read-floor: equal scores past the candidate cut keep the earliest ordinals (pins Reader::id_of's rows)

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

crates/huginn-daemon/src/serve.rs

@@ -792,6 +792,173 @@ mod tests {
         assert_eq!(documents(&mut daemon), 1, "the admission that crossed the wire landed");
     }
 
+    fn question_doc(n: usize) -> huginn_mind::eureka_pipeline::PipelineDocument {
+        use huginn_mind::eureka_pipeline::{Date, PipelineDocument, PipelineQuestion, QuestionOption, Title};
+        PipelineDocument::Question(PipelineQuestion {
+            campaign: slug(crate::daemon::tests::CAMPAIGN),
+            label: format!("Q{n}").as_str().into(),
+            title: Title("Who owns the state?".into()),
+            question: "Who owns the state?".into(),
+            options: vec![
+                QuestionOption { label: "A".into(), text: "the organ".into() },
+                QuestionOption { label: "B".into(), text: "the client".into() },
+            ],
+            recommended: "A".into(),
+            depends: vec![],
+            raised_in: None,
+            asked_on: Date("2026-09-16".into()),
+        })
+    }
+
+    fn resolution_of(subject: PipelineRef, outcome: huginn_mind::eureka_pipeline::ResolutionOutcome) -> huginn_mind::eureka_pipeline::PipelineDocument {
+        huginn_mind::eureka_pipeline::PipelineDocument::Resolution(huginn_mind::eureka_pipeline::PipelineResolution {
+            subject,
+            sequence: 1,
+            outcome,
+            rationale: "Resolved.".into(),
+            resolved_on: huginn_mind::eureka_pipeline::Date("2026-09-16".into()),
+        })
+    }
+
+    /// One client session asks `request` and decodes the answer.
+    fn ask(client: &mut Client, message_id: &str, request: &HuginnMindRequest) -> HuginnMindResponse {
+        let reply = exchange(client, &encode_request(message_id, request, None).unwrap()).unwrap();
+        decode_response(&reply).unwrap().1.unwrap_or_else(|failure| panic!("{message_id}: {failure:?}"))
+    }
+
+    fn connect(endpoint: &str, name: &str) -> Client {
+        let mut client = CultMesh::create_rudp_client_for_endpoint(
+            format!("eureka-state-{name}"),
+            CULTNET_OPERATION_CONNECTION_ID,
+            endpoint,
+            CultMeshRudpSocketOptions::default(),
+        )
+        .unwrap();
+        client.connect(Vec::new()).unwrap();
+        for _ in 0..1000 {
+            let _ = client.receive_once();
+            if client.connected() {
+                return client;
+            }
+            std::thread::sleep(Duration::from_millis(2));
+        }
+        panic!("{name} never connected");
+    }
+
+    /// One client admits batches that close, withdraw and re-open records while three others read
+    /// the same mind: fresh queries, cursor walks across commits, a hop and whoami. The loop is
+    /// serial, so every answer is one snapshot's; at quiesce each answer must equal what a fresh
+    /// derivation from the store gives at the snapshot it names, and no client sees the head go
+    /// backwards. The test pins the behaviour, not the mechanism.
+    #[test]
+    fn reads_racing_admissions_on_the_wire_answer_their_snapshot() {
+        use huginn_mind::eureka_pipeline::{PipelineKind as K, ResolutionOutcome};
+        let root = tempfile::tempdir().unwrap();
+        let mut daemon = open_unindexed(root.path(), &slug(INSTANCE)).unwrap();
+        let seeded = daemon.handle(HuginnMindRequest::Admit(batch(INSTANCE, crate::daemon::tests::campaign_seed())), now()).answered();
+        assert!(matches!(seeded, HuginnMindResponse::Admit(PipelineAdmissionOutcome::Committed { .. })), "{seeded:?}");
+        let mut hub = bind("127.0.0.1:0".parse().unwrap(), &daemon.runtime_id()).unwrap();
+        let endpoint = format!("rudp://{}", hub.local_addr().unwrap());
+        let registry = schema_registry().unwrap();
+        let stopping = Arc::new(AtomicBool::new(false));
+        let loop_stopping = Arc::clone(&stopping);
+        let serving = std::thread::spawn(move || {
+            let result = run(&mut daemon, &mut hub, &registry, &loop_stopping, &ServeOptions::default());
+            (result, daemon)
+        });
+
+        let done = Arc::new(AtomicBool::new(false));
+        let writer = {
+            let (endpoint, done) = (endpoint.clone(), Arc::clone(&done));
+            std::thread::spawn(move || {
+                let mut client = connect(&endpoint, "writer");
+                let admit = |client: &mut Client, n: usize, documents| {
+                    let answer = ask(client, &format!("w-{n}"), &HuginnMindRequest::Admit(batch(INSTANCE, documents)));
+                    assert!(matches!(answer, HuginnMindResponse::Admit(PipelineAdmissionOutcome::Committed { .. })), "{answer:?}");
+                };
+                let withdrawn = || ResolutionOutcome::Withdrawn { reason: "race".into() };
+                let mut n = 0;
+                for cut in 0..14 {
+                    let spec = PipelineRef { kind: K::Question, id: format!("{}:question:Q{cut}", crate::daemon::tests::CAMPAIGN).as_str().into() };
+                    admit(&mut client, n, vec![question_doc(cut)]);
+                    admit(&mut client, n + 1, vec![resolution_of(spec, withdrawn())]);
+                    if cut % 2 == 0 {
+                        let closing = PipelineRef { kind: K::Resolution, id: format!("{}:resolution:question.Q{cut}.n1", crate::daemon::tests::CAMPAIGN).as_str().into() };
+                        admit(&mut client, n + 2, vec![resolution_of(closing, withdrawn())]);
+                    }
+                    n += 3;
+                }
+                done.store(true, Ordering::Relaxed);
+            })
+        };
+        let readers: Vec<_> = (0..3)
+            .map(|index| {
+                let (endpoint, done) = (endpoint.clone(), Arc::clone(&done));
+                std::thread::spawn(move || {
+                    let mut client = connect(&endpoint, &format!("reader-{index}"));
+                    let of_specs = |extra: Selection| Selection { schemas: Some(vec![K::Question.type_id().into()]), ..extra };
+                    let in_force = FieldPredicate { index: "in_force".into(), op: "any_of".into(), values: Some(vec!["true".into()]), number: None };
+                    let mut recorded: Vec<(Selection, huginn_mind::PipelineSelectionPage)> = Vec::new();
+                    let mut status_walk = of_specs(Selection { fields: Some(vec![in_force.clone()]), limit: Some(1), projection: "document".into(), ..Selection::default() });
+                    let mut head = 0;
+                    let mut round = 0;
+                    while !done.load(Ordering::Relaxed) || round < 3 {
+                        round += 1;
+                        let query = |client: &mut Client, selection: &Selection| {
+                            match ask(client, &format!("r-{index}-{round}"), &HuginnMindRequest::Query { instance: slug(INSTANCE), selection: selection.clone(), semantic: None }) {
+                                HuginnMindResponse::Query(page) => page,
+                                other => panic!("expected a page, got {other:?}"),
+                            }
+                        };
+                        let fresh = of_specs(Selection { fields: Some(vec![in_force.clone()]), limit: Some(5), ..Selection::default() });
+                        let page = query(&mut client, &fresh);
+                        assert!(page.as_of >= head, "a client's head never goes backwards");
+                        head = page.as_of;
+                        recorded.push((fresh, page));
+                        let mut walking = of_specs(Selection { limit: Some(1), ..Selection::default() });
+                        for _ in 0..3 {
+                            let page = query(&mut client, &walking);
+                            let next = page.next.clone();
+                            recorded.push((walking.clone(), page));
+                            match next {
+                                Some(cursor) => walking.cursor = Some(cursor),
+                                None => break,
+                            }
+                        }
+                        // A status walk: its cursor pins the snapshot it began at while the writer
+                        // closes and reopens the questions, so a page is read at an old snapshot
+                        // through the status filter and the document, which only the row's
+                        // status_changed can answer.
+                        let page = query(&mut client, &status_walk);
+                        let next = page.next.clone();
+                        recorded.push((status_walk.clone(), page));
+                        status_walk.cursor = next;
+                        let hop = Selection { cited: Some(cultnet_rs::Incoming { role: "subject".into(), exists: true }), ..Selection::default() };
+                        let page = query(&mut client, &hop);
+                        recorded.push((hop, page));
+                        assert!(matches!(ask(&mut client, "whoami", &HuginnMindRequest::Whoami), HuginnMindResponse::Whoami(_)));
+                    }
+                    recorded
+                })
+            })
+            .collect();
+
+        writer.join().unwrap();
+        let recorded: Vec<_> = readers.into_iter().flat_map(|reader| reader.join().unwrap()).collect();
+        stopping.store(true, Ordering::Relaxed);
+        let (result, daemon) = serving.join().unwrap();
+        result.unwrap();
+        let mind = daemon.mind();
+        let final_head = mind.query(&Selection::default()).unwrap().as_of;
+        let mut snapshots = std::collections::BTreeSet::new();
+        for (selection, page) in &recorded {
+            snapshots.insert(page.as_of);
+            assert_eq!(huginn_mind::oracle::oracle_page(mind, selection, page.as_of).as_ref(), Ok(page), "{selection:?} at {}", page.as_of);
+        }
+        assert!(snapshots.len() > 1, "the readers saw more than one snapshot: {snapshots:?}");
+        assert!(snapshots.iter().all(|as_of| *as_of <= final_head));
+    }
+
     fn encoded_len(message: &CultNetMessage) -> u64 {
         encode_cultnet_message_to_vec(message, CultNetWireContract::CultNetSchemaV0).unwrap().len() as u64
     }

