysAsync(cancellationToken);
+        }
+        catch (Exception) when (!cancellationToken.IsCancellationRequested)
+        {
+            throw Refuse("Heimdall keys could not be fetched");
+        }
+    }
+
+    private async Task<Dictionary<string, byte[]>> ReadKeysAsync(CancellationToken cancellationToken)
+    {
+        var httpClient = httpClientFactory.CreateClient(ClientName);
+        using var response = await httpClient.GetAsync("/.well-known/jwks.json", cancellationToken);
+        response.EnsureSuccessStatusCode();
+        await using var body = await response.Content.ReadAsStreamAsync(cancellationToken);
+        using var document = await JsonDocument.ParseAsync(body, cancellationToken: cancellationToken);
+        var keys = new Dictionary<string, byte[]>(StringComparer.Ordinal);
+        foreach (var jwk in document.RootElement.GetProperty("keys").EnumerateArray())
+        {
+            if (jwk.ValueKind != JsonValueKind.Object)
+            {
+                continue;
+            }
+
+            var id = StringClaim(jwk, "kid");
+            var x = StringClaim(jwk, "x");
+            if (StringClaim(jwk, "kty") != "OKP" ||
+                StringClaim(jwk, "crv") != "Ed25519" ||
+                string.IsNullOrEmpty(id) ||
+                x is null)
+            {
+                continue;
+            }
+
+            var key = WebEncoders.Base64UrlDecode(x);
+            if (key.Length == Ed25519.PublicKeySize)
+            {
+                keys[id] = key;
+            }
+        }
+
+        return keys;
+    }
+
+    private static string? StringClaim(JsonElement element, string name) =>
+        element.TryGetProperty(name, out var value) && value.ValueKind == JsonValueKind.String
+            ? value.GetString()
+            : null;
+
+    private static DateTimeOffset? NumericDate(JsonElement element, string name)
+    {
+        if (!element.TryGetProperty(name, out var value) ||
+            value.ValueKind != JsonValueKind.Number ||
+            !value.TryGetInt64(out var seconds) ||
+            seconds is < 0 or > 253402300799)
+        {
+            return null;
+        }
+
+        return DateTimeOffset.FromUnixTimeSeconds(seconds);
+    }
+
+    private static HeimdallAuthException Refuse(string rule) => new($"Heimdall token refused: {rule}.");
+}

src/Bifrost.Web/Features/Oidc/OidcClientSeeder.cs

@@ -0,0 +1,72 @@
+using Bifrost.Web.Configuration;
+using Microsoft.Extensions.Options;
+using OpenIddict.Abstractions;
+using OpenIddict.Server;
+using static OpenIddict.Abstractions.OpenIddictConstants;
+
+namespace Bifrost.Web.Features.Oidc;
+
+/// <summary>
+/// Makes the provider's one client match configuration at startup, creating it or updating it in place, and removes
+/// every other application (with its authorizations and tokens), so a client left by an older configuration cannot get codes.
+/// </summary>
+public sealed class OidcClientSeeder(
+    IServiceScopeFactory scopeFactory,
+    OidcIssuerOptions options,
+    OidcKeyMaterial material,
+    IOptions<OpenIddictServerOptions> serverOptions) : IHostedService
+{
+    public async Task StartAsync(CancellationToken cancellationToken)
+    {
+        // Reading the server options now runs their configuration, so a bad issuer stops startup rather than the first request.
+        _ = serverOptions.Value;
+
+        await using var scope = scopeFactory.CreateAsyncScope();
+        var manager = scope.ServiceProvider.GetRequiredService<IOpenIddictApplicationManager>();
+        var mas = options.Clients.Mas;
+
+        var descriptor = new OpenIddictApplicationDescriptor
+        {
+            ClientId = mas.ClientId,
+            ClientSecret = material.ClientSecret,
+            ClientType = ClientTypes.Confidential,
+            DisplayName = "Matrix Authentication Service",
+            RedirectUris = { new Uri(mas.RedirectUri, UriKind.Absolute) },
+            Permissions =
+            {
+                Permissions.Endpoints.Authorization,
+                Permissions.Endpoints.Token,
+                Permissions.GrantTypes.AuthorizationCode,
+                Permissions.ResponseTypes.Code,
+                Permissions.Scopes.Profile,
+                Permissions.Prefixes.Scope + Scopes.OpenId
+            }
+        };
+
+        var existing = await manager.FindByClientIdAsync(mas.ClientId, cancellationToken);
+        if (existing is null)
+        {
+            await manager.CreateAsync(descriptor, cancellationToken);
+        }
+        else
+        {
+            await manager.UpdateAsync(existing, descriptor, cancellationToken);
+        }
+
+        var applications = new List<object>();
+        await foreach (var application in manager.ListAsync(cancellationToken: cancellationToken))
+        {
+            applications.Add(application);
+        }
+
+        foreach (var application in applications)
+        {
+            if (!string.Equals(await manager.GetClientIdAsync(application, cancellationToken), mas.ClientId, StringComparison.Ordinal))
+            {
+                await manager.DeleteAsync(application, cancellationToken);
+            }
+        }
+    }
+
+    public Task StopAsync(CancellationToken cancellationToken) => Task.CompletedTask;
+}

src/Bifrost.Web/Features/Oidc/OidcEndpoints.cs

@@ -0,0 +1,142 @@
+using System.Security.Claims;
+using Microsoft.AspNetCore;
+using Bifrost.Web.Data;
+using Bifrost.Web.Domain;
+using Bifrost.Web.Features.Shared;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.AspNetCore.Authentication;
+using Microsoft.AspNetCore.Authentication.Cookies;
+using OpenIddict.Abstractions;
+using OpenIddict.Server.AspNetCore;
+using static OpenIddict.Abstractions.OpenIddictConstants;
+
+namespace Bifrost.Web.Features.Oidc;
+
+/// <summary>
+/// The decisions Bifrost owns at the OIDC provider: who the chat user is (sub = UserAccount.Id,
+/// preferred_username = NormalizedBifrostIdentity) and whether they may get a session (membership Active).
+/// OpenIddict does the protocol; these endpoints read the cookie session and the same actor facts the /App policy reads.
+/// </summary>
+public static class OidcEndpoints
+{
+    public const string NotActiveDescription = "The account is not an active GameCult member.";
+    public const string NoIdentityDescription = "The account has no Bifrost identity.";
+
+    private const string OpenIddictScheme = OpenIddictServerAspNetCoreDefaults.AuthenticationScheme;
+    private const string IdentityAuthenticationType = "Bifrost.Oidc";
+
+    public static void MapBifrostOidc(this IEndpointRouteBuilder app)
+    {
+        app.MapMethods(OidcServiceCollectionExtensions.AuthorizationPath, ["GET", "POST"], (Delegate)AuthorizeAsync).AllowAnonymous();
+        app.MapPost(OidcServiceCollectionExtensions.TokenPath, (Delegate)ExchangeAsync).AllowAnonymous();
+        app.MapMethods(OidcServiceCollectionExtensions.UserInfoPath, ["GET", "POST"], (Delegate)UserInfoAsync).AllowAnonymous();
+    }
+
+    private static async Task<IResult> AuthorizeAsync(HttpContext http, ICurrentBifrostActorAccessor actors)
+    {
+        var request = http.GetOpenIddictServerRequest()
+            ?? throw new InvalidOperationException("The OpenIddict request could not be retrieved.");
+
+        if (http.User.Identity?.IsAuthenticated != true)
+        {
+            // OpenIddict has already replaced the request with a short request_uri, so this URL fits a sign-in
+            // return path (LocalReturnPath.MaxLength); a test pins that, because Parse would otherwise fall back to /App.
+            return Results.Challenge(
+                new AuthenticationProperties { RedirectUri = http.Request.PathBase + http.Request.Path + http.Request.QueryString },
+                [CookieAuthenticationDefaults.AuthenticationScheme]);
+        }
+
+        var actor = await actors.GetAsync(http.RequestAborted);
+        if (actor.UserAccount is null || !actor.IsActiveMember)
+        {
+            return Deny(Errors.AccessDenied, NotActiveDescription);
+        }
+
+        var account = actor.UserAccount;
+        if (string.IsNullOrWhiteSpace(account.NormalizedBifrostIdentity))
+        {
+            return Deny(Errors.AccessDenied, NoIdentityDescription);
+        }
+
+        var identity = new ClaimsIdentity(IdentityAuthenticationType, Claims.Name, Claims.Role);
+        identity.SetClaim(Claims.Subject, account.Id.ToString("D"));
+        identity.SetClaim(Claims.PreferredUsername, account.NormalizedBifrostIdentity);
+        identity.SetClaim(
+            Claims.Name,
+            string.IsNullOrWhiteSpace(account.DisplayName) ? account.BifrostIdentity : account.DisplayName);
+
+        var principal = new ClaimsPrincipal(identity);
+        principal.SetScopes(request.GetScopes());
+        principal.SetDestinations(claim => claim.Type switch
+        {
+            Claims.Subject => [Destinations.AccessToken, Destinations.IdentityToken],
+            Claims.PreferredUsername or Claims.Name when principal.HasScope(Scopes.Profile) =>
+                [Destinations.AccessToken, Destinations.IdentityToken],
+            _ => [Destinations.AccessToken]
+        });
+
+        return Results.SignIn(principal, properties: null, OpenIddictScheme);
+    }
+
+    private static async Task<IResult> ExchangeAsync(HttpContext http, BifrostDbContext db)
+    {
+        // Only the authorization code grant is enabled, so OpenIddict has refused every other grant already.
+        // The code's own principal carries the claims chosen at authorize time; membership is read again here,
+        // because the code outlives the authorize decision (a member suspended since gets no tokens).
+        var result = await http.AuthenticateAsync(OpenIddictScheme);
+        var subject = result.Principal?.GetClaim(Claims.Subject);
+        if (!await IsStillActiveMemberAsync(db, subject, http.RequestAborted))
+        {
+            return Deny(Errors.InvalidGrant, NotActiveDescription);
+        }
+
+        return Results.SignIn(result.Principal!, properties: null, OpenIddictScheme);
+    }
+
+    private static async Task<IResult> UserInfoAsync(HttpContext http, BifrostDbContext db)
+    {
+        var result = await http.AuthenticateAsync(OpenIddictScheme);
+        if (!result.Succeeded || result.Principal is null)
+        {
+            return Results.Challenge(authenticationSchemes: [OpenIddictScheme]);
+        }
+
+        // An access token outlives the authorize decision too: a member suspended since is no longer answered.
+        if (!await IsStillActiveMemberAsync(db, result.Principal.GetClaim(Claims.Subject), http.RequestAborted))
+        {
+            return Deny(Errors.InsufficientAccess, NotActiveDescription);
+        }
+
+        var claims = new Dictionary<string, object?> { [Claims.Subject] = result.Principal.GetClaim(Claims.Subject) };
+        if (result.Principal.HasScope(Scopes.Profile))
+        {
+            claims[Claims.PreferredUsername] = result.Principal.GetClaim(Claims.PreferredUsername);
+            claims[Claims.Name] = result.Principal.GetClaim(Claims.Name);
+        }
+
+        return Results.Json(claims);
+    }
+
+    /// <summary>The one reading of "this subject is still an Active member", shared by the token and userinfo endpoints and the logout reconciler.</summary>
+    internal static async Task<bool> IsStillActiveMemberAsync(BifrostDbContext db, string? subject, CancellationToken cancellationToken)
+    {
+        if (!Guid.TryParse(subject, out var accountId))
+        {
+            return false;
+        }
+
+        var account = await db.UserAccounts.AsNoTracking()
+            .Include(x => x.Membership)
+            .SingleOrDefaultAsync(x => x.Id == accountId, cancellationToken);
+        return new CurrentBifrostActor(true, account).IsActiveMember;
+    }
+
+    private static IResult Deny(string error, string description) =>
+        Results.Forbid(
+            new AuthenticationProperties(new Dictionary<string, string?>
+            {
+                [OpenIddictServerAspNetCoreConstants.Properties.Error] = error,
+                [OpenIddictServerAspNetCoreConstants.Properties.ErrorDescription] = description
+            }),
+            [OpenIddictScheme]);
+}

src/Bifrost.Web/Features/Oidc/OidcKeyMaterial.cs

@@ -0,0 +1,140 @@
+using System.Security.Cryptography;
+using Bifrost.Web.Configuration;
+using Microsoft.IdentityModel.Tokens;
+
+namespace Bifrost.Web.Features.Oidc;
+
+/// <summary>A configuration fault in the OIDC provider. The message names the setting, never its value.</summary>
+public sealed class OidcConfigurationException(string message) : InvalidOperationException(message);
+
+/// <summary>
+/// The secrets the OIDC provider runs on, read once from the files <see cref="OidcIssuerOptions"/> names. Any
+/// unreadable or wrong-shaped file stops startup; there is no fallback key.
+/// </summary>
+public sealed class OidcKeyMaterial : IDisposable
+{
+    private const string NistP256Oid = "1.2.840.10045.3.1.7";
+    private const int EncryptionKeyBytes = 32;
+
+    private readonly ECDsa _signingEcdsa;
+
+    private OidcKeyMaterial(ECDsa signingEcdsa, SecurityKey signingKey, SecurityKey encryptionKey, string clientSecret)
+    {
+        _signingEcdsa = signingEcdsa;
+        SigningKey = signingKey;
+        EncryptionKey = encryptionKey;
+        ClientSecret = clientSecret;
+    }
+
+    public SecurityKey SigningKey { get; }
+
+    public SecurityKey EncryptionKey { get; }
+
+    public string ClientSecret { get; }
+
+    public static OidcKeyMaterial Load(OidcIssuerOptions options)
+    {
+        var mas = options.Clients.Mas;
+        Require(options.SigningKeyPath, "Bifrost:Oidc:SigningKeyPath");
+        Require(options.EncryptionKeyPath, "Bifrost:Oidc:EncryptionKeyPath");
+        Require(mas.ClientId, "Bifrost:Oidc:Clients:Mas:ClientId");
+        Require(mas.ClientSecretPath, "Bifrost:Oidc:Clients:Mas:ClientSecretPath");
+        Require(mas.RedirectUri, "Bifrost:Oidc:Clients:Mas:RedirectUri");
+        // A rooted path such as "/callback" parses as an absolute file URI on Linux, so the scheme is checked too.
+        if (!Uri.TryCreate(mas.RedirectUri, UriKind.Absolute, out var redirect) ||
+            redirect.Scheme is not ("https" or "http"))
+        {
+            throw new OidcConfigurationException("Bifrost:Oidc:Clients:Mas:RedirectUri must be an absolute http(s) URI.");
+        }
+
+        if (!string.IsNullOrWhiteSpace(mas.BackchannelLogoutUri) &&
+            (!Uri.TryCreate(mas.BackchannelLogoutUri, UriKind.Absolute, out var logout) ||
+             logout.Scheme is not ("https" or "http")))
+        {
+            throw new OidcConfigurationException("Bifrost:Oidc:Clients:Mas:BackchannelLogoutUri must be an absolute http(s) URI.");
+        }
+
+        var ecdsa = LoadSigningKey(options.SigningKeyPath);
+        try
+        {
+            var signingKey = new ECDsaSecurityKey(ecdsa)
+            {
+                KeyId = Base64UrlEncoder.Encode(SHA256.HashData(ecdsa.ExportSubjectPublicKeyInfo()))
+            };
+            return new OidcKeyMaterial(
+                ecdsa,
+                signingKey,
+                new SymmetricSecurityKey(LoadEncryptionKey(options.EncryptionKeyPath)),
+                ReadFile(mas.ClientSecretPath, "Bifrost:Oidc:Clients:Mas:ClientSecretPath").Trim());
+        }
+        catch
+        {
+            ecdsa.Dispose();
+            throw;
+        }
+    }
+
+    public void Dispose() => _signingEcdsa.Dispose();
+
+    private static ECDsa LoadSigningKey(string path)
+    {
+        const string field = "Bifrost:Oidc:SigningKeyPath";
+        var pem = ReadFile(path, field);
+        var ecdsa = ECDsa.Create();
+        try
+        {
+            ecdsa.ImportFromPem(pem);
+            if (ecdsa.ExportParameters(false).Curve.Oid.Value != NistP256Oid)
+            {
+                throw new CryptographicException();
+            }
+
+            // ImportFromPem accepts a public key; a signing key needs the private half.
+            ecdsa.ExportParameters(true);
+            return ecdsa;
+        }
+        catch (Exception error) when (error is CryptographicException or ArgumentException)
+        {
+            ecdsa.Dispose();
+            throw new OidcConfigurationException($"{field} must name a PEM file holding an EC P-256 private key.");
+        }
+    }
+
+    private static byte[] LoadEncryptionKey(string path)
+    {
+        const string field = "Bifrost:Oidc:EncryptionKeyPath";
+        try
+        {
+            var key = Convert.FromBase64String(ReadFile(path, field).Trim());
+            if (key.Length == EncryptionKeyBytes)
+            {
+                return key;
+            }
+        }
+        catch (FormatException)
+        {
+        }
+
+        throw new OidcConfigurationException($"{field} must name a file holding {EncryptionKeyBytes} bytes as base64.");
+    }
+
+    private static string ReadFile(string path, string field)
+    {
+        try
+        {
+            return File.ReadAllText(path);
+        }
+        catch (Exception error) when (error is IOException or UnauthorizedAccessException or ArgumentException or NotSupportedException)
+        {
+            throw new OidcConfigurationException($"{field} must name a readable file.");
+        }
+    }
+
+    private static void Require(string value, string field)
+    {
+        if (string.IsNullOrWhiteSpace(value))
+        {
+            throw new OidcConfigurationException($"{field} is required when Bifrost:Oidc is configured.");
+        }
+    }
+}

src/Bifrost.Web/Features/Oidc/OidcLogoutReconciler.cs

@@ -0,0 +1,220 @@
+using System.Net;
+using Bifrost.Web.Configuration;
+using Bifrost.Web.Data;
+using Microsoft.IdentityModel.JsonWebTokens;
+using Microsoft.IdentityModel.Tokens;
+using Microsoft.Extensions.Options;
+using OpenIddict.Abstractions;
+using OpenIddict.Server;
+using static OpenIddict.Abstractions.OpenIddictConstants;
+
+namespace Bifrost.Web.Features.Oidc;
+
+/// <summary>
+/// Ends the chat sessions of a subject who is no longer an Active member. Each tick it lists the subjects holding valid
+/// authorizations of the configured client; for each one the shared active-member reading refuses, it POSTs one signed
+/// OIDC back-channel logout token to MAS and, only after a 2xx, revokes that subject's authorizations. The
+/// authorizations table is the queue: nothing is stored, so a restart, a MAS outage or a later-set URI resumes from it.
+/// Per-subject backoff lives in memory only. One subject's unexpected exception is logged and skipped, never aborting the
+/// pass. It never writes membership.
+/// </summary>
+public sealed class OidcLogoutReconciler(
+    IServiceScopeFactory scopeFactory,
+    OidcIssuerOptions options,
+    OidcKeyMaterial material,
+    IOptions<OpenIddictServerOptions> serverOptions,
+    IHttpClientFactory httpClients,
+    TimeProvider time,
+    ILogger<OidcLogoutReconciler> logger) : BackgroundService
+{
+    public const string HttpClientName = "bifrost-oidc-logout";
+    public const string LogoutEvent = "http://schemas.openid.net/event/backchannel-logout";
+    public const string LogoutTokenType = "logout+jwt";
+
+    public static readonly TimeSpan Interval = TimeSpan.FromSeconds(30);
+    public static readonly TimeSpan RequestTimeout = TimeSpan.FromSeconds(10);
+    public static readonly TimeSpan TokenLifetime = TimeSpan.FromMinutes(2);
+    public static readonly TimeSpan MaxBackoff = TimeSpan.FromMinutes(15);
+
+    private readonly Dictionary<string, Backoff> _backoff = new(StringComparer.Ordinal);
+
+    private sealed record Backoff(int Failures, DateTimeOffset NotBefore);
+
+    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
+    {
+        while (!stoppingToken.IsCancellationRequested)
+        {
+            try
+            {
+                await ReconcileOnceAsync(stoppingToken);
+                await Task.Delay(Interval, time, stoppingToken);
+            }
+            catch (OperationCanceledException) when (stoppingToken.IsCancellationRequested)
+            {
+                return;
+            }
+            catch (Exception error)
+            {
+                // The type only: messages can carry connection strings or URLs.
+                logger.LogError("Back-channel logout reconcile failed: {ErrorType}", error.GetType().Name);
+                try
+                {
+                    await Task.Delay(Interval, time, stoppingToken);
+                }
+                catch (OperationCanceledException)
+                {
+                    return;
+                }
+            }
+        }
+    }
+
+    /// <summary>One reconcile pass. Subjects are independent: one that cannot be delivered never blocks another.</summary>
+    public async Task ReconcileOnceAsync(CancellationToken cancellationToken)
+    {
+        var subjects = await ListSubjectsAsync(cancellationToken);
+        foreach (var gone in _backoff.Keys.Except(subjects).ToArray())
+        {
+            _backoff.Remove(gone);
+        }
+
+        foreach (var subject in subjects)
+        {
+            cancellationToken.ThrowIfCancellationRequested();
+            try
+            {
+                await ReconcileSubjectAsync(subject, cancellationToken);
+            }
+            catch (OperationCanceledException) when (cancellationToken.IsCancellationRequested)
+            {
+                throw;
+            }
+            catch (Exception error)
+            {
+                // One subject's fault never stops the pass: its authorizations stay valid and the next tick retries it.
+                // The subject id and the exception type only: messages can carry connection strings or URLs.
+                logger.LogError("Back-channel logout for subject {Subject} failed: {ErrorType}", subject, error.GetType().Name);
+            }
+        }
+    }
+
+    private async Task<HashSet<string>> ListSubjectsAsync(CancellationToken cancellationToken)
+    {
+        await using var scope = scopeFactory.CreateAsyncScope();
+        var applications = scope.ServiceProvider.GetRequiredService<IOpenIddictApplicationManager>();
+        var authorizations = scope.ServiceProvider.GetRequiredService<IOpenIddictAuthorizationManager>();
+
+        var subjects = new HashSet<string>(StringComparer.Ordinal);
+        var application = await applications.FindByClientIdAsync(options.Clients.Mas.ClientId, cancellationToken);
+        if (application is null || await applications.GetIdAsync(application, cancellationToken) is not { } applicationId)
+        {
+            return subjects;
+        }
+
+        await foreach (var authorization in authorizations.FindByApplicationIdAsync(applicationId, cancellationToken))
+        {
+            if (await authorizations.HasStatusAsync(authorization, Statuses.Valid, cancellationToken) &&
+                await authorizations.GetSubjectAsync(authorization, cancellationToken) is { Length: > 0 } subject)
+            {
+                subjects.Add(subject);
+            }
+        }
+
+        return subjects;
+    }
+
+    private async Task ReconcileSubjectAsync(string subject, CancellationToken cancellationToken)
+    {
+        await using var scope = scopeFactory.CreateAsyncScope();
+        var db = scope.ServiceProvider.GetRequiredService<BifrostDbContext>();
+        if (await OidcEndpoints.IsStillActiveMemberAsync(db, subject, cancellationToken))
+        {
+            _backoff.Remove(subject);
+            return;
+        }
+
+        // A subject that recovered is forgotten at once; one still owed a logout waits out its backoff.
+        _backoff.TryGetValue(subject, out var previous);
+        if (previous is not null && time.GetUtcNow() < previous.NotBefore)
+        {
+            return;
+        }
+
+        var failures = (previous?.Failures ?? 0) + 1;
+        var status = await SendLogoutAsync(subject, cancellationToken);
+        if (status is { } code && (int)code is >= 200 and < 300)
+        {
+            var authorizations = scope.ServiceProvider.GetRequiredService<IOpenIddictAuthorizationManager>();
+            await foreach (var authorization in authorizations.FindBySubjectAsync(subject, cancellationToken))
+            {
+                if (await authorizations.HasStatusAsync(authorization, Statuses.Valid, cancellationToken))
+                {
+                    await authorizations.TryRevokeAsync(authorization, cancellationToken);
+                }
+            }
+
+            _backoff.Remove(subject);
+            return;
+        }
+
+        // 400 (token refused) and 404 (unknown provider) are configuration faults: retrying sooner cannot fix them.
+        var fault = status is HttpStatusCode.BadRequest or HttpStatusCode.NotFound;
+        var delay = fault ? MaxBackoff : BackoffFor(failures);
+        _backoff[subject] = new Backoff(failures, time.GetUtcNow() + delay);
+        logger.LogWarning(
+            "Back-channel logout to MAS failed with {Status}; retrying in {Delay}",
+            status is { } s ? (int)s : "no response",
+            delay);
+    }
+
+    internal static TimeSpan BackoffFor(int failures)
+    {
+        var seconds = Interval.TotalSeconds * Math.Pow(2, Math.Min(failures, 16) - 1);
+        return TimeSpan.FromSeconds(Math.Min(seconds, MaxBackoff.TotalSeconds));
+    }
+
+    /// <summary>The status MAS answered, or null on a network fault or timeout. The response body is never read.</summary>
+    private async Task<HttpStatusCode?> SendLogoutAsync(string subject, CancellationToken cancellationToken)
+    {
+        var token = BuildLogoutToken(subject);
+        using var request = new HttpRequestMessage(HttpMethod.Post, options.Clients.Mas.BackchannelLogoutUri)
+        {
+            Content = new FormUrlEncodedContent([new KeyValuePair<string, string>("logout_token", token)])
+        };
+        try
+        {
+            using var response = await httpClients.CreateClient(HttpClientName)
+                .SendAsync(request, HttpCompletionOption.ResponseHeadersRead, cancellationToken);
+            return response.StatusCode;
+        }
+        catch (Exception error) when (error is HttpRequestException or TaskCanceledException && !cancellationToken.IsCancellationRequested)
+        {
+            return null;
+        }
+    }
+
+    /// <summary>
+    /// The OIDC back-channel logout token MAS verifies like an id_token: iss and aud as the id_token carries them, exp
+    /// and iat both present, an events member, and neither nonce nor sid (MAS finds the session by sub).
+    /// </summary>
+    private string BuildLogoutToken(string subject)
+    {
+        var now = time.GetUtcNow();
+        var descriptor = new SecurityTokenDescriptor
+        {
+            TokenType = LogoutTokenType,
+            Issuer = serverOptions.Value.Issuer!.AbsoluteUri,
+            Audience = options.Clients.Mas.ClientId,
+            IssuedAt = now.UtcDateTime,
+            Expires = now.UtcDateTime + TokenLifetime,
+            SigningCredentials = new SigningCredentials(material.SigningKey, SecurityAlgorithms.EcdsaSha256),
+            Claims = new Dictionary<string, object>
+            {
+                [Claims.Subject] = Guid.TryParse(subject, out var id) ? id.ToString("D") : subject,
+                [Claims.JwtId] = Guid.NewGuid().ToString("D"),
+                ["events"] = new Dictionary<string, object> { [LogoutEvent] = new Dictionary<string, object>() }
+            }
+        };
+        return new JsonWebTokenHandler().CreateToken(descriptor);
+    }
+}

src/Bifrost.Web/Features/Oidc/OidcServiceCollectionExtensions.cs

@@ -0,0 +1,81 @@
+using Bifrost.Web.Configuration;
+using Bifrost.Web.Data;
+using Microsoft.Extensions.Options;
+using OpenIddict.Abstractions;
+using OpenIddict.Server;
+using static OpenIddict.Abstractions.OpenIddictConstants;
+
+namespace Bifrost.Web.Features.Oidc;
+
+public static class OidcServiceCollectionExtensions
+{
+    public const string AuthorizationPath = "/connect/authorize";
+    public const string TokenPath = "/connect/token";
+    public const string UserInfoPath = "/connect/userinfo";
+
+    /// <summary>How long a parked authorize request (OpenIddict's request token) can wait for the user to sign in.</summary>
+    private static readonly TimeSpan ParkedRequestLifetime = TimeSpan.FromMinutes(10);
+
+    /// <summary>
+    /// Registers Bifrost as an OIDC provider whose issuer is <see cref="BifrostHostOptions.PublicBaseUrl"/>: authorization-code flow with
+    /// PKCE, ES256 id_tokens, scopes openid and profile, one configured client. Keys come from files, never from
+    /// generated development keys. The authorize request is parked by OpenIddict's own request caching, so the
+    /// sign-in return path carries only a short request_uri.
+    /// </summary>
+    public static IServiceCollection AddBifrostOidc(this IServiceCollection services, OidcIssuerOptions options)
+    {
+        var material = OidcKeyMaterial.Load(options);
+        services.AddSingleton(material);
+        services.AddSingleton(options);
+
+        services.AddOpenIddict()
+            .AddCore(core => core.UseEntityFrameworkCore().UseDbContext<BifrostDbContext>())
+            .AddServer(server =>
+            {
+                server.SetAuthorizationEndpointUris(AuthorizationPath)
+                    .SetTokenEndpointUris(TokenPath)
+                    .SetUserInfoEndpointUris(UserInfoPath);
+
+                server.AllowAuthorizationCodeFlow().RequireProofKeyForCodeExchange();
+                server.RegisterScopes(Scopes.OpenId, Scopes.Profile);
+                server.RegisterClaims(Claims.Subject, Claims.PreferredUsername, Claims.Name);
+                server.EnableAuthorizationRequestCaching();
+                server.Configure(opts =>
+                {
+                    opts.ClientAuthenticationMethods.Clear();
+                    opts.ClientAuthenticationMethods.Add(ClientAuthenticationMethods.ClientSecretBasic);
+                    opts.RequestTokenLifetime = ParkedRequestLifetime;
+                });
+
+                server.AddSigningKey(material.SigningKey);
+                server.AddEncryptionKey(material.EncryptionKey);
+
+                server.UseAspNetCore()
+                    .EnableAuthorizationEndpointPassthrough()
+                    .EnableTokenEndpointPassthrough()
+                    .EnableUserInfoEndpointPassthrough();
+            });
+
+        // The issuer is the public host, read from the bound options so it has one source.
+        services.AddOptions<OpenIddictServerOptions>().Configure<IOptions<BifrostHostOptions>>((server, host) =>
+        {
+            if (!Uri.TryCreate(host.Value.PublicBaseUrl, UriKind.Absolute, out var issuer))
+            {
+                throw new OidcConfigurationException("Host:PublicBaseUrl is required when Bifrost:Oidc is configured.");
+            }
+
+            server.Issuer = issuer;
+        });
+
+        services.AddHostedService<OidcClientSeeder>();
+        if (!string.IsNullOrWhiteSpace(options.Clients.Mas.BackchannelLogoutUri))
+        {
+            // MAS answers the logout POST itself: a redirect is a non-delivery, never followed to some other 2xx.
+            services.AddHttpClient(OidcLogoutReconciler.HttpClientName, client => client.Timeout = OidcLogoutReconciler.RequestTimeout)
+                .ConfigurePrimaryHttpMessageHandler(() => new SocketsHttpHandler { AllowAutoRedirect = false });
+            services.AddHostedService<OidcLogoutReconciler>();
+        }
+
+        return services;
+    }
+}

src/Bifrost.Web/Features/Shared/FixedWindowBudget.cs

@@ -0,0 +1,131 @@
+namespace Bifrost.Web.Features.Shared;
+
+// Why a permit was refused and how long until the answer can change. TableFull is not the caller's own spending: the
+// table holds only spent windows and has no room for a key it does not know.
+public readonly record struct BudgetDenial(TimeSpan RetryAfter, bool TableFull);
+
+// The one rate-limit mechanism: a fixed-window permit budget per caller-chosen partition key, timed on the injected
+// clock's monotonic timestamps (never its wall time, which can step), so a clock adjustment cannot stretch or reset a
+// window. Windows all have one length, so they end in the order they began: a list of entries in start order expires
+// them from the front and the table never holds a key past its window.
+// The table holds at most maxKeys keys. A new key arriving at the cap evicts the least recently used key that still
+// has permits left (nginx limit_req_zone does the same); a key that has spent all its permits is never evicted, so a
+// rotating caller can at most win back a forgotten key's partial budget and never a spent one, and nobody fresh is
+// refused because the table is full. Only when every held key is spent is a new key refused, with the true wait.
+// Every step is O(1): two linked lists, one by window start and one by last use among keys with permits left.
+// System.Threading.RateLimiting is not used because its limiters time themselves on Stopwatch and timers, which a
+// test cannot move.
+public sealed class FixedWindowBudget
+{
+    private readonly int permits;
+    private readonly TimeSpan window;
+    private readonly int maxKeys;
+    private readonly TimeProvider clock;
+    private readonly long origin;
+    private readonly Dictionary<string, Entry> entries = new(StringComparer.Ordinal);
+    private readonly LinkedList<Entry> byStart = new();
+    private readonly LinkedList<Entry> byUse = new();
+    private readonly object gate = new();
+
+    public FixedWindowBudget(int permits, TimeSpan window, int maxKeys, TimeProvider clock)
+    {
+        ArgumentOutOfRangeException.ThrowIfLessThan(permits, 1);
+        ArgumentOutOfRangeException.ThrowIfLessThanOrEqual(window, TimeSpan.Zero);
+        ArgumentOutOfRangeException.ThrowIfLessThan(maxKeys, 1);
+        this.permits = permits;
+        this.window = window;
+        this.maxKeys = maxKeys;
+        this.clock = clock;
+        origin = clock.GetTimestamp();
+    }
+
+    // How many keys are held now: the keys whose window is still open, never more than maxKeys.
+    public int TrackedKeys
+    {
+        get
+        {
+            lock (gate)
+            {
+                return entries.Count;
+            }
+        }
+    }
+
+    // Takes one permit for the key and returns null, or returns why it could not.
+    public BudgetDenial? Spend(string key)
+    {
+        lock (gate)
+        {
+            var now = clock.GetElapsedTime(origin);
+            while (byStart.First is { Value: var oldest } && oldest.Start + window <= now)
+            {
+                Remove(oldest);
+            }
+
+            if (entries.TryGetValue(key, out var entry))
+            {
+                if (entry.Count >= permits)
+                {
+                    return new BudgetDenial(entry.Start + window - now, false);
+                }
+
+                entry.Count++;
+                if (entry.Count >= permits)
+                {
+                    byUse.Remove(entry.UseNode!);
+                    entry.UseNode = null;
+                }
+                else
+                {
+                    byUse.Remove(entry.UseNode!);
+                    byUse.AddLast(entry.UseNode!);
+                }
+
+                return null;
+            }
+
+            if (entries.Count >= maxKeys)
+            {
+                if (byUse.First is not { Value: var forgotten })
+                {
+                    return new BudgetDenial(byStart.First!.Value.Start + window - now, true);
+                }
+
+                Remove(forgotten);
+            }
+
+            var added = new Entry(key, now);
+            entries[key] = added;
+            added.StartNode = byStart.AddLast(added);
+            if (added.Count < permits)
+            {
+                added.UseNode = byUse.AddLast(added);
+            }
+
+            return null;
+        }
+    }
+
+    private void Remove(Entry entry)
+    {
+        entries.Remove(entry.Key);
+        byStart.Remove(entry.StartNode!);
+        if (entry.UseNode is not null)
+        {
+            byUse.Remove(entry.UseNode);
+        }
+    }
+
+    private sealed class Entry(string key, TimeSpan start)
+    {
+        public string Key { get; } = key;
+
+        public TimeSpan Start { get; } = start;
+
+        public int Count { get; set; } = 1;
+
+        public LinkedListNode<Entry>? StartNode { get; set; }
+
+        public LinkedListNode<Entry>? UseNode { get; set; }
+    }
+}

src/Bifrost.Web/Features/Shared/LocalReturnPath.cs

@@ -0,0 +1,34 @@
+namespace Bifrost.Web.Features.Shared;
+
+/// <summary>
+/// A sign-in return target that stays on this site. The only way to make one is <see cref="Parse"/>, which
+/// accepts a path of at most <see cref="MaxLength"/> characters that starts with a single slash and holds no
+/// control character, and otherwise yields <see cref="Default"/>. Callers parse once at entry and carry the typed value from there.
+/// </summary>
+public sealed record LocalReturnPath
+{
+    private LocalReturnPath(string value) => Value = value;
+
+    /// <summary>Bounds the path so the attempt cookie that carries it stays far below a browser's 4096-byte limit.</summary>
+    public const int MaxLength = 256;
+
+    public static LocalReturnPath Default { get; } = new("/App");
+
+    public string Value { get; }
+
+    public static LocalReturnPath Parse(string? candidate)
+    {
+        if (string.IsNullOrEmpty(candidate) ||
+            candidate.Length > MaxLength ||
+            candidate[0] != '/' ||
+            candidate.Any(char.IsControl) ||
+            (candidate.Length > 1 && (candidate[1] == '/' || candidate[1] == '\\')))
+        {
+            return Default;
+        }
+
+        return new LocalReturnPath(candidate);
+    }
+
+    public override string ToString() => Value;
+}

src/Bifrost.Web/Features/Shared/StartupConfigurationValidator.cs

@@ -1,4 +1,5 @@
 using Bifrost.Web.Configuration;
+using Bifrost.Web.Features.ConceptVotes;
 using Microsoft.Extensions.Options;
 
 namespace Bifrost.Web.Features.Shared;
@@ -10,16 +11,45 @@ public sealed class StartupConfigurationValidator(
     IOptions<GitHubAppOptions> gitHubAppOptions,
     IOptions<HeimdallOptions> heimdallOptions,
     IOptions<StripeOptions> stripeOptions,
-    IOptions<BifrostHostOptions> hostOptions)
+    IOptions<BifrostHostOptions> hostOptions,
+    IOptions<ConceptVoteOptions> conceptVoteOptions)
 {
     public void Validate()
     {
-        if (hostEnvironment.IsDevelopment() || hostEnvironment.IsEnvironment("Testing"))
+        var failures = new List<string>();
+
+        // Checked in every environment: a bad value here would otherwise pass startup and throw on every cast.
+        var conceptVotes = conceptVoteOptions.Value;
+        if (!NetworkPrefix.IsValidLength(conceptVotes.IPv4PrefixLength, NetworkPrefix.IPv4Bits))
         {
-            return;
+            failures.Add($"ConceptVotes:IPv4PrefixLength must be between 0 and {NetworkPrefix.IPv4Bits}.");
         }
 
-        var failures = new List<string>();
+        if (!NetworkPrefix.IsValidLength(conceptVotes.IPv6PrefixLength, NetworkPrefix.IPv6Bits))
+        {
+            failures.Add($"ConceptVotes:IPv6PrefixLength must be between 0 and {NetworkPrefix.IPv6Bits}.");
+        }
+
+        if (conceptVotes.CastPermits < 1 || conceptVotes.CastWindow <= TimeSpan.Zero)
+        {
+            failures.Add("ConceptVotes:CastPermits must be at least 1 and ConceptVotes:CastWindow must be positive.");
+        }
+
+        if (conceptVotes.MintPermits < 1 || conceptVotes.MintWindow <= TimeSpan.Zero)
+        {
+            failures.Add("ConceptVotes:MintPermits must be at least 1 and ConceptVotes:MintWindow must be positive.");
+        }
+
+        if (conceptVotes.MaxTrackedKeys < 1)
+        {
+            failures.Add("ConceptVotes:MaxTrackedKeys must be at least 1.");
+        }
+
+        if (hostEnvironment.IsDevelopment() || hostEnvironment.IsEnvironment("Testing"))
+        {
+            Refuse(failures);
+            return;
+        }
 
         if (!gitHubOAuthOptions.Value.IsConfigured)
         {
@@ -66,10 +96,40 @@ public sealed class StartupConfigurationValidator(
             failures.Add("Connection string 'Bifrost' must be configured.");
         }
 
