Huginn/docs/eureka-substrate-target.md

Eureka substrate: target

Status: target, Self, 2026-10-01. Campaign eureka-substrate in Eureka's mind (instance eureka). Its questions, rulings, cut specs, verification and the substrate gaps themselves are typed documents there. This page keeps the rationale and the design truths the campaign produces. The cut map's body facts and model page will live in eureka-substrate-map.md.

Why

The first typed campaign, idunn-watchdog (postmortem: Idunn docs/watchdog-reporting-postmortem.md, 6667f0f), ran its whole pipeline through Huginn and found the substrate's defects by hitting them. The operator ruled, 2026-10-01:

Yep, fixing Mind issues is highest priority, immediately once this campaign closes

The defects that cost the most:

• A finding can be admitted that can never be resolved. A key's local part is bounded at 64 bytes as a whole, and only when it is composed (epiphany-pipeline LOCAL_MAX). A resolution's local embeds its subject's local plus finding./follow_up. and .n<seq>. So a subject whose own key fits can have no admissible resolution, under any outcome. Six findings in idunn-watchdog are stuck in force this way.
• A shape refusal arrives labelled Unavailable. Huginn's admission maps the leaf's key error through anyhow into MindRefusal::Unavailable. The skill tells every agent that Unavailable means the organ is down: retry once, then stop. A faithful agent would halt a campaign over a key that was too long.
• Substrate gaps have no home every campaign can see. Follow-ups are campaign-rooted, so 20 gap-* follow-ups sit under idunn-watchdog, and a later campaign's recipe cannot see them.
• Smaller defects:
  • Revising one spec forced a revision of every spec that named it in depends_on, twice, when the dependency was on a cut.
  • A short sha and the full sha of one commit are different values to admission.
  • A finding cannot be deferred to the cut that fixes it, only to a pointer follow-up.
  • The faculty is named Life, but the enum says MindSteward.
  • Stewardship is universal (operator, 2026-09-30), yet admission demands a per-repo stewardship record that decides nothing.

The code the live mind runs sits on two long-lived branches: Huginn eureka/memory-organ (release 9dd6d80), and Epiphany codex/eureka-pipeline-state, where the leaf Huginn pins lives. The operator ruled that they merge to main first.

Design truths this campaign produces

• Every admitted subject stays resolvable. If admission accepts a document whose kind can be resolved, every outcome its subject allows can be admitted for it, up to a stated sequence bound. A grammar that cannot hold a key refuses the subject at admission, not its resolution later.
• A refusal names what was wrong. A document that breaks a shape, bound or key rule is refused as a typed document refusal. Unavailable means only that the organ could not serve.
• Stored documents stay valid. No change in this campaign re-keys, re-encodes or invalidates a document already in the mind. The epoch stays epiphany.pipeline.epoch.v2. Every change is a widening, an added variant, or an admission rule that judges new batches only.
• One home for substrate gaps. This campaign is the standing home for gaps in the mind's own substrate. The skill's recipe names its root, and every campaign reads it.
• The mind's code comes from main. The Huginn daemon, the leaf and the eureka-state client the live mind runs are built from commits on Huginn's and Epiphany's main.
• The live mind survives its own upgrade. Each deploy upgrades /var/lib/gamecult/huginn/minds/eureka/mind.redb in place under a release symlink that can be flipped back. Every document admitted before the upgrade reads back after it.

Not this campaign

• Verify-stopgap gaps (artifact return, rg in the image, sibling repos): Idunn's verify campaign.
• CultNet selection (gap-citer-faculty-hop): CultLib.
• The cold-embed timeout and a session-id tool: recorded follow-ups.
• Leasing stewardship between agents and hand_off: Huginn Cut 12, parked.
• Re-encoding stewardship ids into a readable form, which would re-key stored documents.
• Persona-state reading in Huginn.