crates/huginn-mind/src/admission.rs

@@ -124,7 +124,8 @@ impl<S: MindStore> Mind<S> {
             return Err(MindRefusal::BatchSize { actual: envelopes.len() as u32 });
         }
         let mind = self.instance().clone();
-        let mut docs = Docs::from_image(self.envelopes())?;
+        let image = self.image()?;
+        let mut docs = Docs::at(image, image.head);
         // A3, A5, then A4 on push.
         for envelope in envelopes {
             docs.push(stage(envelope, &mind)?)?;
@@ -366,7 +367,7 @@ fn references(staged: &Staged, mind: &Slug) -> Result<Vec<Reference>, MindRefusa
 
 /// A7: every referent is in the batch or the image; the image ones are the
 /// receipt's strong reads.
-fn resolve(docs: &Docs, staged: &Staged, mind: &Slug, strong: &mut BTreeSet<(String, String)>) -> Result<(), MindRefusal> {
+fn resolve(docs: &Docs<'_>, staged: &Staged, mind: &Slug, strong: &mut BTreeSet<(String, String)>) -> Result<(), MindRefusal> {
     for reference in references(staged, mind)? {
         if docs.in_batch(reference.kind, &reference.id).is_some() {
             continue;
@@ -389,7 +390,7 @@ fn resolve(docs: &Docs, staged: &Staged, mind: &Slug, strong: &mut BTreeSet<(Str
 /// the stewardship withdrawal on its source side and the stewardship
 /// assignment on its receiving side. One the batch already carries is not
 /// derived again.
-fn derive(docs: &Docs, mind: &Slug) -> Vec<PipelineDocument> {
+fn derive(docs: &Docs<'_>, mind: &Slug) -> Vec<PipelineDocument> {
     use PipelineDocument as D;
     use PipelineKind as K;
     let mut derived = Vec::new();
@@ -444,7 +445,7 @@ fn derive(docs: &Docs, mind: &Slug) -> Vec<PipelineDocument> {
 }
 
 /// A8: the per-kind rules.
-fn check(docs: &Docs, staged: &Staged, mind: &Slug) -> Result<(), MindRefusal> {
+fn check(docs: &Docs<'_>, staged: &Staged, mind: &Slug) -> Result<(), MindRefusal> {
     use PipelineDocument as D;
     use PipelineKind as K;
     let key = staged.key.as_str();
@@ -629,7 +630,7 @@ fn check(docs: &Docs, staged: &Staged, mind: &Slug) -> Result<(), MindRefusal> {
 /// The one rule for a run opening or reinstated by withdrawing its close: every
 /// claim in force (a replay of an admitted run owes none) and held by no other
 /// live run, then at most one live run of hers per instance and turn.
-fn run_rule(docs: &Docs, run_key: &str, run: &PipelineRun, replay: bool) -> Result<(), MindRefusal> {
+fn run_rule(docs: &Docs<'_>, run_key: &str, run: &PipelineRun, replay: bool) -> Result<(), MindRefusal> {
     for claim in &run.claims {
         if !replay && !docs.in_force(claim.kind, &claim.id.0) {
             return Err(MindRefusal::CitesResolvedDocument { kind: claim.kind, id: claim.id.0.clone() });
@@ -647,7 +648,7 @@ fn run_rule(docs: &Docs, run_key: &str, run: &PipelineRun, replay: bool) -> Resu
 /// Revision 1 stands alone; revision N needs a resolution in the batch that
 /// supersedes revision N-1 by this document. The predecessor's key is the
 /// leaf's, from the same document one revision back.
-fn revision_rule(docs: &Docs, kind: PipelineKind, key: &str, revision: u32, predecessor: &PipelineDocument) -> Result<(), MindRefusal> {
+fn revision_rule(docs: &Docs<'_>, kind: PipelineKind, key: &str, revision: u32, predecessor: &PipelineDocument) -> Result<(), MindRefusal> {
     if revision == 1 {
         return Ok(());
     }
@@ -731,7 +732,7 @@ fn matrix(subject: PipelineKind, outcome: &ResolutionOutcome) -> bool {
 /// every referent in force, and the two
 /// coherence rules (an `Answered` ruling answers this question; a cut spec is
 /// superseded within its cut).
-fn resolution_rule(docs: &Docs, resolution: &PipelineResolution) -> Result<(), MindRefusal> {
+fn resolution_rule(docs: &Docs<'_>, resolution: &PipelineResolution) -> Result<(), MindRefusal> {
     use PipelineDocument as D;
     use PipelineKind as K;
     let subject_kind = resolution.subject.kind;
@@ -830,7 +831,7 @@ fn resolution_rule(docs: &Docs, resolution: &PipelineResolution) -> Result<(), M
 /// A10: a write whose identity the image already holds. Every kind answers
 /// the same way now that a resolution key carries a sequence: the identity is
 /// taken. Whether a subject is closed is A8's question, not this one's.
-fn refuse_collisions(docs: &Docs) -> Result<(), MindRefusal> {
+fn refuse_collisions(docs: &Docs<'_>) -> Result<(), MindRefusal> {
     for staged in &docs.batch {
         if docs.in_image(staged.kind, &staged.key).is_some() {
             return Err(MindRefusal::IdentityCollision { kind: staged.kind, id: staged.key.clone() });
@@ -1070,8 +1071,8 @@ mod tests {
         let key = format!("{INSTANCE}:stewardship:gamecult_-epiphany.n1");
         assert!(yggdrasil.envelope(K::Stewardship, &key).is_some());
         assert!(thought_cage.envelope(K::Stewardship, &key).is_none());
-        assert_eq!(yggdrasil.envelopes().len(), 4);
-        assert_eq!(thought_cage.envelopes().len(), 3);
+        assert_eq!(yggdrasil.envelopes().count(), 4);
+        assert_eq!(thought_cage.envelopes().count(), 3);
     }
 
     #[test]
@@ -1577,7 +1578,7 @@ mod tests {
             refusal(admit(&mut mind, vec![resolution(r(K::Resolution, &withdrawal), withdrawn())])),
             MindRefusal::AlreadyStewarded { repo: REPO.into() }
         );
-        let docs = Docs::from_image(mind.envelopes()).unwrap();
+        let docs = docs_of(&mind);
         let in_force = docs.stewardships_of(&slug(INSTANCE), &repo(REPO), None).iter().map(|(key, _)| *key).collect::<Vec<_>>();
         assert_eq!(in_force, vec![again.as_str()], "one assignment stands, and it is the later one");
     }
@@ -1599,8 +1600,9 @@ mod tests {
         assert!(!docs_of(&mind).in_force(K::Target, &id("target", "r1")));
     }
 
-    fn docs_of<S: MindStore>(mind: &Mind<S>) -> Docs {
-        Docs::from_image(mind.envelopes()).unwrap()
+    fn docs_of<S: MindStore>(mind: &Mind<S>) -> Docs<'_> {
+        let image = mind.image().unwrap();
+        Docs::at(image, image.head)
     }
 