+        if (string.IsNullOrWhiteSpace(configuration["DataProtection:KeysPath"]))
+        {
+            failures.Add("DataProtection:KeysPath must be configured for production.");
+        }
+
+        if (string.IsNullOrWhiteSpace(conceptVotes.NetworkTagSecret) ||
+            conceptVotes.NetworkTagSecret.Length < ConceptVoteOptions.MinNetworkTagSecretLength)
+        {
+            failures.Add(
+                $"ConceptVotes:NetworkTagSecret must be configured with at least {ConceptVoteOptions.MinNetworkTagSecretLength} characters for production.");
+        }
+
+        if (!conceptVotes.AllowedOrigins.All(IsExactHttpsOrigin))
+        {
+            failures.Add("ConceptVotes:AllowedOrigins entries must each be exactly https://host with no path, wildcard or trailing slash.");
+        }
+
+        Refuse(failures);
+    }
+
+    private static void Refuse(List<string> failures)
+    {
         if (failures.Count > 0)
         {
             throw new InvalidOperationException(
                 "Bifrost startup configuration is incomplete: " + string.Join(" ", failures));
         }
     }
+
+    // The authority form is the canonical spelling, so a wildcard, path, query, upper-case host or default port
+    // differs from it and is refused; user info is part of the authority, so it is refused on its own.
+    private static bool IsExactHttpsOrigin(string? origin) =>
+        Uri.TryCreate(origin, UriKind.Absolute, out var uri) &&
+        uri.Scheme == Uri.UriSchemeHttps &&
+        uri.UserInfo.Length == 0 &&
+        string.Equals(uri.GetLeftPart(UriPartial.Authority), origin, StringComparison.Ordinal);
 }

src/Bifrost.Web/Pages/Mill/Vote.cshtml

@@ -0,0 +1,56 @@
+@page "/mill/{collection}/{key}"
+@model Bifrost.Web.Pages.Mill.VoteModel
+@{
+    ViewData["Title"] = Model.Subject.Title;
+    var stance = Model.Subject.YourStance;
+}
+
+<section class="panel">
+    <a class="back-link" href="@Model.MillPageLink">Back to the Concept Mill</a>
+    <h1>@Model.Subject.Title</h1>
+
+    <dl class="mill-counts">
+        <dt>Everyone</dt>
+        <dd>@Model.Subject.Tally.Up up, @Model.Subject.Tally.Down down</dd>
+        <dt>Members</dt>
+        <dd>@Model.Subject.Tally.Members.Up up, @Model.Subject.Tally.Members.Down down</dd>
+    </dl>
+
+    <p>
+        @if (stance is null)
+        {
+            <text>You have not voted on this concept.</text>
+        }
+        else
+        {
+            <text>Your vote: @(stance == Bifrost.Web.Domain.ConceptStance.Up ? "up" : "down").</text>
+        }
+    </p>
+
+    <div class="mill-actions">
+        <form method="post" asp-page-handler="Up" asp-antiforgery="false" hx-boost="false">
+            <button class="button" type="submit">Up</button>
+        </form>
+        <form method="post" asp-page-handler="Down" asp-antiforgery="false" hx-boost="false">
+            <button class="button" type="submit">Down</button>
+        </form>
+        @if (stance is not null)
+        {
+            <form method="post" asp-page-handler="Retract" asp-antiforgery="false" hx-boost="false">
+                <button class="button ghost" type="submit">Retract</button>
+            </form>
+        }
+    </div>
+
+    @if (Model.SignedIn)
+    {
+        <p class="muted">Your vote is kept against your Bifrost account. No cookie is set.</p>
+    }
+    else
+    {
+        <p class="muted">
+            Voting saves one small cookie on this device. Its only purpose is to keep your one vote yours so you can
+            change or retract it; it lasts a year and carries nothing else.
+        </p>
+    }
+</section>

src/Bifrost.Web/Pages/Mill/Vote.cshtml.cs

@@ -0,0 +1,179 @@
+using Bifrost.Web.Configuration;
+using Bifrost.Web.Domain;
+using Bifrost.Web.Features.ConceptVotes;
+using Bifrost.Web.Features.Shared;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.Filters;
+using Microsoft.AspNetCore.Mvc.RazorPages;
+using Microsoft.Extensions.Options;
+
+namespace Bifrost.Web.Pages.Mill;
+
+// The anonymous vote page. Counts and the visitor's own stance come from ConceptAppraisalService on every GET; the
+// voter key is decided by VoterIdentity.For from the actor and the device id VoterKeyResolver reads.
+[IgnoreAntiforgeryToken]
+[ResponseCache(NoStore = true, Location = ResponseCacheLocation.None)]
+public sealed class VoteModel(
+    ICurrentBifrostActorAccessor actorAccessor,
+    ConceptAppraisalService appraisals,
+    VoterKeyResolver deviceCookie,
+    ConceptVoteRateLimits limits,
+    IOptions<ConceptVoteOptions> options,
+    IOptions<BifrostHostOptions> host) : PageModel
+{
+    public ConceptSubjectView Subject { get; private set; } = null!;
+
+    public bool SignedIn { get; private set; }
+
+    public string MillPageLink => options.Value.MillPageUrl + "#" + Uri.EscapeDataString(Subject.Key);
+
+    // The single gate before any handler runs. A request that selects no handler (a POST with no or an unknown handler,
+    // any other method) is a client error, never a view over a null subject. A cast is accepted only from the site's own
+    // origin (CastRequestGuard); no antiforgery cookie or token exists on this flow.
+    public override async Task OnPageHandlerExecutionAsync(PageHandlerExecutingContext context, PageHandlerExecutionDelegate next)
+    {
+        var method = context.HttpContext.Request.Method;
+        if (context.HandlerMethod is null)
+        {
+            context.Result = new StatusCodeResult(
+                HttpMethods.IsGet(method) || HttpMethods.IsHead(method) || HttpMethods.IsPost(method)
+                    ? StatusCodes.Status400BadRequest
+                    : StatusCodes.Status405MethodNotAllowed);
+            return;
+        }
+
+        // The handler the request names must be the handler selected: GET ?handler=Up has no OnGetUp to run.
+        var named = context.HttpContext.Request.Query["handler"].ToString();
+        if (string.IsNullOrEmpty(named) != string.IsNullOrEmpty(context.HandlerMethod.Name))
+        {
+            context.Result = new StatusCodeResult(StatusCodes.Status400BadRequest);
+            return;
+        }
+
+        if (HttpMethods.IsPost(method) && !CastRequestGuard.Allows(context.HttpContext.Request, host.Value))
+        {
+            context.Result = new StatusCodeResult(StatusCodes.Status403Forbidden);
+            return;
+        }
+
+        await next();
+    }
+
+    public async Task<IActionResult> OnGetAsync(string collection, string key, CancellationToken cancellationToken)
+    {
+        var actor = await actorAccessor.GetAsync(cancellationToken);
+        var voter = ResolveVoter(actor);
+        SignedIn = voter?.UserAccountId is not null;
+        return await LoadAsync(collection, key, voter, cancellationToken) ? Page() : NotFound();
+    }
+
+    public Task<IActionResult> OnPostUpAsync(string collection, string key, CancellationToken cancellationToken) =>
+        CastAsync(collection, key, ConceptStance.Up, cancellationToken);
+
+    public Task<IActionResult> OnPostDownAsync(string collection, string key, CancellationToken cancellationToken) =>
+        CastAsync(collection, key, ConceptStance.Down, cancellationToken);
+
+    public async Task<IActionResult> OnPostRetractAsync(string collection, string key, CancellationToken cancellationToken)
+    {
+        var actor = await actorAccessor.GetAsync(cancellationToken);
+        var voter = ResolveVoter(actor);
+        if (await appraisals.GetSubjectAsync(collection, key, null, cancellationToken) is null)
+        {
+            return NotFound();
+        }
+
+        if (Throttled(limits.DenyCast(HttpContext.Connection.RemoteIpAddress, voter), CastRefusal, voter) is { } throttled)
+        {
+            return throttled;
+        }
+
+        await appraisals.RetractAsync(collection, key, voter, cancellationToken);
+        return RedirectToPage(new { collection, key });
+    }
+
+    private async Task<IActionResult> CastAsync(
+        string collection,
+        string key,
+        ConceptStance stance,
+        CancellationToken cancellationToken)
+    {
+        var actor = await actorAccessor.GetAsync(cancellationToken);
+        var client = HttpContext.Connection.RemoteIpAddress;
+        var voter = ResolveVoter(actor);
+        if (await appraisals.GetSubjectAsync(collection, key, null, cancellationToken) is null)
+        {
+            return NotFound();
+        }
+
+        if (Throttled(limits.DenyCast(client, voter), CastRefusal, voter) is { } throttled)
+        {
+            return throttled;
+        }
+
+        if (voter is null)
+        {
+            if (Throttled(limits.DenyMint(client), MintRefusal, voter) is { } mintThrottled)
+            {
+                return mintThrottled;
+            }
+
+            voter = VoterIdentity.For(actor, deviceCookie.Mint(HttpContext));
+        }
+
+        var result = await appraisals.CastAsync(
+            collection, key, voter, stance, HttpContext.Connection.RemoteIpAddress, cancellationToken);
+        return result is CastResult.UnknownSubject or CastResult.RetiredSubject
+            ? NotFound()
+            : RedirectToPage(new { collection, key });
+    }
+
+    // Accounts key to the account and never touch the cookie. An anonymous visitor keys to a device cookie that
+    // unprotects to a well-formed id; a cast without one mints it (CastAsync, after the mint budget), and no other path does.
+    private VoterIdentity? ResolveVoter(CurrentBifrostActor actor) =>
+        VoterIdentity.For(actor, null) ?? VoterIdentity.For(actor, deviceCookie.TryRead(HttpContext));
+
+    // A denied budget is a 429 that says when to retry, in words a voter can read; it writes no row, sets no cookie and
+    // repeats nothing of the request. The subject is checked before any budget is spent, so a request for a concept that
+    // does not exist costs the sender nothing and the table nothing. A refused new device is told it can sign in, which
+    // has a budget of its own. A table full of spent windows is not the visitor's doing and says so.
+    private const string CastRefusal = "You are voting too fast. Please wait a little before voting again.";
+
+    private const string MintRefusal =
+        "Too many new voters have voted from your network recently. You can sign in to vote now, or try again later.";
+
+    private const string BusyRefusal = "Voting is very busy right now. Please try again in a little while.";
+
+    // Accounts have their own table, so a visitor who is not signed in can still vote by signing in while a table is full.
+    private const string BusyRefusalSignIn =
+        "Voting is very busy right now. You can sign in to vote now, or try again in a little while.";
+
+    private IActionResult? Throttled(BudgetDenial? denial, string spentRefusal, VoterIdentity? voter)
+    {
+        if (denial is not { } refused)
+        {
+            return null;
+        }
+
+        var busy = voter?.UserAccountId is null ? BusyRefusalSignIn : BusyRefusal;
+        var refusal = refused.TableFull ? busy : spentRefusal;
+        Response.Headers.RetryAfter = ((int)Math.Ceiling(refused.RetryAfter.TotalSeconds)).ToString(System.Globalization.CultureInfo.InvariantCulture);
+        return new ContentResult
+        {
+            StatusCode = StatusCodes.Status429TooManyRequests,
+            ContentType = "text/plain; charset=utf-8",
+            Content = refusal
+        };
+    }
+
+    private async Task<bool> LoadAsync(string collection, string key, VoterIdentity? voter, CancellationToken cancellationToken)
+    {
+        var view = await appraisals.GetSubjectAsync(collection, key, voter, cancellationToken);
+        if (view is null)
+        {
+            return false;
+        }
+
+        Subject = view;
+        return true;
+    }
+}

src/Bifrost.Web/Program.cs

@@ -6,10 +6,12 @@ using Bifrost.Web.Configuration;
 using Bifrost.Web.Data;
 using Bifrost.Web.Domain;
 using Bifrost.Web.Features.Bridge;
+using Bifrost.Web.Features.ConceptVotes;
 using Bifrost.Web.Features.GitHub;
 using Bifrost.Web.Features.Heimdall;
 using Bifrost.Web.Features.Membership;
 using Bifrost.Web.Features.Motions;
+using Bifrost.Web.Features.Oidc;
 using Bifrost.Web.Features.Patronage;
 using Bifrost.Web.Features.Shared;
 using Microsoft.AspNetCore.Authentication;
@@ -17,9 +19,28 @@ using Microsoft.AspNetCore.Authentication.Cookies;
 using Microsoft.AspNetCore.Authentication.OAuth;
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.DataProtection;
+using Microsoft.AspNetCore.HttpOverrides;
 using Microsoft.AspNetCore.HttpLogging;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Options;
+using System.Net;
+
+// Host command: registers Mill concept subjects with configuration and the database only; no web app, no migrations.
+if (args.Length > 0 && args[0] == "concepts")
+{
+    var host = Host.CreateApplicationBuilder([]);
+    host.Services.AddDbContext<BifrostDbContext>(options => options.UseNpgsql(BifrostConnectionString(host.Configuration)));
+    host.Services.AddSingleton(TimeProvider.System);
+    host.Services.AddScoped<AuditTrailService>();
+    host.Services.AddScoped<ConceptSubjectRegistry>();
+    using var commandHost = host.Build();
+    Environment.ExitCode = await ConceptCommand.RunAsync(args[1..], commandHost.Services, Console.Out);
+    return;
+}
+
+static string BifrostConnectionString(IConfiguration configuration) =>
+    configuration.GetConnectionString("Bifrost")
+        ?? "Host=127.0.0.1;Database=bifrost;Username=postgres;Password=postgres";
 
 var builder = WebApplication.CreateBuilder(args);
 
@@ -51,10 +72,15 @@ builder.Services
     .AddOptions<BridgeOptions>()
     .BindConfiguration(BridgeOptions.SectionName);
 
+builder.Services
+    .AddOptions<ConceptVoteOptions>()
+    .BindConfiguration(ConceptVoteOptions.SectionName);
+
 builder.Services.AddRazorPages(options =>
 {
     options.Conventions.AuthorizePage("/Membership/Status");
     options.Conventions.AuthorizeFolder("/App", ActiveMemberRequirement.PolicyName);
+    options.Conventions.AllowAnonymousToFolder("/Mill");
 });
 builder.Services.ConfigureHttpJsonOptions(options =>
 {
@@ -63,10 +89,7 @@ builder.Services.ConfigureHttpJsonOptions(options =>
 
 builder.Services.AddDbContext<BifrostDbContext>(options =>
 {
-    var connectionString = builder.Configuration.GetConnectionString("Bifrost")
-        ?? "Host=127.0.0.1;Database=bifrost;Username=postgres;Password=postgres";
-
-    options.UseNpgsql(connectionString);
+    options.UseNpgsql(BifrostConnectionString(builder.Configuration));
 });
 
 builder.Services.AddHttpLogging(options =>
@@ -95,29 +118,47 @@ builder.Services.AddScoped<MotionEveSurfaceService>();
 builder.Services.AddScoped<PatronageService>();
 builder.Services.AddScoped<StripeWebhookService>();
 builder.Services.AddScoped<HeimdallPatronSupportIntakeService>();
+builder.Services.AddScoped<ConceptAppraisalService>();
+builder.Services.AddScoped<VoterKeyResolver>();
+builder.Services.AddSingleton<ConceptVoteRateLimits>();
+builder.Services.AddScoped<ConceptSubjectRegistry>();
 builder.Services.AddScoped<ReadinessService>();
 builder.Services.AddScoped<ApplicationBootstrapper>();
 builder.Services.AddSingleton<StartupConfigurationValidator>();
 builder.Services.AddScoped<IAuthorizationHandler, ActiveMemberAuthorizationHandler>();
-builder.Services.AddSingleton<HeimdallAuthAttemptStore>();
 builder.Services.AddHttpClient<HeimdallAuthService>((serviceProvider, client) =>
-{
-    var options = serviceProvider.GetRequiredService<IOptions<HeimdallOptions>>().Value;
-    client.BaseAddress = new Uri(options.BaseUrl.TrimEnd('/'));
-});
+    HeimdallAuthService.ConfigureClient(client, serviceProvider.GetRequiredService<IOptions<HeimdallOptions>>().Value))
+    .RedactLoggedHeaders(header => string.Equals(header, HeimdallAuthService.AppSecretHeader, StringComparison.OrdinalIgnoreCase));
+builder.Services.AddSingleton<HeimdallTokenVerifier>();
+builder.Services.AddHttpClient(HeimdallTokenVerifier.ClientName, (serviceProvider, client) =>
+    HeimdallTokenVerifier.ConfigureClient(client, serviceProvider.GetRequiredService<IOptions<HeimdallOptions>>().Value));
 builder.Services.AddHttpClient<StripeCheckoutService>(client =>
 {
     client.BaseAddress = new Uri("https://api.stripe.com/");
 });
 
+var dataProtectionBuilder = builder.Services
+    .AddDataProtection()
+    .SetApplicationName("Bifrost");
 var dataProtectionKeysPath = builder.Configuration["DataProtection:KeysPath"];
 if (!string.IsNullOrWhiteSpace(dataProtectionKeysPath))
 {
-    builder.Services
-        .AddDataProtection()
-        .PersistKeysToFileSystem(new DirectoryInfo(dataProtectionKeysPath));
+    dataProtectionBuilder.PersistKeysToFileSystem(new DirectoryInfo(dataProtectionKeysPath));
 }
 
+// nginx on this host is the only proxy, and it connects from loopback. Trusting exactly
+// those addresses keeps a direct client from choosing its own address with X-Forwarded-For.
+builder.Services.Configure<ForwardedHeadersOptions>(options =>
+{
+    options.ForwardedHeaders = ForwardedHeaders.XForwardedFor | ForwardedHeaders.XForwardedProto;
+    options.KnownNetworks.Clear();
+    options.KnownProxies.Clear();
+    options.KnownProxies.Add(IPAddress.Loopback);
+    options.KnownProxies.Add(IPAddress.IPv6Loopback);
+    options.KnownProxies.Add(IPAddress.Loopback.MapToIPv6());
+    options.ForwardLimit = 1;
+});
+
 var configuredGitHubOAuthOptions = builder.Configuration
     .GetSection(GitHubOAuthOptions.SectionName)
     .Get<GitHubOAuthOptions>() ?? new GitHubOAuthOptions();
@@ -183,6 +224,15 @@ builder.Services.AddAuthorization(options =>
     });
 });
 
+builder.Services.AddConceptTallyCors();
+
+// The OIDC provider is mapped only when Bifrost:Oidc is configured; a configured provider that cannot load its keys stops startup.
+var oidcOptions = OidcIssuerOptions.FromConfiguration(builder.Configuration);
+if (oidcOptions is not null)
+{
+    builder.Services.AddBifrostOidc(oidcOptions);
+}
+
 var app = builder.Build();
 var appJsonSerializerOptions = CreateAppJsonSerializerOptions();
 
@@ -194,6 +244,8 @@ await using (var scope = app.Services.CreateAsyncScope())
         .RunAsync(CancellationToken.None);
 }
 
+app.UseForwardedHeaders();
+
 if (!app.Environment.IsDevelopment())
 {
     app.UseExceptionHandler("/Error");
@@ -204,6 +256,7 @@ app.UseHttpLogging();
 app.UseHttpsRedirection();
 app.UseStaticFiles();
 app.UseRouting();
+app.UseConceptTallyCors();
 app.UseAuthentication();
 app.UseMiddleware<GitHubMembershipSynchronizationMiddleware>();
 app.UseAuthorization();
@@ -220,6 +273,13 @@ app.MapGet("/readyz", async (ReadinessService readinessService, CancellationToke
             statusCode: StatusCodes.Status503ServiceUnavailable);
 }).AllowAnonymous();
 
+app.MapConceptTallyExport();
+
+if (oidcOptions is not null)
+{
+    app.MapBifrostOidc();
+}
+
 app.MapPost("/github/webhooks", async (
     HttpRequest request,
     GitHubWebhookService gitHubWebhookService,
@@ -253,22 +313,18 @@ app.MapPost("/github/webhooks", async (
 
 app.MapGet("/auth/sign-in", async (HttpContext httpContext, IOptions<GitHubOAuthOptions> gitHubOptions) =>
 {
-    var returnUrl = httpContext.Request.Query["returnUrl"].ToString();
-    if (string.IsNullOrWhiteSpace(returnUrl))
-    {
-        returnUrl = "/App";
-    }
+    var returnPath = LocalReturnPath.Parse(httpContext.Request.Query["returnUrl"].ToString());
 
     var provider = httpContext.Request.Query["provider"].ToString();
     if (string.IsNullOrWhiteSpace(provider))
     {
-        await WriteSignInChooserAsync(httpContext, returnUrl);
+        await WriteSignInChooserAsync(httpContext, returnPath.Value);
         return;
     }
 
     if (!provider.Equals("github", StringComparison.OrdinalIgnoreCase))
     {
-        httpContext.Response.Redirect($"/auth/heimdall/{Uri.EscapeDataString(provider)}?returnUrl={Uri.EscapeDataString(returnUrl)}");
+        httpContext.Response.Redirect($"/auth/heimdall/{Uri.EscapeDataString(provider)}?returnUrl={Uri.EscapeDataString(returnPath.Value)}");
         return;
     }
 
@@ -280,7 +336,7 @@ app.MapGet("/auth/sign-in", async (HttpContext httpContext, IOptions<GitHubOAuth
 
     await httpContext.ChallengeAsync(
         GitHubAuthenticationDefaults.AuthenticationScheme,
-        new() { RedirectUri = returnUrl });
+        new() { RedirectUri = returnPath.Value });
 }).AllowAnonymous();
 
 app.MapPost("/auth/bifrost/register", async (
@@ -320,16 +376,12 @@ app.MapGet("/auth/heimdall/{provider}", async (
     HttpContext httpContext,
     HeimdallAuthService heimdallAuthService,
     IOptions<BifrostHostOptions> hostOptions,
+    ILogger<HeimdallAuthService> logger,
     CancellationToken cancellationToken) =>
 {
     try
     {
-        var returnUrl = httpContext.Request.Query["returnUrl"].ToString();
-        if (string.IsNullOrWhiteSpace(returnUrl))
-        {
-            returnUrl = "/App";
-        }
-
+        var returnPath = LocalReturnPath.Parse(httpContext.Request.Query["returnUrl"].ToString());
         var requireMemberAccess = string.Equals(
             httpContext.Request.Query["access"].ToString(),
             "member",
@@ -338,30 +390,18 @@ app.MapGet("/auth/heimdall/{provider}", async (
         var start = await heimdallAuthService.StartAsync(
             provider,
             hostOptions.Value.PublicBaseUrl,
-            returnUrl,
+            returnPath,
             requireMemberAccess,
+            httpContext.Request.Cookies,
             cancellationToken);
 
+        httpContext.Response.Cookies.Append(start.CookieName, start.CookieValue, HeimdallAttemptCookie.Options());
         return Results.Redirect(start.AuthorizationUrl.ToString());
     }
     catch (HeimdallAuthException error)
     {
-        return Results.Redirect($"/?auth=heimdall-error&detail={Uri.EscapeDataString(error.Message)}");
-    }
-}).AllowAnonymous();
-
-app.MapPost("/auth/heimdall/callback", (
-    HeimdallBackendCallbackPayload payload,
-    HeimdallAuthService heimdallAuthService) =>
-{
-    try
-    {
-        heimdallAuthService.StoreBackendCallback(payload);
-        return Results.Accepted();
-    }
-    catch (HeimdallAuthException error)
-    {
-        return Results.BadRequest(error.Message);
+        logger.LogWarning("Heimdall start refused: {Reason}", error.Message);
+        return Results.Redirect(HeimdallAuthService.ErrorRedirect);
     }
 }).AllowAnonymous();
 
@@ -487,31 +527,44 @@ eveGovernance.MapGet("/surface", async (
         "application/json");
 });
 
-app.MapGet("/auth/heimdall/wait", async (
+app.MapGet("/auth/heimdall/complete", (HttpContext httpContext) =>
+{
+    httpContext.Response.Headers.CacheControl = "no-store";
+    httpContext.Response.Headers["Referrer-Policy"] = "no-referrer";
+    return Results.Content(HeimdallCompletePage.Html, "text/html", System.Text.Encoding.UTF8);
+}).AllowAnonymous();
+
+app.MapPost("/auth/heimdall/complete", async (
     HttpContext httpContext,
     HeimdallAuthService heimdallAuthService,
+    IOptions<BifrostHostOptions> hostOptions,
+    ILogger<HeimdallAuthService> logger,
     CancellationToken cancellationToken) =>
 {
-    var attemptId = httpContext.Request.Query["attemptId"].ToString();
-    if (string.IsNullOrWhiteSpace(attemptId))
-    {
-        return Results.Redirect("/?auth=heimdall-error&detail=missing-attempt-id");
-    }
-
+    var form = await ReadFormOrNullAsync(httpContext.Request, cancellationToken);
+    var attempt = form?["attempt"].ToString();
+    var held = heimdallAuthService.FindAttemptCookie(httpContext.Request.Cookies, attempt);
     try
     {
-        var signIn = await heimdallAuthService.CompleteAttemptAsync(attemptId, cancellationToken);
+        var signIn = await heimdallAuthService.CompleteAsync(
+            hostOptions.Value.PublicBaseUrl,
+            attempt,
+            held?.Value,
+            form?["code"].ToString(),
+            cancellationToken);
         await httpContext.SignInAsync(CookieAuthenticationDefaults.AuthenticationScheme, signIn.Principal);
-        return Results.Redirect(signIn.RedirectUri);
-    }
-    catch (HeimdallAuthPendingException)
-    {
-        httpContext.Response.Headers.Append("Refresh", "2");
-        return Results.Text("Waiting for Heimdall sign-in to complete.", "text/plain");
+        httpContext.Response.Cookies.Delete(held!.Value.Name, HeimdallAttemptCookie.DeleteOptions());
+        return Results.LocalRedirect(signIn.ReturnPath.Value);
     }
     catch (HeimdallAuthException error)
     {
-        return Results.Redirect($"/?auth=heimdall-error&detail={Uri.EscapeDataString(error.Message)}");
+        logger.LogWarning("Heimdall completion refused: {Reason}", error.Message);
+        if (held is not null)
+        {
+            httpContext.Response.Cookies.Delete(held.Value.Name, HeimdallAttemptCookie.DeleteOptions());
+        }
+
+        return Results.Redirect(HeimdallAuthService.ErrorRedirect);
     }
 }).AllowAnonymous();
 
@@ -531,6 +584,23 @@ static IResult JsonResult<T>(T value, JsonSerializerOptions options, int statusC
         "application/json",
         statusCode: statusCode);
 
+static async Task<IFormCollection?> ReadFormOrNullAsync(HttpRequest request, CancellationToken cancellationToken)
+{
+    if (!request.HasFormContentType)
+    {
+        return null;
+    }
+
+    try
+    {
+        return await request.ReadFormAsync(cancellationToken);
+    }
+    catch (Exception error) when (error is InvalidDataException or BadHttpRequestException)
+    {
+        return null;
+    }
+}
+
 static async Task WriteSignInChooserAsync(HttpContext httpContext, string returnUrl)
 {
     httpContext.Response.ContentType = "text/html; charset=utf-8";

src/Bifrost.Web/appsettings.json

@@ -27,6 +27,7 @@
   "Heimdall": {
     "BaseUrl": "https://heimdall.gamecult.org",
     "AppSlug": "bifrost",
+    "AppSecret": "",
     "DiscordGuildId": "",
     "DiscordAllowedRoleIds": [],
     "PatreonTierTitle": "Inner Sanctum",

src/Bifrost.Web/packages.lock.json

@@ -0,0 +1,430 @@
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+        "contentHash": "/iUeP3tq1S0XdNNoMz5C9twLSrM/TH+qElHkXWaPvuNOt+99G75NrV0OS2EqHx5wMN7popYjpc8oTjC1y16DLg=="
+      },
+      "System.Text.Encoding.CodePages": {
+        "type": "Transitive",
+        "resolved": "6.0.0",
+        "contentHash": "ZFCILZuOvtKPauZ/j/swhvw68ZRi9ATCfvGbk1QfydmcXBkIWecWKn/250UH7rahZ5OoDBaiAudJtPvLwzw85A==",
+        "dependencies": {
+          "System.Runtime.CompilerServices.Unsafe": "6.0.0"
+        }
+      },
+      "System.Text.Encodings.Web": {
+        "type": "Transitive",
+        "resolved": "8.0.0",
+        "contentHash": "yev/k9GHAEGx2Rg3/tU6MQh4HGBXJs70y7j1LaM1i/ER9po+6nnQ6RRqTJn1E7Xu0fbIFK80Nh5EoODxrbxwBQ=="
+      },
+      "System.Threading.Channels": {
+        "type": "Transitive",
+        "resolved": "6.0.0",
+        "contentHash": "TY8/9+tI0mNaUMgntOxxaq2ndTkdXqLSxvPmas7XEqOlv9lQtB7wLjYGd756lOaO7Dvb5r/WXhluM+0Xe87v5Q=="
+      }
+    }
+  }
+}

tests/Bifrost.Web.Tests/Bifrost.Web.Tests.csproj

@@ -20,6 +20,11 @@
     <ProjectReference Include="..\..\src\Bifrost.Web\Bifrost.Web.csproj" />
   </ItemGroup>
 
+  <ItemGroup>
+    <None Include="Fixtures\*.json" CopyToOutputDirectory="PreserveNewest" />
+    <None Include="Fixtures\*.cjs" CopyToOutputDirectory="PreserveNewest" />
+  </ItemGroup>
+
   <ItemGroup>
     <Using Include="Xunit" />
   </ItemGroup>

tests/Bifrost.Web.Tests/ConceptAppraisalServiceTests.cs

@@ -0,0 +1,600 @@
+using System.Net;
+using System.Reflection;
+using System.Text.Json;
+using Bifrost.Web.Configuration;
+using Bifrost.Web.Data;
+using Bifrost.Web.Domain;
+using Bifrost.Web.Features.ConceptVotes;
+using Bifrost.Web.Features.Shared;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Diagnostics;
+using Microsoft.Extensions.Options;
+using Npgsql;
+
+namespace Bifrost.Web.Tests;
+
+public sealed class ConceptAppraisalServiceTests
+{
+    private const string Collection = "aetheria-concept-mill";
+    private static readonly IPAddress Client = IPAddress.Parse("203.0.113.7");
+
+    [Fact]
+    public async Task Anonymous_device_voter_can_cast_and_is_counted()
+    {
+        await using var f = new Fixture();
+        await f.AddSubject("ship-a");
+
+        var result = await f.Cast("ship-a", f.Anonymous("device-one"), ConceptStance.Up);
+
+        Assert.Equal(CastResult.Recorded, result);
+        var tally = (await f.Service.GetTalliesAsync(Collection, default))["ship-a"];
+        Assert.Equal(new ConceptTally(1, 0, new StanceCounts(0, 0)), tally);
+    }
+
+    [Fact]
+    public async Task Anonymous_without_device_id_gets_no_identity_and_cast_is_refused()
+    {
+        await using var f = new Fixture();
+        await f.AddSubject("ship-a");
+
+        Assert.Null(VoterIdentity.For(CurrentBifrostActor.Anonymous, null));
+        Assert.Null(VoterIdentity.For(CurrentBifrostActor.Anonymous, "has:colon"));
+        Assert.Null(VoterIdentity.For(CurrentBifrostActor.Anonymous, string.Empty));
+        Assert.Equal(CastResult.NoVoter, await f.Cast("ship-a", null, ConceptStance.Up));
+        Assert.Empty(f.Db.ConceptAppraisals);
+    }
+
+    [Theory]
+    [InlineData("abc\n")]
+    [InlineData("abc\r\n")]
+    [InlineData("abc ")]
+    [InlineData("abc\t")]
+    [InlineData("abc\0")]
+    public async Task A_device_id_with_trailing_whitespace_or_control_char_cannot_cast_beside_its_bare_form(string forged)
+    {
+        await using var f = new Fixture();
+        await f.AddSubject("ship-a");
+
+        Assert.Equal(CastResult.Recorded, await f.Cast("ship-a", f.Anonymous("abc"), ConceptStance.Up));
+
+        Assert.Null(VoterIdentity.For(CurrentBifrostActor.Anonymous, forged));
+        Assert.Equal(CastResult.NoVoter, await f.Cast("ship-a", VoterIdentity.For(CurrentBifrostActor.Anonymous, forged), ConceptStance.Down));
+        Assert.Single(f.Db.ConceptAppraisals);
+    }
+
+    [Fact]
+    public async Task A_changed_stance_is_saved_and_read_back_through_a_fresh_context()
+    {
+        var dbName = $"concept-{Guid.NewGuid():N}";
+        await using var first = new Fixture(dbName);
+        await first.AddSubject("ship-a");
+        Assert.Equal(CastResult.Recorded, await first.Cast("ship-a", first.Anonymous("device-one"), ConceptStance.Up));
+        var other = IPAddress.Parse("198.51.100.9");
+
+        // Production scopes one DbContext per request: the recast gets a context that has never tracked the row.
+        await using (var second = new Fixture(dbName))
+        {
+            second.Clock.Advance(TimeSpan.FromMinutes(5));
+            Assert.Equal(
+                CastResult.Changed,
+                await second.Cast("ship-a", second.Anonymous("device-one"), ConceptStance.Down, other));
+        }
+
+        await using var reader = new Fixture(dbName);
+        var row = Assert.Single(reader.Db.ConceptAppraisals);
+        Assert.Equal(ConceptStance.Down, row.Stance);
+        Assert.Equal(NetworkPrefix.Tag(other, 32, 56, Fixture.Secret), row.NetworkTag);
+        Assert.Equal(new DateTimeOffset(2026, 10, 10, 12, 5, 0, TimeSpan.Zero), row.CastAtUtc);
+        Assert.Equal(new ConceptTally(0, 1, new StanceCounts(0, 0)), (await reader.Service.GetTalliesAsync(Collection, default))["ship-a"]);
+    }
+
+    [Fact]
+    public async Task Voter_class_is_stamped_at_cast()
+    {
+        await using var f = new Fixture();
+        await f.AddSubject("ship-a");
+        var account = f.Account(MembershipStatus.Authenticated);
+        var member = f.Account(MembershipStatus.Active);
+
+        await f.Cast("ship-a", f.Anonymous("device-one"), ConceptStance.Up);
+        await f.Cast("ship-a", VoterIdentity.For(account, null), ConceptStance.Up);
+        await f.Cast("ship-a", VoterIdentity.For(member, null), ConceptStance.Up);
+
+        var rows = f.Db.ConceptAppraisals.ToList();
+        Assert.Equal(VoterClass.Anonymous, rows.Single(x => x.VoterKey == "device:device-one").VoterClass);
+        Assert.Null(rows.Single(x => x.VoterKey == "device:device-one").UserAccountId);
+        var accountRow = rows.Single(x => x.UserAccountId == account.UserAccount!.Id);
+        var memberRow = rows.Single(x => x.UserAccountId == member.UserAccount!.Id);
+        Assert.Equal(VoterClass.Account, accountRow.VoterClass);
+        Assert.Equal(VoterClass.Member, memberRow.VoterClass);
+
+        // Membership ends; the same account votes again with the opposite stance. The row keeps its stamp.
+        member.UserAccount!.Membership!.Status = MembershipStatus.Authenticated;
+        var recast = await f.Cast("ship-a", VoterIdentity.For(member, null), ConceptStance.Down);
+
+        Assert.Equal(CastResult.Changed, recast);
+        Assert.Equal(VoterClass.Member, f.Db.ConceptAppraisals.Single(x => x.Id == memberRow.Id).VoterClass);
+    }
+
+    [Fact]
+    public async Task Second_cast_by_the_same_key_changes_stance_without_a_new_row()
+    {
+        await using var f = new Fixture();
+        await f.AddSubject("ship-a");
+        var voter = f.Anonymous("device-one");
+
+        Assert.Equal(CastResult.Recorded, await f.Cast("ship-a", voter, ConceptStance.Up));
+        Assert.Equal(CastResult.Changed, await f.Cast("ship-a", voter, ConceptStance.Down));
+        Assert.Equal(CastResult.Unchanged, await f.Cast("ship-a", voter, ConceptStance.Down));
+
+        var row = Assert.Single(f.Db.ConceptAppraisals);
+        Assert.Equal(ConceptStance.Down, row.Stance);
+    }
+
+    [Fact]
+    public async Task Member_weight_does_not_weight_counts()
+    {
+        await using var f = new Fixture();
+        await f.AddSubject("ship-a");
+        var member = f.Account(MembershipStatus.Active, weight: 5m);
+        Assert.Equal(5m, member.EffectiveVotingWeight);
+
+        await f.Cast("ship-a", VoterIdentity.For(member, null), ConceptStance.Up);
+
+        var tally = (await f.Service.GetTalliesAsync(Collection, default))["ship-a"];
+        Assert.Equal(1, tally.Up);
+        Assert.Equal(1, tally.Members.Up);
+    }
+
+    [Fact]
+    public async Task Member_tally_is_a_filter_over_the_same_rows()
+    {
+        await using var f = new Fixture();
+        await f.AddSubject("ship-a");
+        await f.Cast("ship-a", f.Anonymous("device-one"), ConceptStance.Up);
+        await f.Cast("ship-a", f.Anonymous("device-two"), ConceptStance.Down);
+        await f.Cast("ship-a", VoterIdentity.For(f.Account(MembershipStatus.Authenticated), null), ConceptStance.Up);
+        await f.Cast("ship-a", VoterIdentity.For(f.Account(MembershipStatus.Active), null), ConceptStance.Up);
+        await f.Cast("ship-a", VoterIdentity.For(f.Account(MembershipStatus.Active), null), ConceptStance.Down);
+
+        var tally = (await f.Service.GetTalliesAsync(Collection, default))["ship-a"];
+        var rows = f.Db.ConceptAppraisals.ToList();
+
+        Assert.Equal(rows.Count(x => x.Stance == ConceptStance.Up), tally.Up);
+        Assert.Equal(rows.Count(x => x.Stance == ConceptStance.Down), tally.Down);
+        Assert.Equal(rows.Count(x => x.Stance == ConceptStance.Up && x.VoterClass == VoterClass.Member), tally.Members.Up);
+        Assert.Equal(rows.Count(x => x.Stance == ConceptStance.Down && x.VoterClass == VoterClass.Member), tally.Members.Down);
+        Assert.Equal(new ConceptTally(3, 2, new StanceCounts(1, 1)), tally);
+    }
+
+    [Fact]
+    public async Task Tally_carries_no_voter_identity()
+    {
+        await using var f = new Fixture();
+        await f.AddSubject("ship-a");
+        var account = f.Account(MembershipStatus.Authenticated);
+        var member = f.Account(MembershipStatus.Active);
+        await f.Cast("ship-a", f.Anonymous("device-secret-id"), ConceptStance.Up);
+        await f.Cast("ship-a", VoterIdentity.For(account, null), ConceptStance.Up);
+        await f.Cast("ship-a", VoterIdentity.For(member, null), ConceptStance.Down);
+
+        Assert.Equal(
+            new[] { "Down", "Members", "Up" },
+            typeof(ConceptTally).GetProperties(BindingFlags.Public | BindingFlags.Instance)
+                .Select(p => p.Name).Order().ToArray());
+        Assert.Equal(
+            new[] { "Down", "Up" },
+            typeof(StanceCounts).GetProperties(BindingFlags.Public | BindingFlags.Instance)
+                .Select(p => p.Name).Order().ToArray());
+
+        var json = JsonSerializer.Serialize(await f.Service.GetTalliesAsync(Collection, default));
+        var view = JsonSerializer.Serialize(
+            await f.Service.GetSubjectAsync(Collection, "ship-a", VoterIdentity.For(account, null), default));
+        foreach (var text in new[] { json, view })
+        {
+            Assert.DoesNotContain("device:", text);
+            Assert.DoesNotContain("account:", text);
+            Assert.DoesNotContain("device-secret-id", text);
+            foreach (var id in new[] { account.UserAccount!.Id, member.UserAccount!.Id })
+            {
+                Assert.DoesNotContain(id.ToString("D"), text);
+                Assert.DoesNotContain(id.ToString("N"), text);
+            }
+
+            foreach (var tag in f.Db.ConceptAppraisals.Select(x => x.NetworkTag).Distinct())
+            {
+                Assert.DoesNotContain(tag, text);
+            }
+        }
+    }
+
+    [Fact]
+    public async Task Votes_on_unknown_or_retired_keys_are_refused_and_create_nothing()
+    {
+        await using var f = new Fixture();
+        await f.AddSubject("ship-a");
+        await f.AddSubject("ship-old", retired: true);
+        var subjectsBefore = f.Db.ConceptSubjects.Count();
+        var voter = f.Anonymous("device-one");
+
+        Assert.Equal(CastResult.UnknownSubject, await f.Cast("ship-missing", voter, ConceptStance.Up));
+        Assert.Equal(CastResult.UnknownSubject, await f.Cast("Ship_A", voter, ConceptStance.Up));
+        Assert.Equal(CastResult.RetiredSubject, await f.Cast("ship-old", voter, ConceptStance.Up));
+
+        Assert.Equal(subjectsBefore, f.Db.ConceptSubjects.Count());
+        Assert.Empty(f.Db.ConceptAppraisals);
+        Assert.DoesNotContain("ship-old", (await f.Service.GetTalliesAsync(Collection, default)).Keys);
+        Assert.Contains("ship-a", (await f.Service.GetTalliesAsync(Collection, default)).Keys);
+    }
+
+    [Fact]
+    public async Task Retract_removes_the_row_and_the_count()
+    {
+        await using var f = new Fixture();
+        await f.AddSubject("ship-a");
+        var voter = f.Anonymous("device-one");
+        await f.Cast("ship-a", voter, ConceptStance.Up);
+        await f.Cast("ship-a", f.Anonymous("device-two"), ConceptStance.Up);
+
+        Assert.True(await f.Service.RetractAsync(Collection, "ship-a", voter, default));
+        Assert.False(await f.Service.RetractAsync(Collection, "ship-a", voter, default));
+
+        Assert.Equal(1, (await f.Service.GetTalliesAsync(Collection, default))["ship-a"].Up);
+        Assert.Single(f.Db.ConceptAppraisals);
+    }
+
+    [Fact]
+    public async Task Network_tag_is_an_hmac_never_a_raw_address()
+    {
+        await using var f = new Fixture();
+        await f.AddSubject("ship-a");
+        await f.Cast("ship-a", f.Anonymous("device-one"), ConceptStance.Up);
+
+        var tag = f.Db.ConceptAppraisals.Single().NetworkTag;
+
+        Assert.Matches("^[0-9a-f]{64}$", tag);
+        Assert.Equal(NetworkPrefix.Tag(Client, 32, 56, Fixture.Secret), tag);
+    }
+
+    [Fact]
+    public async Task Unique_violation_at_insert_becomes_a_change()
+    {
+        var dbName = $"race-{Guid.NewGuid():N}";
+        var racer = new RacingInterceptor(dbName);
+        await using var f = new Fixture(dbName, racer);
+        await f.AddSubject("ship-a");
+        racer.Subject = f.Db.ConceptSubjects.Single();
+
+        var result = await f.Cast("ship-a", f.Anonymous("device-one"), ConceptStance.Down);
+
+        Assert.Equal(CastResult.Changed, result);
+        Assert.Equal(1, racer.Fired);
+        var row = Assert.Single(f.Db.ConceptAppraisals);
+        Assert.Equal(ConceptStance.Down, row.Stance);
+    }
+
+    [Fact]
+    public void Unique_indexes_are_declared_in_model_and_migration()
+    {
+        var options = new DbContextOptionsBuilder<BifrostDbContext>().UseNpgsql("Host=unused").Options;
+        using var db = new BifrostDbContext(options);
+
+        Assert.Contains(
+            db.Model.FindEntityType(typeof(ConceptAppraisal))!.GetIndexes(),
+            i => i.IsUnique && i.Properties.Select(p => p.Name).SequenceEqual(["SubjectId", "VoterKey"]));
+        Assert.Contains(
+            db.Model.FindEntityType(typeof(ConceptSubject))!.GetIndexes(),
+            i => i.IsUnique && i.Properties.Select(p => p.Name).SequenceEqual(["Collection", "Key"]));
+
+        var script = db.Database.GenerateCreateScript();
+        Assert.Matches("CREATE UNIQUE INDEX \"IX_ConceptAppraisals_SubjectId_VoterKey\"", script);
+        Assert.Matches("CREATE UNIQUE INDEX \"IX_ConceptSubjects_Collection_Key\"", script);
+
+    }
+
+    [Fact]
+    public async Task Purge_removes_only_rows_in_tag_and_window_and_audits()
+    {
+        await using var f = new Fixture();
+        await f.AddSubject("ship-a");
+        var admin = f.Admin();
+        var t0 = f.Clock.GetUtcNow();
+        var other = IPAddress.Parse("198.51.100.9");
+
+        await f.Cast("ship-a", f.Anonymous("device-in"), ConceptStance.Up);
+        await f.Cast("ship-a", f.Anonymous("device-other-net"), ConceptStance.Up, other);
+        f.Clock.Advance(TimeSpan.FromHours(2));
+        await f.Cast("ship-a", f.Anonymous("device-late"), ConceptStance.Up);
+        var tag = NetworkPrefix.Tag(Client, 32, 56, Fixture.Secret);
+
+        var removed = await f.Service.PurgeAsync(admin, tag, t0, t0.AddHours(1), default);
+
+        Assert.Equal(1, removed);
+        Assert.Equal(
+            ["device:device-late", "device:device-other-net"],
+            f.Db.ConceptAppraisals.Select(x => x.VoterKey).ToList().Order().ToArray());
+        var audit = Assert.Single(f.Db.AuditEvents);
+        Assert.Equal("ConceptAppraisal", audit.EntityType);
+        Assert.Equal("Purge", audit.Action);
+        Assert.DoesNotContain(tag, audit.Detail);
+        Assert.DoesNotContain("tag", audit.Detail);
+        Assert.Equal(admin.UserAccount!.Id, audit.ActorUserAccountId);
+        Assert.Contains("from=" + t0.ToString("O"), audit.Detail);
+        Assert.Contains("count=1", audit.Detail);
+        Assert.DoesNotContain("device", audit.Detail);
+
+        var refused = await Assert.ThrowsAsync<UnauthorizedAccessException>(
+            () => f.Service.PurgeAsync(f.Account(MembershipStatus.Active), tag, t0, t0.AddDays(1), default));
+        Assert.DoesNotContain(tag, refused.Message);
+        Assert.Equal("Only a platform administrator can purge appraisals.", refused.Message);
+        Assert.Equal(2, f.Db.ConceptAppraisals.Count());
+        Assert.Single(f.Db.AuditEvents);
+    }
+
+    [Fact]
+    public async Task Unique_violation_with_no_surviving_row_is_not_swallowed()
+    {
+        var dbName = $"race-{Guid.NewGuid():N}";
+        var racer = new RacingInterceptor(dbName) { InsertRival = false };
+        await using var f = new Fixture(dbName, racer);
+        await f.AddSubject("ship-a");
+        racer.Subject = f.Db.ConceptSubjects.Single();
+
+        await Assert.ThrowsAsync<DbUpdateException>(
+            () => f.Cast("ship-a", f.Anonymous("device-one"), ConceptStance.Up));
+    }
+
+    [Fact]
+    public async Task A_changed_cast_restamps_tag_and_time()
+    {
+        await using var f = new Fixture();
+        await f.AddSubject("ship-a");
+        var voter = f.Anonymous("device-one");
+        await f.Cast("ship-a", voter, ConceptStance.Up, IPAddress.Parse("198.51.100.9"));
+        var first = f.Db.ConceptAppraisals.Single().CastAtUtc;
+        f.Clock.Advance(TimeSpan.FromMinutes(5));
+
+        await f.Cast("ship-a", voter, ConceptStance.Down);
+
+        var row = f.Db.ConceptAppraisals.Single();
+        Assert.Equal(NetworkPrefix.Tag(Client, 32, 56, Fixture.Secret), row.NetworkTag);
+        Assert.Equal(first.AddMinutes(5), row.CastAtUtc);
+    }
+
+    [Fact]
+    public async Task Unknown_client_address_leaves_no_tag_and_purge_never_matches_the_empty_tag()
+    {
+        await using var f = new Fixture();
+        await f.AddSubject("ship-a");
+        await f.Service.CastAsync(Collection, "ship-a", f.Anonymous("device-one"), ConceptStance.Up, null, default);
+
+        Assert.Equal(string.Empty, f.Db.ConceptAppraisals.Single().NetworkTag);
+        var t0 = f.Clock.GetUtcNow();
+        Assert.Equal(0, await f.Service.PurgeAsync(f.Admin(), string.Empty, t0.AddDays(-1), t0.AddDays(1), default));
+        Assert.Single(f.Db.ConceptAppraisals);
+        Assert.Empty(f.Db.AuditEvents);
+    }
+
+    [Fact]
+    public async Task Purge_window_excludes_its_end_and_includes_its_start()
+    {
+        await using var f = new Fixture();
+        await f.AddSubject("ship-a");
+        var t0 = f.Clock.GetUtcNow();
+        await f.Cast("ship-a", f.Anonymous("device-one"), ConceptStance.Up);
+        var tag = NetworkPrefix.Tag(Client, 32, 56, Fixture.Secret);
+
+        Assert.Equal(0, await f.Service.PurgeAsync(f.Admin(), tag, t0.AddDays(-1), t0, default));
+        Assert.Equal(1, await f.Service.PurgeAsync(f.Admin(), tag, t0, t0.AddSeconds(1), default));
+    }
+
+    [Fact]
+    public async Task Retract_by_no_voter_or_on_unknown_subject_is_a_no_op()
+    {
+        await using var f = new Fixture();
+        await f.AddSubject("ship-a");
+        var voter = f.Anonymous("device-one");
+        await f.Cast("ship-a", voter, ConceptStance.Up);
+
+        Assert.False(await f.Service.RetractAsync(Collection, "ship-a", null, default));
+        Assert.False(await f.Service.RetractAsync(Collection, "ship-missing", voter, default));
+        Assert.False(await f.Service.RetractAsync("other-collection", "ship-a", voter, default));
+        Assert.Single(f.Db.ConceptAppraisals);
+    }
+
+    [Fact]
+    public async Task Subject_page_view_counts_only_its_own_subject_and_shows_the_voters_own_stance()
+    {
+        await using var f = new Fixture();
+        await f.AddSubject("ship-a");
+        await f.AddSubject("ship-b");
+        await f.AddSubject("ship-old", retired: true);
+        var mine = f.Anonymous("device-one");
+        await f.Cast("ship-a", mine, ConceptStance.Down);
+        await f.Cast("ship-a", VoterIdentity.For(f.Account(MembershipStatus.Active), null), ConceptStance.Up);
+        await f.Cast("ship-a", VoterIdentity.For(f.Account(MembershipStatus.Authenticated), null), ConceptStance.Up);
+        await f.Cast("ship-b", f.Anonymous("device-two"), ConceptStance.Up);
+
+        var view = await f.Service.GetSubjectAsync(Collection, "ship-a", mine, default);
+        var stranger = await f.Service.GetSubjectAsync(Collection, "ship-a", f.Anonymous("device-nine"), default);
+        var anon = await f.Service.GetSubjectAsync(Collection, "ship-a", null, default);
+
+        Assert.Equal(new ConceptTally(2, 1, new StanceCounts(1, 0)), view!.Tally);
+        Assert.Equal(ConceptStance.Down, view.YourStance);
+        Assert.Null(stranger!.YourStance);
+        Assert.Null(anon!.YourStance);
+        Assert.Null(await f.Service.GetSubjectAsync(Collection, "ship-old", mine, default));
+        Assert.Null(await f.Service.GetSubjectAsync(Collection, "ship-missing", mine, default));
+    }
+
+    [Fact]
+    public async Task Collection_and_key_must_both_be_slugs_even_when_a_row_exists()
+    {
+        await using var f = new Fixture();
+        await f.AddSubject("Ship_A");
+        f.Db.ConceptSubjects.Add(new ConceptSubject
+        {
+            Collection = "Bad_Collection",
+            Key = "ship-a",
+            Title = "t",
+            RegisteredAtUtc = f.Clock.GetUtcNow()
+        });
+        await f.Db.SaveChangesAsync();
+        var voter = f.Anonymous("device-one");
+
+        Assert.Equal(CastResult.UnknownSubject, await f.Cast("Ship_A", voter, ConceptStance.Up));
+        Assert.Equal(
+            CastResult.UnknownSubject,
+            await f.Service.CastAsync("Bad_Collection", "ship-a", voter, ConceptStance.Up, Client, default));
+        Assert.Empty(f.Db.ConceptAppraisals);
+    }
+
+    [Fact]
+    public async Task Voter_keys_have_their_documented_shape()
+    {
+        await using var f = new Fixture();
+        var account = f.Account(MembershipStatus.Authenticated);
+
+        Assert.Equal("device:abc-DEF_123", VoterIdentity.For(CurrentBifrostActor.Anonymous, "abc-DEF_123")!.Key);
+        Assert.Equal("account:" + account.UserAccount!.Id.ToString("N"), VoterIdentity.For(account, "ignored")!.Key);
+        Assert.Null(VoterIdentity.For(CurrentBifrostActor.Anonymous, new string('a', 101)));
+        Assert.NotNull(VoterIdentity.For(CurrentBifrostActor.Anonymous, new string('a', 100)));
+    }
+
+    private sealed class RacingInterceptor(string dbName) : SaveChangesInterceptor
+    {
+        public bool InsertRival { get; init; } = true;
+
+        public ConceptSubject? Subject { get; set; }
+
+        public int Fired { get; private set; }
+
+        public override async ValueTask<InterceptionResult<int>> SavingChangesAsync(
+            DbContextEventData eventData,
+            InterceptionResult<int> result,
+            CancellationToken cancellationToken = default)
+        {
+            var adding = eventData.Context!.ChangeTracker.Entries<ConceptAppraisal>()
+                .Any(e => e.State == EntityState.Added);
+            if (Subject is null || !adding || Fired > 0)
+            {
+                return result;
+            }
+
+            Fired++;
+            if (!InsertRival)
+            {
+                throw new DbUpdateException("conflict", new PostgresException("duplicate", "ERROR", "ERROR", "23505"));
+            }
+
+            var options = new DbContextOptionsBuilder<BifrostDbContext>().UseInMemoryDatabase(dbName).Options;
+            await using (var other = new BifrostDbContext(options))
+            {
+                other.ConceptAppraisals.Add(new ConceptAppraisal
+                {
+                    SubjectId = Subject.Id,
+                    VoterKey = "device:device-one",
+                    Stance = ConceptStance.Up,
+                    VoterClass = VoterClass.Anonymous,
+                    CastAtUtc = DateTimeOffset.UtcNow
+                });
+                await other.SaveChangesAsync(cancellationToken);
+            }
+
+            throw new DbUpdateException(
+                "conflict",
+                new PostgresException("duplicate", "ERROR", "ERROR", "23505"));
+        }
+    }
+
+    private sealed class Fixture : IAsyncDisposable
+    {
+        public const string Secret = "test-tag-secret";
+
+        public Fixture(string? dbName = null, IInterceptor? interceptor = null)
+        {
+            var builder = new DbContextOptionsBuilder<BifrostDbContext>()
+                .UseInMemoryDatabase(dbName ?? $"concept-{Guid.NewGuid():N}");
+            if (interceptor is not null)
+            {
+                builder.AddInterceptors(interceptor);
+            }
+
+            Db = new BifrostDbContext(builder.Options);
+            Clock = new ManualClock(new DateTimeOffset(2026, 10, 10, 12, 0, 0, TimeSpan.Zero));
+            Service = new ConceptAppraisalService(
+                Db,
+                new AuditTrailService(Db, Clock),
+                Clock,
+                Options.Create(new ConceptVoteOptions { NetworkTagSecret = Secret }));
+        }
+
+        public BifrostDbContext Db { get; }
+
+        public ManualClock Clock { get; }
+
+        public ConceptAppraisalService Service { get; }
+
+        public async Task AddSubject(string key, bool retired = false)
+        {
+            Db.ConceptSubjects.Add(new ConceptSubject
+            {
+                Collection = Collection,
+                Key = key,
+                Title = key,
+                RegisteredAtUtc = Clock.GetUtcNow(),
+                RetiredAtUtc = retired ? Clock.GetUtcNow() : null
+            });
+            await Db.SaveChangesAsync();
+        }
+
+        public Task<CastResult> Cast(string key, VoterIdentity? voter, ConceptStance stance, IPAddress? client = null) =>
+            Service.CastAsync(Collection, key, voter, stance, client ?? Client, default);
+
+        public VoterIdentity Anonymous(string deviceId) =>
+            VoterIdentity.For(CurrentBifrostActor.Anonymous, deviceId)!;
+
+        public CurrentBifrostActor Account(MembershipStatus status, decimal weight = 0m, bool admin = false)
+        {
+            var user = new UserAccount
+            {
+                DisplayName = "voter",
+                GitHubLogin = "voter",
+                NormalizedGitHubLogin = "voter",
+                CreatedAtUtc = Clock.GetUtcNow(),
+                LastSeenAtUtc = Clock.GetUtcNow()
+            };
+            user.Membership = new Membership
+            {
+                UserAccountId = user.Id,
+                Status = status,
+                IsPlatformAdmin = admin,
+                CreatedAtUtc = Clock.GetUtcNow()
+            };
+            if (weight > 0m)
+            {
+                user.Membership.TierSnapshots.Add(new TierSnapshot { Weight = weight, IsCurrent = true });
+            }
+
+            Db.UserAccounts.Add(user);
+            Db.SaveChanges();
+            return new CurrentBifrostActor(true, user);
+        }
+
+        public CurrentBifrostActor Admin()
+        {
+            return Account(MembershipStatus.Active, admin: true);
+        }
+
+        public ValueTask DisposeAsync() => Db.DisposeAsync();
+    }
+
+    private sealed class ManualClock(DateTimeOffset start) : TimeProvider
+    {
+        private DateTimeOffset _now = start;
+
+        public override DateTimeOffset GetUtcNow() => _now;
+
+        public void Advance(TimeSpan by) => _now += by;
+    }
+}