     /// The withdrawal a hand-off derives is a record of its subject like any

crates/huginn-mind/src/docs.rs

@@ -13,6 +13,7 @@ use eureka_pipeline::{
 use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
 
+use crate::image::Image;
 use crate::refusal::MindRefusal;
 
 /// A batch document after A3 and A5: decoded, keyed, and its envelope.
@@ -23,16 +24,12 @@ pub(crate) struct Staged {
     pub(crate) envelope: CultCacheEnvelope,
 }
 
-/// An image document, decoded.
-pub(crate) struct Held {
-    pub(crate) kind: PipelineKind,
-    pub(crate) key: String,
-    pub(crate) document: PipelineDocument,
-}
-
-/// The image and the batch, the two places a rule may look.
-pub(crate) struct Docs {
-    pub(crate) image: Vec<Held>,
+/// The held image at one snapshot and the batch, the two places a rule or a view
+/// may look. The one door of visibility: a document is there when its writing
+/// receipt's ordinal is at or before `as_of`. Admission runs at the head.
+pub(crate) struct Docs<'i> {
+    image: &'i Image,
+    as_of: u64,
     pub(crate) batch: Vec<Staged>,
 }
 
@@ -40,17 +37,13 @@ pub(crate) fn kind_of_type(type_id: &str) -> Option<PipelineKind> {
     PipelineKind::ALL.iter().copied().find(|kind| kind.type_id() == type_id)
 }
 
-impl Docs {
-    pub(crate) fn from_image(envelopes: &[CultCacheEnvelope]) -> Result<Self, MindRefusal> {
-        let mut image = Vec::new();
-        for envelope in envelopes {
-            let Some(kind) = kind_of_type(&envelope.r#type) else { continue };
-            let document = PipelineDocument::decode(envelope).map_err(|refusal| MindRefusal::Unavailable {
-                detail: format!("stored document {} does not decode: {refusal}", envelope.key),
-            })?;
-            image.push(Held { kind, key: envelope.key.clone(), document });
-        }
-        Ok(Self { image, batch: Vec::new() })
+impl<'i> Docs<'i> {
+    pub(crate) fn at(image: &'i Image, as_of: u64) -> Self {
+        Self { image, as_of, batch: Vec::new() }
+    }
+
+    fn visible(&self, id: u32) -> bool {
+        self.image.row(id).ordinal <= self.as_of
     }
 
     /// A4: one identity, once.
@@ -67,7 +60,7 @@ impl Docs {
     }
 
     pub(crate) fn in_image(&self, kind: PipelineKind, id: &str) -> Option<&PipelineDocument> {
-        self.image.iter().find(|held| held.kind == kind && held.key == id).map(|held| &held.document)
+        self.image.id_of(kind, id).filter(|row| self.visible(*row)).map(|row| &self.image.row(row).view.document)
     }
 
     pub(crate) fn find(&self, kind: PipelineKind, id: &str) -> Option<&PipelineDocument> {
@@ -76,17 +69,14 @@ impl Docs {
 
     pub(crate) fn of_kind(&self, kind: PipelineKind) -> impl Iterator<Item = (&str, &PipelineDocument)> {
         let batch = self.batch.iter().filter(move |staged| staged.kind == kind).map(|staged| (staged.key.as_str(), &staged.document));
-        let image = self.image.iter().filter(move |held| held.kind == kind).map(|held| (held.key.as_str(), &held.document));
+        let image = self
+            .image
+            .of_kind(kind)
+            .filter(move |(_, row)| self.visible(*row))
+            .map(move |(key, row)| (key, &self.image.row(row).view.document));
         batch.chain(image)
     }
 
-    pub(crate) fn resolutions(&self) -> impl Iterator<Item = (&str, &PipelineResolution)> {
-        self.of_kind(PipelineKind::Resolution).filter_map(|(key, document)| match document {
-            PipelineDocument::Resolution(resolution) => Some((key, resolution)),
-            _ => None,
-        })
-    }
-
     pub(crate) fn stewardships(&self) -> impl Iterator<Item = (&str, &PipelineStewardship)> {
         self.of_kind(PipelineKind::Stewardship).filter_map(|(key, document)| match document {
             PipelineDocument::Stewardship(stewardship) => Some((key, stewardship)),
@@ -97,7 +87,25 @@ impl Docs {
     /// Every resolution of one subject, in image and batch: the scope a
     /// subject's sequence counts in.
     pub(crate) fn resolutions_of(&self, subject: &PipelineRef) -> impl Iterator<Item = (&str, &PipelineResolution)> {
-        self.resolutions().filter(move |(_, resolution)| resolution.subject == *subject)
+        self.resolutions_naming(subject.kind, &subject.id.0)
+    }
+
+    /// The resolutions naming one document: the batch's first, then the held ones visible at
+    /// `as_of` in resolution-key order, the order a closing resolution is found in.
+    fn resolutions_naming(&self, kind: PipelineKind, id: &str) -> impl Iterator<Item = (&str, &PipelineResolution)> {
+        let batch = self.batch.iter().filter_map(move |staged| match &staged.document {
+            PipelineDocument::Resolution(resolution) if resolution.subject.kind == kind && resolution.subject.id.0 == id => {
+                Some((staged.key.as_str(), resolution))
+            }
+            _ => None,
+        });
+        let held = self.image.closers_of(kind, id).filter(move |(_, row)| self.visible(*row)).filter_map(move |(key, row)| {
+            match &self.image.row(row).view.document {
+                PipelineDocument::Resolution(resolution) => Some((key, resolution)),
+                _ => None,
+            }
+        });
+        batch.chain(held)
     }
 
     /// Every assignment of one repo to one mind, in image and batch, in force
@@ -128,8 +136,8 @@ impl Docs {
         subject: &PipelineRef,
         derived: impl Fn(&ResolutionOutcome) -> bool,
     ) -> u32 {
-        self.resolutions()
-            .find(|(_, resolution)| resolution.subject == *subject && derived(&resolution.outcome))
+        self.resolutions_of(subject)
+            .find(|(_, resolution)| derived(&resolution.outcome))
             .map_or_else(|| self.latest_resolution(subject, None) + 1, |(_, resolution)| resolution.sequence)
     }
 
@@ -174,12 +182,7 @@ impl Docs {
         id: &str,
         own: impl Fn(&PipelineResolution) -> bool,
     ) -> Option<(&str, &PipelineResolution)> {
-        self.resolutions().find(|&(key, resolution)| {
-            resolution.subject.kind == kind
-                && resolution.subject.id.0 == id
-                && !own(resolution)
-                && self.in_force(PipelineKind::Resolution, key)
-        })
+        self.resolutions_naming(kind, id).find(|&(key, resolution)| !own(resolution) && self.in_force(PipelineKind::Resolution, key))
     }
 
     /// The repos a campaign's cuts may name: the repo set of the highest-revision
@@ -292,10 +295,8 @@ impl Docs {
         hand_off_key
             .and_then(|hand_off| {
                 candidates.iter().find(|(key, _)| {
-                    self.resolutions().any(|(_, resolution)| {
-                        resolution.subject.kind == PipelineKind::Stewardship
-                            && resolution.subject.id.0 == *key
-                            && matches!(&resolution.outcome, ResolutionOutcome::Withdrawn { reason } if reason.0 == hand_off)
+                    self.resolutions_naming(PipelineKind::Stewardship, key).any(|(_, resolution)| {
+                        matches!(&resolution.outcome, ResolutionOutcome::Withdrawn { reason } if reason.0 == hand_off)
                     })
                 })
             })
@@ -560,10 +561,6 @@ mod tests {
     use PipelineDocument as D;
     use PipelineKind as K;
 
-    fn held(kind: K, key: String, document: D) -> Held {
-        Held { kind, key, document }
-    }
-
     fn named(campaign: &str, revision: u32, repos: &[&str]) -> (String, D) {
         let D::Target(mut target) = target(revision, &[INVARIANT]) else { panic!("a target") };
         target.campaign = campaign.into();
@@ -588,15 +585,13 @@ mod tests {
         let (closed_key, closed) = named(CAMPAIGN, 2, &["GameCult/Closed"]);
         let (foreign_key, foreign) = named("other-campaign", 3, &["GameCult/Foreign"]);
         let closing = resolution(r(K::Target, &closed_key), superseded(&[r(K::Target, &in_force_key)]));
-        let docs = Docs {
-            image: vec![
-                held(K::Target, in_force_key, in_force),
-                held(K::Target, closed_key, closed),
-                held(K::Target, foreign_key, foreign),
-                held(K::Resolution, id("resolution", "target.r2.n1"), closing),
-            ],
-            batch: Vec::new(),
-        };
+        let image = Image::of_documents(vec![
+            (K::Target, in_force_key, in_force),
+            (K::Target, closed_key, closed),
+            (K::Target, foreign_key, foreign),
+            (K::Resolution, id("resolution", "target.r2.n1"), closing),
+        ]);
+        let docs = Docs::at(&image, image.head);
         assert_eq!(docs.repos_in_force(&this), [repo(REPO), repo(OTHER_REPO)], "neither the closed higher revision nor another campaign's higher target decides");
     }
 }