tests/Bifrost.Web.Tests/ConceptSubjectRegistryTests.cs

@@ -0,0 +1,673 @@
+using System.Diagnostics;
+using System.Net;
+using System.Text;
+using System.Text.Encodings.Web;
+using System.Text.Json;
+using Bifrost.Web.Configuration;
+using Bifrost.Web.Data;
+using Bifrost.Web.Domain;
+using Bifrost.Web.Features.ConceptVotes;
+using Bifrost.Web.Features.Shared;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Options;
+
+namespace Bifrost.Web.Tests;
+
+public sealed class ConceptSubjectRegistryTests
+{
+    private const string Collection = "aetheria-concept-mill";
+    private static readonly string[] None = [];
+
+    private static string FixturePath => Path.Combine(AppContext.BaseDirectory, "Fixtures", "mill-three-ships.json");
+
+    private static IReadOnlyList<ManifestShip> Parse(string json) =>
+        ConceptSubjectRegistry.ParseManifest(Encoding.UTF8.GetBytes(json));
+
+    private static IReadOnlyList<ManifestShip> Fixture() =>
+        ConceptSubjectRegistry.ParseManifest(File.ReadAllBytes(FixturePath));
+
+    [Fact]
+    public async Task Rerun_of_the_same_manifest_is_a_no_op()
+    {
+        using var world = new World();
+
+        var first = await world.Apply(Fixture());
+        Assert.All(first.Entries, e => Assert.Equal(SubjectChange.Add, e.Change));
+        Assert.Equal(3, await world.Fresh(db => db.AuditEvents.CountAsync(x => x.EntityType == nameof(ConceptSubject))));
+
+        var before = await world.Fresh(db => db.ConceptSubjects.AsNoTracking().OrderBy(x => x.Key).ToListAsync());
+        world.Clock.Advance(TimeSpan.FromHours(1));
+        var second = await world.Apply(Fixture());
+
+        Assert.All(second.Entries, e => Assert.Equal(SubjectChange.Unchanged, e.Change));
+        Assert.Equal(3, await world.Fresh(db => db.AuditEvents.CountAsync()));
+        var after = await world.Fresh(db => db.ConceptSubjects.AsNoTracking().OrderBy(x => x.Key).ToListAsync());
+        Assert.Equal(before.Select(x => (x.Id, x.Title, x.RegisteredAtUtc, x.RetiredAtUtc)),
+            after.Select(x => (x.Id, x.Title, x.RegisteredAtUtc, x.RetiredAtUtc)));
+    }
+
+    [Fact]
+    public async Task Apply_writes_one_host_command_audit_event_per_change_and_none_for_a_plan()
+    {
+        using var world = new World();
+
+        var plan = await world.Plan(Fixture());
+        Assert.All(plan.Entries, e => Assert.Equal(SubjectChange.Add, e.Change));
+        Assert.Empty(await world.Fresh(db => db.ConceptSubjects.ToListAsync()));
+        Assert.Empty(await world.Fresh(db => db.AuditEvents.ToListAsync()));
+
+        await world.Apply(Fixture());
+
+        var events = await world.Fresh(db => db.AuditEvents.ToListAsync());
+        var subjectIds = (await world.Fresh(db => db.ConceptSubjects.ToListAsync())).Select(x => x.Id.ToString()).ToHashSet();
+        Assert.Equal(3, events.Count);
+        Assert.All(events, e =>
+        {
+            Assert.Equal(nameof(ConceptSubject), e.EntityType);
+            Assert.Equal("Add", e.Action);
+            Assert.Null(e.ActorUserAccountId);
+            Assert.Contains("actor=host-command", e.Detail);
+            Assert.Contains(e.EntityId, subjectIds);
+        });
+    }
+
+    [Fact]
+    public async Task Rename_changes_title_and_keeps_votes()
+    {
+        using var world = new World();
+        await world.Apply(Fixture());
+        await world.Cast("bison", ConceptStance.Up);
+        await world.Cast("kestrel", ConceptStance.Down);
+
+        var renamed = Fixture().Select(s => s.Key == "bison" ? s with { Title = "Bison Prime" } : s).ToList();
+        var plan = await world.Apply(renamed);
+
+        Assert.Equal(SubjectChange.Rename, plan.Entries.Single(e => e.Key == "bison").Change);
+        Assert.Equal(2, plan.Entries.Count(e => e.Change == SubjectChange.Unchanged));
+        var subject = await world.Fresh(db => db.ConceptSubjects.AsNoTracking().SingleAsync(x => x.Key == "bison"));
+        Assert.Equal("Bison Prime", subject.Title);
+        Assert.Null(subject.RetiredAtUtc);
+        Assert.Equal(2, await world.Fresh(db => db.ConceptAppraisals.CountAsync()));
+        var view = await world.Fresh(db => world.Appraisals(db).GetSubjectAsync(Collection, "bison", null, default));
+        Assert.Equal("Bison Prime", view!.Title);
+        Assert.Equal(new ConceptTally(1, 0, new StanceCounts(0, 0)), view.Tally);
+        Assert.Equal(1, await world.Fresh(db => db.AuditEvents.CountAsync(x => x.Action == "Rename")));
+    }
+
+    [Fact]
+    public async Task Absent_key_is_retired_only_when_named()
+    {
+        using var world = new World();
+        await world.Apply(Fixture());
+        await world.Cast("kestrel", ConceptStance.Up);
+        var smaller = Fixture().Where(s => s.Key != "kestrel").ToList();
+
+        var unnamed = await world.Apply(smaller);
+        Assert.Equal(SubjectChange.Absent, unnamed.Entries.Single(e => e.Key == "kestrel").Change);
+        Assert.Null((await world.Fresh(db => db.ConceptSubjects.AsNoTracking().SingleAsync(x => x.Key == "kestrel"))).RetiredAtUtc);
+        Assert.Contains("kestrel", (await world.Fresh(db => world.Appraisals(db).GetTalliesAsync(Collection, default))).Keys);
+
+        var named = await world.Apply(smaller, ["kestrel"]);
+        Assert.Equal(SubjectChange.Retire, named.Entries.Single(e => e.Key == "kestrel").Change);
+        var retired = await world.Fresh(db => db.ConceptSubjects.AsNoTracking().SingleAsync(x => x.Key == "kestrel"));
+        Assert.NotNull(retired.RetiredAtUtc);
+        Assert.Equal(1, await world.Fresh(db => db.ConceptAppraisals.CountAsync()));
+        Assert.DoesNotContain("kestrel", (await world.Fresh(db => world.Appraisals(db).GetTalliesAsync(Collection, default))).Keys);
+        Assert.Equal(CastResult.RetiredSubject, await world.Cast("kestrel", ConceptStance.Down));
+        Assert.Equal(1, await world.Fresh(db => db.AuditEvents.CountAsync(x => x.Action == "Retire")));
+    }
+
+    [Theory]
+    [InlineData("bison")]
+    [InlineData("never-registered")]
+    public async Task Retire_naming_a_key_that_is_not_registered_live_and_absent_is_refused_whole(string named)
+    {
+        using var world = new World();
+        await world.Apply(Fixture());
+        var renamed = Fixture().Select(s => s.Key == "kestrel" ? s with { Title = "Kestrel II" } : s).ToList();
+
+        var refusal = await Assert.ThrowsAsync<ManifestRefusedException>(() => world.Apply(renamed, [named]));
+
+        Assert.Equal(("retire", "NotAbsent"), (refusal.Field, refusal.Code));
+        Assert.DoesNotContain(named, refusal.Message);
+        Assert.Equal("Kestrel", (await world.Fresh(db => db.ConceptSubjects.AsNoTracking().SingleAsync(x => x.Key == "kestrel"))).Title);
+        Assert.Equal(3, await world.Fresh(db => db.AuditEvents.CountAsync()));
+    }
+
+    [Fact]
+    public async Task Rerunning_the_same_retire_list_converges_and_writes_nothing()
+    {
+        using var world = new World();
+        await world.Apply(Fixture());
+        var smaller = Fixture().Where(s => s.Key == "bison").ToList();
+
+        var first = await world.Apply(smaller, ["kestrel", "ibis-mk2"]);
+        Assert.Equal([SubjectChange.Unchanged, SubjectChange.Retire, SubjectChange.Retire], first.Entries.Select(e => e.Change));
+        var before = await world.Fresh(db => db.ConceptSubjects.AsNoTracking().OrderBy(x => x.Key).ToListAsync());
+        var audits = await world.Fresh(db => db.AuditEvents.CountAsync());
+        world.Clock.Advance(TimeSpan.FromHours(1));
+
+        var second = await world.Apply(smaller, ["kestrel", "ibis-mk2"]);
+
+        Assert.Equal(
+            [("bison", SubjectChange.Unchanged), ("ibis-mk2", SubjectChange.Retired), ("kestrel", SubjectChange.Retired)],
+            second.Entries.Select(e => (e.Key, e.Change)));
+        Assert.Equal(audits, await world.Fresh(db => db.AuditEvents.CountAsync()));
+        var after = await world.Fresh(db => db.ConceptSubjects.AsNoTracking().OrderBy(x => x.Key).ToListAsync());
+        Assert.Equal(before.Select(x => (x.Id, x.Title, x.RetiredAtUtc)), after.Select(x => (x.Id, x.Title, x.RetiredAtUtc)));
+    }
+
+    [Fact]
+    public async Task Rerunning_a_retire_list_after_a_partial_apply_retires_the_rest()
+    {
+        using var world = new World();
+        await world.Apply(Fixture());
+        var smaller = Fixture().Where(s => s.Key == "bison").ToList();
+        await world.Apply(smaller, ["kestrel"]);
+
+        var plan = await world.Apply(smaller, ["kestrel", "ibis-mk2"]);
+
+        Assert.Equal(SubjectChange.Retired, plan.Entries.Single(e => e.Key == "kestrel").Change);
+        Assert.Equal(SubjectChange.Retire, plan.Entries.Single(e => e.Key == "ibis-mk2").Change);
+        var rows = await world.Fresh(db => db.ConceptSubjects.AsNoTracking().ToListAsync());
+        Assert.Equal(["ibis-mk2", "kestrel"], rows.Where(r => r.RetiredAtUtc is not null).Select(r => r.Key).Order());
+        Assert.Equal(2, await world.Fresh(db => db.AuditEvents.CountAsync(x => x.Action == "Retire")));
+    }
+
+    [Fact]
+    public async Task Naming_a_retired_key_that_the_manifest_lists_again_is_still_refused()
+    {
+        using var world = new World();
+        await world.Apply(Fixture());
+        await world.Apply(Fixture().Where(s => s.Key != "kestrel").ToList(), ["kestrel"]);
+
+        var refusal = await Assert.ThrowsAsync<ManifestRefusedException>(() => world.Apply(Fixture(), ["kestrel"]));
+
+        Assert.Equal(("retire", "NotAbsent"), (refusal.Field, refusal.Code));
+        Assert.NotNull((await world.Fresh(db => db.ConceptSubjects.AsNoTracking().SingleAsync(x => x.Key == "kestrel"))).RetiredAtUtc);
+    }
+
+    [Fact]
+    public async Task Re_registering_a_retired_key_revives_it()
+    {
+        using var world = new World();
+        await world.Apply(Fixture());
+        await world.Cast("kestrel", ConceptStance.Up);
+        await world.Apply(Fixture().Where(s => s.Key != "kestrel").ToList(), ["kestrel"]);
+
+        var plan = await world.Apply(Fixture());
+
+        Assert.Equal(SubjectChange.Revive, plan.Entries.Single(e => e.Key == "kestrel").Change);
+        var subject = await world.Fresh(db => db.ConceptSubjects.AsNoTracking().SingleAsync(x => x.Key == "kestrel"));
+        Assert.Null(subject.RetiredAtUtc);
+        var tallies = await world.Fresh(db => world.Appraisals(db).GetTalliesAsync(Collection, default));
+        Assert.Equal(new ConceptTally(1, 0, new StanceCounts(0, 0)), tallies["kestrel"]);
+        Assert.Equal(1, await world.Fresh(db => db.AuditEvents.CountAsync(x => x.Action == "Revive")));
+    }
+
+    [Theory]
+    [InlineData("""{"ships":[{"id":"a","name":"A"},{"id":"a","name":"B"}]}""", "ships[1].id", "Duplicate")]
+    [InlineData("""{"ships":[{"id":"Upper","name":"A"}]}""", "ships[0].id", "InvalidKey")]
+    [InlineData("""{"ships":[{"id":"a/b","name":"A"}]}""", "ships[0].id", "InvalidKey")]
+    [InlineData("""{"ships":[{"id":"ship-a\n","name":"A"}]}""", "ships[0].id", "InvalidKey")]
+    [InlineData("""{"ships":[{"id":"","name":"A"}]}""", "ships[0].id", "InvalidKey")]
+    [InlineData("""{"ships":[{"id":"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa","name":"A"}]}""", "ships[0].id", "InvalidKey")]
+    [InlineData("""{"ships":[{"id":"a"}]}""", "ships[0].name", "Missing")]
+    [InlineData("""{"ships":[{"id":"a","name":7}]}""", "ships[0].name", "NotString")]
+    [InlineData("""{"ships":[{"id":"a","name":"  "}]}""", "ships[0].name", "InvalidTitle")]
+    [InlineData("""{"ships":[{"id":"a","name":"bad\ntitle"}]}""", "ships[0].name", "InvalidTitle")]
+    [InlineData("""{"ships":["a"]}""", "ships[0].id", "Missing")]
+    [InlineData("""{"fleet":[]}""", "ships", "Missing")]
+    [InlineData("[]", "ships", "Missing")]
+    [InlineData("""{"ships":5}""", "ships", "Missing")]
+    [InlineData("not json", "manifest", "NotJson")]
+    public async Task Malformed_manifest_is_refused_whole(string json, string field, string code)
+    {
+        using var world = new World();
+        var refusal = Assert.Throws<ManifestRefusedException>(() => Parse(json));
+
+        Assert.Equal((field, code), (refusal.Field, refusal.Code));
+        Assert.Equal($"{field}: {code}", refusal.Message);
+        Assert.Empty(await world.Fresh(db => db.ConceptSubjects.ToListAsync()));
+    }
+
+    [Fact]
+    public void A_title_of_exactly_the_column_width_is_accepted_and_one_more_is_refused()
+    {
+        var fits = new string('t', ConceptSubjectRegistry.MaxTitleLength);
+
+        Assert.Equal(fits, Parse($$"""{"ships":[{"id":"a","name":"{{fits}}"}]}""").Single().Title);
+        var refusal = Assert.Throws<ManifestRefusedException>(() =>
+            Parse($$"""{"ships":[{"id":"a","name":"{{fits}}x"}]}"""));
+        Assert.Equal(("ships[0].name", "TooLong"), (refusal.Field, refusal.Code));
+    }
+
+    private static readonly JsonSerializerOptions Raw = new() { Encoder = JavaScriptEncoder.UnsafeRelaxedJsonEscaping };
+
+    [Theory]
+    [InlineData("\u202Eevil")]
+    [InlineData("a\u202Ab")]
+    [InlineData("a\u2066b")]
+    [InlineData("a\u2069b")]
+    [InlineData("a\u061Cb")]
+    [InlineData("a\u200Eb")]
+    [InlineData("a\u200Fb")]
+    [InlineData("a\u2028b")]
+    [InlineData("a\u2029b")]
+    [InlineData("a\u200Bb")]
+    [InlineData("a\u200Cb")]
+    [InlineData("a\u200Db")]
+    [InlineData("a\u2060b")]
+    [InlineData("a\uFEFFb")]
+    [InlineData("a\u0085b")]
+    [InlineData("a\tb")]
+    [InlineData(" Ibis")]
+    [InlineData("Ibis ")]
+    [InlineData("\u00A0Ibis")]
+    [InlineData("Ibis\u00A0")]
+    [InlineData("\u3000Ibis")]
+    [InlineData("!!!")]
+    public void A_title_with_a_format_character_edge_whitespace_or_no_letter_is_refused(string title)
+    {
+        var json = """{"ships":[{"id":"a","name":""" + JsonSerializer.Serialize(title, Raw) + "}]}";
+
+        var refusal = Assert.Throws<ManifestRefusedException>(() => Parse(json));
+
+        Assert.Equal(("ships[0].name", "InvalidTitle"), (refusal.Field, refusal.Code));
+    }
+
+    [Theory]
+    [InlineData("Ibis Mk II")]
+    [InlineData("Ünïcode Ship")]
+    [InlineData("Ship ★ 7")]
+    [InlineData("7")]
+    [InlineData("Kestrel-2: the \"Bold\"")]
+    public void An_ordinary_title_is_accepted(string title)
+    {
+        var json = """{"ships":[{"id":"a","name":""" + JsonSerializer.Serialize(title, Raw) + "}]}";
+
+        Assert.Equal(title, Parse(json).Single().Title);
+    }
+
+    [Theory]
+    [InlineData("""{"ships":[{"id":"a","name":"x\ud800y"}]}""", "ships[0].name", "BadText")]
+    [InlineData("""{"ships":[{"id":"a\udc00","name":"x"}]}""", "ships[0].id", "BadText")]
+    [InlineData("""{"ships":[{"id":"a","name":"x","na\ud800me":"y"}]}""", "manifest", "BadText")]
+    public void A_lone_surrogate_is_refused_not_thrown(string json, string field, string code)
+    {
+        var refusal = Assert.Throws<ManifestRefusedException>(() => Parse(json));
+
+        Assert.Equal((field, code), (refusal.Field, refusal.Code));
+    }
+
+    [Fact]
+    public void Malformed_utf8_anywhere_in_the_file_is_refused()
+    {
+        byte[] inName = [.. "{\"ships\":[{\"id\":\"a\",\"name\":\"X"u8, 0xC3, 0x28, .. "\"}]}"u8];
+        byte[] inUnreadValue = [.. "{\"ships\":[],\"x\":\"X"u8, 0xFF, .. "\"}"u8];
+
+        foreach (var bytes in new[] { inName, inUnreadValue })
+        {
+            var refusal = Assert.Throws<ManifestRefusedException>(() => ConceptSubjectRegistry.ParseManifest(bytes));
+
+            Assert.Equal(("manifest", "NotUtf8"), (refusal.Field, refusal.Code));
+        }
+    }
+
+    [Theory]
+    [InlineData("""{"ships":[{"id":"a","id":"b","name":"A"}]}""")]
+    [InlineData("""{"ships":[{"id":"a","name":"A","name":"B"}]}""")]
+    [InlineData("""{"ships":[],"ships":[]}""")]
+    [InlineData("""{"ships":[{"id":"a","name":"A"}],"votes":{"x":1,"x":2}}""")]
+    [InlineData("""{"ships":[{"id":"a","name":"A","meta":{"k":[{"z":1,"z":1}]}}]}""")]
+    [InlineData("""{"ships":[{"id":"a","name":"A","id":"b"}]}""")]
+    public void A_duplicate_json_property_is_refused_wherever_it_sits(string json)
+    {
+        var refusal = Assert.Throws<ManifestRefusedException>(() => Parse(json));
+
+        Assert.Equal(("manifest", "DuplicateProperty"), (refusal.Field, refusal.Code));
+    }
+
+    [Fact]
+    public void The_same_property_name_in_sibling_and_nested_objects_is_not_a_duplicate()
+    {
+        var ships = Parse("""{"id":"top","ships":[{"id":"a","name":"A","meta":{"id":"x","name":"y"}},{"id":"b","name":"B"}]}""");
+
+        Assert.Equal(["a", "b"], ships.Select(s => s.Key));
+    }
+
+    [Fact]
+    public void A_manifest_of_exactly_the_byte_bound_is_accepted_and_one_more_byte_is_refused()
+    {
+        const string head = """{"ships":[{"id":"a","name":"A"}]}""";
+        var fits = Encoding.UTF8.GetBytes(head + new string(' ', ConceptSubjectRegistry.MaxManifestBytes - head.Length));
+
+        Assert.Equal(ConceptSubjectRegistry.MaxManifestBytes, fits.Length);
+        Assert.Single(ConceptSubjectRegistry.ParseManifest(fits));
+        var refusal = Assert.Throws<ManifestRefusedException>(() => ConceptSubjectRegistry.ParseManifest(fits.Append((byte)' ').ToArray()));
+        Assert.Equal(("manifest", "TooLarge"), (refusal.Field, refusal.Code));
+    }
+
+    [Fact]
+    public void A_manifest_of_exactly_the_ship_bound_is_accepted_and_one_more_ship_is_refused()
+    {
+        static string Fleet(int count) =>
+            """{"ships":[""" + string.Join(",", Enumerable.Range(0, count).Select(i => $$"""{"id":"s{{i}}","name":"S{{i}}"}""")) + "]}";
+
+        Assert.Equal(ConceptSubjectRegistry.MaxShips, Parse(Fleet(ConceptSubjectRegistry.MaxShips)).Count);
+        var refusal = Assert.Throws<ManifestRefusedException>(() => Parse(Fleet(ConceptSubjectRegistry.MaxShips + 1)));
+        Assert.Equal(("ships", "TooMany"), (refusal.Field, refusal.Code));
+    }
+
+    [Fact]
+    public async Task Absent_keys_are_planned_in_key_order()
+    {
+        using var world = new World();
+        await world.Apply(Fixture());
+
+        var plan = await world.Plan([new ManifestShip("zzz-new", "New")]);
+
+        Assert.Equal(["zzz-new", "bison", "ibis-mk2", "kestrel"], plan.Entries.Select(e => e.Key));
+    }
+
+    [Fact]
+    public async Task A_bad_entry_after_good_ones_refuses_the_file_and_writes_no_row()
+    {
+        using var world = new World();
+        var json = """{"ships":[{"id":"good","name":"Good"},{"id":"ship-a\n","name":"Bad"}]}""";
+
+        Assert.Throws<ManifestRefusedException>(() => Parse(json));
+        Assert.Empty(await world.Fresh(db => db.ConceptSubjects.ToListAsync()));
+    }
+
+    [Fact]
+    public async Task Refusal_never_echoes_the_offending_value()
+    {
+        const string canary = "CANARY-secret/value";
+        var json = $$"""{"ships":[{"id":"{{canary}}","name":"A"}]}""";
+
+        var refusal = Assert.Throws<ManifestRefusedException>(() => Parse(json));
+        Assert.DoesNotContain("CANARY", refusal.Message);
+        using var world = new World();
+        var collection = await Assert.ThrowsAsync<ManifestRefusedException>(() => world.Registry(world.NewDb()).PlanAsync(canary, [], None, default));
+        Assert.DoesNotContain("CANARY", collection.Message);
+        Assert.Equal(("collection", "InvalidKey"), (collection.Field, collection.Code));
+        var retire = await Assert.ThrowsAsync<ManifestRefusedException>(() => world.Registry(world.NewDb()).PlanAsync(Collection, [], [canary], default));
+        Assert.DoesNotContain("CANARY", retire.Message);
+        Assert.Equal(("retire", "InvalidKey"), (retire.Field, retire.Code));
+    }
+
+    [Theory]
+    [InlineData("ship-a\n")]
+    [InlineData("ship-a\r\n")]
+    [InlineData("ship-a ")]
+    public async Task The_key_grammar_rejects_a_trailing_line_feed_wherever_it_is_reused(string forged)
+    {
+        using var world = new World();
+        await world.Apply(Fixture());
+        await world.Registry(world.NewDb()).ApplyAsync(Collection, [new ManifestShip("ship-a", "A")], None, default);
+
+        Assert.False(ConceptKey.IsValid(forged));
+        Assert.False(ConceptKey.IsValid("key\n"));
+        Assert.True(ConceptKey.IsValid("ship-a"));
+        Assert.Equal(CastResult.UnknownSubject, await world.Cast(forged, ConceptStance.Up));
+        Assert.Null(await world.Fresh(db => world.Appraisals(db).GetSubjectAsync(Collection, forged, null, default)));
+        await Assert.ThrowsAsync<ManifestRefusedException>(() =>
+            world.Registry(world.NewDb()).PlanAsync(Collection + "\n", [], None, default));
+        await Assert.ThrowsAsync<ManifestRefusedException>(() =>
+            world.Registry(world.NewDb()).PlanAsync(Collection, [], ["ship-a\n"], default));
+        Assert.Empty(await world.Fresh(db => db.ConceptAppraisals.ToListAsync()));
+    }
+
+    [Fact]
+    public async Task Host_command_plans_and_applies_with_exit_codes()
+    {
+        using var world = new World();
+        var services = world.Services();
+
+        var plan = new StringWriter();
+        Assert.Equal(ConceptCommand.Ok, await ConceptCommand.RunAsync(["plan", Collection, FixturePath], services, plan));
+        Assert.Contains("add bison", plan.ToString());
+        Assert.Contains("add ibis-mk2", plan.ToString());
+        Assert.Empty(await world.Fresh(db => db.ConceptSubjects.ToListAsync()));
+        Assert.Empty(await world.Fresh(db => db.AuditEvents.ToListAsync()));
+
+        var apply = new StringWriter();
+        Assert.Equal(ConceptCommand.Ok, await ConceptCommand.RunAsync(["apply", Collection, FixturePath], services, apply));
+        Assert.Equal(3, await world.Fresh(db => db.ConceptSubjects.CountAsync()));
+
+        var again = new StringWriter();
+        Assert.Equal(ConceptCommand.Ok, await ConceptCommand.RunAsync(["apply", Collection, FixturePath], services, again));
+        Assert.Contains("unchanged bison", again.ToString());
+        Assert.Equal(3, await world.Fresh(db => db.AuditEvents.CountAsync()));
+    }
+
+    [Fact]
+    public async Task Host_command_retire_flag_retires_the_named_absent_key()
+    {
+        using var world = new World();
+        var services = world.Services();
+        await ConceptCommand.RunAsync(["apply", Collection, FixturePath], services, new StringWriter());
+        var smaller = Path.Combine(world.Dir, "two.json");
+        await File.WriteAllTextAsync(smaller, """{"ships":[{"id":"bison","name":"Bison"},{"id":"ibis-mk2","name":"Ibis Mk II"}]}""");
+
+        var output = new StringWriter();
+        Assert.Equal(ConceptCommand.Ok, await ConceptCommand.RunAsync(["apply", Collection, smaller, "--retire", "kestrel"], services, output));
+
+        Assert.Contains("retire kestrel", output.ToString());
+        Assert.NotNull((await world.Fresh(db => db.ConceptSubjects.AsNoTracking().SingleAsync(x => x.Key == "kestrel"))).RetiredAtUtc);
+    }
+
+    [Fact]
+    public async Task Host_command_exits_non_zero_on_refusal_and_never_echoes_input()
+    {
+        using var world = new World();
+        var services = world.Services();
+        var bad = Path.Combine(world.Dir, "bad.json");
+        await File.WriteAllTextAsync(bad, """{"ships":[{"id":"CANARY/Id","name":"A"}]}""");
+
+        var refused = new StringWriter();
+        Assert.Equal(ConceptCommand.Refused, await ConceptCommand.RunAsync(["apply", Collection, bad], services, refused));
+        Assert.Contains("ships[0].id", refused.ToString());
+        Assert.DoesNotContain("CANARY", refused.ToString());
+
+        var missing = new StringWriter();
+        Assert.Equal(ConceptCommand.Refused, await ConceptCommand.RunAsync(["apply", Collection, Path.Combine(world.Dir, "CANARY-missing.json")], services, missing));
+        Assert.DoesNotContain("CANARY", missing.ToString());
+        Assert.Equal("refused manifest Unreadable", missing.ToString().Trim());
+        Assert.Empty(await world.Fresh(db => db.ConceptSubjects.ToListAsync()));
+    }
+
+    [Theory]
+    [InlineData("frobnicate", "c", "m")]
+    [InlineData("plan", "c")]
+    [InlineData("apply", "c", "m", "--bogus", "x")]
+    [InlineData("apply", "c", "m", "--retire")]
+    public async Task Host_command_unknown_subcommand_or_shape_exits_2(params string[] args)
+    {
+        using var world = new World();
+
+        var output = new StringWriter();
+        Assert.Equal(ConceptCommand.Usage, await ConceptCommand.RunAsync(args, world.Services(), output));
+        Assert.StartsWith("usage:", output.ToString());
+        Assert.Empty(await world.Fresh(db => db.ConceptSubjects.ToListAsync()));
+        Assert.Equal(ConceptCommand.Usage, await ConceptCommand.RunAsync([], world.Services(), new StringWriter()));
+    }
+
+    [Theory]
+    [InlineData("")]
+    [InlineData("CANARY\0path.json")]
+    public async Task Host_command_refuses_an_empty_or_nul_path(string path)
+    {
+        using var world = new World();
+
+        var output = new StringWriter();
+        Assert.Equal(ConceptCommand.Refused, await ConceptCommand.RunAsync(["plan", Collection, path], world.Services(), output));
+
+        Assert.Equal("refused manifest Unreadable", output.ToString().Trim());
+    }
+
+    [Fact]
+    public async Task Host_command_refuses_a_directory_and_an_oversized_file()
+    {
+        using var world = new World();
+        var big = Path.Combine(world.Dir, "big.json");
+        await File.WriteAllBytesAsync(big, new byte[ConceptSubjectRegistry.MaxManifestBytes + 1]);
+
+        var dir = new StringWriter();
+        Assert.Equal(ConceptCommand.Refused, await ConceptCommand.RunAsync(["plan", Collection, world.Dir], world.Services(), dir));
+        Assert.Equal("refused manifest Unreadable", dir.ToString().Trim());
+        var large = new StringWriter();
+        Assert.Equal(ConceptCommand.Refused, await ConceptCommand.RunAsync(["plan", Collection, big], world.Services(), large));
+        Assert.Equal("refused manifest TooLarge", large.ToString().Trim());
+    }
+
+    [Fact]
+    public async Task Host_command_refuses_a_manifest_that_is_not_utf8_text()
+    {
+        using var world = new World();
+        var path = Path.Combine(world.Dir, "latin1.json");
+        await File.WriteAllBytesAsync(path, [.. "{\"ships\":[{\"id\":\"a\",\"name\":\"CANARY-"u8, 0xE9, .. "\"}]}"u8]);
+
+        var output = new StringWriter();
+        Assert.Equal(ConceptCommand.Refused, await ConceptCommand.RunAsync(["plan", Collection, path], world.Services(), output));
+
+        Assert.Equal("refused manifest NotUtf8", output.ToString().Trim());
+    }
+
+    [Fact]
+    public async Task Built_command_exits_with_its_documented_codes_and_echoes_no_input()
+    {
+        using var world = new World();
+        var big = Path.Combine(world.Dir, "CANARYBIG.json");
+        await File.WriteAllBytesAsync(big, new byte[ConceptSubjectRegistry.MaxManifestBytes + 1]);
+        var bidi = Path.Combine(world.Dir, "CANARYBIDI.json");
+        await File.WriteAllTextAsync(bidi, """{"ships":[{"id":"a","name":"CANARYTITLE\u202E"}]}""");
+        var dup = Path.Combine(world.Dir, "CANARYDUP.json");
+        await File.WriteAllTextAsync(dup, """{"ships":[{"id":"CANARYID","id":"b","name":"A"}]}""");
+        var surrogate = Path.Combine(world.Dir, "CANARYSURR.json");
+        await File.WriteAllTextAsync(surrogate, """{"ships":[{"id":"a","name":"CANARYNAME\ud800"}]}""");
+        var latin1 = Path.Combine(world.Dir, "CANARYLATIN.json");
+        await File.WriteAllBytesAsync(latin1, [.. "{\"ships\":[{\"id\":\"a\",\"name\":\"CANARYBYTES"u8, 0xE9, .. "\"}]}"u8]);
+
+        var cases = new (string[] Args, int Code)[]
+        {
+            (["plan", Collection, ""], ConceptCommand.Refused),
+            (["plan", Collection, Path.Combine(world.Dir, "CANARYMISSING.json")], ConceptCommand.Refused),
+            (["plan", Collection, world.Dir], ConceptCommand.Refused),
+            (["plan", Collection, big], ConceptCommand.Refused),
+            (["plan", Collection, bidi], ConceptCommand.Refused),
+            (["apply", Collection, dup], ConceptCommand.Refused),
+            (["apply", Collection, surrogate], ConceptCommand.Refused),
+            (["plan", Collection, latin1], ConceptCommand.Refused),
+            (["plan", "CANARYCOLLECTION", bidi], ConceptCommand.Refused),
+            (["frob", "CANARYARG", "x"], ConceptCommand.Usage),
+            (["plan"], ConceptCommand.Usage),
+        };
+        foreach (var (args, code) in cases)
+        {
+            var result = await RunBuiltCommandAsync(args);
+
+            Assert.True(code == result.ExitCode, $"case {args[0]}/{args.Length}: exit {result.ExitCode}, stdout {result.StdOut}, stderr {result.StdErr}");
+            Assert.DoesNotContain("CANARY", result.StdOut + result.StdErr);
+            Assert.DoesNotContain("Unhandled exception", result.StdOut + result.StdErr);
+        }
+    }
+
+    private static async Task<(int ExitCode, string StdOut, string StdErr)> RunBuiltCommandAsync(string[] args)
+    {
+        var dll = Path.Combine(AppContext.BaseDirectory, "Bifrost.Web.dll");
+        Assert.True(File.Exists(Path.ChangeExtension(dll, ".runtimeconfig.json")), "Bifrost.Web.runtimeconfig.json is not beside the test assembly");
+        var start = new ProcessStartInfo("dotnet")
+        {
+            RedirectStandardOutput = true,
+            RedirectStandardError = true,
+            UseShellExecute = false
+        };
+        foreach (var part in new[] { dll, "concepts" }.Concat(args))
+        {
+            start.ArgumentList.Add(part);
+        }
+
+        // Every case refuses before the database is touched; the password is a canary for leaks.
+        start.Environment["ConnectionStrings__Bifrost"] = "Host=127.0.0.1;Port=1;Database=x;Username=u;Password=CANARYPW";
+        using var process = Process.Start(start)!;
+        var stdout = process.StandardOutput.ReadToEndAsync();
+        var stderr = process.StandardError.ReadToEndAsync();
+        using var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(120));
+        await process.WaitForExitAsync(timeout.Token);
+        return (process.ExitCode, await stdout, await stderr);
+    }
+
+    private sealed class World : IDisposable
+    {
+        private readonly string _dbName = $"registry-{Guid.NewGuid():N}";
+
+        public World()
+        {
+            Dir = Path.Combine(Path.GetTempPath(), $"registry-{Guid.NewGuid():N}");
+            Directory.CreateDirectory(Dir);
+        }
+
+        public string Dir { get; }
+
+        public ManualClock Clock { get; } = new(new DateTimeOffset(2026, 10, 10, 12, 0, 0, TimeSpan.Zero));
+
+        public BifrostDbContext NewDb() =>
+            new(new DbContextOptionsBuilder<BifrostDbContext>().UseInMemoryDatabase(_dbName).Options);
+
+        public ConceptSubjectRegistry Registry(BifrostDbContext db) =>
+            new(db, new AuditTrailService(db, Clock), Clock);
+
+        public ConceptAppraisalService Appraisals(BifrostDbContext db) =>
+            new(db, new AuditTrailService(db, Clock), Clock,
+                Options.Create(new ConceptVoteOptions { NetworkTagSecret = "test-tag-secret" }));
+
+        public async Task<SubjectPlan> Apply(IReadOnlyList<ManifestShip> ships, string[]? retire = null)
+        {
+            await using var db = NewDb();
+            return await Registry(db).ApplyAsync(Collection, ships, retire ?? None, default);
+        }
+
+        public async Task<SubjectPlan> Plan(IReadOnlyList<ManifestShip> ships)
+        {
+            await using var db = NewDb();
+            return await Registry(db).PlanAsync(Collection, ships, None, default);
+        }
+
+        public async Task<CastResult> Cast(string key, ConceptStance stance)
+        {
+            await using var db = NewDb();
+            var voter = VoterIdentity.For(CurrentBifrostActor.Anonymous, "device-" + stance)!;
+            return await Appraisals(db).CastAsync(Collection, key, voter, stance, IPAddress.Parse("203.0.113.7"), default);
+        }
+
+        public async Task<T> Fresh<T>(Func<BifrostDbContext, Task<T>> read)
+        {
+            await using var db = NewDb();
+            return await read(db);
+        }
+
+        public IServiceProvider Services()
+        {
+            var services = new ServiceCollection();
+            services.AddDbContext<BifrostDbContext>(o => o.UseInMemoryDatabase(_dbName));
+            services.AddSingleton<TimeProvider>(Clock);
+            services.AddScoped<AuditTrailService>();
+            services.AddScoped<ConceptSubjectRegistry>();
+            return services.BuildServiceProvider();
+        }
+
+        public void Dispose() => Directory.Delete(Dir, true);
+    }
+
+    private sealed class ManualClock(DateTimeOffset start) : TimeProvider
+    {
+        private DateTimeOffset _now = start;
+
+        public override DateTimeOffset GetUtcNow() => _now;
+
+        public void Advance(TimeSpan by) => _now += by;
+    }
+}

tests/Bifrost.Web.Tests/ConceptTallyExportTests.cs

@@ -0,0 +1,383 @@
+using System.Net;
+using System.Text.Json;
+using Bifrost.Web.Data;
+using Bifrost.Web.Domain;
+using Bifrost.Web.Features.ConceptVotes;
+using Bifrost.Web.Features.Shared;
+using Bifrost.Web.Tests.Support;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace Bifrost.Web.Tests;
+
+public sealed class ConceptTallyExportTests : IClassFixture<ConceptTallyExportTests.ExportFactory>
+{
+    private const string AllowedOrigin = "https://aetheria.gamecult.org";
+    private const string Client = "203.0.113.7";
+
+    private readonly ExportFactory _factory;
+
+    public ConceptTallyExportTests(ExportFactory factory)
+    {
+        _factory = factory;
+    }
+
+    [Fact]
+    public async Task Anonymous_request_gets_the_public_counts()
+    {
+        var collection = NewCollection();
+        await AddSubject(collection, "alpha");
+        await AddSubject(collection, "beta");
+        await AddSubject(collection, "untouched");
+        await Cast(collection, "alpha", DeviceVoter("dev-one"), ConceptStance.Up);
+        await Cast(collection, "alpha", DeviceVoter("dev-two"), ConceptStance.Up);
+        await Cast(collection, "alpha", DeviceVoter("dev-three"), ConceptStance.Down);
+        await Cast(collection, "alpha", await AccountVoter(MembershipStatus.Active), ConceptStance.Up);
+        await Cast(collection, "alpha", await AccountVoter(MembershipStatus.Authenticated), ConceptStance.Down);
+        await Cast(collection, "beta", DeviceVoter("dev-one"), ConceptStance.Down);
+
+        using var response = await Get(collection);
+
+        Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+        Assert.Equal("application/json", response.Content.Headers.ContentType?.MediaType);
+        var body = JsonDocument.Parse(await response.Content.ReadAsStringAsync()).RootElement;
+        Assert.Equal(["alpha", "beta", "untouched"], body.EnumerateObject().Select(p => p.Name).Order().ToArray());
+        AssertCounts(body.GetProperty("alpha"), up: 3, down: 2, memberUp: 1, memberDown: 0);
+        AssertCounts(body.GetProperty("beta"), up: 0, down: 1, memberUp: 0, memberDown: 0);
+        AssertCounts(body.GetProperty("untouched"), up: 0, down: 0, memberUp: 0, memberDown: 0);
+    }
+
+    [Fact]
+    public async Task Payload_carries_no_voter_identity()
+    {
+        var collection = NewCollection();
+        await AddSubject(collection, "alpha");
+        var account = await AccountVoter(MembershipStatus.Authenticated);
+        var member = await AccountVoter(MembershipStatus.Active);
+        await Cast(collection, "alpha", DeviceVoter("canary-device-id-9c2e"), ConceptStance.Up);
+        await Cast(collection, "alpha", account, ConceptStance.Down);
+        await Cast(collection, "alpha", member, ConceptStance.Up);
+
+        using var response = await Get(collection);
+
+        var text = await response.Content.ReadAsStringAsync();
+        var alpha = JsonDocument.Parse(text).RootElement.GetProperty("alpha");
+        Assert.Equal(["down", "members", "up"], alpha.EnumerateObject().Select(p => p.Name).Order().ToArray());
+        Assert.Equal(["down", "up"], alpha.GetProperty("members").EnumerateObject().Select(p => p.Name).Order().ToArray());
+
+        string[] tags;
+        using (var scope = _factory.Services.CreateScope())
+        {
+            tags = await scope.ServiceProvider.GetRequiredService<BifrostDbContext>()
+                .ConceptAppraisals.Select(x => x.NetworkTag).Distinct().ToArrayAsync();
+        }
+
+        Assert.All(tags, tag => Assert.NotEmpty(tag));
+        var forbidden = new List<string> { "canary-device-id-9c2e", "device:", "account:", "voterkey", "networktag", "useraccount" };
+        forbidden.AddRange(tags);
+        foreach (var voter in new[] { account, member })
+        {
+            forbidden.Add(voter.UserAccountId!.Value.ToString("N"));
+            forbidden.Add(voter.UserAccountId!.Value.ToString("D"));
+        }
+
+        foreach (var value in forbidden)
+        {
+            Assert.DoesNotContain(value, text, StringComparison.OrdinalIgnoreCase);
+        }
+    }
+
+    [Fact]
+    public async Task Cors_allows_only_the_configured_origin_without_credentials()
+    {
+        var collection = NewCollection();
+        await AddSubject(collection, "alpha");
+
+        using var allowed = await Get(collection, AllowedOrigin);
+        Assert.Equal(HttpStatusCode.OK, allowed.StatusCode);
+        Assert.Equal([AllowedOrigin], allowed.Headers.GetValues("Access-Control-Allow-Origin").ToArray());
+        Assert.False(allowed.Headers.Contains("Access-Control-Allow-Credentials"));
+
+        using var otherHost = await Get(collection, "https://evil.example");
+        Assert.False(otherHost.Headers.Contains("Access-Control-Allow-Origin"));
+        Assert.False(otherHost.Headers.Contains("Access-Control-Allow-Credentials"));
+
+        using var preflightGet = await Preflight(collection, AllowedOrigin, "GET");
+        Assert.Equal([AllowedOrigin], preflightGet.Headers.GetValues("Access-Control-Allow-Origin").ToArray());
+        Assert.False(preflightGet.Headers.Contains("Access-Control-Allow-Credentials"));
+
+        using var preflightPost = await Preflight(collection, AllowedOrigin, "POST");
+        Assert.False(preflightPost.Headers.Contains("Access-Control-Allow-Origin"));
+        Assert.False(preflightPost.Headers.Contains("Access-Control-Allow-Methods"));
+    }
+
+    [Theory]
+    [InlineData("https://aetheria.gamecult.org.evil.example")]
+    [InlineData("https://aetheria.gamecult.orgx")]
+    [InlineData("https://evilaetheria.gamecult.org")]
+    [InlineData("https://www.aetheria.gamecult.org")]
+    [InlineData("HTTPS://AETHERIA.GAMECULT.ORG")]
+    [InlineData("https://Aetheria.gamecult.org")]
+    [InlineData("https://aetheria.gamecult.org/")]
+    [InlineData("https://aetheria.gamecult.org:8443")]
+    [InlineData("http://aetheria.gamecult.org")]
+    [InlineData("null")]
+    [InlineData("*")]
+    [InlineData("")]
+    public async Task Cors_refuses_origins_that_only_resemble_the_configured_one(string origin)
+    {
+        var collection = NewCollection();
+        await AddSubject(collection, "alpha");
+
+        using var response = await Get(collection, origin);
+        using var preflight = await Preflight(collection, origin, "GET");
+
+        Assert.False(response.Headers.Contains("Access-Control-Allow-Origin"));
+        Assert.False(preflight.Headers.Contains("Access-Control-Allow-Origin"));
+    }
+
+    [Fact]
+    public async Task Every_export_response_varies_by_origin()
+    {
+        var collection = NewCollection();
+        await AddSubject(collection, "alpha");
+
+        using var allowed = await Get(collection, AllowedOrigin);
+        using var lookalike = await Get(collection, "https://aetheria.gamecult.org.evil.example");
+        using var noOrigin = await Get(collection);
+        using var unknownAllowed = await Get(NewCollection(), AllowedOrigin);
+        using var unknownNoOrigin = await Get(NewCollection());
+        using var preflightAllowed = await Preflight(collection, AllowedOrigin, "GET");
+        using var preflightLookalike = await Preflight(collection, "https://evil.example", "GET");
+        using var preflightPost = await Preflight(collection, AllowedOrigin, "POST");
+
+        Assert.Equal(HttpStatusCode.OK, allowed.StatusCode);
+        Assert.Equal(HttpStatusCode.OK, lookalike.StatusCode);
+        Assert.Equal(HttpStatusCode.OK, noOrigin.StatusCode);
+        Assert.Equal(HttpStatusCode.NotFound, unknownAllowed.StatusCode);
+        Assert.Equal(HttpStatusCode.NotFound, unknownNoOrigin.StatusCode);
+        foreach (var response in new[] { allowed, lookalike, noOrigin, unknownAllowed, unknownNoOrigin, preflightAllowed, preflightLookalike, preflightPost })
+        {
+            Assert.Contains("Origin", VaryTokens(response));
+        }
+    }
+
+    [Fact]
+    public async Task Origin_is_added_to_an_existing_vary()
+    {
+        var collection = NewCollection();
+        await AddSubject(collection, "alpha");
+        using var client = _factory.CreateClient();
+        using var request = new HttpRequestMessage(HttpMethod.Get, $"/public/concepts/{collection}/tallies");
+        request.Headers.Add("X-Test-Anonymous", "true");
+        request.Headers.Add("X-Test-Vary", "Accept-Encoding");
+        request.Headers.TryAddWithoutValidation("Origin", AllowedOrigin);
+
+        using var response = await client.SendAsync(request);
+
+        Assert.Equal(["Accept-Encoding", "Origin"], VaryTokens(response).Order().ToArray());
+    }
+
+    private static string[] VaryTokens(HttpResponseMessage response) =>
+        response.Headers.Vary.ToArray();
+
+    [Fact]
+    public async Task Other_routes_carry_no_cors_headers()
+    {
+        using var client = _factory.CreateClient();
+        using var request = new HttpRequestMessage(HttpMethod.Get, "/healthz");
+        request.Headers.Add("Origin", AllowedOrigin);
+
+        using var response = await client.SendAsync(request);
+
+        Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+        Assert.False(response.Headers.Contains("Access-Control-Allow-Origin"));
+    }
+
+    [Fact]
+    public async Task Retired_subject_leaves_the_export()
+    {
+        var collection = NewCollection();
+        await AddSubject(collection, "alpha");
+        await AddSubject(collection, "gone");
+        await Cast(collection, "gone", DeviceVoter("dev-one"), ConceptStance.Up);
+        await Retire(collection, "gone");
+
+        using var response = await Get(collection);
+
+        var body = JsonDocument.Parse(await response.Content.ReadAsStringAsync()).RootElement;
+        Assert.Equal(["alpha"], body.EnumerateObject().Select(p => p.Name).ToArray());
+        using var scope = _factory.Services.CreateScope();
+        var db = scope.ServiceProvider.GetRequiredService<BifrostDbContext>();
+        Assert.Single(db.ConceptAppraisals.Where(x => x.Subject!.Key == "gone" && x.Subject.Collection == collection));
+    }
+
+    [Fact]
+    public async Task Cache_control_is_public_sixty_seconds()
+    {
+        var collection = NewCollection();
+        await AddSubject(collection, "alpha");
+
+        using var response = await Get(collection);
+
+        var cache = response.Headers.CacheControl;
+        Assert.NotNull(cache);
+        Assert.True(cache!.Public);
+        Assert.Equal(TimeSpan.FromSeconds(60), cache.MaxAge);
+    }
+
+    [Fact]
+    public async Task Unknown_collection_is_not_found()
+    {
+        using var response = await Get(NewCollection());
+
+        Assert.Equal(HttpStatusCode.NotFound, response.StatusCode);
+    }
+
+    [Fact]
+    public async Task The_export_only_reads()
+    {
+        var collection = NewCollection();
+        await AddSubject(collection, "alpha");
+
+        int rowsBefore, auditBefore;
+        using (var scope = _factory.Services.CreateScope())
+        {
+            var db = scope.ServiceProvider.GetRequiredService<BifrostDbContext>();
+            rowsBefore = db.ConceptAppraisals.Count();
+            auditBefore = db.AuditEvents.Count();
+        }
+
+        using var response = await Get(collection);
+
+        Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+        Assert.False(response.Headers.Contains("Set-Cookie"));
+        using var after = _factory.Services.CreateScope();
+        var dbAfter = after.ServiceProvider.GetRequiredService<BifrostDbContext>();
+        Assert.Equal(rowsBefore, dbAfter.ConceptAppraisals.Count());
+        Assert.Equal(auditBefore, dbAfter.AuditEvents.Count());
+    }
+
+    private async Task<HttpResponseMessage> Get(string collection, string? origin = null)
+    {
+        using var client = _factory.CreateClient();
+        using var request = new HttpRequestMessage(HttpMethod.Get, $"/public/concepts/{collection}/tallies");
+        request.Headers.Add("X-Test-Anonymous", "true");
+        if (origin is not null)
+        {
+            request.Headers.TryAddWithoutValidation("Origin", origin);
+        }
+
+        return await client.SendAsync(request);
+    }
+
+    private async Task<HttpResponseMessage> Preflight(string collection, string origin, string method)
+    {
+        using var client = _factory.CreateClient();
+        using var request = new HttpRequestMessage(HttpMethod.Options, $"/public/concepts/{collection}/tallies");
+        request.Headers.Add("X-Test-Anonymous", "true");
+        request.Headers.TryAddWithoutValidation("Origin", origin);
+        request.Headers.Add("Access-Control-Request-Method", method);
+        return await client.SendAsync(request);
+    }
+
+    private static void AssertCounts(JsonElement tally, int up, int down, int memberUp, int memberDown)
+    {
+        Assert.Equal(up, tally.GetProperty("up").GetInt32());
+        Assert.Equal(down, tally.GetProperty("down").GetInt32());
+        Assert.Equal(memberUp, tally.GetProperty("members").GetProperty("up").GetInt32());
+        Assert.Equal(memberDown, tally.GetProperty("members").GetProperty("down").GetInt32());
+    }
+
+    private static string NewCollection() => "c" + Guid.NewGuid().ToString("N");
+
+    private static VoterIdentity DeviceVoter(string deviceId) =>
+        VoterIdentity.For(CurrentBifrostActor.Anonymous, deviceId)!;
+
+    private async Task<VoterIdentity> AccountVoter(MembershipStatus status)
+    {
+        using var scope = _factory.Services.CreateScope();
+        var db = scope.ServiceProvider.GetRequiredService<BifrostDbContext>();
+        var now = DateTimeOffset.UtcNow;
+        var user = new UserAccount
+        {
+            DisplayName = "voter",
+            GitHubLogin = "voter",
+            NormalizedGitHubLogin = "voter",
+            CreatedAtUtc = now,
+            LastSeenAtUtc = now,
+            Membership = new Membership { Status = status, CreatedAtUtc = now }
+        };
+        user.Membership.UserAccountId = user.Id;
+        db.UserAccounts.Add(user);
+        await db.SaveChangesAsync();
+        return VoterIdentity.For(new CurrentBifrostActor(true, user), null)!;
+    }
+
+    private async Task AddSubject(string collection, string key)
+    {
+        using var scope = _factory.Services.CreateScope();
+        var db = scope.ServiceProvider.GetRequiredService<BifrostDbContext>();
+        db.ConceptSubjects.Add(new ConceptSubject
+        {
+            Collection = collection,
+            Key = key,
+            Title = key,
+            RegisteredAtUtc = DateTimeOffset.UtcNow
+        });
+        await db.SaveChangesAsync();
+    }
+
+    private async Task Retire(string collection, string key)
+    {
+        using var scope = _factory.Services.CreateScope();
+        var db = scope.ServiceProvider.GetRequiredService<BifrostDbContext>();
+        var subject = await db.ConceptSubjects.SingleAsync(x => x.Collection == collection && x.Key == key);
+        subject.RetiredAtUtc = DateTimeOffset.UtcNow;
+        await db.SaveChangesAsync();
+    }
+
+    private async Task Cast(string collection, string key, VoterIdentity voter, ConceptStance stance)
+    {
+        using var scope = _factory.Services.CreateScope();
+        var result = await scope.ServiceProvider.GetRequiredService<ConceptAppraisalService>()
+            .CastAsync(collection, key, voter, stance, IPAddress.Parse(Client), default);
+        Assert.Equal(CastResult.Recorded, result);
+    }
+
+    // Stands in for any earlier middleware that already set a Vary: a request header names the value to preset.
+    private sealed class PriorVaryFilter : IStartupFilter
+    {
+        public Action<IApplicationBuilder> Configure(Action<IApplicationBuilder> next) => app =>
+        {
+            app.Use((context, nextMiddleware) =>
+            {
+                if (context.Request.Headers.TryGetValue("X-Test-Vary", out var prior))
+                {
+                    context.Response.Headers.Vary = prior;
+                }
+
+                return nextMiddleware(context);
+            });
+            next(app);
+        };
+    }
+
+    public sealed class ExportFactory : TestWebApplicationFactory
+    {
+        protected override void ConfigureWebHost(IWebHostBuilder builder)
+        {
+            base.ConfigureWebHost(builder);
+            builder.ConfigureServices(services => services.AddTransient<IStartupFilter, PriorVaryFilter>());
+            builder.ConfigureAppConfiguration((_, configuration) =>
+                configuration.AddInMemoryCollection(new Dictionary<string, string?>
+                {
+                    ["ConceptVotes:AllowedOrigins:0"] = AllowedOrigin,
+                    ["ConceptVotes:NetworkTagSecret"] = "export-test-tag-secret-0123456789-abcdef"
+                }));
+        }
+    }
+}

tests/Bifrost.Web.Tests/ConceptVotePageTests.cs

@@ -0,0 +1,673 @@
+using System.Net;
+using System.Text.RegularExpressions;
+using Bifrost.Web.Data;
+using Bifrost.Web.Domain;
+using Bifrost.Web.Tests.Support;
+using Microsoft.AspNetCore.DataProtection;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc.Testing;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+
+namespace Bifrost.Web.Tests;
+
+public sealed partial class ConceptVotePageTests : IClassFixture<TestWebApplicationFactory>
+{
+    private const string CookieName = "bifrost_voter";
+    private const string Purpose = "Bifrost.ConceptVotes.DeviceToken.v1";
+
+    private readonly TestWebApplicationFactory _factory;
+
+    public ConceptVotePageTests(TestWebApplicationFactory factory)
+    {
+        _factory = factory;
+    }
+
+    [Fact]
+    public async Task Anonymous_visitor_can_cast_change_and_retract()
+    {
+        var collection = NewCollection();
+        await AddSubject(collection, "alpha");
+        var visitor = NewVisitor(anonymous: true);
+
+        using var cast = await visitor.Post(collection, "alpha", "Up");
+
+        Assert.Equal(HttpStatusCode.Redirect, cast.StatusCode);
+        var setCookie = SetCookieHeader(cast, CookieName);
+        Assert.NotNull(setCookie);
+        var attributes = setCookie!.Split(';').Select(x => x.Trim().ToLowerInvariant()).ToArray();
+        Assert.Contains("httponly", attributes);
+        Assert.Contains("secure", attributes);
+        Assert.Contains("samesite=lax", attributes);
+        Assert.Contains("path=/mill", attributes);
+        Assert.Contains("max-age=31536000", attributes);
+
+        using (var page = await visitor.Get(collection, "alpha"))
+        {
+            var (everyone, members) = Counts(await page.Content.ReadAsStringAsync());
+            Assert.Equal("1 up, 0 down", everyone);
+            Assert.Equal("0 up, 0 down", members);
+        }
+
+        var firstRow = Assert.Single(await Rows(collection, "alpha"));
+        Assert.Equal(ConceptStance.Up, firstRow.Stance);
+        Assert.Equal(VoterClass.Anonymous, firstRow.VoterClass);
+
+        // The cookie from the first cast is the voter: casting again changes the row and mints nothing.
+        using var change = await visitor.Post(collection, "alpha", "Down");
+        Assert.Equal(HttpStatusCode.Redirect, change.StatusCode);
+        Assert.Null(SetCookieHeader(change, CookieName));
+        var changed = Assert.Single(await Rows(collection, "alpha"));
+        Assert.Equal(ConceptStance.Down, changed.Stance);
+        Assert.Equal(firstRow.VoterKey, changed.VoterKey);
+
+        using var retract = await visitor.Post(collection, "alpha", "Retract");
+        Assert.Equal(HttpStatusCode.Redirect, retract.StatusCode);
+        Assert.Null(SetCookieHeader(retract, CookieName));
+        Assert.Empty(await Rows(collection, "alpha"));
+    }
+
+    [Fact]
+    public async Task Get_never_sets_the_device_cookie()
+    {
+        var collection = NewCollection();
+        await AddSubject(collection, "alpha");
+        var visitor = NewVisitor(anonymous: true);
+
+        using (var first = await visitor.Get(collection, "alpha"))
+        {
+            Assert.Equal(HttpStatusCode.OK, first.StatusCode);
+            Assert.Null(SetCookieHeader(first, CookieName));
+        }
+
+        using (var retract = await visitor.Post(collection, "alpha", "Retract"))
+        {
+            Assert.Equal(HttpStatusCode.Redirect, retract.StatusCode);
+            Assert.Null(SetCookieHeader(retract, CookieName));
+        }
+
+        Assert.False(visitor.Jar.ContainsKey(CookieName));
+        Assert.Empty(await Rows(collection, "alpha"));
+
+        using var cast = await visitor.Post(collection, "alpha", "Up");
+        Assert.NotNull(SetCookieHeader(cast, CookieName));
+        using var later = await visitor.Get(collection, "alpha");
+        Assert.Null(SetCookieHeader(later, CookieName));
+    }
+
+    [Fact]
+    public async Task Signed_in_vote_is_keyed_to_the_account()
+    {
+        var collection = NewCollection();
+        await AddSubject(collection, "alpha");
+        var visitor = NewVisitor(anonymous: false);
+
+        using var cast = await visitor.Post(collection, "alpha", "Up");
+
+        Assert.Equal(HttpStatusCode.Redirect, cast.StatusCode);
+        Assert.Null(SetCookieHeader(cast, CookieName));
+        var row = Assert.Single(await Rows(collection, "alpha"));
+        Assert.StartsWith("account:", row.VoterKey, StringComparison.Ordinal);
+        Assert.Equal(VoterClass.Member, row.VoterClass);
+        Assert.NotNull(row.UserAccountId);
+
+        using var page = await visitor.Get(collection, "alpha");
+        var (everyone, members) = Counts(await page.Content.ReadAsStringAsync());
+        Assert.Equal("1 up, 0 down", everyone);
+        Assert.Equal("1 up, 0 down", members);
+        Assert.Null(SetCookieHeader(page, CookieName));
+    }
+
+    private const string SiteOrigin = "https://localhost";
+
+    [Fact]
+    public async Task Cast_from_the_sites_own_origin_is_accepted_and_writes_one_row()
+    {
+        var collection = NewCollection();
+        await AddSubject(collection, "alpha");
+        var visitor = NewVisitor(anonymous: true);
+
+        using var byOrigin = await visitor.Post(collection, "alpha", "Up", origin: SiteOrigin);
+        Assert.Equal(HttpStatusCode.Redirect, byOrigin.StatusCode);
+        Assert.Single(await Rows(collection, "alpha"));
+
+        using var byFetchSite = await visitor.Post(collection, "alpha", "Down", origin: null, fetchSite: "same-origin");
+        Assert.Equal(HttpStatusCode.Redirect, byFetchSite.StatusCode);
+        Assert.Equal(ConceptStance.Down, Assert.Single(await Rows(collection, "alpha")).Stance);
+    }
+
+    [Theory]
+    [InlineData("https://localhost.evil.example")]
+    [InlineData("https://evil-localhost")]
+    [InlineData("https://sub.localhost")]
+    [InlineData("https://LOCALHOST")]
+    [InlineData("HTTPS://localhost")]
+    [InlineData("https://localhost:8443")]
+    [InlineData("http://localhost")]
+    [InlineData("null")]
+    [InlineData("https://localhost/")]
+    [InlineData("https://evil.example")]
+    public async Task Cast_from_any_other_origin_is_refused_even_when_fetch_site_says_same_origin(string origin)
+    {
+        var collection = NewCollection();
+        await AddSubject(collection, "alpha");
+        var visitor = NewVisitor(anonymous: true);
+
+        foreach (var handler in new[] { "Up", "Down", "Retract" })
+        {
+            using var response = await visitor.Post(collection, "alpha", handler, origin: origin, fetchSite: "same-origin");
+            Assert.Equal(HttpStatusCode.Forbidden, response.StatusCode);
+            Assert.Null(SetCookieHeader(response, CookieName));
+            Assert.False(response.Headers.Contains("Set-Cookie"));
+            Assert.Equal(string.Empty, await response.Content.ReadAsStringAsync());
+        }
+
+        Assert.Empty(await Rows(collection, "alpha"));
+    }
+
+    [Fact]
+    public async Task Cast_with_the_origin_header_repeated_is_refused_even_when_every_value_is_the_sites()
+    {
+        var collection = NewCollection();
+        await AddSubject(collection, "alpha");
+        var visitor = NewVisitor(anonymous: true);
+        var request = new HttpRequestMessage(HttpMethod.Post, $"/mill/{collection}/alpha?handler=Up")
+        {
+            Content = new FormUrlEncodedContent([])
+        };
+        request.Headers.TryAddWithoutValidation("Origin", [SiteOrigin, SiteOrigin]);
+
+        using var response = await visitor.Send(request);
+
+        Assert.Equal(HttpStatusCode.Forbidden, response.StatusCode);
+        Assert.Empty(await Rows(collection, "alpha"));
+    }
+
+    [Theory]
+    [InlineData(null)]
+    [InlineData("same-origin")]
+    public async Task Cast_with_an_empty_origin_header_is_refused_whatever_fetch_site_says(string? fetchSite)
+    {
+        var collection = NewCollection();
+        await AddSubject(collection, "alpha");
+
+        // HttpClient drops a header whose value is empty, so the request is built on the server itself, where an
+        // Origin header with an empty value is present in the dictionary as a browser's would be.
+        var context = await _factory.Server.SendAsync(http =>
+        {
+            http.Request.Method = HttpMethods.Post;
+            http.Request.Scheme = "https";
+            http.Request.Host = new HostString("localhost");
+            http.Request.Path = $"/mill/{collection}/alpha";
+            http.Request.QueryString = new QueryString("?handler=Up");
+            http.Request.ContentType = "application/x-www-form-urlencoded";
+            http.Request.Headers["X-Test-Anonymous"] = "true";
+            http.Request.Headers["Origin"] = string.Empty;
+            if (fetchSite is not null)
+            {
+                http.Request.Headers["Sec-Fetch-Site"] = fetchSite;
+            }
+        });
+
+        Assert.Equal(StatusCodes.Status403Forbidden, context.Response.StatusCode);
+        Assert.False(context.Response.Headers.ContainsKey("Set-Cookie"));
+        Assert.Empty(await Rows(collection, "alpha"));
+    }
+
+    [Theory]
+    [InlineData("same-origin", true)]
+    [InlineData("same-site", false)]
+    [InlineData("cross-site", false)]
+    [InlineData("none", false)]
+    [InlineData("Same-Origin", false)]
+    [InlineData("same-origin, cross-site", false)]
+    [InlineData(null, false)]
+    public async Task Cast_without_an_origin_header_needs_fetch_site_same_origin(string? fetchSite, bool accepted)
+    {
+        var collection = NewCollection();
+        await AddSubject(collection, "alpha");
+        var visitor = NewVisitor(anonymous: true);
+
+        using var response = await visitor.Post(collection, "alpha", "Up", origin: null, fetchSite: fetchSite);
+
+        Assert.Equal(accepted ? HttpStatusCode.Redirect : HttpStatusCode.Forbidden, response.StatusCode);
+        Assert.Equal(accepted ? 1 : 0, (await Rows(collection, "alpha")).Count);
+    }
+
+    [Fact]
+    public async Task Refusal_never_echoes_the_origin_or_fetch_site_values()
+    {
+        const string canary = "https://CANARY-origin-5e1c.example";
+        var logs = new CapturingLoggerProvider();
+        var factory = _factory.WithWebHostBuilder(b => b.ConfigureServices(s => s.AddLogging(l => l.AddProvider(logs))));
+        var collection = NewCollection();
+        await AddSubject(collection, "alpha");
+        var visitor = NewVisitor(anonymous: true, factory);
+
+        using var byOrigin = await visitor.Post(collection, "alpha", "Up", origin: canary);
+        using var byFetchSite = await visitor.Post(collection, "alpha", "Up", origin: null, fetchSite: "CANARY-site-5e1c");
+
+        foreach (var response in new[] { byOrigin, byFetchSite })
+        {
+            Assert.Equal(HttpStatusCode.Forbidden, response.StatusCode);
+            var seen = await response.Content.ReadAsStringAsync()
+                + string.Join("\n", response.Headers.Select(h => h.Key + ":" + string.Join(",", h.Value)));
+            Assert.DoesNotContain("CANARY", seen, StringComparison.OrdinalIgnoreCase);
+        }
+
+        Assert.DoesNotContain(logs.Lines, line => line.Contains("CANARY", StringComparison.OrdinalIgnoreCase));
+    }
+
+    [Fact]
+    public async Task A_page_view_sets_no_cookie_at_all_and_a_cast_sets_only_the_device_cookie()
+    {
+        var collection = NewCollection();
+        await AddSubject(collection, "alpha");
+        var visitor = NewVisitor(anonymous: true);
+
+        using (var view = await visitor.Get(collection, "alpha"))
+        {
+            Assert.Equal(HttpStatusCode.OK, view.StatusCode);
+            Assert.False(view.Headers.Contains("Set-Cookie"));
+            var html = await view.Content.ReadAsStringAsync();
+            Assert.DoesNotContain("__RequestVerificationToken", html, StringComparison.Ordinal);
+        }
+
+        using var cast = await visitor.Post(collection, "alpha", "Up");
+        var cookies = cast.Headers.GetValues("Set-Cookie").ToArray();
+        Assert.Single(cookies);
+        Assert.StartsWith(CookieName + "=", cookies[0], StringComparison.Ordinal);
+
+        using var later = await visitor.Get(collection, "alpha");
+        Assert.False(later.Headers.Contains("Set-Cookie"));
+    }
+
+    [Fact]
+    public async Task A_request_that_selects_no_handler_is_a_client_error_and_never_a_500()
+    {
+        var collection = NewCollection();
+        await AddSubject(collection, "alpha");
+        var visitor = NewVisitor(anonymous: true);
+
+        using var noHandler = await visitor.Post(collection, "alpha", handler: null);
+        using var bogus = await visitor.Post(collection, "alpha", "CANARYQ9");
+        using var put = await visitor.Post(collection, "alpha", "Up", method: HttpMethod.Put);
+        using var delete = await visitor.Post(collection, "alpha", null, method: HttpMethod.Delete);
+        using var getBogus = await visitor.Send(new HttpRequestMessage(HttpMethod.Get, $"/mill/{collection}/alpha?handler=CANARYQ9"));
+        using var getUp = await visitor.Send(new HttpRequestMessage(HttpMethod.Get, $"/mill/{collection}/alpha?handler=Up"));
+
+        Assert.Equal(HttpStatusCode.BadRequest, noHandler.StatusCode);
+        Assert.Equal(HttpStatusCode.BadRequest, bogus.StatusCode);
+        Assert.Equal(HttpStatusCode.MethodNotAllowed, put.StatusCode);
+        Assert.Equal(HttpStatusCode.MethodNotAllowed, delete.StatusCode);
+        Assert.Equal(HttpStatusCode.BadRequest, getBogus.StatusCode);
+        Assert.Equal(HttpStatusCode.BadRequest, getUp.StatusCode);
+        foreach (var response in new[] { noHandler, bogus, put, delete, getBogus, getUp })
+        {
+            var status = (int)response.StatusCode;
+            Assert.InRange(status, 400, 499);
+            Assert.DoesNotContain("CANARYQ9", await response.Content.ReadAsStringAsync(), StringComparison.Ordinal);
+            Assert.False(response.Headers.Contains("Set-Cookie"));
+        }
+
+        Assert.Empty(await Rows(collection, "alpha"));
+    }
+
+    public enum Forgery
+    {
+        OneCharacterChanged,
+        BareDeviceId,
+        SameKeyRingOtherPurpose,
+        OtherKeyRingSamePurpose
+    }
+
+    [Theory]
+    [InlineData(Forgery.OneCharacterChanged)]
+    [InlineData(Forgery.BareDeviceId)]
+    [InlineData(Forgery.SameKeyRingOtherPurpose)]
+    [InlineData(Forgery.OtherKeyRingSamePurpose)]
+    public async Task Tampered_or_foreign_cookie_is_ignored_and_a_new_one_minted(Forgery kind)
+    {
+        var collection = NewCollection();
+        await AddSubject(collection, "alpha");
+        var victim = NewVisitor(anonymous: true);
+        using (await victim.Post(collection, "alpha", "Up"))
+        {
+        }
+
+        var genuine = victim.Jar[CookieName];
+        var victimRow = Assert.Single(await Rows(collection, "alpha"));
+        var deviceId = victimRow.VoterKey["device:".Length..];
+        var forged = Forge(kind, genuine, deviceId);
+        Assert.NotEqual(genuine, forged);
+        if (kind is not Forgery.BareDeviceId)
+        {
+            Assert.Equal(genuine.Length, forged.Length);
+            Assert.Matches("^[A-Za-z0-9_-]+$", forged);
+        }
+
+        var attacker = NewVisitor(anonymous: true);
+        attacker.Jar[CookieName] = forged;
+        using var cast = await attacker.Post(collection, "alpha", "Down");
+
+        Assert.Equal(HttpStatusCode.Redirect, cast.StatusCode);
+        Assert.NotNull(SetCookieHeader(cast, CookieName));
+        Assert.NotEqual(forged, attacker.Jar[CookieName]);
+        Assert.NotEqual(genuine, attacker.Jar[CookieName]);
+        var rows = await Rows(collection, "alpha");
+        Assert.Equal(2, rows.Count);
+        var victimNow = Assert.Single(rows, x => x.VoterKey == victimRow.VoterKey);
+        Assert.Equal(ConceptStance.Up, victimNow.Stance);
+        var attackerRow = Assert.Single(rows, x => x.VoterKey != victimRow.VoterKey);
+        Assert.Equal(ConceptStance.Down, attackerRow.Stance);
+        Assert.Equal(VoterClass.Anonymous, attackerRow.VoterClass);
+    }
+
+    [Fact]
+    public async Task A_forged_cookie_value_is_echoed_by_no_response_and_no_log_line()
+    {
+        const string canary = "CANARY-forged-voter-cookie-7f3a";
+        var logs = new CapturingLoggerProvider();
+        var factory = _factory.WithWebHostBuilder(b => b.ConfigureServices(s => s.AddLogging(l => l.AddProvider(logs))));
+        var collection = NewCollection();
+        await AddSubject(collection, "alpha");
+        var visitor = NewVisitor(anonymous: true, factory);
+        visitor.Jar[CookieName] = canary;
+
+        using var page = await visitor.Get(collection, "alpha");
+        using var cast = await visitor.Post(collection, "alpha", "Up");
+
+        foreach (var response in new[] { page, cast })
+        {
+            Assert.DoesNotContain(canary, await response.Content.ReadAsStringAsync(), StringComparison.Ordinal);
+            Assert.DoesNotContain(
+                canary,
+                string.Join("\n", response.Headers.Select(h => h.Key + ":" + string.Join(",", h.Value))),
+                StringComparison.Ordinal);
+        }
+
+        Assert.NotEmpty(logs.Lines);
+        Assert.DoesNotContain(logs.Lines, line => line.Contains(canary, StringComparison.Ordinal));
+    }
+
+    [Fact]
+    public async Task Unknown_or_retired_key_is_404()
+    {
+        var collection = NewCollection();
+        await AddSubject(collection, "alpha");
+        await AddSubject(collection, "gone");
+        await Retire(collection, "gone");
+        var visitor = NewVisitor(anonymous: true);
+
+        foreach (var (c, k) in new[] { (collection, "gone"), (collection, "never-registered"), (NewCollection(), "alpha") })
+        {
+            using var get = await visitor.Get(c, k);
+            Assert.Equal(HttpStatusCode.NotFound, get.StatusCode);
+            foreach (var handler in new[] { "Up", "Down", "Retract" })
+            {
+                using var post = await visitor.Post(c, k, handler);
+                Assert.Equal(HttpStatusCode.NotFound, post.StatusCode);
+                Assert.Null(SetCookieHeader(post, CookieName));
+            }
+        }
+
+        Assert.Empty(await Rows(collection, "gone"));
+        Assert.Empty(await Rows(collection, "alpha"));
+        Assert.False(visitor.Jar.ContainsKey(CookieName));
+    }
+
+    [Fact]
+    public async Task Page_shows_counts_by_class_and_no_voter_identity()
+    {
+        var collection = NewCollection();
+        await AddSubject(collection, "alpha");
+        var memberId = Guid.NewGuid();
+        var accountId = Guid.NewGuid();
+        await AddRows(collection, "alpha",
+            Row("device:canary-device-id-4b1d", VoterClass.Anonymous, ConceptStance.Up, null, "canarytag-aaaa"),
+            Row("device:canary-device-id-5c2e", VoterClass.Anonymous, ConceptStance.Down, null, "canarytag-bbbb"),
+            Row("account:" + memberId.ToString("N"), VoterClass.Member, ConceptStance.Up, memberId, "canarytag-cccc"),
+            Row("account:" + accountId.ToString("N"), VoterClass.Account, ConceptStance.Down, accountId, "canarytag-dddd"));
+        var visitor = NewVisitor(anonymous: true);
+        using (await visitor.Post(collection, "alpha", "Up"))
+        {
+        }
+
+        using var page = await visitor.Get(collection, "alpha");
+        var html = await page.Content.ReadAsStringAsync();
+
+        var (everyone, members) = Counts(html);
+        Assert.Equal("3 up, 2 down", everyone);
+        Assert.Equal("1 up, 0 down", members);
+        Assert.Contains("Your vote: up.", html, StringComparison.Ordinal);
+
+        var visitorRow = Assert.Single(await Rows(collection, "alpha"), x => x.UserAccountId is null && !x.VoterKey.Contains("canary"));
+        var forbidden = new List<string>
+        {
+            "device:", "account:", "canary-device-id", "canarytag", visitorRow.VoterKey,
+            visitor.Jar[CookieName],
+            memberId.ToString("N"), memberId.ToString("D"), accountId.ToString("N"), accountId.ToString("D")
+        };
+        foreach (var value in forbidden)
+        {
+            Assert.DoesNotContain(value, html, StringComparison.OrdinalIgnoreCase);
+        }
+
+        Assert.True(page.Headers.CacheControl is { NoStore: true } or { NoCache: true });
+
+        var signedIn = NewVisitor(anonymous: false);
+        using var signedInPage = await signedIn.Get(collection, "alpha");
+        var signedInHtml = await signedInPage.Content.ReadAsStringAsync();
+        using var signedInCast = await signedIn.Post(collection, "alpha", "Down");
+        var accountRow = Assert.Single(
+            await Rows(collection, "alpha"),
+            x => x.UserAccountId is { } id && id != memberId && id != accountId);
+        using var afterCast = await signedIn.Get(collection, "alpha");
+        var afterHtml = await afterCast.Content.ReadAsStringAsync();
+        Assert.Contains("Your vote: down.", afterHtml, StringComparison.Ordinal);
+        foreach (var text in new[] { signedInHtml, afterHtml })
+        {
+            Assert.DoesNotContain("account:", text, StringComparison.OrdinalIgnoreCase);
+            Assert.DoesNotContain(accountRow.UserAccountId!.Value.ToString("N"), text, StringComparison.OrdinalIgnoreCase);
+            Assert.DoesNotContain(accountRow.UserAccountId!.Value.ToString("D"), text, StringComparison.OrdinalIgnoreCase);
+        }
+    }
+
+    [Fact]
+    public async Task Cookie_notice_is_shown_to_anonymous_visitors_and_the_page_links_back_to_the_mill()
+    {
+        var collection = NewCollection();
+        await AddSubject(collection, "alpha");
+
+        using var anonymousPage = await NewVisitor(anonymous: true).Get(collection, "alpha");
+        var html = await anonymousPage.Content.ReadAsStringAsync();
+        using var signedInPage = await NewVisitor(anonymous: false).Get(collection, "alpha");
+        var signedInHtml = await signedInPage.Content.ReadAsStringAsync();
+
+        Assert.Contains("only purpose is to keep your one vote yours", html, StringComparison.Ordinal);
+        Assert.Contains("lasts a year", html, StringComparison.Ordinal);
+        Assert.Contains("carries nothing else", html, StringComparison.Ordinal);
+        Assert.DoesNotContain("only purpose is to keep your one vote yours", signedInHtml, StringComparison.Ordinal);
+        Assert.Contains(
+            "href=\"https://aetheria.gamecult.org/Game-Design/Concept-Mill#alpha\"",
+            html,
+            StringComparison.Ordinal);
+    }
+
+    [Fact]
+    public async Task Page_loads_no_script_and_posts_with_plain_forms()
+    {
+        var collection = NewCollection();
+        await AddSubject(collection, "alpha");
+
+        using var page = await NewVisitor(anonymous: true).Get(collection, "alpha");
+        var html = await page.Content.ReadAsStringAsync();
+        var main = html[html.IndexOf("<main", StringComparison.Ordinal)..html.IndexOf("</main>", StringComparison.Ordinal)];
+
+        Assert.DoesNotContain("<script", main, StringComparison.OrdinalIgnoreCase);
+        Assert.DoesNotContain("hx-post", main, StringComparison.OrdinalIgnoreCase);
+        Assert.DoesNotContain("hx-get", main, StringComparison.OrdinalIgnoreCase);
+        Assert.Contains("method=\"post\"", main, StringComparison.Ordinal);
+    }
+
+    private string Forge(Forgery kind, string genuine, string deviceId) => kind switch
+    {
+        Forgery.OneCharacterChanged => genuine[..(genuine.Length / 2)]
+            + (genuine[genuine.Length / 2] == 'A' ? 'B' : 'A')
+            + genuine[(genuine.Length / 2 + 1)..],
+        Forgery.BareDeviceId => deviceId,
+        Forgery.SameKeyRingOtherPurpose => _factory.Services.GetRequiredService<IDataProtectionProvider>()
+            .CreateProtector(Purpose + ".other").Protect(deviceId),
+        Forgery.OtherKeyRingSamePurpose => new EphemeralDataProtectionProvider()
+            .CreateProtector(Purpose).Protect(deviceId),
+        _ => throw new ArgumentOutOfRangeException(nameof(kind))
+    };
+
+    private static string NewCollection() => "c" + Guid.NewGuid().ToString("N");
+
+    private Visitor NewVisitor(bool anonymous, WebApplicationFactory<Program>? factory = null) =>
+        new((factory ?? _factory).CreateClient(new WebApplicationFactoryClientOptions
+        {
+            AllowAutoRedirect = false,
+            HandleCookies = false,
+            BaseAddress = new Uri("https://localhost")
+        }), anonymous);
+
+    private static string? SetCookieHeader(HttpResponseMessage response, string name) =>
+        response.Headers.TryGetValues("Set-Cookie", out var values)
+            ? values.FirstOrDefault(x => x.StartsWith(name + "=", StringComparison.Ordinal))
+            : null;
+
+    private static (string Everyone, string Members) Counts(string html)
+    {
+        var cells = DefinitionCell().Matches(html).Select(m => m.Groups[1].Value.Trim()).ToArray();
+        Assert.Equal(2, cells.Length);
+        return (cells[0], cells[1]);
+    }
+
+    [GeneratedRegex("<dd>(.*?)</dd>", RegexOptions.Singleline)]
+    private static partial Regex DefinitionCell();
+
+    private async Task AddSubject(string collection, string key)
+    {
+        using var scope = _factory.Services.CreateScope();
+        var db = scope.ServiceProvider.GetRequiredService<BifrostDbContext>();
+        db.ConceptSubjects.Add(new ConceptSubject
+        {
+            Collection = collection,
+            Key = key,
+            Title = key,
+            RegisteredAtUtc = DateTimeOffset.UtcNow
+        });
+        await db.SaveChangesAsync();
+    }
+
+    private async Task Retire(string collection, string key)
+    {
+        using var scope = _factory.Services.CreateScope();
+        var db = scope.ServiceProvider.GetRequiredService<BifrostDbContext>();
+        var subject = await db.ConceptSubjects.SingleAsync(x => x.Collection == collection && x.Key == key);
+        subject.RetiredAtUtc = DateTimeOffset.UtcNow;
+        await db.SaveChangesAsync();
+    }
+
+    private static ConceptAppraisal Row(string key, VoterClass voterClass, ConceptStance stance, Guid? accountId, string tag) =>
+        new()
+        {
+            VoterKey = key,
+            VoterClass = voterClass,
+            Stance = stance,
+            UserAccountId = accountId,
+            NetworkTag = tag,
+            CastAtUtc = DateTimeOffset.UtcNow
+        };
+
+    private async Task AddRows(string collection, string key, params ConceptAppraisal[] rows)
+    {
+        using var scope = _factory.Services.CreateScope();
+        var db = scope.ServiceProvider.GetRequiredService<BifrostDbContext>();
+        var subject = await db.ConceptSubjects.SingleAsync(x => x.Collection == collection && x.Key == key);
+        foreach (var row in rows)
+        {
+            row.SubjectId = subject.Id;
+            db.ConceptAppraisals.Add(row);
+        }
+
+        await db.SaveChangesAsync();
+    }
+
+    // A fresh DbContext per read: what a later request would see, not what this test's tracker remembers.
+    private async Task<List<ConceptAppraisal>> Rows(string collection, string key)
+    {
+        using var scope = _factory.Services.CreateScope();
+        var db = scope.ServiceProvider.GetRequiredService<BifrostDbContext>();
+        return await db.ConceptAppraisals.AsNoTracking()
+            .Where(x => x.Subject!.Collection == collection && x.Subject.Key == key)
+            .ToListAsync();
+    }
+
+    private sealed class Visitor(HttpClient client, bool anonymous)
+    {
+        public Dictionary<string, string> Jar { get; } = new(StringComparer.Ordinal);
+
+        public Task<HttpResponseMessage> Get(string collection, string key) =>
+            Send(new HttpRequestMessage(HttpMethod.Get, $"/mill/{collection}/{key}"));
+
+        // A cookieless POST as a browser form would send it: Origin the site's own by default, null to omit it.
+        public Task<HttpResponseMessage> Post(
+            string collection,
+            string key,
+            string? handler,
+            string? origin = SiteOrigin,
+            string? fetchSite = null,
+            HttpMethod? method = null)
+        {
+            var request = new HttpRequestMessage(
+                method ?? HttpMethod.Post,
+                $"/mill/{collection}/{key}" + (handler is null ? string.Empty : "?handler=" + handler))
+            {
+                Content = new FormUrlEncodedContent([])
+            };
+            if (origin is not null)
+            {
+                request.Headers.TryAddWithoutValidation("Origin", origin);
+            }
+
+            if (fetchSite is not null)
+            {
+                request.Headers.TryAddWithoutValidation("Sec-Fetch-Site", fetchSite);
+            }
+
+            return Send(request);
+        }
+
+        public async Task<HttpResponseMessage> Send(HttpRequestMessage request)
+        {
+            if (anonymous)
+            {
+                request.Headers.Add("X-Test-Anonymous", "true");
+            }
+
+            if (Jar.Count > 0)
+            {
+                request.Headers.TryAddWithoutValidation(
+                    "Cookie",
+                    string.Join("; ", Jar.Select(x => x.Key + "=" + x.Value)));
+            }
+
+            var response = await client.SendAsync(request);
+            if (response.Headers.TryGetValues("Set-Cookie", out var values))
+            {
+                foreach (var header in values)
+                {
+                    var pair = header.Split(';')[0];
+                    var split = pair.IndexOf('=');
+                    Jar[pair[..split]] = pair[(split + 1)..];
+                }
+            }
+
+            return response;
+        }
+    }
+}