crates/huginn-mind/src/image.rs

@@ -0,0 +1,378 @@
+//! The mind's one decoded, indexed image: a pure fold of the commit receipts
+//! in ordinal order. It is built only by replaying the receipts and advanced
+//! only by the function the replay calls, so a held image and a fresh fold of
+//! the same store are equal by construction. Nothing here is stored: a restart
+//! re-folds the store, which is the truth.
+//!
+//! A row is the only decoded copy of its document. Status is derived through
+//! the closing resolutions at an `as_of` and is never stored in a document;
+//! a row holds the head's answer and `status_changed` says from which
+//! snapshot that answer holds. The postings, closers, citers and kind maps
+//! only narrow which rows a read hands the substrate: `universe` is a superset
+//! of what `select` can match, and `select` still decides membership, order,
+//! cursors and edges.
+
+use std::collections::{BTreeMap, BTreeSet, HashMap};
+
+use cultcache_rs::DatabaseEntry;
+use cultnet_rs::Selection;
+use eureka_pipeline::{PipelineDocument, PipelineKind, PipelineRef, PipelineResolution, Short};
+
+use crate::docs::{Docs, citations, kind_of_id, kind_of_type};
+use crate::mind::Envelopes;
+use crate::persona::HuginnPersonaEntry;
+use crate::query::{AdmissionFacts, AdmissionIndex, PipelineDocumentView, PipelineStatus};
+use crate::receipt::HuginnCommitReceipt;
+use crate::refusal::MindRefusal;
+use crate::rows::{Alias, STATUS_ALIASES, SelectionRow, root_and_local};
+
+type Postings = BTreeMap<PipelineKind, BTreeMap<&'static str, HashMap<String, BTreeSet<u32>>>>;
+
+#[derive(Clone, Debug, PartialEq)]
+pub(crate) struct Image {
+    /// The newest receipt's ordinal: `N` of a dense `1..=N`.
+    pub(crate) head: u64,
+    /// Append-only; a row's index is its id. Receipts' order, then identity order within one.
+    pub(crate) rows: Vec<SelectionRow>,
+    /// Per row, the newest ordinal at which its status changed.
+    pub(crate) status_changed: Vec<u64>,
+    /// Kind, then key, to row id, in key order: the image's identity lookup and its per-kind order.
+    by_kind: BTreeMap<PipelineKind, BTreeMap<String, u32>>,
+    /// (kind, alias, value) to the rows answering it.
+    postings: Postings,
+    /// Subject kind and id to the resolutions naming it, by resolution key.
+    closers: BTreeMap<PipelineKind, HashMap<String, BTreeMap<String, u32>>>,
+    /// Target id to the (role, citer) edges that name it.
+    citers: HashMap<String, BTreeSet<(&'static str, u32)>>,
+    /// Root to the newest row written under it.
+    roots: BTreeMap<String, u32>,
+    /// Whether every citation edge names a target of its role's kinds. When one does not, a hop
+    /// selection reads every row, so the substrate refuses it exactly as it would over the whole mind.
+    pub(crate) edges_in_target: bool,
+}
+
+fn integrity(type_id: &str, key: &str, fault: &str) -> MindRefusal {
+    MindRefusal::Unavailable { detail: format!("document {type_id}/{key} {fault}") }
+}
+
+pub(crate) fn status_of(closing: Option<(&str, &PipelineResolution)>) -> PipelineStatus {
+    match closing {
+        Some((key, record)) => PipelineStatus::Resolved {
+            resolution: PipelineRef { kind: PipelineKind::Resolution, id: Short(key.to_string()) },
+            record: record.clone(),
+        },
+        None => PipelineStatus::InForce,
+    }
+}
+
+impl Image {
+    pub(crate) fn empty() -> Self {
+        Self {
+            head: 0,
+            rows: Vec::new(),
+            status_changed: Vec::new(),
+            by_kind: BTreeMap::new(),
+            postings: BTreeMap::new(),
+            closers: BTreeMap::new(),
+            citers: HashMap::new(),
+            roots: BTreeMap::new(),
+            edges_in_target: true,
+        }
+    }
+
+    /// The fold of a store's envelopes. Faults, in order: a pipeline document that does not decode,
+    /// the receipts (undecodable, not dense, a document written twice), a document no receipt wrote.
+    /// There is no other way to make an image: this replays the receipts through `advance`.
+    pub(crate) fn build(
+        envelopes: &Envelopes,
+        receipts: &Result<Vec<HuginnCommitReceipt>, MindRefusal>,
+    ) -> Result<Self, MindRefusal> {
+        let mut decoded: HashMap<(&str, &str), PipelineDocument> = HashMap::new();
+        for (type_id, keyed) in envelopes {
+            if kind_of_type(type_id).is_none() {
+                continue;
+            }
+            for (key, envelope) in keyed {
+                let document = PipelineDocument::decode(envelope).map_err(|refusal| MindRefusal::Unavailable {
+                    detail: format!("stored document {key} does not decode: {refusal}"),
+                })?;
+                decoded.insert((type_id.as_str(), key.as_str()), document);
+            }
+        }
+        let receipts = receipts.clone()?;
+        let index = AdmissionIndex::build(&receipts)?;
+        for (type_id, keyed) in envelopes {
+            if kind_of_type(type_id).is_some()
+                && let Some(key) = keyed.keys().find(|key| !index.contains(type_id, key))
+            {
+                return Err(integrity(type_id, key, "has no commit receipt"));
+            }
+        }
+        let mut ordered: Vec<&HuginnCommitReceipt> = receipts.iter().collect();
+        ordered.sort_by_key(|receipt| receipt.ordinal);
+        let mut image = Self::empty();
+        for receipt in ordered {
+            let mut documents = Vec::new();
+            for write in receipt.writes.iter().filter(|write| write.document_type != HuginnPersonaEntry::TYPE) {
+                let Some(kind) = kind_of_type(&write.document_type) else { continue };
+                // A receipted document the store no longer holds gets no row; read_back names it.
+                if let Some(document) = decoded.remove(&(write.document_type.as_str(), write.document_key.as_str())) {
+                    documents.push((kind, write.document_key.clone(), document));
+                }
+            }
+            image.advance(&AdmissionFacts::of(receipt), documents)?;
+        }
+        Ok(image)
+    }
+
+    pub(crate) fn id_of(&self, kind: PipelineKind, key: &str) -> Option<u32> {
+        self.by_kind.get(&kind)?.get(key).copied()
+    }
+
+    pub(crate) fn row(&self, id: u32) -> &SelectionRow {
+        &self.rows[id as usize]
+    }
+
+    /// The ids of one kind in key order.
+    pub(crate) fn of_kind(&self, kind: PipelineKind) -> impl Iterator<Item = (&str, u32)> {
+        self.by_kind.get(&kind).into_iter().flat_map(|keyed| keyed.iter().map(|(key, id)| (key.as_str(), *id)))
+    }
+
+    /// The resolutions naming one subject, in resolution-key order.
+    pub(crate) fn closers_of(&self, kind: PipelineKind, id: &str) -> impl Iterator<Item = (&str, u32)> {
+        self.closers.get(&kind).and_then(|named| named.get(id)).into_iter().flat_map(|keyed| keyed.iter().map(|(key, id)| (key.as_str(), *id)))
+    }
+
+    /// Every root with the newest row under it.
+    pub(crate) fn roots(&self) -> impl Iterator<Item = (&str, &SelectionRow)> {
+        self.roots.iter().map(|(root, id)| (root.as_str(), self.row(*id)))
+    }
+
+    /// Folds one receipt's documents, given in the receipt's write order, into the image. The same
+    /// function replays the log and follows each commit.
+    pub(crate) fn advance(
+        &mut self,
+        facts: &AdmissionFacts,
+        documents: Vec<(PipelineKind, String, PipelineDocument)>,
+    ) -> Result<(), MindRefusal> {
+        let first = self.rows.len() as u32;
+        // Phase 1: every document of the receipt gets a row, so a subject that sorts after its
+        // resolution in one batch is found by phase 2.
+        for (kind, key, document) in documents {
+            if self.id_of(kind, &key).is_some() {
+                return Err(integrity(kind.type_id(), &key, "is written by two receipts"));
+            }
+            let id = self.rows.len() as u32;
+            let edges = citations(&document);
+            for (role, target) in &edges {
+                let in_target = kind_of_id(&target.id.0).is_some_and(|named| role.target_kinds().contains(&named));
+                self.edges_in_target &= in_target;
+                self.citers.entry(target.id.0.clone()).or_default().insert((role.name(), id));
+            }
+            if let PipelineDocument::Resolution(resolution) = &document {
+                self.closers
+                    .entry(resolution.subject.kind)
+                    .or_default()
+                    .entry(resolution.subject.id.0.clone())
+                    .or_default()
+                    .insert(key.clone(), id);
+            }
+            self.roots.insert(root_and_local(&key).0.to_string(), id);
+            self.by_kind.entry(kind).or_default().insert(key.clone(), id);
+            let view = PipelineDocumentView {
+                id: PipelineRef { kind, id: Short(key.clone()) },
+                document,
+                admission: facts.clone(),
+                status: PipelineStatus::InForce,
+            };
+            self.rows.push(SelectionRow::new(kind, &key, None, view, edges));
+            self.status_changed.push(facts.ordinal);
+        }
+        self.head = facts.ordinal;
+        // Phase 2: a new resolution changes its subject's status, and a subject that is itself a
+        // resolution reopens or closes its own subject in turn, so the chain is walked to the first
+        // document that is not a resolution.
+        let mut touched: BTreeSet<u32> = (first..self.rows.len() as u32).collect();
+        for id in first..self.rows.len() as u32 {
+            let mut current = id;
+            while let PipelineDocument::Resolution(resolution) = &self.row(current).view.document {
+                let Some(subject) = self.id_of(resolution.subject.kind, &resolution.subject.id.0) else { break };
+                touched.insert(subject);
+                current = subject;
+            }
+        }
+        for id in touched {
+            self.rebuild(id, id >= first, facts.ordinal);
+        }
+        Ok(())
+    }
+
+    /// The row with `status`, its base walked through the subjects held.
+    pub(crate) fn make_row(&self, id: u32, status: PipelineStatus) -> SelectionRow {
+        let old = self.row(id);
+        let mut view = old.view.clone();
+        view.status = status;
+        let mut current = id;
+        while let PipelineDocument::Resolution(resolution) = &self.row(current).view.document {
+            let Some(subject) = self.id_of(resolution.subject.kind, &resolution.subject.id.0) else { break };
+            current = subject;
+        }
+        let base = self.row(current);
+        SelectionRow::new(old.kind, &old.key, Some((&base.key, &base.view.document)), view, citations(&old.view.document))
+    }
+
+    fn rebuild(&mut self, id: u32, fresh: bool, ordinal: u64) {
+        let (kind, key) = {
+            let row = self.row(id);
+            (row.kind, row.key.clone())
+        };
+        let status = status_of(Docs::at(self, u64::MAX).closing_resolution(kind, &key));
+        let row = self.make_row(id, status);
+        if !fresh {
+            self.unindex(id);
+        }
+        if row.view.status != self.row(id).view.status {
+            self.status_changed[id as usize] = ordinal;
+        }
+        self.rows[id as usize] = row;
+        self.index(id);
+    }
+
+    fn index(&mut self, id: u32) {
+        let row = &self.rows[id as usize];
+        for (alias, values) in row.alias_values() {
+            for value in values {
+                self.postings
+                    .entry(row.kind)
+                    .or_default()
+                    .entry(alias)
+                    .or_default()
+                    .entry(value.clone())
+                    .or_default()
+                    .insert(id);
+            }
+        }
+    }
+
+    fn unindex(&mut self, id: u32) {
+        let row = &self.rows[id as usize];
+        for (alias, values) in row.alias_values() {
+            for value in values {
+                if let Some(posting) = self.postings.get_mut(&row.kind).and_then(|aliases| aliases.get_mut(alias)).and_then(|values| values.get_mut(value)) {
+                    posting.remove(&id);
+                }
+            }
+        }
+    }
+
+    fn posting(&self, kind: PipelineKind, alias: &str, value: &str) -> Option<&BTreeSet<u32>> {
+        self.postings.get(&kind)?.get(alias)?.get(value)
+    }
+
+    /// The row ids a selection can match at `as_of`, ascending, with those written after `as_of`
+    /// among them for the caller to drop: a superset of what `select` matches, never a verdict.
+    pub(crate) fn universe(&self, selection: &Selection, as_of: u64) -> Vec<u32> {
+        let hop = selection.has_hop();
+        if hop && !self.edges_in_target {
+            return (0..self.rows.len() as u32).collect();
+        }
+        let hop_only_cites = selection.cites.is_some() && selection.cited.is_none();
+        let base = if hop_only_cites { BTreeSet::new() } else { self.base_candidates(selection, as_of) };
+        let mut ids: BTreeSet<u32> = BTreeSet::new();
+        let citers_of = |key: &str, role: Option<&str>| -> Vec<u32> {
+            self.citers
+                .get(key)
+                .into_iter()
+                .flatten()
+                .filter(|(named, _)| role.is_none_or(|role| role == *named))
+                .map(|(_, citer)| *citer)
+                .collect()
+        };
+        match (&selection.cites, &selection.cited) {
+            (None, None) => ids = base,
+            (Some(cites), None) => {
+                let key = cites.target.record_key.as_str();
+                // A row that passes the hop cites the target, so the citers are the superset; the kinds,
+                // keys and fields only the substrate decides.
+                ids.extend(citers_of(key, cites.role.as_deref()));
+                ids.extend(self.any_kind(key));
+            }
+            (cites, Some(cited)) => {
+                for id in &base {
+                    ids.extend(citers_of(&self.row(*id).key, Some(&cited.role)));
+                }
+                if let Some(cites) = cites {
+                    ids.extend(self.any_kind(&cites.target.record_key));
+                }
+                ids.extend(base);
+            }
+        }
+        ids.into_iter().collect()
+    }
+
+    fn any_kind(&self, key: &str) -> Vec<u32> {
+        match kind_of_id(key) {
+            Some(kind) => self.id_of(kind, key).into_iter().collect(),
+            None => PipelineKind::ALL.iter().filter_map(|kind| self.id_of(*kind, key)).collect(),
+        }
+    }
+
+    /// The smallest set the kinds, keys and any_of fields of a selection allow.
+    fn base_candidates(&self, selection: &Selection, as_of: u64) -> BTreeSet<u32> {
+        if let Some(keys) = &selection.keys {
+            return keys.iter().flat_map(|key| self.any_kind(key)).collect();
+        }
+        let kinds: Vec<PipelineKind> = match &selection.schemas {
+            Some(schemas) => schemas.iter().filter_map(|schema| kind_of_type(schema)).collect(),
+            None => PipelineKind::ALL.to_vec(),
+        };
+        let mut out = BTreeSet::new();
+        for kind in kinds {
+            let mut best: Option<(usize, Vec<&BTreeSet<u32>>)> = None;
+            for field in selection.fields.iter().flatten() {
+                if field.op != "any_of" {
+                    continue;
+                }
+                let Some(alias) = Alias::from_name(&field.index) else { continue };
+                if STATUS_ALIASES.contains(&alias) && as_of != self.head {
+                    continue;
+                }
+                let sets: Vec<&BTreeSet<u32>> =
+                    field.values.iter().flatten().filter_map(|value| self.posting(kind, alias.name(), value)).collect();
+                let size = sets.iter().map(|set| set.len()).sum();
+                if best.as_ref().is_none_or(|(smallest, _)| size < *smallest) {
+                    best = Some((size, sets));
+                }
+            }
+            let whole = self.by_kind.get(&kind).map_or(0, BTreeMap::len);
+            match best {
+                Some((size, sets)) if size < whole => out.extend(sets.into_iter().flatten().copied()),
+                _ => out.extend(self.by_kind.get(&kind).into_iter().flat_map(|keyed| keyed.values().copied())),
+            }
+        }
+        out
+    }
+}
+
+#[cfg(test)]
+impl Image {
+    /// An image of hand-made documents, one receipt each in the order given.
+    pub(crate) fn of_documents(documents: Vec<(PipelineKind, String, PipelineDocument)>) -> Self {
+        let mut image = Self::empty();
+        for (n, document) in documents.into_iter().enumerate() {
+            let facts = AdmissionFacts {
+                receipt_id: format!("receipt-{}", n + 1),
+                admitted_at: "2026-09-16T12:00:00Z".into(),
+                provenance: crate::receipt::PipelineProvenance {
+                    faculty: crate::receipt::Faculty::Hands,
+                    agent: Short("claude".into()),
+                    session: Short("session-1".into()),
+                    tool: Short("admit".into()),
+                },
+                ordinal: n as u64 + 1,
+            };
+            image.advance(&facts, vec![document]).unwrap();
+        }
+        image
+    }
+}

crates/huginn-mind/src/index.rs

@@ -10,9 +10,7 @@
 use eureka_pipeline::{PipelineDocument, PipelineKind, PipelineRef};
 use sha2::{Digest, Sha256};
 