tests/Bifrost.Web.Tests/ConceptVoteRateLimitTests.cs

@@ -0,0 +1,621 @@
+using System.Net;
+using Bifrost.Web.Data;
+using Bifrost.Web.Domain;
+using Bifrost.Web.Features.ConceptVotes;
+using Bifrost.Web.Tests.Support;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Mvc.Testing;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection.Extensions;
+using Microsoft.Extensions.Logging;
+
+namespace Bifrost.Web.Tests;
+
+// The vote budgets through the full pipeline: a loopback peer (the proxy) forwards the client address in
+// X-Forwarded-For, the clock is the test's own, and Cast is 3 per 10 minutes, Mint 2 per hour.
+public sealed class ConceptVoteRateLimitTests : IClassFixture<ConceptVoteRateLimitTests.LimitedFactory>
+{
+    private const string Site = "https://localhost";
+    private const string CookieName = "bifrost_voter";
+
+    private readonly LimitedFactory _factory;
+
+    public ConceptVoteRateLimitTests(LimitedFactory factory) => _factory = factory;
+
+    [Fact]
+    public async Task Burst_from_one_prefix_gets_429_while_another_prefix_is_unaffected()
+    {
+        var collection = await NewSubject();
+        var device = new Client(_factory, "203.0.113.10");
+        foreach (var handler in new[] { "Up", "Down", "Up" })
+        {
+            using var ok = await device.Post(collection, handler);
+            Assert.Equal(HttpStatusCode.Redirect, ok.StatusCode);
+        }
+
+        using var denied = await device.Post(collection, "Down");
+        Assert.Equal(HttpStatusCode.TooManyRequests, denied.StatusCode);
+
+        var other = new Client(_factory, "203.0.113.11");
+        using var unaffected = await other.Post(collection, "Up");
+        Assert.Equal(HttpStatusCode.Redirect, unaffected.StatusCode);
+    }
+
+    [Fact]
+    public async Task Retract_spends_the_cast_budget()
+    {
+        var collection = await NewSubject();
+        var device = new Client(_factory, "203.0.113.12");
+        await device.Post(collection, "Up");
+        await device.Post(collection, "Retract");
+        await device.Post(collection, "Retract");
+
+        using var denied = await device.Post(collection, "Retract");
+
+        Assert.Equal(HttpStatusCode.TooManyRequests, denied.StatusCode);
+    }
+
+    [Fact]
+    public async Task Addresses_in_one_ipv6_prefix_share_a_bucket_and_another_prefix_does_not()
+    {
+        var collection = await NewSubject();
+        var first = new Client(_factory, "2001:db8:1:100::1");
+        var sameBlock = new Client(_factory, "2001:db8:1:1ff::2");
+        await first.Post(collection, "Up");
+        await first.Post(collection, "Down");
+        using var third = await sameBlock.Post(collection, "Up");
+        Assert.Equal(HttpStatusCode.Redirect, third.StatusCode);
+
+        using var denied = await sameBlock.Post(collection, "Down");
+        Assert.Equal(HttpStatusCode.TooManyRequests, denied.StatusCode);
+
+        var elsewhere = new Client(_factory, "2001:db8:1:200::1");
+        using var unaffected = await elsewhere.Post(collection, "Up");
+        Assert.Equal(HttpStatusCode.Redirect, unaffected.StatusCode);
+    }
+
+    [Fact]
+    public async Task The_window_ends_exactly_at_its_length_and_retry_after_counts_down_to_it()
+    {
+        var collection = await NewSubject();
+        var device = new Client(_factory, "203.0.113.13");
+        for (var i = 0; i < 3; i++)
+        {
+            await device.Post(collection, "Up");
+        }
+
+        using (var first = await device.Post(collection, "Up"))
+        {
+            Assert.Equal(HttpStatusCode.TooManyRequests, first.StatusCode);
+            Assert.Equal("600", RetryAfter(first));
+        }
+
+        // 499.5 s remain: Retry-After rounds up, so a client told to wait never retries early.
+        _factory.Clock.Advance(TimeSpan.FromMilliseconds(100_500));
+        using (var later = await device.Post(collection, "Up"))
+        {
+            Assert.Equal(HttpStatusCode.TooManyRequests, later.StatusCode);
+            Assert.Equal("500", RetryAfter(later));
+        }
+
+        _factory.Clock.Advance(TimeSpan.FromMilliseconds(498_500));
+        using (var last = await device.Post(collection, "Up"))
+        {
+            Assert.Equal(HttpStatusCode.TooManyRequests, last.StatusCode);
+            Assert.Equal("1", RetryAfter(last));
+        }
+
+        _factory.Clock.Advance(TimeSpan.FromSeconds(1));
+        using var reopened = await device.Post(collection, "Up");
+        Assert.Equal(HttpStatusCode.Redirect, reopened.StatusCode);
+    }
+
+    [Fact]
+    public async Task Forged_forwarded_header_from_non_loopback_peer_does_not_move_the_bucket()
+    {
+        var collection = await NewSubject();
+        var device = new Client(_factory, "198.51.100.9") { Peer = "198.51.100.9" };
+        for (var i = 0; i < 3; i++)
+        {
+            using var ok = await device.Post(collection, "Up", forwardedFor: $"192.0.2.{i + 1}");
+            Assert.Equal(HttpStatusCode.Redirect, ok.StatusCode);
+        }
+
+        using var denied = await device.Post(collection, "Up", forwardedFor: "192.0.2.200");
+        Assert.Equal(HttpStatusCode.TooManyRequests, denied.StatusCode);
+    }
+
+    [Fact]
+    public async Task Signed_in_accounts_are_limited_per_account()
+    {
+        var collection = await NewSubject();
+        var alice = new Client(_factory, "203.0.113.20") { Account = ("7001", "alice-limits") };
+        var aliceElsewhere = new Client(_factory, "203.0.113.21") { Account = ("7001", "alice-limits") };
+        var bob = new Client(_factory, "203.0.113.20") { Account = ("7002", "bob-limits") };
+        var visitor = new Client(_factory, "203.0.113.20");
+
+        await alice.Post(collection, "Up");
+        await alice.Post(collection, "Down");
+        await aliceElsewhere.Post(collection, "Up");
+        using var denied = await aliceElsewhere.Post(collection, "Down");
+        Assert.Equal(HttpStatusCode.TooManyRequests, denied.StatusCode);
+
+        var aliceAgain = new Client(_factory, "203.0.113.22") { Account = ("7001", "alice-limits") };
+        using var sameAccountNewPrefix = await aliceAgain.Post(collection, "Down");
+        Assert.Equal(HttpStatusCode.TooManyRequests, sameAccountNewPrefix.StatusCode);
+
+        using var bobOk = await bob.Post(collection, "Up");
+        Assert.Equal(HttpStatusCode.Redirect, bobOk.StatusCode);
+        using var visitorOk = await visitor.Post(collection, "Up");
+        Assert.Equal(HttpStatusCode.Redirect, visitorOk.StatusCode);
+    }
+
+    [Fact]
+    public async Task Retract_by_a_signed_in_account_spends_the_account_budget_from_any_prefix()
+    {
+        var collection = await NewSubject();
+        var home = new Client(_factory, "203.0.113.60") { Account = ("7003", "carol-limits") };
+        var away = new Client(_factory, "203.0.113.61") { Account = ("7003", "carol-limits") };
+        var elsewhere = new Client(_factory, "203.0.113.62") { Account = ("7003", "carol-limits") };
+        await home.Post(collection, "Up");
+        await home.Post(collection, "Down");
+        using var third = await away.Post(collection, "Retract");
+        Assert.Equal(HttpStatusCode.Redirect, third.StatusCode);
+
+        using var denied = await elsewhere.Post(collection, "Retract");
+
+        Assert.Equal(HttpStatusCode.TooManyRequests, denied.StatusCode);
+    }
+
+    [Fact]
+    public async Task Mint_budget_is_spent_only_by_minting_casts()
+    {
+        var collection = await NewSubject();
+        const string prefix = "203.0.113.30";
+        var first = new Client(_factory, prefix);
+        using (var mint = await first.Post(collection, "Up"))
+        {
+            Assert.NotNull(SetCookie(mint));
+        }
+
+        // Recasts by the existing device spend cast permits only; they would exhaust a budget of 2 if they spent mint.
+        using (var recast = await first.Post(collection, "Down"))
+        {
+            Assert.Equal(HttpStatusCode.Redirect, recast.StatusCode);
+            Assert.Null(SetCookie(recast));
+        }
+
+        using (var recastAgain = await first.Post(collection, "Up"))
+        {
+            Assert.Equal(HttpStatusCode.Redirect, recastAgain.StatusCode);
+        }
+
+        _factory.Clock.Advance(TimeSpan.FromMinutes(10));
+        var second = new Client(_factory, prefix);
+        using (var secondMint = await second.Post(collection, "Up"))
+        {
+            Assert.Equal(HttpStatusCode.Redirect, secondMint.StatusCode);
+            Assert.NotNull(SetCookie(secondMint));
+        }
+
+        var rowsBefore = (await Rows(collection)).Count;
+        var third = new Client(_factory, prefix);
+        using var denied = await third.Post(collection, "Up");
+        Assert.Equal(HttpStatusCode.TooManyRequests, denied.StatusCode);
+        Assert.Null(SetCookie(denied));
+        Assert.Equal(rowsBefore, (await Rows(collection)).Count);
+        Assert.StartsWith("text/plain", denied.Content.Headers.ContentType?.MediaType);
+        var refusal = await denied.Content.ReadAsStringAsync();
+        Assert.Contains("sign in", refusal, StringComparison.OrdinalIgnoreCase);
+        Assert.DoesNotContain("203.0.113", refusal);
+
+        // An hour after the first mint the budget is whole again.
+        _factory.Clock.Advance(TimeSpan.FromMinutes(50));
+        using var reopened = await third.Post(collection, "Up");
+        Assert.Equal(HttpStatusCode.Redirect, reopened.StatusCode);
+    }
+
+    [Fact]
+    public async Task Anonymous_cast_under_the_limit_succeeds()
+    {
+        var collection = await NewSubject();
+        var visitor = new Client(_factory, "203.0.113.40");
+
+        using var response = await visitor.Post(collection, "Up");
+
+        Assert.Equal(HttpStatusCode.Redirect, response.StatusCode);
+        var row = Assert.Single(await Rows(collection));
+        Assert.Equal(VoterClass.Anonymous, row.VoterClass);
+        Assert.Equal(ConceptStance.Up, row.Stance);
+    }
+
+    [Fact]
+    public async Task Rejection_writes_nothing_says_when_to_retry_and_echoes_no_address()
+    {
+        var logs = new CapturingLoggerProvider();
+        var factory = _factory.WithWebHostBuilder(b => b.ConfigureServices(s => s.AddLogging(l => l.AddProvider(logs))));
+        var collection = await NewSubject();
+        var visitor = new Client(factory, "203.0.113.77");
+        for (var i = 0; i < 3; i++)
+        {
+            await visitor.Post(collection, i == 1 ? "Down" : "Up");
+        }
+
+        var before = Assert.Single(await Rows(collection));
+        using var denied = await visitor.Post(collection, "Down");
+
+        Assert.Equal(HttpStatusCode.TooManyRequests, denied.StatusCode);
+        Assert.NotNull(RetryAfter(denied));
+        Assert.Null(SetCookie(denied));
+        var after = Assert.Single(await Rows(collection));
+        Assert.Equal(before.Stance, after.Stance);
+        var body = await denied.Content.ReadAsStringAsync();
+        Assert.Contains("too fast", body);
+        var seen = body
+            + string.Join("\n", denied.Headers.Select(h => h.Key + ":" + string.Join(",", h.Value)));
+        Assert.DoesNotContain("203.0.113", seen);
+        Assert.DoesNotContain(logs.Lines, line => line.Contains("203.0.113", StringComparison.Ordinal));
+    }
+
+    [Fact]
+    public void Defaults_allow_thirty_new_devices_an_hour_per_address()
+    {
+        var defaults = new Bifrost.Web.Configuration.ConceptVoteOptions();
+
+        Assert.Equal(30, defaults.MintPermits);
+        Assert.Equal(TimeSpan.FromHours(1), defaults.MintWindow);
+        Assert.Equal(100_000, defaults.MaxTrackedKeys);
+    }
+
+    [Fact]
+    public void Every_table_holds_at_most_the_configured_keys_and_accounts_have_a_table_of_their_own()
+    {
+        var limits = new Bifrost.Web.Features.ConceptVotes.ConceptVoteRateLimits(
+            Microsoft.Extensions.Options.Options.Create(
+                new Bifrost.Web.Configuration.ConceptVoteOptions { MaxTrackedKeys = 1, CastPermits = 1, MintPermits = 1 }),
+            new TestClock());
+        var account = new VoterIdentity("account:test", VoterClass.Account, Guid.NewGuid());
+
+        Assert.Null(limits.DenyCast(IPAddress.Parse("198.51.100.1"), null));
+        Assert.True(limits.DenyCast(IPAddress.Parse("198.51.100.2"), null)!.Value.TableFull);
+        Assert.Null(limits.DenyCast(IPAddress.Parse("198.51.100.2"), account));
+        var otherAccount = new VoterIdentity("account:other", VoterClass.Account, Guid.NewGuid());
+        Assert.True(limits.DenyCast(IPAddress.Parse("198.51.100.2"), otherAccount)!.Value.TableFull);
+        Assert.Null(limits.DenyMint(IPAddress.Parse("198.51.100.1")));
+        Assert.True(limits.DenyMint(IPAddress.Parse("198.51.100.2"))!.Value.TableFull);
+    }
+
+    [Fact]
+    public async Task Filling_the_table_with_unspent_keys_locks_out_neither_a_fresh_visitor_nor_a_fresh_account()
+    {
+        var factory = Capped(4);
+        var collection = await NewSubject();
+        for (var i = 0; i < 4; i++)
+        {
+            using var filler = await new Client(factory, $"203.0.113.{80 + i}").Post(collection, "Up");
+            Assert.Equal(HttpStatusCode.Redirect, filler.StatusCode);
+        }
+
+        using var visitor = await new Client(factory, "203.0.113.90").Post(collection, "Up");
+        using var account = await new Client(factory, "203.0.113.91") { Account = ("7101", "fresh-account") }
+            .Post(collection, "Up");
+
+        Assert.Equal(HttpStatusCode.Redirect, visitor.StatusCode);
+        Assert.NotNull(SetCookie(visitor));
+        Assert.Equal(HttpStatusCode.Redirect, account.StatusCode);
+    }
+
+    [Fact]
+    public async Task A_spent_key_survives_eviction_pressure_and_stays_refused_while_rotating_callers_succeed()
+    {
+        var factory = Capped(4);
+        var collection = await NewSubject();
+        var spender = new Client(factory, "203.0.113.100");
+        for (var i = 0; i < 3; i++)
+        {
+            using var ok = await spender.Post(collection, "Up");
+            Assert.Equal(HttpStatusCode.Redirect, ok.StatusCode);
+        }
+
+        for (var i = 0; i < 12; i++)
+        {
+            using var rotating = await new Client(factory, $"203.0.114.{i + 1}").Post(collection, "Up");
+            Assert.Equal(HttpStatusCode.Redirect, rotating.StatusCode);
+        }
+
+        using var denied = await spender.Post(collection, "Up");
+
+        Assert.Equal(HttpStatusCode.TooManyRequests, denied.StatusCode);
+        Assert.Contains("too fast", await denied.Content.ReadAsStringAsync());
+    }
+
+    [Fact]
+    public async Task A_rotating_caller_wins_back_only_a_forgotten_keys_unspent_budget()
+    {
+        var factory = Capped(2);
+        var collection = await NewSubject();
+        var forgotten = new Client(factory, "203.0.113.110");
+        await forgotten.Post(collection, "Up");
+        await forgotten.Post(collection, "Up");
+        var recent = new Client(factory, "203.0.113.111");
+        await recent.Post(collection, "Up");
+        await new Client(factory, "203.0.113.112").Post(collection, "Up");
+
+        // forgotten was least recently used and had one permit left: it was evicted, so it has all three again, no more.
+        for (var i = 0; i < 3; i++)
+        {
+            using var ok = await forgotten.Post(collection, "Up");
+            Assert.Equal(HttpStatusCode.Redirect, ok.StatusCode);
+        }
+
+        using var denied = await forgotten.Post(collection, "Up");
+        Assert.Equal(HttpStatusCode.TooManyRequests, denied.StatusCode);
+    }
+
+    [Fact]
+    public async Task A_table_full_of_spent_keys_refuses_a_new_visitor_with_its_true_reason_and_leaves_accounts_alone()
+    {
+        var factory = Capped(4);
+        var collection = await NewSubject();
+        for (var i = 0; i < 4; i++)
+        {
+            var spender = new Client(factory, $"203.0.113.{120 + i}");
+            for (var cast = 0; cast < 3; cast++)
+            {
+                using var ok = await spender.Post(collection, "Up");
+                Assert.Equal(HttpStatusCode.Redirect, ok.StatusCode);
+            }
+        }
+
+        var rowsBefore = (await Rows(collection)).Count;
+        using var visitor = await new Client(factory, "203.0.113.130").Post(collection, "Up");
+        using var account = await new Client(factory, "203.0.113.131") { Account = ("7102", "spared-account") }
+            .Post(collection, "Up");
+
+        Assert.Equal(HttpStatusCode.TooManyRequests, visitor.StatusCode);
+        Assert.NotNull(RetryAfter(visitor));
+        Assert.Null(SetCookie(visitor));
+        var body = await visitor.Content.ReadAsStringAsync();
+        Assert.Contains("busy", body);
+        Assert.DoesNotContain("too fast", body);
+        Assert.Contains("sign in", body, StringComparison.OrdinalIgnoreCase);
+        Assert.DoesNotContain("203.0.113", body + string.Join(";", visitor.Headers.Select(h => string.Join(",", h.Value))));
+        Assert.Equal(HttpStatusCode.Redirect, account.StatusCode);
+        Assert.Equal(rowsBefore + 1, (await Rows(collection)).Count);
+    }
+
+    [Fact]
+    public async Task A_full_account_table_refuses_a_new_account_as_busy_without_offering_sign_in()
+    {
+        var factory = Capped(4);
+        var collection = await NewSubject();
+        for (var i = 0; i < 4; i++)
+        {
+            var spender = new Client(factory, $"203.0.113.{150 + i}") { Account = ($"72{i:00}", $"spent-account-{i}") };
+            for (var cast = 0; cast < 3; cast++)
+            {
+                using var ok = await spender.Post(collection, "Up");
+                Assert.Equal(HttpStatusCode.Redirect, ok.StatusCode);
+            }
+        }
+
+        using var fresh = await new Client(factory, "203.0.113.160") { Account = ("7299", "fresh-signed-in") }
+            .Post(collection, "Up");
+
+        Assert.Equal(HttpStatusCode.TooManyRequests, fresh.StatusCode);
+        var body = await fresh.Content.ReadAsStringAsync();
+        Assert.Contains("busy", body);
+        Assert.DoesNotContain("sign in", body, StringComparison.OrdinalIgnoreCase);
+    }
+
+    [Fact]
+    public async Task Posts_to_a_missing_subject_spend_no_budget_and_mint_no_device()
+    {
+        var collection = await NewSubject();
+        var sender = new Client(_factory, "203.0.113.140");
+        foreach (var handler in new[] { "Up", "Down", "Retract" })
+        {
+            for (var i = 0; i < 4; i++)
+            {
+                using var missing = await sender.Post("c" + Guid.NewGuid().ToString("N"), handler);
+                Assert.Equal(HttpStatusCode.NotFound, missing.StatusCode);
+                Assert.Null(SetCookie(missing));
+            }
+        }
+
+        for (var i = 0; i < 3; i++)
+        {
+            using var ok = await sender.Post(collection, "Up");
+            Assert.Equal(HttpStatusCode.Redirect, ok.StatusCode);
+        }
+
+        using var denied = await sender.Post(collection, "Up");
+        Assert.Equal(HttpStatusCode.TooManyRequests, denied.StatusCode);
+    }
+
+    [Fact]
+    public void A_request_with_no_client_address_shares_one_bucket_apart_from_every_address()
+    {
+        var limits = new Bifrost.Web.Features.ConceptVotes.ConceptVoteRateLimits(
+            Microsoft.Extensions.Options.Options.Create(new Bifrost.Web.Configuration.ConceptVoteOptions { CastPermits = 1 }),
+            new TestClock());
+
+        Assert.Null(limits.DenyCast(null, null));
+        Assert.NotNull(limits.DenyCast(null, null));
+        Assert.Null(limits.DenyCast(IPAddress.Parse("198.51.100.1"), null));
+    }
+
+    [Fact]
+    public async Task Reads_are_not_under_the_vote_budgets()
+    {
+        var collection = await NewSubject();
+        var visitor = new Client(_factory, "203.0.113.50");
+        for (var i = 0; i < 4; i++)
+        {
+            await visitor.Post(collection, "Up");
+        }
+
+        using var page = await visitor.Get($"/mill/{collection}/alpha");
+        using var export = await visitor.Get($"/public/concepts/{collection}/tallies");
+
+        Assert.Equal(HttpStatusCode.OK, page.StatusCode);
+        Assert.Equal(HttpStatusCode.OK, export.StatusCode);
+    }
+
+    private WebApplicationFactory<Program> Capped(int maxTrackedKeys) =>
+        _factory.WithWebHostBuilder(b => b.ConfigureAppConfiguration((_, configuration) =>
+            configuration.AddInMemoryCollection(new Dictionary<string, string?>
+            {
+                ["ConceptVotes:MaxTrackedKeys"] = maxTrackedKeys.ToString(System.Globalization.CultureInfo.InvariantCulture)
+            })));
+
+    private static string? RetryAfter(HttpResponseMessage response) =>
+        response.Headers.TryGetValues("Retry-After", out var values) ? values.Single() : null;
+
+    private static string? SetCookie(HttpResponseMessage response) =>
+        response.Headers.TryGetValues("Set-Cookie", out var values)
+            ? values.FirstOrDefault(x => x.StartsWith(CookieName + "=", StringComparison.Ordinal))
+            : null;
+
+    private async Task<string> NewSubject()
+    {
+        var collection = "c" + Guid.NewGuid().ToString("N");
+        using var scope = _factory.Services.CreateScope();
+        var db = scope.ServiceProvider.GetRequiredService<BifrostDbContext>();
+        db.ConceptSubjects.Add(new ConceptSubject
+        {
+            Collection = collection,
+            Key = "alpha",
+            Title = "alpha",
+            RegisteredAtUtc = DateTimeOffset.UtcNow
+        });
+        await db.SaveChangesAsync();
+        return collection;
+    }
+
+    private async Task<List<ConceptAppraisal>> Rows(string collection)
+    {
+        using var scope = _factory.Services.CreateScope();
+        var db = scope.ServiceProvider.GetRequiredService<BifrostDbContext>();
+        return await db.ConceptAppraisals.AsNoTracking()
+            .Where(x => x.Subject!.Collection == collection)
+            .ToListAsync();
+    }
+
+    // One browser: a client address that reaches the app through the proxy, a cookie jar, optionally an account.
+    private sealed class Client(WebApplicationFactory<Program> factory, string address)
+    {
+        private readonly HttpClient _http = factory.CreateClient(new WebApplicationFactoryClientOptions
+        {
+            AllowAutoRedirect = false,
+            HandleCookies = false,
+            BaseAddress = new Uri(Site)
+        });
+
+        private string? _cookie;
+
+        public string Peer { get; init; } = "127.0.0.1";
+
+        public (string Id, string Login)? Account { get; init; }
+
+        public Task<HttpResponseMessage> Post(string collection, string handler, string? forwardedFor = null) =>
+            Send(
+                new HttpRequestMessage(HttpMethod.Post, $"/mill/{collection}/alpha?handler={handler}")
+                {
+                    Content = new FormUrlEncodedContent([])
+                },
+                forwardedFor);
+
+        public Task<HttpResponseMessage> Get(string path) => Send(new HttpRequestMessage(HttpMethod.Get, path), null);
+
+        private async Task<HttpResponseMessage> Send(HttpRequestMessage request, string? forwardedFor)
+        {
+            request.Headers.TryAddWithoutValidation("Origin", Site);
+            request.Headers.TryAddWithoutValidation("X-Forwarded-For", forwardedFor ?? address);
+            request.Headers.TryAddWithoutValidation("X-Test-Peer", Peer);
+            if (Account is { } account)
+            {
+                request.Headers.TryAddWithoutValidation("X-Test-GitHub-Id", account.Id);
+                request.Headers.TryAddWithoutValidation("X-Test-GitHub-Login", account.Login);
+            }
+            else
+            {
+                request.Headers.TryAddWithoutValidation("X-Test-Anonymous", "true");
+            }
+
+            if (_cookie is not null)
+            {
+                request.Headers.TryAddWithoutValidation("Cookie", _cookie);
+            }
+
+            var response = await _http.SendAsync(request);
+            if (SetCookie(response) is { } set)
+            {
+                _cookie = set.Split(';')[0];
+            }
+
+            return response;
+        }
+    }
+
+    public sealed class LimitedFactory : TestWebApplicationFactory
+    {
+        public TestClock Clock { get; } = new();
+
+        protected override void ConfigureWebHost(IWebHostBuilder builder)
+        {
+            base.ConfigureWebHost(builder);
+            builder.ConfigureAppConfiguration((_, configuration) =>
+                configuration.AddInMemoryCollection(new Dictionary<string, string?>
+                {
+                    ["ConceptVotes:CastPermits"] = "3",
+                    ["ConceptVotes:CastWindow"] = "00:10:00",
+                    ["ConceptVotes:MintPermits"] = "2",
+                    ["ConceptVotes:MintWindow"] = "01:00:00",
+                    ["ConceptVotes:NetworkTagSecret"] = "rate-limit-test-tag-secret-0123456789"
+                }));
+            builder.ConfigureServices(services =>
+            {
+                services.RemoveAll<TimeProvider>();
+                services.AddSingleton<TimeProvider>(Clock);
+                services.AddTransient<IStartupFilter, PeerFilter>();
+            });
+        }
+    }
+
+    public sealed class TestClock : TimeProvider
+    {
+        private DateTimeOffset _now = DateTimeOffset.UtcNow;
+        private long _ticks = 5_000_000;
+
+        public override long TimestampFrequency => TimeSpan.TicksPerSecond;
+
+        public override DateTimeOffset GetUtcNow() => _now;
+
+        public override long GetTimestamp() => _ticks;
+
+        public void Advance(TimeSpan by)
+        {
+            _now += by;
+            _ticks += by.Ticks;
+        }
+    }
+
+    // The proxy's connection: TestServer has no socket, so the peer address is set ahead of the app pipeline.
+    private sealed class PeerFilter : IStartupFilter
+    {
+        public Action<IApplicationBuilder> Configure(Action<IApplicationBuilder> next) => app =>
+        {
+            app.Use((context, nextMiddleware) =>
+            {
+                context.Connection.RemoteIpAddress =
+                    IPAddress.Parse(context.Request.Headers["X-Test-Peer"].FirstOrDefault() ?? "127.0.0.1");
+                return nextMiddleware(context);
+            });
+            next(app);
+        };
+    }
+}

tests/Bifrost.Web.Tests/FixedWindowBudgetTests.cs

@@ -0,0 +1,299 @@
+using Bifrost.Web.Features.Shared;
+
+namespace Bifrost.Web.Tests;
+
+public sealed class FixedWindowBudgetTests
+{
+    private static readonly TimeSpan Window = TimeSpan.FromSeconds(60);
+    private const int Cap = 1000;
+
+    [Fact]
+    public void Permits_are_spent_per_key_and_the_next_is_denied_with_the_time_left()
+    {
+        var clock = new Clock();
+        var budget = new FixedWindowBudget(2, Window, Cap, clock);
+
+        Assert.True(Try(budget, "a", out _));
+        clock.Advance(TimeSpan.FromSeconds(10));
+        Assert.True(Try(budget, "a", out _));
+        Assert.False(Try(budget, "a", out var wait));
+
+        Assert.Equal(TimeSpan.FromSeconds(50), wait);
+        Assert.True(Try(budget, "b", out _));
+    }
+
+    [Fact]
+    public void A_window_opens_at_its_first_permit_and_closes_exactly_one_window_later()
+    {
+        var clock = new Clock();
+        var budget = new FixedWindowBudget(1, Window, Cap, clock);
+        Assert.True(Try(budget, "a", out _));
+
+        clock.Advance(Window - TimeSpan.FromTicks(1));
+        Assert.False(Try(budget, "a", out var wait));
+        Assert.Equal(TimeSpan.FromTicks(1), wait);
+
+        clock.Advance(TimeSpan.FromTicks(1));
+        Assert.True(Try(budget, "a", out _));
+        Assert.False(Try(budget, "a", out wait));
+        Assert.Equal(Window, wait);
+    }
+
+    [Fact]
+    public void A_denied_attempt_does_not_extend_the_window()
+    {
+        var clock = new Clock();
+        var budget = new FixedWindowBudget(1, Window, Cap, clock);
+        Try(budget, "a", out _);
+        for (var i = 0; i < 5; i++)
+        {
+            clock.Advance(TimeSpan.FromSeconds(10));
+            Assert.False(Try(budget, "a", out _));
+        }
+
+        clock.Advance(TimeSpan.FromSeconds(10));
+        Assert.True(Try(budget, "a", out _));
+    }
+
+    [Fact]
+    public void An_expired_window_is_dropped_and_a_live_one_keeps_counting_to_its_exact_end()
+    {
+        var clock = new Clock();
+        var budget = new FixedWindowBudget(1, Window, Cap, clock);
+        Try(budget, "a", out _);
+        clock.Advance(TimeSpan.FromSeconds(30));
+        Try(budget, "b", out _);
+        clock.Advance(TimeSpan.FromSeconds(30));
+
+        // At 60 s a has ended and b has 30 s left.
+        Try(budget, "c", out _);
+        Assert.Equal(2, budget.TrackedKeys);
+        Assert.False(Try(budget, "b", out var wait));
+        Assert.Equal(TimeSpan.FromSeconds(30), wait);
+
+        clock.Advance(TimeSpan.FromSeconds(30) - TimeSpan.FromTicks(1));
+        Assert.False(Try(budget, "b", out _));
+        clock.Advance(TimeSpan.FromTicks(1));
+        Assert.True(Try(budget, "b", out _));
+    }
+
+    [Fact]
+    public void A_wall_clock_step_back_does_not_extend_a_window_or_its_retry_after()
+    {
+        var clock = new Clock();
+        var budget = new FixedWindowBudget(1, Window, Cap, clock);
+        Try(budget, "a", out _);
+        clock.Advance(TimeSpan.FromSeconds(10));
+        clock.StepWall(-TimeSpan.FromHours(1));
+
+        Assert.False(Try(budget, "a", out var wait));
+        Assert.Equal(TimeSpan.FromSeconds(50), wait);
+        clock.Advance(TimeSpan.FromSeconds(50));
+        Assert.True(Try(budget, "a", out _));
+        Assert.Equal(1, budget.TrackedKeys);
+    }
+
+    [Fact]
+    public void A_wall_clock_step_forward_does_not_reset_a_window()
+    {
+        var clock = new Clock();
+        var budget = new FixedWindowBudget(1, Window, Cap, clock);
+        Try(budget, "a", out _);
+        clock.StepWall(TimeSpan.FromHours(1));
+
+        Assert.False(Try(budget, "a", out var wait));
+        Assert.Equal(Window, wait);
+    }
+
+    [Fact]
+    public void A_new_key_at_the_cap_evicts_the_least_recently_used_key_with_permits_left()
+    {
+        var clock = new Clock();
+        var budget = new FixedWindowBudget(3, Window, 2, clock);
+        Assert.True(Try(budget, "a", out _));
+        clock.Advance(TimeSpan.FromSeconds(1));
+        Assert.True(Try(budget, "b", out _));
+        clock.Advance(TimeSpan.FromSeconds(1));
+        Assert.True(Try(budget, "a", out _));
+
+        // b was used least recently, though a began first: c takes b's place and a keeps its count.
+        Assert.True(Try(budget, "c", out _));
+        Assert.Equal(2, budget.TrackedKeys);
+        Assert.True(Try(budget, "a", out _));
+        Assert.False(Try(budget, "a", out _));
+    }
+
+    [Fact]
+    public void A_forgotten_key_regains_only_what_it_had_not_spent_and_a_spent_key_regains_nothing()
+    {
+        var clock = new Clock();
+        var budget = new FixedWindowBudget(2, Window, 2, clock);
+        Assert.True(Try(budget, "spent", out _));
+        Assert.True(Try(budget, "spent", out _));
+        Assert.True(Try(budget, "partial", out _));
+        clock.Advance(TimeSpan.FromSeconds(10));
+
+        // Rotating callers evict partial, never spent.
+        for (var i = 0; i < 10; i++)
+        {
+            Assert.True(Try(budget, "rot" + i, out _));
+        }
+
+        Assert.False(Try(budget, "spent", out var wait));
+        Assert.Equal(TimeSpan.FromSeconds(50), wait);
+        Assert.Equal(2, budget.TrackedKeys);
+
+        // partial came back whole (2 permits), which is all a rotating caller can win: its own forgotten budget.
+        Assert.True(Try(budget, "partial", out _));
+    }
+
+    [Fact]
+    public void A_key_that_spends_its_last_permit_leaves_the_evictable_set()
+    {
+        var clock = new Clock();
+        var budget = new FixedWindowBudget(2, Window, 2, clock);
+        Assert.True(Try(budget, "a", out _));
+        Assert.True(Try(budget, "a", out _));
+        Assert.True(Try(budget, "b", out _));
+
+        // a is spent and b is not: the newcomer evicts b although a was used less recently.
+        Assert.True(Try(budget, "c", out _));
+        Assert.False(Try(budget, "a", out _));
+        Assert.True(Try(budget, "b", out _));
+    }
+
+    [Fact]
+    public void A_table_full_of_spent_keys_refuses_a_new_key_as_table_full_with_the_wait_for_the_oldest_window()
+    {
+        var clock = new Clock();
+        var budget = new FixedWindowBudget(1, Window, 2, clock);
+        Assert.True(Try(budget, "a", out _));
+        clock.Advance(TimeSpan.FromSeconds(20));
+        Assert.True(Try(budget, "b", out _));
+        clock.Advance(TimeSpan.FromSeconds(10));
+
+        var denial = budget.Spend("c");
+        Assert.Equal(new BudgetDenial(TimeSpan.FromSeconds(30), true), denial);
+        Assert.Equal(new BudgetDenial(TimeSpan.FromSeconds(30), false), budget.Spend("a"));
+        Assert.Equal(2, budget.TrackedKeys);
+
+        clock.Advance(TimeSpan.FromSeconds(30));
+        Assert.True(Try(budget, "c", out _));
+        Assert.Equal(2, budget.TrackedKeys);
+        Assert.False(Try(budget, "b", out var wait));
+        Assert.Equal(TimeSpan.FromSeconds(20), wait);
+    }
+
+    [Fact]
+    public void An_evicted_key_leaves_the_expiry_list_so_its_old_window_end_cannot_remove_the_key_that_took_its_name()
+    {
+        var clock = new Clock();
+        var budget = new FixedWindowBudget(2, Window, 2, clock);
+        Try(budget, "a", out _);
+        clock.Advance(TimeSpan.FromSeconds(1));
+        Try(budget, "b", out _);
+        clock.Advance(TimeSpan.FromSeconds(1));
+        Try(budget, "c", out _);
+        clock.Advance(TimeSpan.FromSeconds(1));
+        Try(budget, "a", out _);
+
+        // The first a began at 0 and ended at 60; the a that returned at 3 is still inside its window.
+        clock.Advance(TimeSpan.FromSeconds(57));
+        Try(budget, "c", out _);
+
+        Assert.Equal(2, budget.TrackedKeys);
+    }
+
+    [Fact]
+    public void A_held_key_under_its_permits_is_served_even_when_the_table_is_full()
+    {
+        var clock = new Clock();
+        var budget = new FixedWindowBudget(2, Window, 1, clock);
+        Assert.True(Try(budget, "a", out _));
+
+        Assert.True(Try(budget, "a", out _));
+        Assert.False(Try(budget, "a", out _));
+    }
+
+    [Fact]
+    public void Eviction_work_does_not_scan_the_table()
+    {
+        var clock = new Clock();
+        var budget = new FixedWindowBudget(2, Window, 50_000, clock);
+        for (var i = 0; i < 50_000; i++)
+        {
+            budget.Spend("k" + i);
+        }
+
+        var started = System.Diagnostics.Stopwatch.StartNew();
+        for (var i = 0; i < 200_000; i++)
+        {
+            budget.Spend("n" + i);
+        }
+
+        Assert.Equal(50_000, budget.TrackedKeys);
+        Assert.True(started.Elapsed < TimeSpan.FromSeconds(10), $"200000 evicting inserts took {started.Elapsed}");
+    }
+
+    [Fact]
+    public void Expired_windows_are_dropped_so_the_table_does_not_grow_with_every_key_ever_seen()
+    {
+        var clock = new Clock();
+        var budget = new FixedWindowBudget(1, Window, Cap, clock);
+        for (var i = 0; i < 100; i++)
+        {
+            Try(budget, "k" + i, out _);
+        }
+
+        Assert.Equal(100, budget.TrackedKeys);
+        clock.Advance(Window);
+        Try(budget, "fresh", out _);
+
+        Assert.Equal(1, budget.TrackedKeys);
+    }
+
+    [Theory]
+    [InlineData(0, 60)]
+    [InlineData(-1, 60)]
+    [InlineData(1, 0)]
+    [InlineData(1, -5)]
+    public void A_budget_that_cannot_be_enforced_is_refused(int permits, int seconds)
+    {
+        Assert.ThrowsAny<ArgumentException>(
+            () => new FixedWindowBudget(permits, TimeSpan.FromSeconds(seconds), Cap, new Clock()));
+    }
+
+    [Fact]
+    public void A_cap_below_one_is_refused()
+    {
+        Assert.Throws<ArgumentOutOfRangeException>(() => new FixedWindowBudget(1, Window, 0, new Clock()));
+    }
+
+    private static bool Try(FixedWindowBudget budget, string key, out TimeSpan wait)
+    {
+        var denial = budget.Spend(key);
+        wait = denial?.RetryAfter ?? TimeSpan.Zero;
+        return denial is null;
+    }
+
+    // Time advances monotonic and wall together; StepWall moves only the wall clock, as an NTP step would.
+    private sealed class Clock : TimeProvider
+    {
+        private DateTimeOffset _wall = new(2026, 10, 11, 12, 0, 0, TimeSpan.Zero);
+        private long _ticks = 5_000_000;
+
+        public override long TimestampFrequency => TimeSpan.TicksPerSecond;
+
+        public override DateTimeOffset GetUtcNow() => _wall;
+
+        public override long GetTimestamp() => _ticks;
+
+        public void Advance(TimeSpan by)
+        {
+            _wall += by;
+            _ticks += by.Ticks;
+        }
+
+        public void StepWall(TimeSpan by) => _wall += by;
+    }
+}

tests/Bifrost.Web.Tests/Fixtures/complete-page-harness.cjs

@@ -0,0 +1,64 @@
+// Runs the complete page's real inline script against a simulated browser, once per scenario, and prints
+// what it did as JSON: the ordered events, and the address and form values at the moment of the submit.
+// Usage: node complete-page-harness.cjs <page.html>
+const fs = require("fs");
+const vm = require("vm");
+
+const html = fs.readFileSync(process.argv[2], "utf8");
+const scripts = [...html.matchAll(/<script>([\s\S]*?)<\/script>/g)];
+if (scripts.length !== 1) {
+  throw new Error(`expected exactly one inline script, found ${scripts.length}`);
+}
+const script = scripts[0][1];
+
+function run(name, search, hash) {
+  const events = [];
+  let submit = null;
+  const location = {
+    pathname: "/auth/heimdall/complete",
+    search,
+    hash,
+    get href() {
+      return this.pathname + this.search + this.hash;
+    },
+    replace(url) {
+      events.push(`replace:${url}`);
+    },
+  };
+  const history = {
+    replaceState(_state, _title, url) {
+      events.push(`replaceState:${url}`);
+      const next = new URL(url, "https://bifrost.test" + location.href);
+      location.pathname = next.pathname;
+      location.search = next.search;
+      location.hash = next.hash;
+    },
+  };
+  const form = {
+    elements: { attempt: { value: "" }, code: { value: "" } },
+    submit() {
+      events.push("submit");
+      submit = {
+        attempt: form.elements.attempt.value,
+        code: form.elements.code.value,
+        href: location.href,
+        hash: location.hash,
+      };
+    },
+  };
+  const document = { getElementById: (id) => (id === "complete" ? form : null) };
+  vm.runInNewContext(script, { URLSearchParams, location, history, document });
+  return { name, events, submit };
+}
+
+const complete = "&heimdall_completion_code=CODE123";
+console.log(
+  JSON.stringify([
+    run("success", "?attempt=NONCE", "#heimdall_status=success" + complete),
+    run("success-with-decoy-query-code", "?attempt=NONCE&heimdall_completion_code=QCODE", "#heimdall_status=success" + complete),
+    run("error-status-with-code", "?attempt=NONCE", "#heimdall_status=error&heimdall_error=denied" + complete),
+    run("no-code", "?attempt=NONCE", "#heimdall_status=success"),
+    run("no-attempt", "", "#heimdall_status=success" + complete),
+    run("code-in-query-only", "?attempt=NONCE&heimdall_completion_code=QCODE", ""),
+  ]),
+);

tests/Bifrost.Web.Tests/Fixtures/mill-three-ships.json

@@ -0,0 +1,9 @@
+{
+  "sections": [],
+  "votes": {},
+  "ships": [
+    { "id": "bison", "name": "Bison", "code": "AU", "role": "Swarm escort" },
+    { "id": "ibis-mk2", "name": "Ibis Mk II", "code": "AU" },
+    { "id": "kestrel", "name": "Kestrel" }
+  ]
+}

tests/Bifrost.Web.Tests/HeimdallCompletePageScriptTests.cs

@@ -0,0 +1,107 @@
+using System.ComponentModel;
+using System.Diagnostics;
+using System.Text.Json;
+using Bifrost.Web.Tests.Support;
+
+namespace Bifrost.Web.Tests;
+
+/// <summary>
+/// Runs the complete page's inline script, as the server serves it, under Node against a simulated browser
+/// (Fixtures/complete-page-harness.cjs). Node is required: a missing Node fails these tests, it does not skip them.
+/// </summary>
+public sealed class HeimdallCompletePageScriptTests
+{
+    private const string ErrorTarget = "replace:/?auth=heimdall-error";
+
+    private sealed record Run(string Name, string[] Events, Submit? Submit);
+
+    private sealed record Submit(string Attempt, string Code, string Href, string Hash);
+
+    private static async Task<Dictionary<string, Run>> RunScenariosAsync()
+    {
+        using var host = new HeimdallHost();
+        using var client = host.NewClient();
+        var page = await client.GetStringAsync("/auth/heimdall/complete");
+        var pagePath = Path.Combine(Path.GetTempPath(), $"bifrost-complete-{Guid.NewGuid():N}.html");
+        await File.WriteAllTextAsync(pagePath, page);
+        try
+        {
+            var harness = Path.Combine(AppContext.BaseDirectory, "Fixtures", "complete-page-harness.cjs");
+            var start = new ProcessStartInfo("node") { RedirectStandardOutput = true, RedirectStandardError = true };
+            start.ArgumentList.Add(harness);
+            start.ArgumentList.Add(pagePath);
+            Process process;
+            try
+            {
+                process = Process.Start(start)!;
+            }
+            catch (Win32Exception error)
+            {
+                throw new InvalidOperationException("Node must be on PATH to run the complete page's script: " + error.Message, error);
+            }
+
+            using (process)
+            {
+                var output = process.StandardOutput.ReadToEndAsync();
+                var errors = process.StandardError.ReadToEndAsync();
+                using var timeout = new CancellationTokenSource(TimeSpan.FromSeconds(60));
+                await process.WaitForExitAsync(timeout.Token);
+                Assert.True(process.ExitCode == 0, await errors);
+                var runs = JsonSerializer.Deserialize<Run[]>(await output, new JsonSerializerOptions(JsonSerializerDefaults.Web))!;
+                return runs.ToDictionary(x => x.Name);
+            }
+        }
+        finally
+        {
+            File.Delete(pagePath);
+        }
+    }
+
+    [Fact]
+    public async Task The_fragment_is_dropped_from_the_address_before_the_code_is_posted()
+    {
+        var runs = await RunScenariosAsync();
+
+        foreach (var name in new[] { "success", "success-with-decoy-query-code" })
+        {
+            var run = runs[name];
+            Assert.Equal(2, run.Events.Length);
+            Assert.StartsWith("replaceState:/auth/heimdall/complete?attempt=NONCE", run.Events[0]);
+            Assert.DoesNotContain("#", run.Events[0]);
+            Assert.DoesNotContain("CODE123", run.Events[0]);
+            Assert.Equal("submit", run.Events[1]);
+            Assert.Equal("", run.Submit!.Hash);
+            Assert.DoesNotContain("CODE123", run.Submit.Href);
+            Assert.DoesNotContain("#", run.Submit.Href);
+        }
+    }
+
+    [Fact]
+    public async Task The_code_is_read_only_from_the_fragment()
+    {
+        var runs = await RunScenariosAsync();
+
+        Assert.Equal(new Submit("NONCE", "CODE123", "/auth/heimdall/complete?attempt=NONCE", ""), runs["success"].Submit);
+        Assert.Equal("CODE123", runs["success-with-decoy-query-code"].Submit!.Code);
+
+        var queryOnly = runs["code-in-query-only"];
+        Assert.Null(queryOnly.Submit);
+        Assert.DoesNotContain("submit", queryOnly.Events);
+        Assert.Equal(ErrorTarget, queryOnly.Events[^1]);
+    }
+
+    [Theory]
+    [InlineData("error-status-with-code")]
+    [InlineData("no-code")]
+    [InlineData("no-attempt")]
+    public async Task A_failed_or_incomplete_handoff_never_submits_and_leaves_through_the_error_redirect(string scenario)
+    {
+        var run = (await RunScenariosAsync())[scenario];
+
+        Assert.Null(run.Submit);
+        Assert.DoesNotContain("submit", run.Events);
+        Assert.Equal(ErrorTarget, run.Events[^1]);
+        Assert.Contains(run.Events, x => x.StartsWith("replaceState:", StringComparison.Ordinal) && !x.Contains('#'));
+        Assert.DoesNotContain("CODE123", string.Join("\n", run.Events));
+    }
+}

tests/Bifrost.Web.Tests/HostTrustTests.cs

@@ -0,0 +1,375 @@
+using System.Net;
+using Bifrost.Web.Configuration;
+using Bifrost.Web.Features.Shared;
+using Bifrost.Web.Tests.Support;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.DataProtection;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.HttpOverrides;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging.Abstractions;
+using Microsoft.Extensions.Options;
+
+namespace Bifrost.Web.Tests;
+
+public sealed class HostTrustTests : IClassFixture<TestWebApplicationFactory>
+{
+    private readonly TestWebApplicationFactory _factory;
+
+    public HostTrustTests(TestWebApplicationFactory factory)
+    {
+        _factory = factory;
+    }
+
+    [Theory]
+    [InlineData("127.0.0.1")]
+    [InlineData("::1")]
+    [InlineData("::ffff:127.0.0.1")]
+    public async Task Forwarded_for_from_loopback_peer_becomes_remote_ip(string peer)
+    {
+        var context = await RunForwardedHeaders(peer, "203.0.113.7", "https");
+
+        Assert.Equal(IPAddress.Parse("203.0.113.7"), context.Connection.RemoteIpAddress);
+        Assert.Equal("https", context.Request.Scheme);
+    }
+
+    [Fact]
+    public async Task Forwarded_for_from_non_loopback_peer_is_ignored()
+    {
+        var context = await RunForwardedHeaders("198.51.100.9", "203.0.113.7", "https");
+
+        Assert.Equal(IPAddress.Parse("198.51.100.9"), context.Connection.RemoteIpAddress);
+        Assert.Equal("http", context.Request.Scheme);
+    }
+
+    [Fact]
+    public async Task Only_the_rightmost_forwarded_entry_is_used()
+    {
+        var context = await RunForwardedHeaders("127.0.0.1", "6.6.6.6, 203.0.113.7", null);
+
+        Assert.Equal(IPAddress.Parse("203.0.113.7"), context.Connection.RemoteIpAddress);
+    }
+
+    [Fact]
+    public async Task A_loopback_forwarded_entry_does_not_chain_to_earlier_entries()
+    {
+        var context = await RunForwardedHeaders("127.0.0.1", "6.6.6.6, 127.0.0.1", null);
+
+        Assert.Equal(IPAddress.Loopback, context.Connection.RemoteIpAddress);
+    }
+
+    [Fact]
+    public async Task Only_the_exact_loopback_addresses_are_trusted_not_the_loopback_range()
+    {
+        var context = await RunForwardedHeaders("127.0.0.2", "203.0.113.7", null);
+
+        Assert.Equal(IPAddress.Parse("127.0.0.2"), context.Connection.RemoteIpAddress);
+    }
+
+    [Fact]
+    public void Payload_protected_under_one_content_root_unprotects_under_another()
+    {
+        var root = NewRoot();
+        var keys = Path.Combine(root, "keys");
+        try
+        {
+            using var hostA = WithContentRoot(MakeRelease(root, "release-a"), keys);
+            using var hostB = WithContentRoot(MakeRelease(root, "release-b"), keys);
+
+            var sealedPayload = Protect(hostA, "payload");
+
+            Assert.Equal("payload", Unprotect(hostB, sealedPayload));
+            Assert.NotEmpty(Directory.GetFiles(keys, "key-*.xml"));
+        }
+        finally
+        {
+            Directory.Delete(root, recursive: true);
+        }
+    }
+
+    [Fact]
+    public void A_different_keys_path_does_not_unprotect_the_payload()
+    {
+        var root = NewRoot();
+        try
+        {
+            using var hostA = WithContentRoot(MakeRelease(root, "release-a"), Path.Combine(root, "keys-a"));
+            using var hostB = WithContentRoot(MakeRelease(root, "release-b"), Path.Combine(root, "keys-b"));
+
+            var sealedPayload = Protect(hostA, "payload");
+
+            Assert.ThrowsAny<System.Security.Cryptography.CryptographicException>(
+                () => Unprotect(hostB, sealedPayload));
+        }
+        finally
+        {
+            Directory.Delete(root, recursive: true);
+        }
+    }
+
+    [Fact]
+    public void The_container_image_does_not_set_the_forwarded_headers_switch()
+    {
+        var directory = new DirectoryInfo(AppContext.BaseDirectory);
+        while (directory is not null && !File.Exists(Path.Combine(directory.FullName, "Dockerfile")))
+        {
+            directory = directory.Parent;
+        }
+
+        Assert.NotNull(directory);
+        Assert.DoesNotContain(
+            "ASPNETCORE_FORWARDEDHEADERS_ENABLED",
+            File.ReadAllText(Path.Combine(directory!.FullName, "Dockerfile")));
+    }
+
+    [Fact]
+    public void Production_without_keys_path_fails_startup_validation()
+    {
+        var withoutKey = Assert.Throws<InvalidOperationException>(() => Validate(keysPath: null));
+        Assert.Contains("DataProtection:KeysPath", withoutKey.Message);
+
+        Validate(keysPath: "/not/echoed/anywhere");
+    }
+
+    [Fact]
+    public void Startup_refusal_names_the_key_and_never_echoes_configured_values()
+    {
+        var canary = "canary-secret-4f1e";
+        var refusal = Assert.Throws<InvalidOperationException>(
+            () => Validate(keysPath: null, connectionString: canary));
+
+        Assert.Contains("DataProtection:KeysPath", refusal.Message);
+        Assert.DoesNotContain(canary, refusal.Message);
+    }
+
+    [Fact]
+    public void Production_without_network_tag_secret_fails_and_never_echoes_values()
+    {
+        var canary = "canary-keys-path-77aa";
+        var refusal = Assert.Throws<InvalidOperationException>(
+            () => Validate(keysPath: canary, tagSecret: " "));
+
+        Assert.Contains("ConceptVotes:NetworkTagSecret", refusal.Message);
+        Assert.DoesNotContain(canary, refusal.Message);
+        Assert.DoesNotContain("DataProtection:KeysPath", refusal.Message);
+    }
+
+    [Theory]
+    [InlineData("short-secret")]
+    [InlineData("0123456789012345678901234567890")]
+    public void Production_refuses_a_short_network_tag_secret_without_echoing_it(string secret)
+    {
+        var refusal = Assert.Throws<InvalidOperationException>(
+            () => Validate(keysPath: "/keys", tagSecret: secret));
+
+        Assert.Contains("ConceptVotes:NetworkTagSecret", refusal.Message);
+        Assert.DoesNotContain(secret, refusal.Message);
+        Validate(keysPath: "/keys", tagSecret: "01234567890123456789012345678901");
+    }
+
+    [Theory]
+    [InlineData(33, 56, "ConceptVotes:IPv4PrefixLength")]
+    [InlineData(-1, 56, "ConceptVotes:IPv4PrefixLength")]
+    [InlineData(32, 129, "ConceptVotes:IPv6PrefixLength")]
+    [InlineData(32, -1, "ConceptVotes:IPv6PrefixLength")]
+    public void Production_refuses_prefix_lengths_outside_the_address_family(int v4, int v6, string key)
+    {
+        var refusal = Assert.Throws<InvalidOperationException>(
+            () => Validate(keysPath: "/keys", ipv4Length: v4, ipv6Length: v6));
+
+        Assert.Contains(key, refusal.Message);
+        Validate(keysPath: "/keys", ipv4Length: 32, ipv6Length: 128);
+        Validate(keysPath: "/keys", ipv4Length: 0, ipv6Length: 0);
+    }
+
+    [Theory]
+    [InlineData("Development")]
+    [InlineData("Testing")]
+    [InlineData("Production")]
+    public void Every_environment_refuses_prefix_lengths_outside_the_address_family(string environment)
+    {
+        var v4 = Assert.Throws<InvalidOperationException>(
+            () => Validate(keysPath: "/keys", environment: environment, ipv4Length: 33));
+        Assert.Contains("ConceptVotes:IPv4PrefixLength", v4.Message);
+        Assert.DoesNotContain("IPv6PrefixLength", v4.Message);
+
+        var v6 = Assert.Throws<InvalidOperationException>(
+            () => Validate(keysPath: "/keys", environment: environment, ipv6Length: 129));
+        Assert.Contains("ConceptVotes:IPv6PrefixLength", v6.Message);
+        Assert.DoesNotContain("IPv4PrefixLength", v6.Message);
+
+        Validate(keysPath: "/keys", environment: environment, ipv4Length: 0, ipv6Length: 0);
+    }
+
+    [Theory]
+    [InlineData("Development", 0, 1, 5, 1, "ConceptVotes:CastPermits")]
+    [InlineData("Testing", 30, 0, 5, 1, "ConceptVotes:CastPermits")]
+    [InlineData("Production", 30, 1, 0, 1, "ConceptVotes:MintPermits")]
+    [InlineData("Production", 30, 1, 5, 0, "ConceptVotes:MintPermits")]
+    public void Every_environment_refuses_a_vote_budget_that_cannot_be_enforced(
+        string environment,
+        int castPermits,
+        int castMinutes,
+        int mintPermits,
+        int mintMinutes,
+        string key)
+    {
+        var refusal = Assert.Throws<InvalidOperationException>(() => Validate(
+            keysPath: "/keys",
+            environment: environment,
+            castPermits: castPermits,
+            castWindow: TimeSpan.FromMinutes(castMinutes),
+            mintPermits: mintPermits,
+            mintWindow: TimeSpan.FromMinutes(mintMinutes)));
+
+        Assert.Contains(key, refusal.Message);
+        Validate(keysPath: "/keys", environment: environment);
+    }
+
+    [Theory]
+    [InlineData("Development")]
+    [InlineData("Testing")]
+    [InlineData("Production")]
+    public void Every_environment_refuses_a_vote_table_cap_below_one(string environment)
+    {
+        var refusal = Assert.Throws<InvalidOperationException>(
+            () => Validate(keysPath: "/keys", environment: environment, maxTrackedKeys: 0));
+
+        Assert.Contains("ConceptVotes:MaxTrackedKeys", refusal.Message);
+    }
+
+    [Theory]
+    [InlineData("*")]
+    [InlineData("")]
+    [InlineData("null")]
+    [InlineData("https://canary-origin-5d1c.example/")]
+    [InlineData("https://canary-origin-5d1c.example/path")]
+    [InlineData("https://Canary-Origin-5d1c.example")]
+    [InlineData("http://canary-origin-5d1c.example")]
+    [InlineData("canary-origin-5d1c.example")]
+    [InlineData("https://canary-origin-5d1c.example:443")]
+    [InlineData("https://user@canary-origin-5d1c.example")]
+    public void Production_refuses_an_allowed_origin_that_is_not_an_exact_https_origin_without_echoing_it(string origin)
+    {
+        var refusal = Assert.Throws<InvalidOperationException>(
+            () => Validate(keysPath: "/keys", allowedOrigins: ["https://good.example", origin]));
+
+        Assert.Contains("ConceptVotes:AllowedOrigins", refusal.Message);
+        Assert.DoesNotContain("canary-origin-5d1c", refusal.Message, StringComparison.OrdinalIgnoreCase);
+        Validate(keysPath: "/keys", allowedOrigins: ["https://good.example", "https://other.example:8443"]);
+        Validate(keysPath: "/keys", allowedOrigins: []);
+    }
+
+    [Fact]
+    public void Development_does_not_require_keys_path_or_tag_secret()
+    {
+        Validate(keysPath: null, environment: Environments.Development, tagSecret: null);
+    }
+
+    private async Task<HttpContext> RunForwardedHeaders(string peer, string forwardedFor, string? forwardedProto)
+    {
+        var options = _factory.Services.GetRequiredService<IOptions<ForwardedHeadersOptions>>();
+        var middleware = new ForwardedHeadersMiddleware(
+            _ => Task.CompletedTask,
+            NullLoggerFactory.Instance,
+            options);
+        var context = new DefaultHttpContext();
+        context.Request.Scheme = "http";
+        context.Connection.RemoteIpAddress = IPAddress.Parse(peer);
+        context.Request.Headers["X-Forwarded-For"] = forwardedFor;
+        if (forwardedProto is not null)
+        {
+            context.Request.Headers["X-Forwarded-Proto"] = forwardedProto;
+        }
+
+        await middleware.Invoke(context);
+        return context;
+    }
+
+    private static string NewRoot() =>
+        Path.Combine(Path.GetTempPath(), "bifrost-dp-" + Guid.NewGuid().ToString("N"));
+
+    private static string MakeRelease(string root, string name) =>
+        Directory.CreateDirectory(Path.Combine(root, name)).FullName;
+
+    private static string Protect(TestWebApplicationFactory host, string value) =>
+        host.Services.GetRequiredService<IDataProtectionProvider>().CreateProtector("P").Protect(value);
+
+    private static string Unprotect(TestWebApplicationFactory host, string value) =>
+        host.Services.GetRequiredService<IDataProtectionProvider>().CreateProtector("P").Unprotect(value);
+
+    private TestWebApplicationFactory WithContentRoot(string contentRoot, string keysPath) =>
+        new KeyRingFactory(contentRoot, keysPath);
+
+    private sealed class KeyRingFactory(string contentRoot, string keysPath) : TestWebApplicationFactory
+    {
+        protected override void ConfigureWebHost(IWebHostBuilder builder)
+        {
+            base.ConfigureWebHost(builder);
+            builder.UseContentRoot(contentRoot);
+            builder.UseSetting("DataProtection:KeysPath", keysPath);
+        }
+    }
+
+    private const string ValidTagSecret = "tag-secret-0123456789-0123456789-abcdef";
+
+    private static void Validate(
+        string? keysPath,
+        string environment = "Production",
+        string? connectionString = "Host=db",
+        string? tagSecret = ValidTagSecret,
+        int ipv4Length = 32,
+        int ipv6Length = 56,
+        string[]? allowedOrigins = null,
+        int castPermits = 30,
+        TimeSpan? castWindow = null,
+        int mintPermits = 5,
+        TimeSpan? mintWindow = null,
+        int maxTrackedKeys = 100_000)
+    {
+        var values = new Dictionary<string, string?>
+        {
+            ["AllowedHosts"] = "bifrost.example",
+            ["ConnectionStrings:Bifrost"] = connectionString,
+            ["DataProtection:KeysPath"] = keysPath,
+        };
+        var configuration = new ConfigurationBuilder().AddInMemoryCollection(values).Build();
+        var hostEnvironment = new StubHostEnvironment(environment);
+
+        new StartupConfigurationValidator(
+            configuration,
+            hostEnvironment,
+            Options.Create(new GitHubOAuthOptions { ClientId = "id", ClientSecret = "secret" }),
+            Options.Create(new GitHubAppOptions { EnableWebhookSync = false }),
+            Options.Create(new HeimdallOptions { EnablePatronSupportIntake = false }),
+            Options.Create(new StripeOptions()),
+            Options.Create(new BifrostHostOptions
+            {
+                PublicBaseUrl = "https://bifrost.example",
+                ExpectedHost = "bifrost.example"
+            }),
+            Options.Create(new ConceptVoteOptions
+            {
+                NetworkTagSecret = tagSecret ?? string.Empty,
+                IPv4PrefixLength = ipv4Length,
+                IPv6PrefixLength = ipv6Length,
+                AllowedOrigins = allowedOrigins ?? [],
+                CastPermits = castPermits,
+                CastWindow = castWindow ?? TimeSpan.FromMinutes(10),
+                MintPermits = mintPermits,
+                MintWindow = mintWindow ?? TimeSpan.FromHours(1),
+                MaxTrackedKeys = maxTrackedKeys
+            })).Validate();
+    }
+
+    private sealed class StubHostEnvironment(string environmentName) : IHostEnvironment
+    {
+        public string EnvironmentName { get; set; } = environmentName;
+        public string ApplicationName { get; set; } = "Bifrost.Web";
+        public string ContentRootPath { get; set; } = string.Empty;
+        public Microsoft.Extensions.FileProviders.IFileProvider ContentRootFileProvider { get; set; } = null!;
+    }
+}

tests/Bifrost.Web.Tests/MemberConsoleTests.cs

@@ -1,4 +1,9 @@
 using System.Net;
+using Bifrost.Web.Configuration;
+using Bifrost.Web.Features.ConceptVotes;
+using Bifrost.Web.Features.Shared;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Options;
 using Bifrost.Web.Data;
 using Bifrost.Web.Domain;
 using Bifrost.Web.Tests.Support;
@@ -143,4 +148,51 @@ public sealed class MemberConsoleTests : IClassFixture<TestWebApplicationFactory
         Assert.Contains("Draft motion implementation PR", html);
         Assert.Contains("nibu", html);
     }
+
+    [Fact]
+    public async Task Member_console_activity_shows_a_purge_without_its_network_tag()
+    {
+        using (var warmupClient = _factory.CreateClient())
+        {
+            _ = await warmupClient.GetAsync("/App");
+        }
+
+        string tag;
+        using (var scope = _factory.Services.CreateScope())
+        {
+            var dbContext = scope.ServiceProvider.GetRequiredService<BifrostDbContext>();
+            var admin = await dbContext.UserAccounts
+                .Include(x => x.Membership)
+                .SingleAsync(x => x.NormalizedGitHubLogin == "TEST-ADMIN");
+            var now = DateTimeOffset.UtcNow;
+            dbContext.ConceptSubjects.Add(new ConceptSubject
+            {
+                Collection = "aetheria-concept-mill",
+                Key = "ship-a",
+                Title = "ship-a",
+                RegisteredAtUtc = now
+            });
+            await dbContext.SaveChangesAsync();
+
+            var service = scope.ServiceProvider.GetRequiredService<ConceptAppraisalService>();
+            var options = scope.ServiceProvider.GetRequiredService<IOptions<ConceptVoteOptions>>().Value;
+            var client = System.Net.IPAddress.Parse("203.0.113.7");
+            tag = NetworkPrefix.Tag(client, options.IPv4PrefixLength, options.IPv6PrefixLength, options.NetworkTagSecret);
+            var voter = VoterIdentity.For(CurrentBifrostActor.Anonymous, "member-view-device")!;
+            await service.CastAsync("aetheria-concept-mill", "ship-a", voter, ConceptStance.Up, client, default);
+
+            var removed = await service.PurgeAsync(
+                new CurrentBifrostActor(true, admin), tag, now.AddHours(-1), now.AddHours(1), default);
+            Assert.Equal(1, removed);
+        }
+
+        using var memberClient = _factory.CreateClient();
+        using var response = await memberClient.GetAsync("/App");
+        var html = await response.Content.ReadAsStringAsync();
+
+        Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+        Assert.Contains("Purge", html);
+        Assert.Contains("count", html);
+        Assert.DoesNotContain(tag, html);
+    }
 }

tests/Bifrost.Web.Tests/MigrationDiscoveryTests.cs

@@ -0,0 +1,58 @@
+using Bifrost.Web.Data;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+namespace Bifrost.Web.Tests;
+
+public sealed class MigrationDiscoveryTests
+{
+    private static readonly string[] ExpectedMigrations =
+    [
+        "20260422084653_InitialAlphaFoundation",
+        "20260608210000_AddHeimdallUserIdentity",
+        "20260609143000_AddPatronSupportDerivation",
+        "20260609160000_AddExternalPatronProviderIntake",
+        "20260617010537_AddBridgeActionLedger",
+        "20260617022305_AddAgentDispatchRuns",
+        "20260617033635_AddAgentTransportReceipts",
+        "20260617041417_AddGovernanceActivityReceipts",
+        "20260622142000_AddBridgeActionIdentityProvenance",
+        "20260622165000_AddBifrostNativeIdentity",
+        "20260622202000_AddBridgeActionTargetSurfaceName",
+        "20260705190000_AddPatronSupportProjectAttribution",
+        "20261010043937_AddConceptVotes",
+        "20261022163159_AddOpenIddict",
+    ];
+
+    // Database.GetMigrations() reads assembly metadata only; no connection is opened.
+    private static List<string> Discovered()
+    {
+        var options = new DbContextOptionsBuilder<BifrostDbContext>()
+            .UseNpgsql("Host=unused")
+            .Options;
+        using var db = new BifrostDbContext(options);
+        return db.Database.GetMigrations().ToList();
+    }
+
+    [Fact]
+    public void Every_migration_type_is_discovered()
+    {
+        var discovered = Discovered();
+        var declared = typeof(BifrostDbContext).Assembly.GetTypes()
+            .Where(t => !t.IsAbstract && typeof(Migration).IsAssignableFrom(t))
+            .ToList();
+
+        Assert.NotEmpty(declared);
+        Assert.Equal(declared.Count, discovered.Count);
+        foreach (var type in declared)
+        {
+            Assert.Contains(discovered, id => id.EndsWith("_" + type.Name, StringComparison.Ordinal));
+        }
+    }
+
+    [Fact]
+    public void All_fourteen_migrations_are_listed_in_order()
+    {
+        Assert.Equal(ExpectedMigrations, Discovered());
+    }
+}

tests/Bifrost.Web.Tests/NetworkPrefixTests.cs

@@ -0,0 +1,64 @@
+using System.Net;
+using Bifrost.Web.Features.ConceptVotes;
+
+namespace Bifrost.Web.Tests;
+
+public sealed class NetworkPrefixTests
+{
+    private const string Secret = "prefix-secret";
+
+    private static string Tag(string address, int v4 = 24, int v6 = 56, string secret = Secret) =>
+        NetworkPrefix.Tag(IPAddress.Parse(address), v4, v6, secret);
+
+    [Fact]
+    public void Two_addresses_inside_one_prefix_share_a_tag_and_other_prefixes_do_not()
+    {
+        Assert.Equal(Tag("203.0.113.7"), Tag("203.0.113.200"));
+        Assert.NotEqual(Tag("203.0.113.7"), Tag("203.0.114.7"));
+        Assert.Equal(Tag("2001:db8:1:ff::1"), Tag("2001:db8:1:ff:aaaa::9"));
+        Assert.NotEqual(Tag("2001:db8:1:ff::1"), Tag("2001:db8:2:ff::1"));
+        Assert.Equal("203.0.113.0/24", NetworkPrefix.Of(IPAddress.Parse("203.0.113.7"), 24, 56));
+        Assert.Equal("2001:db8:1:ff00::/56", NetworkPrefix.Of(IPAddress.Parse("2001:db8:1:ffee::1"), 24, 56));
+    }
+
+    [Fact]
+    public void Prefix_length_is_the_configured_one()
+    {
+        Assert.NotEqual(Tag("203.0.113.7", v4: 32), Tag("203.0.113.8", v4: 32));
+        Assert.Equal(Tag("2001:db8:1:ff::1", v6: 48), Tag("2001:db8:1:aa::1", v6: 48));
+    }
+
+    [Fact]
+    public void IPv4_mapped_IPv6_equals_the_IPv4_address()
+    {
+        Assert.Equal(Tag("203.0.113.7"), Tag("::ffff:203.0.113.7"));
+    }
+
+    [Fact]
+    public void A_different_secret_gives_a_different_tag_and_the_tag_is_lowercase_hex()
+    {
+        var tag = Tag("203.0.113.7");
+
+        Assert.NotEqual(tag, Tag("203.0.113.7", secret: "other-secret"));
+        Assert.Matches("^[0-9a-f]{64}$", tag);
+    }
+
+    [Fact]
+    public void A_length_outside_the_family_is_refused_without_echoing_the_address()
+    {
+        var ex = Assert.Throws<ArgumentOutOfRangeException>(
+            () => NetworkPrefix.Of(IPAddress.Parse("203.0.113.7"), 33, 56));
+
+        Assert.DoesNotContain("203.0.113.7", ex.Message);
+        Assert.Contains("Prefix length", ex.Message);
+    }
+
+    [Fact]
+    public void Masking_is_exact_inside_a_byte_and_a_zero_length_is_the_whole_family()
+    {
+        Assert.Equal("203.0.112.0/20", NetworkPrefix.Of(IPAddress.Parse("203.0.127.200"), 20, 56));
+        Assert.Equal("2001:db8:1:f0::/60", NetworkPrefix.Of(IPAddress.Parse("2001:db8:1:ff::1"), 24, 60));
+        Assert.Equal("0.0.0.0/0", NetworkPrefix.Of(IPAddress.Parse("203.0.113.7"), 0, 56));
+        Assert.Equal("203.0.113.7/32", NetworkPrefix.Of(IPAddress.Parse("203.0.113.7"), 32, 56));
+    }
+}

tests/Bifrost.Web.Tests/OidcIssuerTests.cs

@@ -0,0 +1,737 @@
+using System.Net;
+using System.Net.Http.Headers;
+using System.Net.Http.Json;
+using System.Security.Cryptography;
+using System.Text;
+using System.Text.Json;
+using Bifrost.Web.Domain;
+using Bifrost.Web.Features.Shared;
+using Bifrost.Web.Tests.Support;
+using Microsoft.AspNetCore.Mvc.Testing;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+using Microsoft.IdentityModel.JsonWebTokens;
+using Microsoft.IdentityModel.Tokens;
+
+namespace Bifrost.Web.Tests;
+
+public sealed class OidcIssuerTests : IClassFixture<OidcWebApplicationFactory>
+{
+    private static readonly Uri Origin = new("https://localhost");
+    private readonly OidcWebApplicationFactory _factory;
+
+    public OidcIssuerTests(OidcWebApplicationFactory factory) => _factory = factory;
+
+    [Fact]
+    public async Task Discovery_advertises_ES256_and_the_code_flow_only()
+    {
+        using var client = NewClient();
+        var discovery = await client.GetFromJsonAsync<JsonElement>("/.well-known/openid-configuration");
+
+        Assert.Equal(Origin.AbsoluteUri, discovery.GetProperty("issuer").GetString());
+        Assert.Equal("/.well-known/jwks", new Uri(discovery.GetProperty("jwks_uri").GetString()!).AbsolutePath);
+        Assert.Equal(["ES256"], Strings(discovery, "id_token_signing_alg_values_supported"));
+        Assert.Equal(["code"], Strings(discovery, "response_types_supported"));
+        Assert.Equal(["authorization_code"], Strings(discovery, "grant_types_supported"));
+        Assert.Contains("S256", Strings(discovery, "code_challenge_methods_supported"));
+        Assert.Equal(["client_secret_basic"], Strings(discovery, "token_endpoint_auth_methods_supported"));
+        Assert.Equal(["openid", "profile"], Strings(discovery, "scopes_supported").Order());
+    }
+
+    [Fact]
+    public async Task Jwks_holds_exactly_the_configured_P256_key()
+    {
+        using var client = NewClient();
+        var jwks = await GetJwksAsync(client);
+
+        var key = Assert.Single(jwks.GetProperty("keys").EnumerateArray());
+        Assert.Equal("EC", key.GetProperty("kty").GetString());
+        Assert.Equal("P-256", key.GetProperty("crv").GetString());
+        Assert.Equal("ES256", key.GetProperty("alg").GetString());
+
+        using var ec = ECDsa.Create();
+        ec.ImportFromPem(_factory.Kit.SigningPublicKeyPem);
+        var expected = ec.ExportParameters(false);
+        Assert.Equal(Base64UrlEncoder.Encode(expected.Q.X), key.GetProperty("x").GetString());
+        Assert.Equal(Base64UrlEncoder.Encode(expected.Q.Y), key.GetProperty("y").GetString());
+        Assert.False(key.TryGetProperty("d", out _));
+    }
+
+    [Fact]
+    public async Task An_active_member_completes_code_and_pkce_and_gets_the_right_claims()
+    {
+        var (client, identity) = await SignedInAsync(MembershipStatus.Active, "Ada Lovelace");
+        var accountId = _factory.AccountId(identity);
+        await SetLinksAsync(identity, "heimdall-canary-7", "github-canary-7");
+
+        var tokens = await CompleteFlowAsync(client);
+
+        var verified = await ValidateIdTokenAsync(tokens.IdToken, tokens.Request.Nonce);
+        Assert.Equal(accountId.ToString("D"), verified.Claim("sub"));
+        Assert.Equal(identity, verified.Claim("preferred_username"));
+        Assert.Equal("Ada Lovelace", verified.Claim("name"));
+        Assert.Equal(["ES256"], [verified.Alg]);
+
+        // Nothing about the authenticator links, e-mail or membership leaves Bifrost.
+        Assert.DoesNotContain("heimdall-canary-7", verified.PayloadJson);
+        Assert.DoesNotContain("github-canary-7", verified.PayloadJson);
+        Assert.DoesNotContain("email", verified.PayloadJson, StringComparison.OrdinalIgnoreCase);
+        Assert.DoesNotContain("urn:bifrost", verified.PayloadJson);
+
+        using var userinfo = new HttpRequestMessage(HttpMethod.Get, "/connect/userinfo");
+        userinfo.Headers.Authorization = new AuthenticationHeaderValue("Bearer", tokens.AccessToken);
+        using var userinfoResponse = await NewClient().SendAsync(userinfo);
+        Assert.Equal(HttpStatusCode.OK, userinfoResponse.StatusCode);
+        var body = await userinfoResponse.Content.ReadAsStringAsync();
+        var info = JsonDocument.Parse(body).RootElement;
+        Assert.Equal(accountId.ToString("D"), info.GetProperty("sub").GetString());
+        Assert.Equal(identity, info.GetProperty("preferred_username").GetString());
+        Assert.Equal("Ada Lovelace", info.GetProperty("name").GetString());
+        Assert.DoesNotContain("canary", body);
+    }
+
+    [Fact]
+    public async Task Sub_and_preferred_username_are_stable_across_display_name_changes()
+    {
+        var (client, identity) = await SignedInAsync(MembershipStatus.Active, "First Name");
+
+        var first = await ValidateIdTokenAsync((await CompleteFlowAsync(client)).IdToken, null);
+        await _factory.SetDisplayNameAsync(identity, "Second Name");
+        var second = await ValidateIdTokenAsync((await CompleteFlowAsync(client)).IdToken, null);
+
+        Assert.Equal(first.Claim("sub"), second.Claim("sub"));
+        Assert.Equal(first.Claim("preferred_username"), second.Claim("preferred_username"));
+        Assert.Equal("First Name", first.Claim("name"));
+        Assert.Equal("Second Name", second.Claim("name"));
+    }
+
+    [Theory]
+    [InlineData(MembershipStatus.Authenticated)]
+    [InlineData(MembershipStatus.PendingApproval)]
+    [InlineData(MembershipStatus.Suspended)]
+    public async Task A_member_who_is_not_active_is_refused_with_access_denied_and_no_code(MembershipStatus status)
+    {
+        var (client, _) = await SignedInAsync(status, "Not Active");
+        var request = NewRequest();
+
+        var final = await DriveAsync(client, request);
+
+        var redirect = AssertRedirectToClient(final, request.State);
+        Assert.Equal("access_denied", redirect["error"]);
+        Assert.Equal(Bifrost.Web.Features.Oidc.OidcEndpoints.NotActiveDescription, redirect["error_description"]);
+        Assert.False(redirect.ContainsKey("code"));
+    }
+
+    [Fact]
+    public async Task An_active_account_with_no_bifrost_identity_is_refused_never_given_an_empty_username()
+    {
+        using var factory = new OidcNoIdentityFactory();
+        using var client = factory.CreateClient(ClientOptions());
+        await RegisterAsync(client, $"noid-{Guid.NewGuid():N}");
+        var request = NewRequest();
+
+        var final = await DriveAsync(client, request);
+
+        var redirect = AssertRedirectToClient(final, request.State);
+        Assert.Equal("access_denied", redirect["error"]);
+        Assert.Equal(Bifrost.Web.Features.Oidc.OidcEndpoints.NoIdentityDescription, redirect["error_description"]);
+        Assert.False(redirect.ContainsKey("code"));
+    }
+
+    [Theory]
+    [InlineData("unknown-client", OidcTestKit.RedirectUri, true)]
+    [InlineData(OidcTestKit.ClientId, "https://evil.example.test/callback", true)]
+    [InlineData(OidcTestKit.ClientId, OidcTestKit.RedirectUri, false)]
+    public async Task Unknown_client_wrong_redirect_uri_and_missing_pkce_are_refused_before_any_sign_in_redirect(
+        string clientId, string redirectUri, bool pkce)
+    {
+        using var client = NewClient();
+        var request = NewRequest(clientId, redirectUri, pkce);
+
+        using var response = await client.GetAsync(request.Path);
+
+        var location = response.Headers.Location?.OriginalString ?? string.Empty;
+        Assert.DoesNotContain("/auth/sign-in", location);
+        Assert.DoesNotContain("request_uri=", location);
+        Assert.DoesNotContain("code=", location);
+        Assert.NotEqual(HttpStatusCode.OK, response.StatusCode);
+    }
+
+    [Fact]
+    public async Task A_mas_sized_authorize_request_survives_sign_in_and_its_handle_is_single_use()
+    {
+        var request = NewRequest(extra: "&ui_locales=en&prompt=login&claims_locales=en&max_age=3600");
+        Assert.True(request.Path.Length > LocalReturnPath.MaxLength, "the request must be longer than a sign-in return path");
+
+        using var client = NewClient();
+        var signIn = await DriveAsync(client, request);
+        Assert.Equal(HttpStatusCode.Redirect, signIn.StatusCode);
+        Assert.Equal("/auth/sign-in", signIn.Headers.Location!.IsAbsoluteUri
+            ? signIn.Headers.Location.AbsolutePath
+            : signIn.Headers.Location.OriginalString.Split('?')[0]);
+        var resume = ReturnUrl(signIn);
+        Assert.True(resume.Length <= LocalReturnPath.MaxLength, "the resume path must fit the sign-in return path");
+        Assert.Equal(resume, LocalReturnPath.Parse(resume).Value);
+
+        var identity = await RegisterAsync(client, $"resume-{Guid.NewGuid():N}");
+        await _factory.SetMembershipAsync(identity, MembershipStatus.Active);
+
+        using var resumed = await client.GetAsync(resume);
+        var redirect = AssertRedirectToClient(resumed, request.State);
+        Assert.True(redirect.ContainsKey("code"), "the resumed request issues a code");
+
+        var tokens = await ExchangeAsync(client, request, redirect["code"]!);
+        var verified = await ValidateIdTokenAsync(tokens.IdToken, request.Nonce);
+        Assert.Equal(request.Nonce, verified.Claim("nonce"));
+
+        // The handle was spent by the first resume.
+        using var replay = await client.GetAsync(resume);
+        var replayRedirect = replay.Headers.Location?.OriginalString ?? string.Empty;
+        Assert.DoesNotContain("code=", replayRedirect);
+        Assert.NotEqual(HttpStatusCode.OK, replay.StatusCode);
+    }
+
+    [Fact]
+    public async Task A_parked_authorize_request_expires()
+    {
+        // Own host: moving the clock must not skew the id_token checks of the other tests.
+        using var own = new OidcWebApplicationFactory();
+        await new OidcIssuerTests(own).ParkedRequestIsRefusedAfterItsLifetimeAsync();
+    }
+
+    private async Task ParkedRequestIsRefusedAfterItsLifetimeAsync()
+    {
+        // Fixed probe times, not the constant: a lifetime of a day, or of a minute, must show.
+        var early = NewRequest();
+        var late = NewRequest();
+        using var client = NewClient();
+        var earlyResume = ReturnUrl(await DriveAsync(client, early));
+        var lateResume = ReturnUrl(await DriveAsync(client, late));
+        var identity = await RegisterAsync(client, $"late-{Guid.NewGuid():N}");
+        await _factory.SetMembershipAsync(identity, MembershipStatus.Active);
+
+        _factory.Clock.Advance(TimeSpan.FromMinutes(5));
+        using var withinLifetime = await client.GetAsync(earlyResume);
+        Assert.True(AssertRedirectToClient(withinLifetime, early.State).ContainsKey("code"), "five minutes is within the lifetime");
+
+        _factory.Clock.Advance(TimeSpan.FromMinutes(25));
+        using var expired = await client.GetAsync(lateResume);
+        var location = expired.Headers.Location?.OriginalString ?? string.Empty;
+        Assert.DoesNotContain("code=", location);
+        Assert.NotEqual(HttpStatusCode.OK, expired.StatusCode);
+    }
+
+    [Fact]
+    public async Task The_token_endpoint_accepts_client_secret_basic_only()
+    {
+        var (client, _) = await SignedInAsync(MembershipStatus.Active, "Basic Only");
+        var request = NewRequest();
+        var code = await CodeAsync(client, request);
+
+        var wrongSecret = await TokenAsync(client, request, code, secret: "wrong-secret");
+        Assert.NotEqual(HttpStatusCode.OK, wrongSecret.StatusCode);
+
+        var asPost = await TokenAsync(client, request, code, secretInBody: true);
+        Assert.NotEqual(HttpStatusCode.OK, asPost.StatusCode);
+    }
+
+    [Fact]
+    public async Task Identity_is_minted_once()
+    {
+        using var scope = _factory.Services.CreateScope();
+        var service = scope.ServiceProvider.GetRequiredService<Bifrost.Web.Features.Membership.BifrostIdentityService>();
+        var account = new UserAccount { BifrostIdentity = "Original", NormalizedBifrostIdentity = "original" };
+
+        await service.EnsureIdentityAsync(account, "someone-else", CancellationToken.None);
+
+        Assert.Equal("original", account.NormalizedBifrostIdentity);
+        Assert.Equal("Original", account.BifrostIdentity);
+    }
+
+    [Fact]
+    public async Task The_openid_scope_alone_releases_the_subject_and_nothing_else()
+    {
+        var (client, identity) = await SignedInAsync(MembershipStatus.Active, "Scoped Down");
+        var request = NewRequest(scope: "openid");
+        var code = await CodeAsync(client, request);
+
+        var tokens = await ExchangeAsync(client, request, code);
+
+        var verified = await ValidateIdTokenAsync(tokens.IdToken, request.Nonce);
+        Assert.Equal(_factory.AccountId(identity).ToString("D"), verified.Claim("sub"));
+        Assert.Null(verified.Claim("preferred_username"));
+        Assert.Null(verified.Claim("name"));
+
+        using var userinfo = new HttpRequestMessage(HttpMethod.Get, "/connect/userinfo");
+        userinfo.Headers.Authorization = new AuthenticationHeaderValue("Bearer", tokens.AccessToken);
+        using var response = await NewClient().SendAsync(userinfo);
+        var info = (await response.Content.ReadFromJsonAsync<JsonElement>()).EnumerateObject().Select(x => x.Name).ToArray();
+        Assert.Equal(["sub"], info);
+    }
+
+    [Fact]
+    public async Task A_blank_display_name_falls_back_to_the_bifrost_identity()
+    {
+        var (client, identity) = await SignedInAsync(MembershipStatus.Active, "   ");
+
+        var verified = await ValidateIdTokenAsync((await CompleteFlowAsync(client)).IdToken, null);
+
+        Assert.Equal(identity, verified.Claim("name"));
+    }
+
+    [Fact]
+    public async Task Userinfo_without_a_valid_token_is_refused()
+    {
+        using var client = NewClient();
+        using var none = await client.GetAsync("/connect/userinfo");
+        Assert.Equal(HttpStatusCode.Unauthorized, none.StatusCode);
+
+        using var forged = new HttpRequestMessage(HttpMethod.Get, "/connect/userinfo");
+        forged.Headers.Authorization = new AuthenticationHeaderValue("Bearer", "not-a-token");
+        using var forgedResponse = await client.SendAsync(forged);
+        Assert.Equal(HttpStatusCode.Unauthorized, forgedResponse.StatusCode);
+    }
+
+    [Fact]
+    public async Task Startup_makes_the_one_client_match_configuration_again()
+    {
+        // Own host: the drift below leaves the application manager's cache stale for every other test.
+        using var own = new OidcWebApplicationFactory();
+        await new OidcIssuerTests(own).SeederRestoresTheClientAsync();
+    }
+
+    private async Task SeederRestoresTheClientAsync()
+    {
+        using var warm = NewClient();
+        await warm.GetAsync("/healthz");
+        using var scope = _factory.Services.CreateScope();
+        var manager = scope.ServiceProvider.GetRequiredService<OpenIddict.Abstractions.IOpenIddictApplicationManager>();
+        var application = await manager.FindByClientIdAsync(OidcTestKit.ClientId);
+        Assert.NotNull(application);
+
+        // Someone widened the client in the database; the next start puts configuration back.
+        var drifted = new OpenIddict.Abstractions.OpenIddictApplicationDescriptor
+        {
+            ClientId = OidcTestKit.ClientId,
+            ClientType = OpenIddict.Abstractions.OpenIddictConstants.ClientTypes.Confidential,
+            ClientSecret = "drifted-secret",
+            RedirectUris = { new Uri("https://evil.example.test/callback") }
+        };
+        await manager.UpdateAsync(application, drifted);
+        var seeders = _factory.Services.GetServices<IHostedService>().OfType<Bifrost.Web.Features.Oidc.OidcClientSeeder>().ToList();
+        var seeder = Assert.Single(seeders);
+        await seeder.StartAsync(CancellationToken.None);
+
+        // Read the stored row, not through the manager: the manager's cache still holds the drifted instance.
+        using var fresh = _factory.Services.CreateScope();
+        var rows = fresh.ServiceProvider.GetRequiredService<Bifrost.Web.Data.BifrostDbContext>()
+            .Set<OpenIddict.EntityFrameworkCore.Models.OpenIddictEntityFrameworkCoreApplication>()
+            .AsNoTracking().ToList();
+        var stored = Assert.Single(rows);
+        Assert.Equal([OidcTestKit.RedirectUri], (await manager.GetRedirectUrisAsync(stored)).ToArray());
+        Assert.True(await manager.ValidateClientSecretAsync(stored, _factory.Kit.ClientSecret));
+        Assert.False(await manager.ValidateClientSecretAsync(stored, "drifted-secret"));
+    }
+
+    [Theory]
+    [InlineData(MembershipStatus.Authenticated)]
+    [InlineData(MembershipStatus.PendingApproval)]
+    [InlineData(MembershipStatus.Suspended)]
+    [InlineData(null)]
+    public async Task A_member_no_longer_active_after_authorize_gets_no_tokens(MembershipStatus? status)
+    {
+        var (client, identity) = await SignedInAsync(MembershipStatus.Active, "Soon Gone");
+        var request = NewRequest();
+        var code = await CodeAsync(client, request);
+
+        await LeaveActiveAsync(identity, status);
+
+        using var response = await TokenAsync(client, request, code);
+        var body = await response.Content.ReadAsStringAsync();
+        Assert.Equal(HttpStatusCode.BadRequest, response.StatusCode);
+        Assert.Contains("invalid_grant", body);
+        Assert.DoesNotContain("id_token", body);
+        Assert.DoesNotContain("access_token", body);
+    }
+
+    [Theory]
+    [InlineData(MembershipStatus.Authenticated)]
+    [InlineData(MembershipStatus.PendingApproval)]
+    [InlineData(MembershipStatus.Suspended)]
+    [InlineData(null)]
+    public async Task Userinfo_refuses_an_access_token_whose_member_is_no_longer_active(MembershipStatus? status)
+    {
+        var (client, identity) = await SignedInAsync(MembershipStatus.Active, "Soon Gone");
+        var tokens = await CompleteFlowAsync(client);
+
+        using (var before = await UserInfoAsync(tokens.AccessToken))
+        {
+            Assert.Equal(HttpStatusCode.OK, before.StatusCode);
+        }
+
+        await LeaveActiveAsync(identity, status);
+
+        using var after = await UserInfoAsync(tokens.AccessToken);
+        Assert.Equal(HttpStatusCode.Forbidden, after.StatusCode);
+        Assert.DoesNotContain(identity, await after.Content.ReadAsStringAsync());
+    }
+
+    private Task<HttpResponseMessage> UserInfoAsync(string accessToken)
+    {
+        var request = new HttpRequestMessage(HttpMethod.Get, "/connect/userinfo");
+        request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
+        return NewClient().SendAsync(request);
+    }
+
+    /// <summary>A null status deletes the account instead.</summary>
+    private Task LeaveActiveAsync(string identity, MembershipStatus? status) =>
+        status is { } value ? _factory.SetMembershipAsync(identity, value) : _factory.DeleteAccountAsync(identity);
+
+    [Fact]
+    public async Task Startup_removes_every_client_but_the_configured_one_with_its_tokens_and_authorizations()
+    {
+        // Own host: the stale clients are rows the other tests must not see.
+        using var own = new OidcCascadeFactory();
+        await new OidcIssuerTests(own).StaleClientsAreRemovedAsync();
+    }
+
+    private async Task StaleClientsAreRemovedAsync()
+    {
+        // Two stale clients, one of them differing from the configured id only in case.
+        var stale = new[]
+        {
+            (Id: "old-mas", Redirect: "https://old.example.test/callback"),
+            (Id: OidcTestKit.ClientId.ToUpperInvariant(), Redirect: "https://shouting.example.test/callback")
+        };
+        var (client, _) = await SignedInAsync(MembershipStatus.Active, "Member");
+        using (var scope = _factory.Services.CreateScope())
+        {
+            var manager = scope.ServiceProvider.GetRequiredService<OpenIddict.Abstractions.IOpenIddictApplicationManager>();
+            foreach (var (id, redirect) in stale)
+            {
+                await manager.CreateAsync(new OpenIddict.Abstractions.OpenIddictApplicationDescriptor
+                {
+                    ClientId = id,
+                    ClientSecret = "stale-secret",
+                    ClientType = OpenIddict.Abstractions.OpenIddictConstants.ClientTypes.Confidential,
+                    RedirectUris = { new Uri(redirect) },
+                    Permissions =
+                    {
+                        OpenIddict.Abstractions.OpenIddictConstants.Permissions.Endpoints.Authorization,
+                        OpenIddict.Abstractions.OpenIddictConstants.Permissions.Endpoints.Token,
+                        OpenIddict.Abstractions.OpenIddictConstants.Permissions.GrantTypes.AuthorizationCode,
+                        OpenIddict.Abstractions.OpenIddictConstants.Permissions.ResponseTypes.Code,
+                        OpenIddict.Abstractions.OpenIddictConstants.Permissions.Scopes.Profile,
+                        OpenIddict.Abstractions.OpenIddictConstants.Permissions.Prefixes.Scope + OpenIddict.Abstractions.OpenIddictConstants.Scopes.OpenId
+                    }
+                });
+            }
+        }
+
+        // The control: before seeding every client, stale or configured, really can obtain a code and so holds
+        // an authorization and a token.
+        foreach (var (id, redirect) in stale)
+        {
+            using var issued = await DriveAsync(client, NewRequest(id, redirect));
+            Assert.Contains("code=", issued.Headers.Location?.OriginalString ?? string.Empty);
+        }
+
+        _ = await CodeAsync(client, NewRequest());
+        var staleCounts = Counts(stale.Select(x => x.Id));
+        Assert.Equal(stale.Length, staleCounts.Count);
+        Assert.All(staleCounts, x => Assert.True(x.Tokens > 0 && x.Authorizations > 0, "the control must leave grants to remove"));
+        var configuredBefore = Counts([OidcTestKit.ClientId]).Single();
+        Assert.True(configuredBefore.Tokens > 0 && configuredBefore.Authorizations > 0);
+
+        var seeder = Assert.Single(_factory.Services.GetServices<IHostedService>().OfType<Bifrost.Web.Features.Oidc.OidcClientSeeder>());
+        await seeder.StartAsync(CancellationToken.None);
+
+        foreach (var (id, redirect) in stale)
+        {
+            using var refused = await DriveAsync(client, NewRequest(id, redirect));
+            Assert.DoesNotContain("code=", refused.Headers.Location?.OriginalString ?? string.Empty);
+            Assert.NotEqual(HttpStatusCode.OK, refused.StatusCode);
+        }
+
+        using var fresh = _factory.Services.CreateScope();
+        var db = fresh.ServiceProvider.GetRequiredService<Bifrost.Web.Data.BifrostDbContext>();
+        var rows = db.Set<OpenIddict.EntityFrameworkCore.Models.OpenIddictEntityFrameworkCoreApplication>().AsNoTracking().ToList();
+        Assert.Equal([OidcTestKit.ClientId], rows.Select(x => x.ClientId).ToArray());
+
+        // Nothing issued to a removed client survives, and the configured client's grants are untouched.
+        var keptId = rows.Single().Id;
+        Assert.Empty(db.Set<OpenIddict.EntityFrameworkCore.Models.OpenIddictEntityFrameworkCoreToken>().AsNoTracking().Where(x => x.Application!.Id != keptId));
+        Assert.Empty(db.Set<OpenIddict.EntityFrameworkCore.Models.OpenIddictEntityFrameworkCoreAuthorization>().AsNoTracking().Where(x => x.Application!.Id != keptId));
+        Assert.Equal(configuredBefore, Counts([OidcTestKit.ClientId]).Single());
+    }
+
+    private sealed record GrantCount(int Tokens, int Authorizations);
+
+    private List<GrantCount> Counts(IEnumerable<string> clientIds)
+    {
+        using var scope = _factory.Services.CreateScope();
+        var db = scope.ServiceProvider.GetRequiredService<Bifrost.Web.Data.BifrostDbContext>();
+        var applications = db.Set<OpenIddict.EntityFrameworkCore.Models.OpenIddictEntityFrameworkCoreApplication>().AsNoTracking().ToList();
+        return clientIds
+            .Select(id => applications.Single(x => x.ClientId == id).Id)
+            .Select(applicationId => new GrantCount(
+                db.Set<OpenIddict.EntityFrameworkCore.Models.OpenIddictEntityFrameworkCoreToken>().Count(x => x.Application!.Id == applicationId),
+                db.Set<OpenIddict.EntityFrameworkCore.Models.OpenIddictEntityFrameworkCoreAuthorization>().Count(x => x.Application!.Id == applicationId)))
+            .ToList();
+    }
+
+    [Fact]
+    public async Task The_issuer_is_the_configured_public_base_url_not_the_request_origin()
+    {
+        using var factory = new OidcForeignIssuerFactory();
+        using var client = factory.CreateClient(ClientOptions());
+        var discovery = await client.GetFromJsonAsync<JsonElement>("/.well-known/openid-configuration");
+
+        Assert.Equal(OidcForeignIssuerFactory.PublicBaseUrl, discovery.GetProperty("issuer").GetString());
+    }
+
+    // ---- helpers ----
+
+    private static WebApplicationFactoryClientOptions ClientOptions() => new()
+    {
+        AllowAutoRedirect = false,
+        HandleCookies = true,
+        BaseAddress = Origin
+    };
+
+    private HttpClient NewClient() => _factory.CreateClient(ClientOptions());
+
+    private static async Task<string> RegisterAsync(HttpClient client, string identity)
+    {
+        using var response = await client.PostAsJsonAsync("/auth/bifrost/register", new { identity, displayName = identity });
+        Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+        return identity.ToLowerInvariant();
+    }
+
+    private async Task<(HttpClient Client, string Identity)> SignedInAsync(MembershipStatus status, string displayName)
+    {
+        var client = NewClient();
+        var identity = await RegisterAsync(client, $"member-{Guid.NewGuid():N}");
+        await _factory.SetMembershipAsync(identity, status);
+        await _factory.SetDisplayNameAsync(identity, displayName);
+        return (client, identity);
+    }
+
+    private async Task SetLinksAsync(string identity, string heimdallAccountId, string gitHubLogin)
+    {
+        using var scope = _factory.Services.CreateScope();
+        var db = scope.ServiceProvider.GetRequiredService<Bifrost.Web.Data.BifrostDbContext>();
+        var account = db.UserAccounts.Single(x => x.NormalizedBifrostIdentity == identity);
+        account.HeimdallAccountId = heimdallAccountId;
+        account.GitHubLogin = gitHubLogin;
+        await db.SaveChangesAsync();
+    }
+
+    private sealed record AuthRequest(string Verifier, string State, string Nonce, string Path)
+    {
+        public string Challenge => Base64UrlEncoder.Encode(SHA256.HashData(Encoding.ASCII.GetBytes(Verifier)));
+    }
+
+    private static AuthRequest NewRequest(
+        string clientId = OidcTestKit.ClientId,
+        string redirectUri = OidcTestKit.RedirectUri,
+        bool pkce = true,
+        string extra = "",
+        string scope = "openid%20profile")
+    {
+        var verifier = Base64UrlEncoder.Encode(RandomNumberGenerator.GetBytes(48));
+        var state = Base64UrlEncoder.Encode(RandomNumberGenerator.GetBytes(24));
+        var nonce = Base64UrlEncoder.Encode(RandomNumberGenerator.GetBytes(24));
+        var challenge = Base64UrlEncoder.Encode(SHA256.HashData(Encoding.ASCII.GetBytes(verifier)));
+        var path = "/connect/authorize?response_type=code" +
+            $"&client_id={Uri.EscapeDataString(clientId)}" +
+            $"&redirect_uri={Uri.EscapeDataString(redirectUri)}" +
+            $"&scope={scope}" +
+            $"&state={state}&nonce={nonce}" +
+            (pkce ? $"&code_challenge={challenge}&code_challenge_method=S256" : string.Empty) +
+            extra;
+        return new AuthRequest(verifier, state, nonce, path);
+    }
+
+    /// <summary>Starts an authorize request and follows the provider's own redirects until the first response that is not one of them.</summary>
+    private static async Task<HttpResponseMessage> DriveAsync(HttpClient client, AuthRequest request)
+    {
+        var response = await client.GetAsync(request.Path);
+        for (var hops = 0; hops < 4 && IsAuthorizeRedirect(response); hops++)
+        {
+            var next = response.Headers.Location!;
+            response.Dispose();
+            response = await client.GetAsync(next.IsAbsoluteUri ? next.PathAndQuery : next.OriginalString);
+        }
+
+        return response;
+    }
+
+    private static bool IsAuthorizeRedirect(HttpResponseMessage response) =>
+        response.StatusCode is HttpStatusCode.Redirect or HttpStatusCode.Found &&
+        response.Headers.Location is { } location &&
+        (location.IsAbsoluteUri ? location.AbsolutePath : location.OriginalString).StartsWith("/connect/authorize", StringComparison.Ordinal);
+
+    private static string ReturnUrl(HttpResponseMessage signInRedirect)
+    {
+        var location = signInRedirect.Headers.Location!;
+        var query = location.IsAbsoluteUri ? location.Query : location.OriginalString[location.OriginalString.IndexOf('?')..];
+        return Microsoft.AspNetCore.WebUtilities.QueryHelpers.ParseQuery(query)
+            .Single(x => string.Equals(x.Key, "returnUrl", StringComparison.OrdinalIgnoreCase)).Value.ToString();
+    }
+
+    private static Dictionary<string, string?> AssertRedirectToClient(HttpResponseMessage response, string state)
+    {
+        Assert.True(response.StatusCode is HttpStatusCode.Redirect or HttpStatusCode.Found, $"expected a redirect, got {(int)response.StatusCode}");
+        var location = response.Headers.Location!;
+        Assert.Equal(new Uri(OidcTestKit.RedirectUri).GetLeftPart(UriPartial.Path), location.GetLeftPart(UriPartial.Path));
+        var query = Microsoft.AspNetCore.WebUtilities.QueryHelpers.ParseQuery(location.Query);
+        Assert.Equal(state, query["state"].ToString());
+        return query.ToDictionary(x => x.Key, x => (string?)x.Value.ToString());
+    }
+
+    private async Task<string> CodeAsync(HttpClient signedIn, AuthRequest request)
+    {
+        var final = await DriveAsync(signedIn, request);
+        return AssertRedirectToClient(final, request.State)["code"]!;
+    }
+
+    private sealed record Tokens(AuthRequest Request, string IdToken, string AccessToken);
+
+    private async Task<Tokens> CompleteFlowAsync(HttpClient signedIn)
+    {
+        var request = NewRequest();
+        var code = await CodeAsync(signedIn, request);
+        return await ExchangeAsync(signedIn, request, code);
+    }
+
+    private async Task<Tokens> ExchangeAsync(HttpClient client, AuthRequest request, string code)
+    {
+        using var response = await TokenAsync(client, request, code);
+        Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+        var body = await response.Content.ReadFromJsonAsync<JsonElement>();
+        Assert.DoesNotContain("refresh_token", body.EnumerateObject().Select(x => x.Name));
+        return new Tokens(request, body.GetProperty("id_token").GetString()!, body.GetProperty("access_token").GetString()!);
+    }
+
+    private async Task<HttpResponseMessage> TokenAsync(
+        HttpClient client, AuthRequest request, string code, string? secret = null, bool secretInBody = false)
+    {
+        var form = new Dictionary<string, string>
+        {
+            ["grant_type"] = "authorization_code",
+            ["code"] = code,
+            ["redirect_uri"] = OidcTestKit.RedirectUri,
+            ["code_verifier"] = request.Verifier
+        };
+        var message = new HttpRequestMessage(HttpMethod.Post, "/connect/token");
+        var effectiveSecret = secret ?? _factory.Kit.ClientSecret;
+        if (secretInBody)
+        {
+            form["client_id"] = OidcTestKit.ClientId;
+            form["client_secret"] = effectiveSecret;
+        }
+        else
+        {
+            message.Headers.Authorization = new AuthenticationHeaderValue(
+                "Basic",
+                Convert.ToBase64String(Encoding.ASCII.GetBytes($"{OidcTestKit.ClientId}:{effectiveSecret}")));
+        }
+
+        message.Content = new FormUrlEncodedContent(form);
+        // The code is bound to the client; use a cookieless client so a session cannot influence the exchange.
+        using var bare = NewClient();
+        return await bare.SendAsync(message);
+    }
+
+    private sealed record Verified(string Alg, string PayloadJson, JsonElement Payload)
+    {
+        public string? Claim(string name) => Payload.TryGetProperty(name, out var value) ? value.GetString() : null;
+    }
+
+    private async Task<Verified> ValidateIdTokenAsync(string idToken, string? nonce)
+    {
+        using var client = NewClient();
+        var jwks = new JsonWebKeySet((await GetJwksAsync(client)).GetRawText());
+        var result = await new JsonWebTokenHandler().ValidateTokenAsync(idToken, new TokenValidationParameters
+        {
+            ValidIssuer = Origin.AbsoluteUri,
+            ValidAudience = OidcTestKit.ClientId,
+            IssuerSigningKeys = jwks.GetSigningKeys(),
+            ValidAlgorithms = ["ES256"]
+        });
+        Assert.True(result.IsValid, result.Exception?.Message);
+        var jwt = (JsonWebToken)result.SecurityToken;
+        var payload = Encoding.UTF8.GetString(Base64UrlEncoder.DecodeBytes(jwt.EncodedPayload));
+        if (nonce is not null)
+        {
+            Assert.Equal(nonce, JsonDocument.Parse(payload).RootElement.GetProperty("nonce").GetString());
+        }
+
+        return new Verified(jwt.Alg, payload, JsonDocument.Parse(payload).RootElement.Clone());
+    }
+
+    private static async Task<JsonElement> GetJwksAsync(HttpClient client)
+    {
+        var discovery = await client.GetFromJsonAsync<JsonElement>("/.well-known/openid-configuration");
+        var jwksUri = new Uri(discovery.GetProperty("jwks_uri").GetString()!);
+        return await client.GetFromJsonAsync<JsonElement>(jwksUri.PathAndQuery);
+    }
+
+    private static string[] Strings(JsonElement document, string property) =>
+        document.GetProperty(property).EnumerateArray().Select(x => x.GetString()!).ToArray();
+}
+
+public sealed class OidcSurfaceAbsentTests : IClassFixture<TestWebApplicationFactory>
+{
+    private readonly TestWebApplicationFactory _factory;
+
+    public OidcSurfaceAbsentTests(TestWebApplicationFactory factory) => _factory = factory;
+
+    [Theory]
+    [InlineData("/.well-known/openid-configuration")]
+    [InlineData("/.well-known/jwks")]
+    [InlineData("/connect/authorize")]
+    [InlineData("/connect/token")]
+    [InlineData("/connect/userinfo")]
+    public async Task Without_the_configuration_section_no_provider_surface_exists(string path)
+    {
+        using var client = _factory.CreateClient();
+        using var response = await client.GetAsync(path);
+
+        Assert.Equal(HttpStatusCode.NotFound, response.StatusCode);
+    }
+}
+
+public sealed class OidcStartupFailureTests
+{
+    [Theory]
+    [InlineData(OidcKeyFault.MissingFile)]
+    [InlineData(OidcKeyFault.RsaKey)]
+    [InlineData(OidcKeyFault.PublicKeyOnly)]
+    [InlineData(OidcKeyFault.NotPem)]
+    public void A_configured_provider_with_an_unusable_signing_key_stops_startup_naming_the_setting_not_the_path(OidcKeyFault fault)
+    {
+        using var factory = new OidcKeyFaultFactory(fault);
+
+        var failure = Assert.ThrowsAny<Exception>(() => factory.CreateClient());
+
+        var messages = Flatten(failure).ToList();
+        Assert.Contains(messages, m => m.Contains("Bifrost:Oidc:SigningKeyPath", StringComparison.Ordinal));
+        Assert.DoesNotContain(messages, m => m.Contains("canary-", StringComparison.Ordinal));
+        Assert.DoesNotContain(messages, m => m.Contains("BEGIN", StringComparison.Ordinal));
+    }
+
+    private static IEnumerable<string> Flatten(Exception error)
+    {
+        for (var current = error; current is not null; current = current.InnerException!)
+        {
+            yield return current.Message;
+            if (current.InnerException is null)
+            {
+                yield break;
+            }
+        }
+    }
+}