-use crate::docs::Docs;
 use crate::mind::Mind;
-use crate::query::AdmissionIndex;
 use crate::refusal::MindRefusal;
 use crate::rows::root_and_local;
 use crate::store::MindStore;
@@ -114,32 +112,31 @@ impl<S: MindStore> Mind<S> {
     /// document the mind does not hold is a refusal, not a silent omission: a
     /// caller names what a commit just landed.
     pub fn index_entries(&self, only: Option<&[PipelineRef]>) -> Result<Vec<IndexEntry>, MindRefusal> {
-        let documents: Vec<(PipelineKind, String, PipelineDocument)> = match only {
+        let image = self.image()?;
+        let held: Vec<(PipelineKind, &str, &PipelineDocument, u64)> = match only {
             Some(refs) => {
                 let mut held = Vec::with_capacity(refs.len());
                 for reference in refs {
                     reference.validate_ref()?;
-                    let document = self.get(reference.kind, &reference.id.0)?.ok_or_else(|| {
+                    let row = image.id_of(reference.kind, &reference.id.0).map(|id| image.row(id)).ok_or_else(|| {
                         MindRefusal::Unavailable { detail: format!("index: {} is not held", reference.id.0) }
                     })?;
-                    held.push((reference.kind, reference.id.0.clone(), document));
+                    held.push((reference.kind, row.key.as_str(), &row.view.document, row.ordinal));
                 }
                 held
             }
-            None => Docs::from_image(self.envelopes())?
-                .image
-                .into_iter()
-                .map(|held| (held.kind, held.key, held.document))
-                .collect(),
+            None => {
+                let mut held: Vec<_> = image.rows.iter().map(|row| (row.kind, row.key.as_str(), &row.view.document, row.ordinal)).collect();
+                held.sort_by(|left, right| (left.0.type_id(), left.1).cmp(&(right.0.type_id(), right.1)));
+                held
+            }
         };
-        let facts = AdmissionIndex::build(self)?;
         let mut entries = Vec::new();
-        for (kind, key, document) in documents {
-            let Some(text) = index_text(&document) else { continue };
-            let ordinal = facts.ordinal_of(kind, &key)?;
+        for (kind, key, document, ordinal) in held {
+            let Some(text) = index_text(document) else { continue };
             entries.push(IndexEntry {
-                root: root_and_local(&key).0.to_string(),
-                id: PipelineRef { kind, id: key.as_str().into() },
+                root: root_and_local(key).0.to_string(),
+                id: PipelineRef { kind, id: key.into() },
                 text_sha256: sha256_hex(&text),
                 text,
                 ordinal,

crates/huginn-mind/src/lib.rs

@@ -10,9 +10,10 @@
 //! cross-document rule, every derived write, and the replay check, in one
 //! ordered path that `admit`, the daemon's sink and the hand-off all share.
 //!
-//! The read side derives status, joins the receipts and answers one typed
-//! selection (CultNet's, over rows this crate supplies) through the same
-//! `docs` the rules use; nothing is stored for it.
+//! The read side answers one typed selection (CultNet's, over rows this crate
+//! supplies) from the mind's held image: a fold of the receipts, held by `Mind`,
+//! advanced per commit, rebuilt on restart and on a lost swap. Status is derived
+//! through the same `docs` the rules use; nothing is stored for it.
 //!
 //! The wire vocabulary and its operation envelope (`envelope`) are here too,
 //! so the daemon and the client share one set
@@ -27,11 +28,14 @@
 
 pub mod admission;
 mod docs;
+mod image;
 pub mod envelope;
 pub mod index;
 pub mod mind;
 pub mod persona;
 mod rows;
+#[cfg(any(test, feature = "test-support"))]
+pub mod oracle;
 pub mod query;
 pub mod receipt;
 pub mod refusal;
@@ -41,6 +45,9 @@ pub mod wire;
 #[cfg(test)]
 pub(crate) mod fixtures;
 
+#[cfg(test)]
+mod read_tests;
+
 pub use docs::CitationRole;
 pub use index::{INDEX_TEXT_MAX_BYTES, INDEX_TEXT_VERSION, IndexEntry, index_text};
 pub use admission::{BATCH_MAX, PipelineAdmissionBatch, PipelineAdmissionOutcome};

crates/huginn-mind/src/mind.rs

@@ -9,13 +9,16 @@
 //! every gate before it attaches, so a refused store is never read into an
 //! image.
 
+use std::collections::BTreeMap;
 use std::path::{Path, PathBuf};
 
 use cultcache_rs::{CultCache, CultCacheEnvelope, DatabaseEntry, OwnedRedbMessagePackBackingStore};
 use cultnet_rs::CursorKey;
 use eureka_pipeline::{PIPELINE_SCHEMA_EPOCH, PipelineDocument, PipelineKind, Slug, register_pipeline_document_types};
 
-use crate::persona::HuginnPersonaEntry;
+use crate::image::Image;
+use crate::persona::{HuginnPersonaEntry, persona_receipt_of};
+use crate::query::AdmissionFacts;
 use crate::receipt::HuginnCommitReceipt;
 use crate::refusal::MindRefusal;
 use crate::store::MindStore;
@@ -91,15 +94,53 @@ fn is_known_type(type_id: &str) -> bool {
         || PipelineKind::ALL.iter().any(|kind| kind.type_id() == type_id)
 }
 
-/// One instance's mind: the declared instance, the store, the registered
-/// cache attached to it, and the image (the store's envelopes as last pulled,
-/// in identity order). The image is a cache of the store and is re-pulled
-/// after every commit; nothing writes it directly.
+/// The store's envelopes by type and key: the bytes as stored, in identity order.
+pub(crate) type Envelopes = BTreeMap<String, BTreeMap<String, CultCacheEnvelope>>;
+
+fn envelopes_of(raw: Vec<CultCacheEnvelope>) -> Envelopes {
+    let mut envelopes = Envelopes::new();
+    for envelope in raw {
+        envelopes.entry(envelope.r#type.clone()).or_default().insert(envelope.key.clone(), envelope);
+    }
+    envelopes
+}
+
+/// Every commit receipt in the envelopes, in receipt-id order.
+pub(crate) fn decode_receipts(envelopes: &Envelopes) -> Result<Vec<HuginnCommitReceipt>, MindRefusal> {
+    envelopes
+        .get(HuginnCommitReceipt::TYPE)
+        .into_iter()
+        .flat_map(|keyed| keyed.values())
+        .map(|envelope| {
+            rmp_serde::from_slice::<HuginnCommitReceipt>(&envelope.payload).map_err(|error| MindRefusal::Unavailable {
+                detail: format!("receipt {} does not decode: {error}", envelope.key),
+            })
+        })
+        .collect()
+}
+
+/// The one fold: the image and the persona's receipt, both read out of the receipts. A fault is
+/// held, not raised, so a faulted store still opens and every read answers the fault.
+fn fold(envelopes: &Envelopes, instance: &Slug) -> (Result<Image, MindRefusal>, Result<Option<String>, MindRefusal>) {
+    let receipts = decode_receipts(envelopes);
+    let persona = receipts.as_ref().map(|receipts| persona_receipt_of(receipts, instance)).map_err(Clone::clone);
+    (Image::build(envelopes, &receipts), persona)
+}
+
+/// One instance's mind: the declared instance, the store, the registry of
+/// the nineteen schemas, the store's envelopes as last pulled, and the image
+/// folded from them. The envelopes are the store's bytes and the image is a
+/// pure fold of the receipts among them: both advance with each commit and
+/// are rebuilt from the store on a lost swap, a store error and a restart.
+/// A cache of the store, never its authority; only `Mind::advance` and
+/// `refresh` write them.
 pub struct Mind<S: MindStore> {
     instance: Slug,
     store: S,
     cache: CultCache,
-    image: Vec<CultCacheEnvelope>,
+    pub(crate) envelopes: Envelopes,
+    image: Result<Image, MindRefusal>,
+    pub(crate) persona_receipt: Result<Option<String>, MindRefusal>,
     /// Mints and verifies this process's selection cursors. Never stored: a
     /// cursor does not survive a reopen, which the substrate accepts.
     cursor_key: CursorKey,
@@ -186,8 +227,10 @@ impl<S: MindStore> Mind<S> {
         refuse_foreign_epoch(&raw)?;
         refuse_foreign_types(&raw)?;
         refuse_foreign_identity(&raw, instance)?;
-        let (cache, image) = attach(store.clone())?;
-        Ok(Self { instance: instance.clone(), store, cache, image, cursor_key: CursorKey::random() })
+        let cache = schema_cache()?;
+        let envelopes = envelopes_of(raw);
+        let (image, persona_receipt) = fold(&envelopes, instance);
+        Ok(Self { instance: instance.clone(), store, cache, envelopes, image, persona_receipt, cursor_key: CursorKey::random() })
     }
 