tests/Bifrost.Web.Tests/OidcKeyMaterialTests.cs

@@ -0,0 +1,129 @@
+using System.Security.Cryptography;
+using Bifrost.Web.Configuration;
+using Bifrost.Web.Features.Oidc;
+using Bifrost.Web.Tests.Support;
+using Microsoft.IdentityModel.Tokens;
+
+namespace Bifrost.Web.Tests;
+
+public sealed class OidcKeyMaterialTests : IDisposable
+{
+    private readonly OidcTestKit _kit = new();
+
+    public void Dispose() => _kit.Dispose();
+
+    [Fact]
+    public void A_complete_configuration_loads_the_signing_key_the_secret_and_the_encryption_key()
+    {
+        using var material = OidcKeyMaterial.Load(Options());
+
+        var signing = Assert.IsType<ECDsaSecurityKey>(material.SigningKey);
+        Assert.False(string.IsNullOrEmpty(signing.KeyId));
+        Assert.Equal(_kit.ClientSecret, material.ClientSecret);
+        Assert.Equal(32, Assert.IsType<SymmetricSecurityKey>(material.EncryptionKey).Key.Length);
+    }
+
+    [Theory]
+    [InlineData("SigningKeyPath", "Bifrost:Oidc:SigningKeyPath")]
+    [InlineData("EncryptionKeyPath", "Bifrost:Oidc:EncryptionKeyPath")]
+    [InlineData("ClientId", "Bifrost:Oidc:Clients:Mas:ClientId")]
+    [InlineData("ClientSecretPath", "Bifrost:Oidc:Clients:Mas:ClientSecretPath")]
+    [InlineData("RedirectUri", "Bifrost:Oidc:Clients:Mas:RedirectUri")]
+    public void A_missing_setting_stops_startup_naming_that_setting(string blank, string expectedField)
+    {
+        var failure = Assert.Throws<OidcConfigurationException>(() => OidcKeyMaterial.Load(Options(blank: blank)));
+
+        Assert.Contains(expectedField, failure.Message, StringComparison.Ordinal);
+    }
+
+    [Fact]
+    public void A_redirect_uri_that_is_not_absolute_stops_startup()
+    {
+        var failure = Assert.Throws<OidcConfigurationException>(() => OidcKeyMaterial.Load(Options(redirectUri: "/callback")));
+
+        Assert.Contains("Bifrost:Oidc:Clients:Mas:RedirectUri", failure.Message, StringComparison.Ordinal);
+    }
+
+    [Theory]
+    [InlineData("missing")]
+    [InlineData("not base64 !!")]
+    [InlineData("AAAAAAAAAAAAAAAAAAAAAA==")]
+    public void An_unusable_encryption_key_stops_startup_naming_the_setting_not_the_path(string content)
+    {
+        if (content == "missing")
+        {
+            File.Delete(_kit.EncryptionKeyPath);
+        }
+        else
+        {
+            File.WriteAllText(_kit.EncryptionKeyPath, content);
+        }
+
+        var failure = Assert.Throws<OidcConfigurationException>(() => OidcKeyMaterial.Load(Options()));
+
+        Assert.Contains("Bifrost:Oidc:EncryptionKeyPath", failure.Message, StringComparison.Ordinal);
+        Assert.DoesNotContain("canary-", failure.Message, StringComparison.Ordinal);
+    }
+
+    [Fact]
+    public void A_missing_client_secret_file_stops_startup_naming_the_setting_not_the_path()
+    {
+        File.Delete(_kit.ClientSecretPath);
+
+        var failure = Assert.Throws<OidcConfigurationException>(() => OidcKeyMaterial.Load(Options()));
+
+        Assert.Contains("Bifrost:Oidc:Clients:Mas:ClientSecretPath", failure.Message, StringComparison.Ordinal);
+        Assert.DoesNotContain("canary-", failure.Message, StringComparison.Ordinal);
+    }
+
+    [Fact]
+    public void A_P384_key_is_not_a_P256_key()
+    {
+        using var p384 = ECDsa.Create(ECCurve.NamedCurves.nistP384);
+        File.WriteAllText(_kit.SigningKeyPath, p384.ExportPkcs8PrivateKeyPem());
+
+        var failure = Assert.Throws<OidcConfigurationException>(() => OidcKeyMaterial.Load(Options()));
+
+        Assert.Contains("Bifrost:Oidc:SigningKeyPath", failure.Message, StringComparison.Ordinal);
+    }
+
+    [Theory]
+    [InlineData("not a uri")]
+    [InlineData("/upstream/backchannel-logout/01ABC")]
+    [InlineData("ftp://mas.example.test/upstream/backchannel-logout/01ABC")]
+    public void A_back_channel_logout_uri_that_is_not_absolute_http_stops_startup_naming_the_setting_not_the_value(string uri)
+    {
+        var failure = Assert.Throws<OidcConfigurationException>(() => OidcKeyMaterial.Load(Options(logoutUri: uri)));
+
+        Assert.Contains("Bifrost:Oidc:Clients:Mas:BackchannelLogoutUri", failure.Message, StringComparison.Ordinal);
+        Assert.DoesNotContain(uri, failure.Message, StringComparison.Ordinal);
+    }
+
+    [Theory]
+    [InlineData("")]
+    [InlineData("   ")]
+    [InlineData("https://mas.example.test/upstream/backchannel-logout/01ABC")]
+    [InlineData("http://mas.internal/upstream/backchannel-logout/01ABC")]
+    public void An_absent_or_absolute_http_back_channel_logout_uri_loads(string uri)
+    {
+        using var material = OidcKeyMaterial.Load(Options(logoutUri: uri));
+
+        Assert.NotNull(material.SigningKey);
+    }
+
+    private OidcIssuerOptions Options(string? blank = null, string? redirectUri = null, string logoutUri = "") => new()
+    {
+        SigningKeyPath = blank == "SigningKeyPath" ? "" : _kit.SigningKeyPath,
+        EncryptionKeyPath = blank == "EncryptionKeyPath" ? "" : _kit.EncryptionKeyPath,
+        Clients = new OidcClientsOptions
+        {
+            Mas = new OidcClientOptions
+            {
+                ClientId = blank == "ClientId" ? "" : OidcTestKit.ClientId,
+                ClientSecretPath = blank == "ClientSecretPath" ? "" : _kit.ClientSecretPath,
+                RedirectUri = blank == "RedirectUri" ? "" : redirectUri ?? OidcTestKit.RedirectUri,
+                BackchannelLogoutUri = logoutUri
+            }
+        }
+    };
+}

tests/Bifrost.Web.Tests/OidcLogoutTests.cs

@@ -0,0 +1,499 @@
+using System.Text.Json;
+using Bifrost.Web.Domain;
+using Bifrost.Web.Features.Oidc;
+using Bifrost.Web.Tests.Support;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Hosting;
+using Microsoft.IdentityModel.JsonWebTokens;
+using Microsoft.IdentityModel.Tokens;
+using OpenIddict.Abstractions;
+
+namespace Bifrost.Web.Tests;
+
+public sealed class OidcLogoutTests
+{
+    private static readonly TimeSpan[] ExpectedBackoff =
+        new[] { 30, 60, 120, 240, 480, 900, 900 }.Select(x => TimeSpan.FromSeconds(x)).ToArray();
+
+    [Fact]
+    public async Task Probe_authorizations_carry_the_subject_and_a_valid_status_after_a_code_flow()
+    {
+        using var factory = new OidcLogoutFactory();
+        var (identity, _) = await factory.GrantAsync();
+
+        Assert.True(factory.ValidAuthorizations(factory.AccountId(identity).ToString("D")) > 0);
+        using var scope = factory.Services.CreateScope();
+        var manager = scope.ServiceProvider.GetRequiredService<IOpenIddictAuthorizationManager>();
+        var found = new List<object>();
+        await foreach (var authorization in manager.FindBySubjectAsync(factory.AccountId(identity).ToString("D")))
+        {
+            found.Add(authorization);
+        }
+
+        Assert.NotEmpty(found);
+        Assert.True(await manager.TryRevokeAsync(found[0]));
+    }
+
+    [Theory]
+    [InlineData(MembershipStatus.Suspended)]
+    [InlineData(MembershipStatus.PendingApproval)]
+    [InlineData(MembershipStatus.Authenticated)]
+    public async Task A_member_who_is_not_active_gets_one_signed_logout_and_loses_the_authorizations(MembershipStatus status)
+    {
+        using var factory = new OidcLogoutFactory();
+        var (identity, idToken) = await factory.GrantAsync(status);
+        var subject = factory.AccountId(identity).ToString("D");
+        var reconciler = factory.Reconciler;
+
+        await reconciler.ReconcileOnceAsync(CancellationToken.None);
+
+        var token = Assert.Single(factory.Mas.LogoutTokens());
+        var result = await new JsonWebTokenHandler().ValidateTokenAsync(token, new TokenValidationParameters
+        {
+            ValidIssuer = OidcLogoutFactory.Origin.AbsoluteUri,
+            ValidAudience = OidcTestKit.ClientId,
+            IssuerSigningKeys = (await factory.JwksAsync()).GetSigningKeys(),
+            ValidAlgorithms = ["ES256"],
+            ValidTypes = ["logout+jwt"],
+            ValidateLifetime = false
+        });
+        Assert.True(result.IsValid, result.Exception?.Message);
+        var jwt = (JsonWebToken)result.SecurityToken;
+        Assert.Equal("logout+jwt", jwt.Typ);
+        Assert.Equal(new JsonWebToken(idToken).Issuer, jwt.Issuer);
+        Assert.Equal(subject, jwt.Subject);
+        Assert.Equal(TimeSpan.FromMinutes(2), jwt.ValidTo - jwt.IssuedAt);
+        Assert.Equal(factory.Time.GetUtcNow().ToUnixTimeSeconds(), new DateTimeOffset(jwt.IssuedAt).ToUnixTimeSeconds());
+        Assert.False(string.IsNullOrEmpty(jwt.Id));
+        var payload = JsonDocument.Parse(Base64UrlEncoder.Decode(jwt.EncodedPayload)).RootElement;
+        var events = payload.GetProperty("events");
+        Assert.Equal(["http://schemas.openid.net/event/backchannel-logout"], events.EnumerateObject().Select(x => x.Name).ToArray());
+        Assert.Equal(JsonValueKind.Object, events.EnumerateObject().Single().Value.ValueKind);
+        Assert.False(payload.TryGetProperty("nonce", out _));
+        Assert.False(payload.TryGetProperty("sid", out _));
+        Assert.Equal(0, factory.ValidAuthorizations(subject));
+
+        await reconciler.ReconcileOnceAsync(CancellationToken.None);
+        Assert.Single(factory.Mas.Bodies);
+    }
+
+    [Fact]
+    public async Task Two_logouts_for_one_subject_carry_different_jti()
+    {
+        using var factory = new OidcLogoutFactory();
+        var (identity, _) = await factory.GrantAsync(MembershipStatus.Suspended);
+        factory.Mas.Script(500, 200);
+
+        await factory.Reconciler.ReconcileOnceAsync(CancellationToken.None);
+        factory.Time.Advance(TimeSpan.FromSeconds(30));
+        await factory.Reconciler.ReconcileOnceAsync(CancellationToken.None);
+
+        var ids = factory.Mas.LogoutTokens().Select(x => new JsonWebToken(x).Id).ToArray();
+        Assert.Equal(2, ids.Length);
+        Assert.NotEqual(ids[0], ids[1]);
+        Assert.Equal(0, factory.ValidAuthorizations(factory.AccountId(identity).ToString("D")));
+    }
+
+    [Fact]
+    public async Task An_active_member_is_never_sent_and_keeps_the_authorizations()
+    {
+        using var factory = new OidcLogoutFactory();
+        var (suspended, _) = await factory.GrantAsync(MembershipStatus.Suspended);
+        var (active, _) = await factory.GrantAsync(MembershipStatus.Active);
+        var activeSubject = factory.AccountId(active).ToString("D");
+        var before = factory.ValidAuthorizations(activeSubject);
+        Assert.True(before > 0);
+
+        await factory.Reconciler.ReconcileOnceAsync(CancellationToken.None);
+
+        var token = Assert.Single(factory.Mas.LogoutTokens());
+        Assert.Equal(factory.AccountId(suspended).ToString("D"), new JsonWebToken(token).Subject);
+        Assert.Equal(before, factory.ValidAuthorizations(activeSubject));
+    }
+
+    [Fact]
+    public async Task One_subject_that_cannot_be_delivered_does_not_block_another()
+    {
+        using var factory = new OidcLogoutFactory();
+        var (first, _) = await factory.GrantAsync(MembershipStatus.Suspended);
+        var (second, _) = await factory.GrantAsync(MembershipStatus.Suspended);
+        factory.Mas.Script(500);
+
+        await factory.Reconciler.ReconcileOnceAsync(CancellationToken.None);
+
+        Assert.Equal(2, factory.Mas.Bodies.Count);
+        var delivered = new[] { first, second }.Count(x => factory.ValidAuthorizations(factory.AccountId(x).ToString("D")) == 0);
+        Assert.Equal(1, delivered);
+    }
+
+    [Fact]
+    public async Task Delivery_retries_with_exponential_capped_backoff_and_revokes_only_after_a_2xx()
+    {
+        using var factory = new OidcLogoutFactory();
+        var (identity, _) = await factory.GrantAsync(MembershipStatus.Suspended);
+        var subject = factory.AccountId(identity).ToString("D");
+        factory.Mas.Script(500, 500, 500, 500, 500, 500, 500, 200);
+        var reconciler = factory.Reconciler;
+
+        var posts = 0;
+        foreach (var delay in ExpectedBackoff)
+        {
+            await reconciler.ReconcileOnceAsync(CancellationToken.None);
+            Assert.Equal(++posts, factory.Mas.Bodies.Count);
+            Assert.True(factory.ValidAuthorizations(subject) > 0, "a failed delivery must not revoke");
+
+            factory.Time.Advance(delay - TimeSpan.FromSeconds(1));
+            await reconciler.ReconcileOnceAsync(CancellationToken.None);
+            Assert.Equal(posts, factory.Mas.Bodies.Count);
+
+            factory.Time.Advance(TimeSpan.FromSeconds(1));
+        }
+
+        await reconciler.ReconcileOnceAsync(CancellationToken.None);
+        Assert.Equal(8, factory.Mas.Bodies.Count);
+        Assert.Equal(0, factory.ValidAuthorizations(subject));
+    }
+
+    [Theory]
+    [InlineData(FakeMasHandler.NetworkFault)]
+    [InlineData(FakeMasHandler.Timeout)]
+    [InlineData(300)]
+    [InlineData(302)]
+    [InlineData(401)]
+    public async Task A_network_fault_timeout_or_unexpected_status_keeps_the_authorizations_and_retries(int fault)
+    {
+        using var factory = new OidcLogoutFactory();
+        var (identity, _) = await factory.GrantAsync(MembershipStatus.Suspended);
+        var subject = factory.AccountId(identity).ToString("D");
+        factory.Mas.Script(fault);
+
+        await factory.Reconciler.ReconcileOnceAsync(CancellationToken.None);
+        Assert.True(factory.ValidAuthorizations(subject) > 0);
+        factory.Time.Advance(TimeSpan.FromSeconds(30));
+        await factory.Reconciler.ReconcileOnceAsync(CancellationToken.None);
+
+        Assert.Equal(2, factory.Mas.Bodies.Count);
+        Assert.Equal(0, factory.ValidAuthorizations(subject));
+    }
+
+    [Fact]
+    public async Task A_restarted_reconciler_resumes_the_pending_subject_from_the_table()
+    {
+        using var factory = new OidcLogoutFactory();
+        var (identity, _) = await factory.GrantAsync(MembershipStatus.Suspended);
+        var subject = factory.AccountId(identity).ToString("D");
+        factory.Mas.Script(500);
+
+        await factory.Reconciler.ReconcileOnceAsync(CancellationToken.None);
+        Assert.Single(factory.Mas.Bodies);
+        await factory.NewReconciler().ReconcileOnceAsync(CancellationToken.None);
+
+        Assert.Equal(2, factory.Mas.Bodies.Count);
+        Assert.Equal(0, factory.ValidAuthorizations(subject));
+    }
+
+    [Theory]
+    [InlineData(400)]
+    [InlineData(404)]
+    public async Task A_400_or_404_is_a_fault_not_success_and_backs_off_at_the_cap(int status)
+    {
+        using var factory = new OidcLogoutFactory();
+        var (identity, _) = await factory.GrantAsync(MembershipStatus.Suspended);
+        var subject = factory.AccountId(identity).ToString("D");
+        factory.Mas.Script(status, status);
+        var reconciler = factory.Reconciler;
+
+        await reconciler.ReconcileOnceAsync(CancellationToken.None);
+        factory.Time.Advance(OidcLogoutReconciler.MaxBackoff - TimeSpan.FromSeconds(1));
+        await reconciler.ReconcileOnceAsync(CancellationToken.None);
+        Assert.Single(factory.Mas.Bodies);
+        Assert.True(factory.ValidAuthorizations(subject) > 0);
+
+        factory.Time.Advance(TimeSpan.FromSeconds(1));
+        await reconciler.ReconcileOnceAsync(CancellationToken.None);
+        Assert.Equal(2, factory.Mas.Bodies.Count);
+        factory.Time.Advance(OidcLogoutReconciler.MaxBackoff - TimeSpan.FromSeconds(1));
+        await reconciler.ReconcileOnceAsync(CancellationToken.None);
+        Assert.Equal(2, factory.Mas.Bodies.Count);
+        Assert.True(factory.ValidAuthorizations(subject) > 0);
+    }
+
+    [Fact]
+    public async Task A_subject_that_is_not_an_account_id_is_treated_as_not_active()
+    {
+        using var factory = new OidcLogoutFactory();
+        var (active, _) = await factory.GrantAsync(MembershipStatus.Active);
+        await factory.AddAuthorizationAsync("not-a-guid");
+
+        await factory.Reconciler.ReconcileOnceAsync(CancellationToken.None);
+
+        var token = Assert.Single(factory.Mas.LogoutTokens());
+        Assert.Equal("not-a-guid", new JsonWebToken(token).Subject);
+        Assert.Equal(0, factory.ValidAuthorizations("not-a-guid"));
+        Assert.True(factory.ValidAuthorizations(factory.AccountId(active).ToString("D")) > 0);
+    }
+
+    [Fact]
+    public async Task A_deleted_account_is_treated_as_not_active()
+    {
+        using var factory = new OidcLogoutFactory();
+        var (identity, _) = await factory.GrantAsync(MembershipStatus.Active);
+        var subject = factory.AccountId(identity).ToString("D");
+        await factory.DeleteAccountAsync(identity);
+
+        await factory.Reconciler.ReconcileOnceAsync(CancellationToken.None);
+
+        Assert.Equal(subject, new JsonWebToken(Assert.Single(factory.Mas.LogoutTokens())).Subject);
+        Assert.Equal(0, factory.ValidAuthorizations(subject));
+    }
+
+    [Theory]
+    [InlineData(201)]
+    [InlineData(204)]
+    [InlineData(299)]
+    public async Task Any_2xx_is_delivery(int status)
+    {
+        using var factory = new OidcLogoutFactory();
+        var (identity, _) = await factory.GrantAsync(MembershipStatus.Suspended);
+        factory.Mas.Script(status);
+
+        await factory.Reconciler.ReconcileOnceAsync(CancellationToken.None);
+
+        Assert.Equal(0, factory.ValidAuthorizations(factory.AccountId(identity).ToString("D")));
+    }
+
+    [Fact]
+    public async Task A_failure_is_logged_by_status_and_delay_only_and_a_success_logs_no_failure()
+    {
+        using var factory = new OidcLogoutFactory();
+        await factory.GrantAsync(MembershipStatus.Suspended);
+        await factory.GrantAsync(MembershipStatus.Suspended);
+        var log = new ListLogger<OidcLogoutReconciler>();
+        factory.Mas.Script(503, FakeMasHandler.NetworkFault);
+
+        await factory.NewReconciler(logger: log).ReconcileOnceAsync(CancellationToken.None);
+
+        // The first subject failed with 503, the second with no response; both were delivered nothing.
+        var warnings = log.Entries.Where(x => x.Level == LogLevel.Warning).Select(x => x.Message).ToArray();
+        Assert.Equal(2, warnings.Length);
+        Assert.Contains(warnings, x => x.Contains("503", StringComparison.Ordinal) && x.Contains("00:00:30", StringComparison.Ordinal));
+        Assert.Contains(warnings, x => x.Contains("no response", StringComparison.Ordinal));
+        Assert.All(log.Entries, x =>
+        {
+            Assert.DoesNotContain(FakeMasHandler.BodyCanary, x.Message, StringComparison.Ordinal);
+            Assert.DoesNotContain("mas.example.test", x.Message, StringComparison.Ordinal);
+            Assert.DoesNotContain("logout_token", x.Message, StringComparison.Ordinal);
+        });
+
+        var clean = new ListLogger<OidcLogoutReconciler>();
+        await factory.NewReconciler(logger: clean).ReconcileOnceAsync(CancellationToken.None);
+        Assert.Empty(clean.Entries.Where(x => x.Level >= LogLevel.Warning));
+    }
+
+    [Fact]
+    public async Task A_subject_who_recovers_or_whose_grants_vanish_carries_no_stale_backoff()
+    {
+        using var factory = new OidcLogoutFactory();
+        var (identity, _) = await factory.GrantAsync(MembershipStatus.Suspended);
+        var subject = factory.AccountId(identity).ToString("D");
+        factory.Mas.Script(500, 500);
+        var reconciler = factory.Reconciler;
+
+        // Recovered: Active again clears the backoff, so the next demotion is delivered at once.
+        await reconciler.ReconcileOnceAsync(CancellationToken.None);
+        Assert.Single(factory.Mas.Bodies);
+        await factory.SetMembershipAsync(identity, MembershipStatus.Active);
+        await reconciler.ReconcileOnceAsync(CancellationToken.None);
+        await factory.SetMembershipAsync(identity, MembershipStatus.Suspended);
+        await reconciler.ReconcileOnceAsync(CancellationToken.None);
+        Assert.Equal(2, factory.Mas.Bodies.Count);
+
+        // Vanished: grants revoked elsewhere drop the subject from the list, which drops its backoff.
+        await factory.RevokeAllAsync(subject);
+        await reconciler.ReconcileOnceAsync(CancellationToken.None);
+        await factory.AddAuthorizationAsync(subject);
+        await reconciler.ReconcileOnceAsync(CancellationToken.None);
+        Assert.Equal(3, factory.Mas.Bodies.Count);
+        Assert.Equal(0, factory.ValidAuthorizations(subject));
+    }
+
+    [Fact]
+    public async Task One_subject_that_throws_unexpectedly_does_not_stop_the_pass_and_keeps_its_authorizations()
+    {
+        using var factory = new OidcLogoutFactory();
+        var log = new ListLogger<OidcLogoutReconciler>();
+        var reconciler = factory.NewReconciler(logger: log);
+        var (first, _) = await factory.GrantAsync(MembershipStatus.Suspended);
+        var (second, _) = await factory.GrantAsync(MembershipStatus.Suspended);
+        var subjects = new[] { first, second }.Select(x => factory.AccountId(x).ToString("D")).ToArray();
+
+        // Whichever subject the pass reaches first throws; the other is still logged out and revoked.
+        factory.Mas.Script(FakeMasHandler.Unexpected);
+        await reconciler.ReconcileOnceAsync(CancellationToken.None);
+
+        Assert.Equal(2, factory.Mas.Bodies.Count);
+        var firstToken = factory.Mas.LogoutTokens()[0];
+        var thrown = new JsonWebToken(firstToken).Subject;
+        var other = subjects.Single(x => x != thrown);
+        Assert.Equal(0, factory.ValidAuthorizations(other));
+        Assert.True(factory.ValidAuthorizations(thrown) > 0);
+        var failure = Assert.Single(log.Entries, x => x.Level == LogLevel.Error);
+        Assert.Contains(thrown, failure.Message, StringComparison.Ordinal);
+        Assert.Contains(nameof(InvalidOperationException), failure.Message, StringComparison.Ordinal);
+        Assert.DoesNotContain("not a network fault", failure.Message, StringComparison.Ordinal);
+        Assert.DoesNotContain(firstToken, failure.Message, StringComparison.Ordinal);
+
+        // The failed subject was not backed off: the next pass tries it again and delivers.
+        await reconciler.ReconcileOnceAsync(CancellationToken.None);
+        Assert.Equal(3, factory.Mas.Bodies.Count);
+        Assert.Equal(0, factory.ValidAuthorizations(thrown));
+    }
+
+    [Fact]
+    public async Task A_cancelled_post_stops_the_pass_and_is_not_a_failed_delivery()
+    {
+        using var factory = new OidcLogoutFactory();
+        var (identity, _) = await factory.GrantAsync(MembershipStatus.Suspended);
+        var subject = factory.AccountId(identity).ToString("D");
+        var reconciler = factory.Reconciler;
+
+        // Stopping while the post is in flight surfaces as cancellation and records no backoff: the next pass posts at once.
+        factory.Mas.Script(FakeMasHandler.Hang);
+        using var stop = new CancellationTokenSource(TimeSpan.FromMilliseconds(300));
+        await Assert.ThrowsAnyAsync<OperationCanceledException>(() => reconciler.ReconcileOnceAsync(stop.Token));
+        Assert.Single(factory.Mas.Bodies);
+        await reconciler.ReconcileOnceAsync(CancellationToken.None);
+        Assert.Equal(2, factory.Mas.Bodies.Count);
+        Assert.Equal(0, factory.ValidAuthorizations(subject));
+    }
+
+    [Fact]
+    public async Task A_redirect_from_mas_is_not_followed_and_is_not_delivery()
+    {
+        using var mas = new RedirectingMas();
+        using var factory = new OidcLogoutFactory(mas.LogoutUri);
+        var (identity, _) = await factory.GrantAsync(MembershipStatus.Suspended);
+        var subject = factory.AccountId(identity).ToString("D");
+        var before = factory.ValidAuthorizations(subject);
+        Assert.True(before > 0);
+
+        await factory.Reconciler.ReconcileOnceAsync(CancellationToken.None);
+
+        Assert.Equal(["POST /logout"], mas.Requests);
+        Assert.Equal(before, factory.ValidAuthorizations(subject));
+
+        // A redirect is a non-delivery like any non-2xx: it backs off, then posts again.
+        factory.Time.Advance(TimeSpan.FromSeconds(30));
+        await factory.Reconciler.ReconcileOnceAsync(CancellationToken.None);
+        Assert.Equal(["POST /logout", "POST /logout"], mas.Requests);
+        Assert.Equal(before, factory.ValidAuthorizations(subject));
+    }
+
+    [Fact]
+    public void The_logout_client_times_out_after_ten_seconds()
+    {
+        using var factory = new OidcLogoutFactory();
+        using var client = factory.CreateClient();
+
+        Assert.Equal(TimeSpan.FromSeconds(10), OidcLogoutReconciler.RequestTimeout);
+        Assert.Equal(
+            TimeSpan.FromSeconds(10),
+            factory.Services.GetRequiredService<IHttpClientFactory>().CreateClient(OidcLogoutReconciler.HttpClientName).Timeout);
+    }
+
+    [Fact]
+    public async Task The_hosted_loop_ticks_again_after_each_interval_and_survives_a_failed_tick()
+    {
+        using var factory = new OidcLogoutFactory();
+        var clock = new ControlledClock();
+        var log = new ListLogger<OidcLogoutReconciler>();
+        var reconciler = factory.NewReconciler(clock, log);
+        var (first, _) = await factory.GrantAsync(MembershipStatus.Suspended);
+        await reconciler.StartAsync(CancellationToken.None);
+        try
+        {
+            await WaitForAsync(() => factory.Mas.Bodies.Count == 1);
+            Assert.Equal(0, factory.ValidAuthorizations(factory.AccountId(first).ToString("D")));
+
+            // A failing tick is logged and retried only after the interval, never in a tight loop.
+            var (second, _) = await factory.GrantAsync(MembershipStatus.Suspended);
+            factory.Mas.Script(FakeMasHandler.Unexpected);
+            await WaitForAsync(() => clock.Waiting > 0);
+            clock.FireTimers();
+            await WaitForAsync(() => factory.Mas.Bodies.Count == 2);
+            await Task.Delay(300);
+            Assert.Equal(2, factory.Mas.Bodies.Count);
+
+            await WaitForAsync(() => clock.Waiting > 0);
+            clock.FireTimers();
+            await WaitForAsync(() => factory.Mas.Bodies.Count == 3);
+            var failure = Assert.Single(log.Entries, x => x.Level == LogLevel.Error);
+            Assert.Contains(nameof(InvalidOperationException), failure.Message, StringComparison.Ordinal);
+            Assert.DoesNotContain("not a network fault", failure.Message, StringComparison.Ordinal);
+            await WaitForAsync(() => factory.ValidAuthorizations(factory.AccountId(second).ToString("D")) == 0);
+        }
+        finally
+        {
+            await reconciler.StopAsync(CancellationToken.None);
+        }
+    }
+
+    [Fact]
+    public async Task A_pass_that_cannot_read_its_subjects_is_logged_by_type_and_retried_after_the_interval()
+    {
+        using var factory = new OidcLogoutFactory();
+        var clock = new ControlledClock();
+        var log = new ListLogger<OidcLogoutReconciler>();
+        var flaky = new FlakyScopeFactory(factory.Services.GetRequiredService<IServiceScopeFactory>(), failures: 1);
+        var reconciler = factory.NewReconciler(clock, log, flaky);
+        var (identity, _) = await factory.GrantAsync(MembershipStatus.Suspended);
+        await reconciler.StartAsync(CancellationToken.None);
+        try
+        {
+            await WaitForAsync(() => log.Entries.Any(x => x.Level == LogLevel.Error) && clock.Waiting > 0);
+            var failure = Assert.Single(log.Entries, x => x.Level == LogLevel.Error);
+            Assert.Contains(nameof(InvalidOperationException), failure.Message, StringComparison.Ordinal);
+            Assert.DoesNotContain(FlakyScopeFactory.Secret, failure.Message, StringComparison.Ordinal);
+
+            // Never a tight loop: nothing posts until the interval passes, then the pass succeeds.
+            await Task.Delay(300);
+            Assert.Empty(factory.Mas.Bodies);
+            clock.FireTimers();
+            await WaitForAsync(() => factory.Mas.Bodies.Count == 1);
+            await WaitForAsync(() => factory.ValidAuthorizations(factory.AccountId(identity).ToString("D")) == 0);
+        }
+        finally
+        {
+            await reconciler.StopAsync(CancellationToken.None);
+        }
+    }
+
+    private static async Task WaitForAsync(Func<bool> condition)
+    {
+        var deadline = DateTime.UtcNow.AddSeconds(10);
+        while (!condition())
+        {
+            Assert.True(DateTime.UtcNow < deadline, "timed out waiting for the reconciler");
+            await Task.Delay(20);
+        }
+    }
+
+    [Fact]
+    public void Without_a_back_channel_logout_uri_the_reconciler_is_not_hosted_and_nothing_is_revoked()
+    {
+        using var factory = new OidcWebApplicationFactory();
+        using var client = factory.CreateClient();
+
+        Assert.Empty(factory.Services.GetServices<IHostedService>().OfType<OidcLogoutReconciler>());
+    }
+
+    [Fact]
+    public void The_reconciler_is_hosted_when_the_uri_is_set()
+    {
+        using var factory = new OidcLogoutFactory();
+        using var client = factory.CreateClient();
+
+        Assert.NotNull(factory.Reconciler);
+    }
+}

tests/Bifrost.Web.Tests/Support/CapturingLoggerProvider.cs

@@ -0,0 +1,45 @@
+using Microsoft.Extensions.Logging;
+
+namespace Bifrost.Web.Tests.Support;
+
+public sealed class CapturingLoggerProvider : ILoggerProvider
+{
+    private readonly List<string> _lines = [];
+
+    public IReadOnlyList<string> Lines
+    {
+        get
+        {
+            lock (_lines)
+            {
+                return _lines.ToArray();
+            }
+        }
+    }
+
+    public ILogger CreateLogger(string categoryName) => new Capture(this);
+
+    public void Dispose()
+    {
+    }
+
+    private sealed class Capture(CapturingLoggerProvider owner) : ILogger
+    {
+        public IDisposable? BeginScope<TState>(TState state) where TState : notnull => null;
+
+        public bool IsEnabled(LogLevel logLevel) => true;
+
+        public void Log<TState>(
+            LogLevel logLevel,
+            EventId eventId,
+            TState state,
+            Exception? exception,
+            Func<TState, Exception?, string> formatter)
+        {
+            lock (owner._lines)
+            {
+                owner._lines.Add(formatter(state, exception) + (exception is null ? string.Empty : "\n" + exception));
+            }
+        }
+    }
+}

tests/Bifrost.Web.Tests/Support/HeimdallTestKit.cs

@@ -0,0 +1,521 @@
+using System.Net;
+using System.Security.Cryptography;
+using System.Text;
+using System.Text.Json;
+using Bifrost.Web.Data;
+using Bifrost.Web.Features.Heimdall;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Mvc.Testing;
+using Microsoft.AspNetCore.WebUtilities;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection.Extensions;
+using Microsoft.Extensions.Logging;
+using Org.BouncyCastle.Math.EC.Rfc8032;
+
+namespace Bifrost.Web.Tests.Support;
+
+/// <summary>An Ed25519 key shaped like Heimdall's signing key: a "ed25519-" kid over a thumbprint prefix.</summary>
+public sealed class HeimdallKey
+{
+    private readonly byte[] _seed;
+
+    private HeimdallKey(byte[] seed, byte[] publicKey, string kid)
+    {
+        _seed = seed;
+        PublicKey = publicKey;
+        Kid = kid;
+    }
+
+    public string Kid { get; }
+
+    public byte[] PublicKey { get; }
+
+    public static HeimdallKey Generate(string? kid = null)
+    {
+        var seed = RandomNumberGenerator.GetBytes(Ed25519.SecretKeySize);
+        var publicKey = new byte[Ed25519.PublicKeySize];
+        Ed25519.GeneratePublicKey(seed, 0, publicKey, 0);
+        kid ??= "ed25519-" + Convert.ToHexString(SHA256.HashData(publicKey)).ToLowerInvariant()[..12];
+        return new HeimdallKey(seed, publicKey, kid);
+    }
+
+    public object Jwk() => new Dictionary<string, object?>
+    {
+        ["kty"] = "OKP",
+        ["crv"] = "Ed25519",
+        ["x"] = WebEncoders.Base64UrlEncode(PublicKey),
+        ["alg"] = "EdDSA",
+        ["kid"] = Kid,
+        ["use"] = "sig"
+    };
+
+    /// <summary>Signs like Heimdall's signJwt: header {alg, kid, typ}, compact JWS.</summary>
+    public string Sign(IDictionary<string, object?> claims, string alg = "EdDSA", string? kid = "") =>
+        SignParts(HeaderBytes(alg, kid), JsonSerializer.SerializeToUtf8Bytes(claims));
+
+    public byte[] HeaderBytes(string alg = "EdDSA", string? kid = "")
+    {
+        var header = new Dictionary<string, object?> { ["alg"] = alg, ["typ"] = "JWT" };
+        if (kid is not null)
+        {
+            header["kid"] = kid.Length == 0 ? Kid : kid;
+        }
+
+        return JsonSerializer.SerializeToUtf8Bytes(header);
+    }
+
+    /// <summary>Signs exactly these header and payload bytes, whatever they hold.</summary>
+    public string SignParts(byte[] headerBytes, byte[] payloadBytes)
+    {
+        var signingInput = WebEncoders.Base64UrlEncode(headerBytes) + "." + WebEncoders.Base64UrlEncode(payloadBytes);
+        var message = Encoding.ASCII.GetBytes(signingInput);
+        var signature = new byte[Ed25519.SignatureSize];
+        Ed25519.Sign(_seed, 0, message, 0, message.Length, signature, 0);
+        return signingInput + "." + WebEncoders.Base64UrlEncode(signature);
+    }
+}
+
+public static class HeimdallShapes
+{
+    public const string Issuer = "https://heimdall.test";
+
+    public static string NewAccountId() => Guid.NewGuid().ToString();
+
+    /// <summary>The claim set of Heimdall src/claims.ts issueAccessClaim.</summary>
+    public static Dictionary<string, object?> AccessClaims(
+        string accountId,
+        DateTimeOffset now,
+        string[]? capabilities = null,
+        string? displayName = "Genuine Name",
+        Action<Dictionary<string, object?>>? mutate = null)
+    {
+        var issuedAt = now.ToUnixTimeSeconds();
+        var claims = new Dictionary<string, object?>
+        {
+            ["iss"] = Issuer,
+            ["aud"] = "bifrost",
+            ["sub"] = accountId,
+            ["sid"] = Guid.NewGuid().ToString(),
+            ["jti"] = Guid.NewGuid().ToString(),
+            ["iat"] = issuedAt,
+            ["nbf"] = issuedAt,
+            ["exp"] = issuedAt + 900,
+            ["typ"] = "heimdall_access",
+            ["account_id"] = accountId,
+            ["access_revision"] = 1,
+            ["app"] = new Dictionary<string, object?> { ["slug"] = "bifrost", ["profile_version"] = 1 },
+            ["facts"] = Array.Empty<string>(),
+            ["capabilities"] = capabilities ?? [],
+            ["identities"] = new[]
+            {
+                new Dictionary<string, object?> { ["provider"] = "discord", ["providerUserId"] = "1234567890" }
+            }
+        };
+        if (displayName is not null)
+        {
+            claims["display_name"] = displayName;
+        }
+
+        mutate?.Invoke(claims);
+        return claims;
+    }
+
+    /// <summary>
+    /// The body Heimdall's redeem route answers with: the completionPayload of src/app.ts, whose unsigned
+    /// fields (loose capabilities, facts, name) Bifrost must not decide anything from.
+    /// </summary>
+    public static Dictionary<string, object?> Completion(
+        string returnTo,
+        string accountId,
+        string accessToken,
+        string[]? looseCapabilities = null,
+        string[]? looseFacts = null,
+        string looseName = "Loose Name") => new()
+    {
+        ["status"] = "success",
+        ["provider"] = "discord",
+        ["mode"] = "sign_in",
+        ["appSlug"] = "bifrost",
+        ["account"] = new Dictionary<string, object?> { ["id"] = accountId, ["displayName"] = looseName },
+        ["entitlements"] = new Dictionary<string, object?>
+        {
+            ["facts"] = looseFacts ?? [],
+            ["snapshots"] = Array.Empty<string>()
+        },
+        ["returnTo"] = returnTo,
+        ["connection"] = null,
+        ["session"] = new Dictionary<string, object?> { ["accountId"] = accountId, ["appSlug"] = "bifrost" },
+        ["accessToken"] = accessToken,
+        ["refreshToken"] = "refresh-token-not-read",
+        ["refresh"] = new Dictionary<string, object?> { ["expiresAt"] = "2026-11-11T00:00:00.000Z" },
+        ["verification"] = new Dictionary<string, object?> { ["issuer"] = Issuer },
+        ["sharedCapabilities"] = looseCapabilities ?? [],
+        ["hybridCapabilities"] = Array.Empty<string>()
+    };
+}
+
+public sealed class TestClock : TimeProvider
+{
+    private DateTimeOffset _now = new(2026, 10, 11, 12, 0, 0, TimeSpan.Zero);
+
+    public DateTimeOffset Now => _now;
+
+    public void Advance(TimeSpan by) => _now += by;
+
+    public override DateTimeOffset GetUtcNow() => _now;
+}
+
+/// <summary>
+/// Stands in for Heimdall's HTTP surface: the JWKS, the oauth start endpoint (which, like app.ts, answers
+/// a policy start only when the app caller's secret is present) and the completion-code redeem route.
+/// </summary>
+public sealed class FakeHeimdall : HttpMessageHandler
+{
+    private readonly Dictionary<string, Dictionary<string, object?>> _codes = new(StringComparer.Ordinal);
+
+    public List<HeimdallKey> Published { get; } = [];
+
+    public List<object> ExtraJwks { get; } = [];
+
+    public int JwksFetches { get; private set; }
+
+    public HttpStatusCode JwksStatus { get; set; } = HttpStatusCode.OK;
+
+    private TaskCompletionSource? _jwksHold;
+
+    /// <summary>Completes when a JWKS request arrives after <see cref="HoldJwks"/>.</summary>
+    public TaskCompletionSource JwksArrived { get; private set; } = new(TaskCreationOptions.RunContinuationsAsynchronously);
+
+    /// <summary>Holds the next JWKS responses until the returned source completes.</summary>
+    public TaskCompletionSource HoldJwks()
+    {
+        JwksArrived = new(TaskCreationOptions.RunContinuationsAsynchronously);
+        return _jwksHold = new(TaskCreationOptions.RunContinuationsAsynchronously);
+    }
+
+    public Exception? JwksFailure { get; set; }
+
+    public List<string> StartBodies { get; } = [];
+
+    public List<string?> StartSecrets { get; } = [];
+
+    /// <summary>The secret a policy start must carry in x-heimdall-app-secret; null means Heimdall asks for none.</summary>
+    public string? RequiredAppSecret { get; set; }
+
+    public HttpStatusCode StartStatus { get; set; } = HttpStatusCode.OK;
+
+    public string StartBody { get; set; } =
+        """{"authorizationUrl":"https://heimdall.test/oauth/discord/authorize?state=fixture"}""";
+
+    public int RedeemCalls { get; private set; }
+
+    public HttpStatusCode? RedeemStatus { get; set; }
+
+    public string? RedeemBody { get; set; }
+
+    /// <summary>Registers a completion code Heimdall will redeem once, answering with this payload.</summary>
+    public string RegisterCode(Dictionary<string, object?> completion)
+    {
+        var code = Convert.ToHexString(RandomNumberGenerator.GetBytes(16)).ToLowerInvariant();
+        _codes[code] = completion;
+        return code;
+    }
+
+    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
+    {
+        var path = request.RequestUri!.AbsolutePath;
+        if (request.Method == HttpMethod.Get && path == "/.well-known/jwks.json")
+        {
+            JwksFetches++;
+            JwksArrived.TrySetResult();
+            if (_jwksHold is not null)
+            {
+                await _jwksHold.Task.WaitAsync(cancellationToken);
+            }
+
+            if (JwksFailure is not null)
+            {
+                throw JwksFailure;
+            }
+
+            var keys = Published.Select(x => x.Jwk()).Concat(ExtraJwks).ToArray();
+            return new HttpResponseMessage(JwksStatus)
+            {
+                Content = new StringContent(JsonSerializer.Serialize(new { keys }), Encoding.UTF8, "application/json")
+            };
+        }
+
+        if (request.Method == HttpMethod.Post && path.StartsWith("/v1/oauth/", StringComparison.Ordinal) && path.EndsWith("/start", StringComparison.Ordinal))
+        {
+            var body = await request.Content!.ReadAsStringAsync(cancellationToken);
+            var secret = request.Headers.TryGetValues("x-heimdall-app-secret", out var values) ? values.Single() : null;
+            StartBodies.Add(body);
+            StartSecrets.Add(secret);
+            var wantsPolicy = JsonDocument.Parse(body).RootElement.TryGetProperty("entitlementPolicy", out _);
+            if (wantsPolicy && RequiredAppSecret is not null && secret != RequiredAppSecret)
+            {
+                return new HttpResponseMessage(HttpStatusCode.Unauthorized)
+                {
+                    Content = new StringContent("""{"error":"app_auth_required"}""", Encoding.UTF8, "application/json")
+                };
+            }
+
+            return new HttpResponseMessage(StartStatus)
+            {
+                Content = new StringContent(StartBody, Encoding.UTF8, "application/json")
+            };
+        }
+
+        if (request.Method == HttpMethod.Post && path == "/v1/apps/bifrost/auth-completions/redeem")
+        {
+            RedeemCalls++;
+            if (RedeemStatus is { } status)
+            {
+                return new HttpResponseMessage(status)
+                {
+                    Content = new StringContent(RedeemBody ?? "{}", Encoding.UTF8, "application/json")
+                };
+            }
+
+            var code = JsonDocument.Parse(await request.Content!.ReadAsStringAsync(cancellationToken))
+                .RootElement.GetProperty("completionCode").GetString()!;
+            if (!_codes.Remove(code, out var completion))
+            {
+                return new HttpResponseMessage(HttpStatusCode.Gone)
+                {
+                    Content = new StringContent("""{"error":"invalid_or_expired_completion_code"}""", Encoding.UTF8, "application/json")
+                };
+            }
+
+            return new HttpResponseMessage(HttpStatusCode.Created)
+            {
+                Content = new StringContent(RedeemBody ?? JsonSerializer.Serialize(completion), Encoding.UTF8, "application/json")
+            };
+        }
+
+        return new HttpResponseMessage(HttpStatusCode.NotFound);
+    }
+}
+
+public sealed class CapturedLogs : ILoggerProvider
+{
+    private readonly List<string> _lines = [];
+
+    public IReadOnlyList<string> Lines
+    {
+        get
+        {
+            lock (_lines)
+            {
+                return _lines.ToArray();
+            }
+        }
+    }
+
+    public ILogger CreateLogger(string categoryName) => new Capture(this);
+
+    public void Dispose()
+    {
+    }
+
+    private sealed class Capture(CapturedLogs owner) : ILogger
+    {
+        public IDisposable? BeginScope<TState>(TState state) where TState : notnull => null;
+
+        public bool IsEnabled(LogLevel logLevel) => true;
+
+        public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception? exception, Func<TState, Exception?, string> formatter)
+        {
+            lock (owner._lines)
+            {
+                owner._lines.Add(formatter(state, exception) + (exception is null ? string.Empty : "\n" + exception));
+            }
+        }
+    }
+}
+
+/// <summary>An attempt Start issued: its nonce, the cookie it set, and the returnTo it sent Heimdall.</summary>
+public sealed record StartedAttempt(string Nonce, string? CookieName, string? Cookie, string ReturnTo, HttpResponseMessage Response);
+
+public sealed record CompletionResult(HttpResponseMessage Response, bool SignedIn);
+
+/// <summary>A local Bifrost with Heimdall faked in-process: a test JWKS, a test clock, captured logs.</summary>
+public sealed class HeimdallHost : TestWebApplicationFactory
+{
+    public const string AppSecret = "test-heimdall-app-secret";
+
+    private readonly string _appSecret;
+    private readonly string _appSlug;
+    private readonly string _baseUrl;
+    private readonly string _publicBaseUrl;
+    private readonly bool _discordRoles;
+
+    public TestClock Clock { get; } = new();
+
+    public FakeHeimdall Heimdall { get; } = new();
+
+    public CapturedLogs Logs { get; } = new();
+
+    public HeimdallKey Key { get; } = HeimdallKey.Generate();
+
+    public HeimdallHost(
+        string appSecret = AppSecret,
+        string baseUrl = HeimdallShapes.Issuer,
+        string publicBaseUrl = "https://localhost",
+        bool discordRoles = true,
+        string appSlug = "bifrost")
+    {
+        _appSecret = appSecret;
+        _appSlug = appSlug;
+        _baseUrl = baseUrl;
+        _publicBaseUrl = publicBaseUrl;
+        _discordRoles = discordRoles;
+        Heimdall.Published.Add(Key);
+        Heimdall.RequiredAppSecret = AppSecret;
+    }
+
+    protected override void ConfigureWebHost(IWebHostBuilder builder)
+    {
+        base.ConfigureWebHost(builder);
+        // The GitHub OAuth scheme is registered from configuration read while the app builds, which only host settings reach.
+        builder.UseSetting("GitHubOAuth:ClientId", "configured-for-tests");
+        builder.UseSetting("GitHubOAuth:ClientSecret", "configured-for-tests");
+        builder.ConfigureAppConfiguration((_, configuration) =>
+        {
+            configuration.AddInMemoryCollection(new Dictionary<string, string?>
+            {
+                ["Heimdall:BaseUrl"] = _baseUrl,
+                ["Heimdall:AppSecret"] = _appSecret,
+                ["Heimdall:AppSlug"] = _appSlug,
+                ["Heimdall:DiscordGuildId"] = "guild-1",
+                ["Host:PublicBaseUrl"] = _publicBaseUrl
+            });
+            if (_discordRoles)
+            {
+                configuration.AddInMemoryCollection(new Dictionary<string, string?> { ["Heimdall:DiscordAllowedRoleIds:0"] = "role-1" });
+            }
+        });
+        builder.ConfigureLogging(logging => logging.AddProvider(Logs));
+        builder.ConfigureServices(services =>
+        {
+            services.RemoveAll<TimeProvider>();
+            services.AddSingleton<TimeProvider>(Clock);
+            services.AddHttpClient(HeimdallTokenVerifier.ClientName).ConfigurePrimaryHttpMessageHandler(() => Heimdall);
+            services.AddHttpClient<HeimdallAuthService>().ConfigurePrimaryHttpMessageHandler(() => Heimdall);
+        });
+    }
+
+    public HttpClient NewClient() => CreateClient(new WebApplicationFactoryClientOptions
+    {
+        AllowAutoRedirect = false,
+        HandleCookies = false,
+        BaseAddress = new Uri("https://localhost")
+    });
+
+    public string Token(string accountId, string[]? capabilities = null, string? displayName = "Genuine Name",
+        Action<Dictionary<string, object?>>? mutate = null, HeimdallKey? signer = null) =>
+        (signer ?? Key).Sign(HeimdallShapes.AccessClaims(accountId, Clock.Now, capabilities, displayName, mutate));
+
+    public Task<StartedAttempt> StartAsync(
+        bool member = false, string provider = "discord", string returnUrl = "/App/Mill", string? cookieHeader = null) =>
+        StartAtAsync(
+            $"/auth/heimdall/{provider}?returnUrl={Uri.EscapeDataString(returnUrl)}" + (member ? "&access=member" : string.Empty),
+            cookieHeader);
+
+    public async Task<StartedAttempt> StartAtAsync(string url, string? cookieHeader = null)
+    {
+        using var client = NewClient();
+        var before = Heimdall.StartBodies.Count;
+        using var request = new HttpRequestMessage(HttpMethod.Get, url);
+        if (cookieHeader is not null)
+        {
+            request.Headers.Add("Cookie", cookieHeader);
+        }
+
+        var response = await client.SendAsync(request);
+        if (Heimdall.StartBodies.Count == before)
+        {
+            return new StartedAttempt(string.Empty, null, null, string.Empty, response);
+        }
+
+        var returnTo = JsonDocument.Parse(Heimdall.StartBodies[^1]).RootElement.GetProperty("returnTo").GetString()!;
+        var nonce = QueryHelpers.ParseQuery(new Uri(returnTo).Query)["attempt"].ToString();
+        var slot = HeimdallAttemptCookie.SlotNames.FirstOrDefault(x => CookieValue(response, x) is { Length: > 0 });
+        return new StartedAttempt(nonce, slot, slot is null ? null : CookieValue(response, slot), returnTo, response);
+    }
+
+    /// <summary>Registers a completion code as Heimdall would mint it after authenticating this attempt.</summary>
+    public string CodeFor(StartedAttempt attempt, string accountId, string? accessToken = null, string[]? looseCapabilities = null,
+        string[]? looseFacts = null, string looseName = "Loose Name", string? returnTo = null)
+    {
+        var completion = HeimdallShapes.Completion(
+            returnTo ?? attempt.ReturnTo, accountId, accessToken ?? Token(accountId), looseCapabilities, looseFacts, looseName);
+        return Heimdall.RegisterCode(completion);
+    }
+
+    /// <summary>The browser's POST from the complete page: the attempt and code in a form, the attempt cookie by name.</summary>
+    public Task<CompletionResult> CompleteAsync(string? nonce, string? code, string? cookie, string? cookieName = null) =>
+        CompleteWithHeaderAsync(
+            nonce, code, cookie is null ? null : $"{cookieName ?? HeimdallAttemptCookie.SlotNames[0]}={cookie}");
+
+    /// <summary>The same POST carrying a browser's whole Cookie header (a jar), not one attempt cookie.</summary>
+    public async Task<CompletionResult> CompleteWithHeaderAsync(string? nonce, string? code, string? cookieHeader)
+    {
+        using var client = NewClient();
+        var fields = new Dictionary<string, string>();
+        if (nonce is not null)
+        {
+            fields["attempt"] = nonce;
+        }
+
+        if (code is not null)
+        {
+            fields["code"] = code;
+        }
+
+        using var request = new HttpRequestMessage(HttpMethod.Post, "/auth/heimdall/complete") { Content = new FormUrlEncodedContent(fields) };
+        if (cookieHeader is not null)
+        {
+            request.Headers.Add("Cookie", cookieHeader);
+        }
+
+        var response = await client.SendAsync(request);
+        var session = CookieValue(response, ".AspNetCore.Cookies");
+        return new CompletionResult(response, !string.IsNullOrEmpty(session));
+    }
+
+    public Task<CompletionResult> CompleteAsync(StartedAttempt attempt, string code) =>
+        CompleteAsync(attempt.Nonce, code, attempt.Cookie, attempt.CookieName);
+
+    public static string? CookieValue(HttpResponseMessage response, string name)
+    {
+        if (!response.Headers.TryGetValues("Set-Cookie", out var headers))
+        {
+            return null;
+        }
+
+        var prefix = name + "=";
+        var header = headers.FirstOrDefault(x => x.StartsWith(prefix, StringComparison.Ordinal));
+        return header?[prefix.Length..].Split(';')[0];
+    }
+
+    public static string? SetCookieHeader(HttpResponseMessage response, string name) =>
+        response.Headers.TryGetValues("Set-Cookie", out var headers)
+            ? headers.FirstOrDefault(x => x.StartsWith(name + "=", StringComparison.Ordinal))
+            : null;
+
+    public async Task<T> Db<T>(Func<BifrostDbContext, Task<T>> query)
+    {
+        using var scope = Services.CreateScope();
+        return await query(scope.ServiceProvider.GetRequiredService<BifrostDbContext>());
+    }
+
+    public Task<Bifrost.Web.Domain.UserAccount?> Account(string heimdallAccountId) =>
+        Db(db => db.UserAccounts
+            .Include(x => x.Membership!).ThenInclude(x => x.RoleAssignments)
+            .SingleOrDefaultAsync(x => x.HeimdallAccountId == heimdallAccountId));
+
+    public Task<int> AccountCount() => Db(db => db.UserAccounts.CountAsync());
+}

tests/Bifrost.Web.Tests/Support/OidcLogoutKit.cs

@@ -0,0 +1,503 @@
+using System.Net;
+using System.Net.Http.Headers;
+using System.Net.Http.Json;
+using System.Security.Cryptography;
+using System.Text;
+using System.Text.Json;
+using Bifrost.Web.Configuration;
+using Bifrost.Web.Data;
+using Bifrost.Web.Domain;
+using Bifrost.Web.Features.Oidc;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.Mvc.Testing;
+using Microsoft.AspNetCore.WebUtilities;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.DependencyInjection.Extensions;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Logging.Abstractions;
+using Microsoft.Extensions.Options;
+using Microsoft.IdentityModel.Tokens;
+using OpenIddict.Abstractions;
+using OpenIddict.EntityFrameworkCore.Models;
+using OpenIddict.Server;
+
+namespace Bifrost.Web.Tests.Support;
+
+/// <summary>A clock the test moves; its timers never fire, so the hosted reconciler only ticks when a test calls it.</summary>
+public sealed class ManualClock : TimeProvider
+{
+    private DateTimeOffset _now = DateTimeOffset.UtcNow;
+
+    public override DateTimeOffset GetUtcNow() => _now;
+
+    public void Advance(TimeSpan by) => _now += by;
+
+    public override ITimer CreateTimer(TimerCallback callback, object? state, TimeSpan dueTime, TimeSpan period) =>
+        base.CreateTimer(callback, state, Timeout.InfiniteTimeSpan, Timeout.InfiniteTimeSpan);
+}
+
+/// <summary>A clock whose timers fire only when the test says so, to drive the reconciler's own loop.</summary>
+public sealed class ControlledClock : TimeProvider
+{
+    private readonly List<PendingTimer> _timers = [];
+    private DateTimeOffset _now = DateTimeOffset.UtcNow;
+
+    public override DateTimeOffset GetUtcNow() => _now;
+
+    public override ITimer CreateTimer(TimerCallback callback, object? state, TimeSpan dueTime, TimeSpan period)
+    {
+        var timer = new PendingTimer(() => callback(state));
+        lock (_timers)
+        {
+            _timers.Add(timer);
+        }
+
+        return timer;
+    }
+
+    /// <summary>How many delays are currently waiting to be fired.</summary>
+    public int Waiting
+    {
+        get
+        {
+            lock (_timers)
+            {
+                return _timers.Count(x => !x.Disposed);
+            }
+        }
+    }
+
+    /// <summary>Fires every timer that is waiting (each delay the loop is sitting in).</summary>
+    public void FireTimers()
+    {
+        PendingTimer[] due;
+        lock (_timers)
+        {
+            due = _timers.Where(x => !x.Disposed).ToArray();
+            _timers.Clear();
+        }
+
+        foreach (var timer in due)
+        {
+            timer.Fire();
+        }
+    }
+
+    private sealed class PendingTimer(Action fire) : ITimer
+    {
+        public bool Disposed { get; private set; }
+
+        public void Fire() => fire();
+
+        public bool Change(TimeSpan dueTime, TimeSpan period) => true;
+
+        public void Dispose() => Disposed = true;
+
+        public ValueTask DisposeAsync()
+        {
+            Disposed = true;
+            return ValueTask.CompletedTask;
+        }
+    }
+}
+
+/// <summary>Collects what a component logs, formatted, so a test can say what must and must not appear.</summary>
+public sealed class ListLogger<T> : ILogger<T>
+{
+    private readonly List<(LogLevel Level, string Message)> _entries = [];
+
+    public IReadOnlyList<(LogLevel Level, string Message)> Entries
+    {
+        get
+        {
+            lock (_entries)
+            {
+                return _entries.ToArray();
+            }
+        }
+    }
+
+    public IDisposable? BeginScope<TState>(TState state) where TState : notnull => null;
+
+    public bool IsEnabled(LogLevel logLevel) => true;
+
+    public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception? exception, Func<TState, Exception?, string> formatter)
+    {
+        lock (_entries)
+        {
+            _entries.Add((logLevel, formatter(state, exception)));
+        }
+    }
+}
+
+/// <summary>
+/// A stand-in for MAS's back-channel logout route: answers a scripted status per POST (then 200), records every form
+/// body, and can fail like the network does.
+/// </summary>
+public sealed class FakeMasHandler : HttpMessageHandler
+{
+    public const int NetworkFault = -1;
+    public const int Timeout = -2;
+    public const int Unexpected = -3;
+    public const int Hang = -4;
+
+    private readonly Queue<int> _script = new();
+    private readonly List<string> _bodies = [];
+
+    public void Script(params int[] statuses)
+    {
+        lock (_script)
+        {
+            foreach (var status in statuses)
+            {
+                _script.Enqueue(status);
+            }
+        }
+    }
+
+    public IReadOnlyList<string> Bodies
+    {
+        get
+        {
+            lock (_bodies)
+            {
+                return _bodies.ToArray();
+            }
+        }
+    }
+
+    /// <summary>The logout_tokens posted, in order; asserts each body is exactly one logout_token field.</summary>
+    public IReadOnlyList<string> LogoutTokens() => Bodies.Select(body =>
+    {
+        var form = QueryHelpers.ParseQuery(body);
+        Assert.Equal(["logout_token"], form.Keys.ToArray());
+        return form["logout_token"].ToString();
+    }).ToArray();
+
+    protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
+    {
+        Assert.Equal(HttpMethod.Post, request.Method);
+        Assert.Equal("application/x-www-form-urlencoded", request.Content!.Headers.ContentType!.MediaType);
+        var body = await request.Content.ReadAsStringAsync(cancellationToken);
+        lock (_bodies)
+        {
+            _bodies.Add(body);
+        }
+
+        int status;
+        lock (_script)
+        {
+            status = _script.Count > 0 ? _script.Dequeue() : 200;
+        }
+
+        return status switch
+        {
+            NetworkFault => throw new HttpRequestException("network down"),
+            Timeout => throw new TaskCanceledException("timed out"),
+            Unexpected => throw new InvalidOperationException("not a network fault"),
+            Hang => await HangAsync(cancellationToken),
+            _ => new HttpResponseMessage((HttpStatusCode)status) { Content = new StringContent(BodyCanary) }
+        };
+    }
+
+    public const string BodyCanary = "mas-body-canary";
+
+    private static async Task<HttpResponseMessage> HangAsync(CancellationToken cancellationToken)
+    {
+        await Task.Delay(System.Threading.Timeout.InfiniteTimeSpan, cancellationToken);
+        throw new InvalidOperationException("unreachable");
+    }
+}
+
+/// <summary>
+/// A real HTTP listener on loopback standing in for a MAS that answers every POST with 302 to /login and GET /login with
+/// 200: what a real HttpClient does with that answer is the registered handler's rule, which a fake handler cannot see.
+/// </summary>
+public sealed class RedirectingMas : IDisposable
+{
+    private readonly System.Net.Sockets.TcpListener _listener = new(IPAddress.Loopback, 0);
+    private readonly List<string> _requests = [];
+    private readonly CancellationTokenSource _stop = new();
+    private readonly Task _accepting;
+
+    public RedirectingMas()
+    {
+        _listener.Start();
+        _accepting = Task.Run(AcceptAsync);
+    }
+
+    public string LogoutUri => $"http://127.0.0.1:{((IPEndPoint)_listener.LocalEndpoint).Port}/logout";
+
+    /// <summary>"METHOD path" for every request received, in order.</summary>
+    public IReadOnlyList<string> Requests
+    {
+        get
+        {
+            lock (_requests)
+            {
+                return _requests.ToArray();
+            }
+        }
+    }
+
+    private async Task AcceptAsync()
+    {
+        try
+        {
+            while (!_stop.IsCancellationRequested)
+            {
+                var connection = await _listener.AcceptTcpClientAsync(_stop.Token);
+                _ = Task.Run(() => ServeAsync(connection));
+            }
+        }
+        catch (Exception) when (_stop.IsCancellationRequested)
+        {
+        }
+    }
+
+    private async Task ServeAsync(System.Net.Sockets.TcpClient connection)
+    {
+        using var owned = connection;
+        try
+        {
+            var stream = connection.GetStream();
+            using var reader = new StreamReader(stream, Encoding.ASCII, leaveOpen: true);
+            var requestLine = await reader.ReadLineAsync(_stop.Token) ?? "";
+            var length = 0;
+            while (await reader.ReadLineAsync(_stop.Token) is { Length: > 0 } header)
+            {
+                if (header.StartsWith("Content-Length:", StringComparison.OrdinalIgnoreCase))
+                {
+                    length = int.Parse(header["Content-Length:".Length..].Trim());
+                }
+            }
+
+            var body = new char[length];
+            var read = 0;
+            while (read < length)
+            {
+                var n = await reader.ReadAsync(body.AsMemory(read), _stop.Token);
+                if (n == 0)
+                {
+                    break;
+                }
+
+                read += n;
+            }
+
+            var parts = requestLine.Split(' ');
+            lock (_requests)
+            {
+                _requests.Add($"{parts[0]} {parts[1]}");
+            }
+
+            var response = parts[0] == "POST"
+                ? "HTTP/1.1 302 Found\r\nLocation: /login\r\nContent-Length: 0\r\nConnection: close\r\n\r\n"
+                : "HTTP/1.1 200 OK\r\nContent-Length: 0\r\nConnection: close\r\n\r\n";
+            await stream.WriteAsync(Encoding.ASCII.GetBytes(response), _stop.Token);
+        }
+        catch (Exception error) when (error is IOException or OperationCanceledException or ObjectDisposedException)
+        {
+        }
+    }
+
+    public void Dispose()
+    {
+        _stop.Cancel();
+        _listener.Stop();
+        try
+        {
+            _accepting.Wait(TimeSpan.FromSeconds(2));
+        }
+        catch (AggregateException)
+        {
+        }
+    }
+}
+
+/// <summary>A scope factory that fails the first scopes asked of it, as a database outage would.</summary>
+public sealed class FlakyScopeFactory(IServiceScopeFactory inner, int failures) : IServiceScopeFactory
+{
+    public const string Secret = "scope-factory-secret-detail";
+
+    private int _failures = failures;
+
+    public IServiceScope CreateScope()
+    {
+        if (Interlocked.Decrement(ref _failures) >= 0)
+        {
+            throw new InvalidOperationException(Secret);
+        }
+
+        return inner.CreateScope();
+    }
+}
+
+/// <summary>An OIDC host with MAS's back-channel logout URI set, a fake MAS behind it and a clock the test drives.</summary>
+public sealed class OidcLogoutFactory : OidcWebApplicationFactory
+{
+    public const string LogoutUri = "https://mas.example.test/upstream/backchannel-logout/01TESTPROVIDER";
+    public static readonly Uri Origin = new("https://localhost");
+
+    private readonly string _logoutUri;
+    private readonly bool _fakeTransport;
+
+    public OidcLogoutFactory()
+    {
+        _logoutUri = LogoutUri;
+        _fakeTransport = true;
+    }
+
+    /// <summary>Keeps the real registered HttpClient and its primary handler and posts to <paramref name="logoutUri"/>.</summary>
+    public OidcLogoutFactory(string logoutUri)
+    {
+        _logoutUri = logoutUri;
+        _fakeTransport = false;
+    }
+
+    public FakeMasHandler Mas { get; } = new();
+
+    public ManualClock Time { get; } = new();
+
+    public OidcLogoutReconciler Reconciler => Services.GetServices<IHostedService>().OfType<OidcLogoutReconciler>().Single();
+
+    protected override void ConfigureWebHost(IWebHostBuilder builder)
+    {
+        base.ConfigureWebHost(builder);
+        builder.UseSetting("Bifrost:Oidc:Clients:Mas:BackchannelLogoutUri", _logoutUri);
+        builder.ConfigureServices(services =>
+        {
+            services.RemoveAll<TimeProvider>();
+            services.AddSingleton<TimeProvider>(Time);
+            if (_fakeTransport)
+            {
+                services.AddHttpClient(OidcLogoutReconciler.HttpClientName).ConfigurePrimaryHttpMessageHandler(() => Mas);
+            }
+        });
+    }
+
+    /// <summary>A reconciler with no memory, built over this host's database, as a restarted process would have.</summary>
+    public OidcLogoutReconciler NewReconciler(
+        TimeProvider? time = null,
+        ILogger<OidcLogoutReconciler>? logger = null,
+        IServiceScopeFactory? scopes = null) => new(
+        scopes ?? Services.GetRequiredService<IServiceScopeFactory>(),
+        Services.GetRequiredService<OidcIssuerOptions>(),
+        Services.GetRequiredService<OidcKeyMaterial>(),
+        Services.GetRequiredService<IOptions<OpenIddictServerOptions>>(),
+        Services.GetRequiredService<IHttpClientFactory>(),
+        time ?? Time,
+        logger ?? NullLogger<OidcLogoutReconciler>.Instance);
+
+    public WebApplicationFactoryClientOptions HostClientOptions() => new()
+    {
+        AllowAutoRedirect = false,
+        HandleCookies = true,
+        BaseAddress = Origin
+    };
+
+    /// <summary>Registers a member, sets <paramref name="status"/>, and completes one authorization-code flow for them.</summary>
+    public async Task<(string Identity, string IdToken)> GrantAsync(MembershipStatus status = MembershipStatus.Active)
+    {
+        using var client = CreateClient(HostClientOptions());
+        var identity = $"member-{Guid.NewGuid():N}";
+        using (var register = await client.PostAsJsonAsync("/auth/bifrost/register", new { identity, displayName = identity }))
+        {
+            Assert.Equal(HttpStatusCode.OK, register.StatusCode);
+        }
+
+        await SetMembershipAsync(identity, MembershipStatus.Active);
+
+        var verifier = Base64UrlEncoder.Encode(RandomNumberGenerator.GetBytes(48));
+        var state = Base64UrlEncoder.Encode(RandomNumberGenerator.GetBytes(24));
+        var challenge = Base64UrlEncoder.Encode(SHA256.HashData(Encoding.ASCII.GetBytes(verifier)));
+        var response = await client.GetAsync(
+            "/connect/authorize?response_type=code" +
+            $"&client_id={Uri.EscapeDataString(OidcTestKit.ClientId)}" +
+            $"&redirect_uri={Uri.EscapeDataString(OidcTestKit.RedirectUri)}" +
+            $"&scope=openid%20profile&state={state}&nonce=n-{state}" +
+            $"&code_challenge={challenge}&code_challenge_method=S256");
+        for (var hops = 0; hops < 4 && IsAuthorizeRedirect(response); hops++)
+        {
+            var next = response.Headers.Location!;
+            response.Dispose();
+            response = await client.GetAsync(next.IsAbsoluteUri ? next.PathAndQuery : next.OriginalString);
+        }
+
+        var code = QueryHelpers.ParseQuery(response.Headers.Location!.Query)["code"].ToString();
+        response.Dispose();
+
+        using var bare = CreateClient(HostClientOptions());
+        using var exchange = new HttpRequestMessage(HttpMethod.Post, "/connect/token")
+        {
+            Content = new FormUrlEncodedContent(new Dictionary<string, string>
+            {
+                ["grant_type"] = "authorization_code",
+                ["code"] = code,
+                ["redirect_uri"] = OidcTestKit.RedirectUri,
+                ["code_verifier"] = verifier
+            })
+        };
+        exchange.Headers.Authorization = new AuthenticationHeaderValue(
+            "Basic", Convert.ToBase64String(Encoding.ASCII.GetBytes($"{OidcTestKit.ClientId}:{Kit.ClientSecret}")));
+        using var tokens = await bare.SendAsync(exchange);
+        Assert.Equal(HttpStatusCode.OK, tokens.StatusCode);
+        var idToken = (await tokens.Content.ReadFromJsonAsync<JsonElement>()).GetProperty("id_token").GetString()!;
+
+        if (status != MembershipStatus.Active)
+        {
+            await SetMembershipAsync(identity, status);
+        }
+
+        return (identity, idToken);
+    }
+
+    private static bool IsAuthorizeRedirect(HttpResponseMessage response) =>
+        response.StatusCode is HttpStatusCode.Redirect or HttpStatusCode.Found &&
+        response.Headers.Location is { } location &&
+        (location.IsAbsoluteUri ? location.AbsolutePath : location.OriginalString).StartsWith("/connect/authorize", StringComparison.Ordinal);
+
+    /// <summary>Gives <paramref name="subject"/> one more valid ad hoc authorization of the MAS client.</summary>
+    public async Task AddAuthorizationAsync(string subject)
+    {
+        using var scope = Services.CreateScope();
+        var applications = scope.ServiceProvider.GetRequiredService<IOpenIddictApplicationManager>();
+        var authorizations = scope.ServiceProvider.GetRequiredService<IOpenIddictAuthorizationManager>();
+        var application = (await applications.FindByClientIdAsync(OidcTestKit.ClientId))!;
+        await authorizations.CreateAsync(new OpenIddictAuthorizationDescriptor
+        {
+            ApplicationId = await applications.GetIdAsync(application),
+            Subject = subject,
+            Status = OpenIddictConstants.Statuses.Valid,
+            Type = OpenIddictConstants.AuthorizationTypes.AdHoc
+        });
+    }
+
+    /// <summary>Revokes every authorization of the subject, as an operator would outside the reconciler.</summary>
+    public async Task RevokeAllAsync(string subject)
+    {
+        using var scope = Services.CreateScope();
+        var authorizations = scope.ServiceProvider.GetRequiredService<IOpenIddictAuthorizationManager>();
+        await foreach (var authorization in authorizations.FindBySubjectAsync(subject))
+        {
+            await authorizations.TryRevokeAsync(authorization);
+        }
+    }
+
+    /// <summary>How many of the subject's authorizations are still valid.</summary>
+    public int ValidAuthorizations(string subject)
+    {
+        using var scope = Services.CreateScope();
+        return scope.ServiceProvider.GetRequiredService<BifrostDbContext>()
+            .Set<OpenIddictEntityFrameworkCoreAuthorization>().AsNoTracking()
+            .Count(x => x.Subject == subject && x.Status == "valid");
+    }
+
+    public async Task<JsonWebKeySet> JwksAsync()
+    {
+        using var client = CreateClient(HostClientOptions());
+        return new JsonWebKeySet(await client.GetStringAsync("/.well-known/jwks"));
+    }
+}