     pub fn instance(&self) -> &Slug {
@@ -209,10 +252,20 @@ impl<S: MindStore> Mind<S> {
         Ok(())
     }
 
-    /// The image: every envelope the store held at the last pull, in
-    /// identity order. Cut 10's snapshot source reads this.
-    pub fn envelopes(&self) -> &[CultCacheEnvelope] {
-        &self.image
+    /// Every envelope the store held at the last pull, in identity order.
+    pub fn envelopes(&self) -> impl Iterator<Item = &CultCacheEnvelope> {
+        self.envelopes.values().flat_map(|keyed| keyed.values())
+    }
+
+    /// The held image, or the fault the store holds: the same answer at any snapshot.
+    pub(crate) fn image(&self) -> Result<&Image, MindRefusal> {
+        self.image.as_ref().map_err(Clone::clone)
+    }
+
+    /// The image folded from a fresh pull of the store: what a restart would hold.
+    pub(crate) fn fresh_image(&self) -> Result<Image, MindRefusal> {
+        let envelopes = envelopes_of(self.store.pull_all().map_err(unavailable)?);
+        fold(&envelopes, &self.instance).0
     }
 
     pub(crate) fn cursor_key(&self) -> &CursorKey {
@@ -220,7 +273,7 @@ impl<S: MindStore> Mind<S> {
     }
 
     pub fn is_empty(&self) -> bool {
-        self.image.is_empty()
+        self.envelopes.values().all(BTreeMap::is_empty)
     }
 
     /// The stored bytes of one document, by kind and id.
@@ -237,15 +290,7 @@ impl<S: MindStore> Mind<S> {
 
     /// Every commit receipt in the image, in receipt-id order.
     pub(crate) fn receipts(&self) -> Result<Vec<HuginnCommitReceipt>, MindRefusal> {
-        self.image
-            .iter()
-            .filter(|envelope| envelope.r#type == HuginnCommitReceipt::TYPE)
-            .map(|envelope| {
-                rmp_serde::from_slice::<HuginnCommitReceipt>(&envelope.payload).map_err(|error| {
-                    MindRefusal::Unavailable { detail: format!("receipt {} does not decode: {error}", envelope.key) }
-                })
-            })
-            .collect()
+        decode_receipts(&self.envelopes)
     }
 
     /// The mind's own identity: the receipt id of its first admission
@@ -259,7 +304,7 @@ impl<S: MindStore> Mind<S> {
     }
 
     pub(crate) fn raw_envelope(&self, type_id: &str, key: &str) -> Option<&CultCacheEnvelope> {
-        self.image.iter().find(|envelope| envelope.r#type == type_id && envelope.key == key)
+        self.envelopes.get(type_id)?.get(key)
     }
 
     pub(crate) fn cache(&self) -> &CultCache {
@@ -270,11 +315,55 @@ impl<S: MindStore> Mind<S> {
         &self.store
     }
 
-    /// Re-pulls the image from the store through the attached cache.
+    /// Rebuilds the envelopes and the image from the store: the one rebuild, run only when a swap
+    /// was lost or the store errored, the two signals that the store moved beneath the holder.
+    /// One rule for a look that fails: the holder no longer knows the store, so it holds the fault
+    /// (reads and admission refuse with it) until a restart, exactly as a fold fault is held.
     pub(crate) fn refresh(&mut self) -> Result<(), MindRefusal> {
-        self.cache.pull_all_backing_stores().map_err(unavailable)?;
-        self.image = snapshot(&self.cache);
-        Ok(())
+        match self.store.pull_all().map_err(unavailable) {
+            Ok(raw) => {
+                self.envelopes = envelopes_of(raw);
+                (self.image, self.persona_receipt) = fold(&self.envelopes, &self.instance);
+                Ok(())
+            }
+            Err(fault) => {
+                self.image = Err(fault.clone());
+                self.persona_receipt = Err(fault.clone());
+                Err(fault)
+            }
+        }
+    }
+
+    /// Folds a commit the compare-and-swap said landed into the held state. If the fold itself
+    /// faults on bytes that already landed, the state is rebuilt from the store, so the fault held
+    /// is exactly what a reopen would hold, and the commit stays committed.
+    pub(crate) fn advance(&mut self, receipt: &HuginnCommitReceipt, receipt_envelope: CultCacheEnvelope, writes: &[CultCacheEnvelope]) {
+        for envelope in writes.iter().chain(std::iter::once(&receipt_envelope)) {
+            self.envelopes.entry(envelope.r#type.clone()).or_default().insert(envelope.key.clone(), envelope.clone());
+        }
+        if receipt.writes.iter().any(|write| write.document_type == HuginnPersonaEntry::TYPE && write.document_key == self.instance.0)
+            && let Ok(held) = &mut self.persona_receipt
+        {
+            *held = Some(receipt.receipt_id.clone());
+        }
+        let Ok(image) = &mut self.image else { return };
+        let mut documents = Vec::new();
+        let mut faulted = false;
+        for write in &receipt.writes {
+            let Some(kind) = PipelineKind::ALL.iter().copied().find(|kind| kind.type_id() == write.document_type) else { continue };
+            let Some(envelope) = writes.iter().find(|envelope| envelope.r#type == write.document_type && envelope.key == write.document_key) else {
+                faulted = true;
+                break;
+            };
+            match PipelineDocument::decode(envelope) {
+                Ok(document) => documents.push((kind, write.document_key.clone(), document)),
+                Err(_) => faulted = true,
+            }
+        }
+        if faulted || image.advance(&AdmissionFacts::of(receipt), documents).is_err() {
+            // A failed look holds its own fault.
+            let _ = self.refresh();
+        }
     }
 }
 
@@ -343,22 +432,6 @@ fn refuse_foreign_identity(raw: &[CultCacheEnvelope], instance: &Slug) -> Result
     Ok(())
 }
 
-/// Step 5: the registered cache, the store as its one generic home, and the
-/// image pulled through it.
-fn attach<S: MindStore>(store: S) -> Result<(CultCache, Vec<CultCacheEnvelope>), MindRefusal> {
-    let mut cache = schema_cache()?;
-    cache.add_generic_backing_store(store).map_err(unavailable)?;
-    cache.pull_all_backing_stores().map_err(unavailable)?;
-    let image = snapshot(&cache);
-    Ok((cache, image))
-}
-
-fn snapshot(cache: &CultCache) -> Vec<CultCacheEnvelope> {
-    let mut image = cache.snapshot_envelopes();
-    image.sort_by(|left, right| (&left.r#type, &left.key).cmp(&(&right.r#type, &right.key)));
-    image
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -464,11 +537,11 @@ mod tests {
                 Some(MindRefusal::ForeignEpoch { found: "2 records".into(), expected: PIPELINE_SCHEMA_EPOCH.into() })
             );
         }
-        // A store that passes every gate attaches, which is the second pull.
+        // A store that passes every gate is read once: the pull the gates ran on is the one the image folds.
         let store = planted(vec![epoch(), prepare(&instance(INSTANCE))]);
         let mind = Mind::open_with(store.clone(), &yggdrasil).unwrap();
-        assert_eq!(store.pull_count(), 2);
-        assert_eq!(mind.envelopes().len(), 2);
+        assert_eq!(store.pull_count(), 1);
+        assert_eq!(mind.envelopes().count(), 2);
         assert!(!mind.is_empty());
         let empty = MemoryStore::new();
         assert!(Mind::open_with(empty, &yggdrasil).unwrap().is_empty());
@@ -559,7 +632,7 @@ mod tests {
         let store = OwnedRedbMessagePackBackingStore::new(&moved).unwrap();
         let mind = Mind::open_with(store, &slug(INSTANCE)).unwrap();
         assert_eq!(mind.instance(), &slug(INSTANCE));
-        assert_eq!(mind.envelopes().len(), 2);
+        assert_eq!(mind.envelopes().count(), 2);
     }
 
     /// One check, one owner: the value admission refuses a foreign instance

crates/huginn-mind/src/oracle.rs

@@ -0,0 +1,336 @@
+//! The read side's definition, frozen: decode every stored document and every
+//! receipt on each call, derive status by a linear recursive scan, build every
+//! row, and let the substrate select over all of them. It shares nothing with
+//! the held `Image` or with `Docs`, so a test that sets the two side by side
+//! compares two derivations, not one with itself. No production consumer.
+//!
+//! Also the synthetic history the floor test scales a store with.
+
+use std::collections::BTreeMap;
+use std::path::Path;
+
+use chrono::{TimeZone, Utc};
+use cultcache_rs::{CultCacheEnvelope, DatabaseEntry};
+use cultnet_rs::{Selection, select, validate};
+use eureka_pipeline::{
+    CodeLocation, CommitRange, Date, Evidence, EvidenceKind, FindingConfidence, FindingOrigin, FindingSeverity, Label, MutationRecord,
+    PipelineCutReport, PipelineDocument, PipelineFinding, PipelineKind, PipelineRef, PipelineResolution, ReportCommit, ResolutionOutcome, Sha,
+    Line, Para, Short, Slug, StructuralDelta, pipeline_key,
+};
+
+use crate::docs::{citations, kind_of_type};
+use crate::mind::{Mind, schema_cache};
+use crate::persona::HuginnPersonaEntry;
+use crate::query::{AdmissionFacts, PipelineDocumentView, PipelineSelectionPage, PipelineStatus};
+use crate::receipt::{self, Faculty, HuginnCommitReceipt, PipelineProvenance};
+use crate::refusal::MindRefusal;
+use crate::rows::{SelectionRow, Vocabulary, refuse_values};
+use crate::store::MindStore;
+
+struct Doc {
+    kind: PipelineKind,
+    key: String,
+    document: PipelineDocument,
+    facts: AdmissionFacts,
+}
+
+/// The mind as the store holds it, derived from nothing but the store.
+struct Fresh {
+    docs: Vec<Doc>,
+}
+
+fn fault(detail: String) -> MindRefusal {
+    MindRefusal::Unavailable { detail }
+}
+
+impl Fresh {
+    fn pull<S: MindStore>(mind: &Mind<S>) -> Result<Self, MindRefusal> {
+        let mut raw = mind.store().pull_all().map_err(|error| fault(format!("{error:#}")))?;
+        raw.sort_by(|left, right| (&left.r#type, &left.key).cmp(&(&right.r#type, &right.key)));
+        let mut held = Vec::new();
+        for envelope in &raw {
+            let Some(kind) = kind_of_type(&envelope.r#type) else { continue };
+            let document = PipelineDocument::decode(envelope)
+                .map_err(|refusal| fault(format!("stored document {} does not decode: {refusal}", envelope.key)))?;
+            held.push((kind, envelope.key.clone(), document));
+        }
+        let mut receipts = Vec::new();
+        for envelope in raw.iter().filter(|envelope| envelope.r#type == HuginnCommitReceipt::TYPE) {
+            receipts.push(rmp_serde::from_slice::<HuginnCommitReceipt>(&envelope.payload).map_err(|error| {
+                fault(format!("receipt {} does not decode: {error}", envelope.key))
+            })?);
+        }
+        let mut ordinals: Vec<u64> = receipts.iter().map(|receipt| receipt.ordinal).collect();
+        ordinals.sort_unstable();
+        if !ordinals.iter().copied().eq(1..=ordinals.len() as u64) {
+            return Err(fault("receipt ordinals are not 1..=N: found a duplicate or a gap".into()));
+        }
+        let mut facts: BTreeMap<(String, String), AdmissionFacts> = BTreeMap::new();
+        for receipt in &receipts {
+            for write in receipt.writes.iter().filter(|write| write.document_type != HuginnPersonaEntry::TYPE) {
+                let landed = AdmissionFacts {
+                    receipt_id: receipt.receipt_id.clone(),
+                    admitted_at: receipt.committed_at.clone(),
+                    provenance: receipt.provenance.clone(),
+                    ordinal: receipt.ordinal,
+                };
+                if facts.insert((write.document_type.clone(), write.document_key.clone()), landed).is_some() {
+                    return Err(fault(format!("document {}/{} is written by two receipts", write.document_type, write.document_key)));
+                }
+            }
+        }
+        let mut docs = Vec::new();
+        for (kind, key, document) in held {
+            let type_id = kind.type_id();
+            let landed = facts
+                .get(&(type_id.to_string(), key.clone()))
+                .cloned()
+                .ok_or_else(|| fault(format!("document {type_id}/{key} has no commit receipt")))?;
+            docs.push(Doc { kind, key, document, facts: landed });
+        }
+        Ok(Self { docs })
+    }
+
+    fn visible(&self, as_of: u64) -> Vec<&Doc> {
+        self.docs.iter().filter(|doc| doc.facts.ordinal <= as_of).collect()
+    }
+}
+
+/// The recursive derivation, by linear scan over the visible documents.
+fn closing<'a>(visible: &[&'a Doc], kind: PipelineKind, key: &str) -> Option<(&'a str, &'a PipelineResolution)> {
+    visible.iter().find_map(|doc| match &doc.document {
+        PipelineDocument::Resolution(resolution)
+            if resolution.subject.kind == kind
+                && resolution.subject.id.0 == key
+                && closing(visible, PipelineKind::Resolution, &doc.key).is_none() =>
+        {
+            Some((doc.key.as_str(), resolution))
+        }
+        _ => None,
+    })
+}
+
+fn view_of(visible: &[&Doc], doc: &Doc) -> PipelineDocumentView {
+    let status = match closing(visible, doc.kind, &doc.key) {
+        Some((key, record)) => PipelineStatus::Resolved {
+            resolution: PipelineRef { kind: PipelineKind::Resolution, id: Short(key.to_string()) },
+            record: record.clone(),
+        },
+        None => PipelineStatus::InForce,
+    };
+    PipelineDocumentView {
+        id: PipelineRef { kind: doc.kind, id: Short(doc.key.clone()) },
+        document: doc.document.clone(),
+        admission: doc.facts.clone(),
+        status,
+    }
+}
+
+fn base<'a>(visible: &[&'a Doc], doc: &'a Doc) -> &'a Doc {
+    let mut current = doc;
+    while let PipelineDocument::Resolution(resolution) = &current.document {
+        let Some(subject) = visible.iter().find(|other| other.kind == resolution.subject.kind && other.key == resolution.subject.id.0) else {
+            return current;
+        };
+        current = subject;
+    }
+    current
+}
+
+fn row_of(visible: &[&Doc], doc: &Doc) -> SelectionRow {
+    let base = base(visible, doc);
+    SelectionRow::new(doc.kind, &doc.key, Some((&base.key, &base.document)), view_of(visible, doc), citations(&doc.document))
+}
+
+/// The page a selection earns at `as_of`, derived from the store alone.
+pub fn oracle_page<S: MindStore>(mind: &Mind<S>, selection: &Selection, as_of: u64) -> Result<PipelineSelectionPage, MindRefusal> {
+    validate(selection, &Vocabulary).map_err(cultnet_rs::SelectionRefusal::Invalid)?;
+    let selection = refuse_values(selection)?;
+    let fresh = Fresh::pull(mind)?;
+    let visible = fresh.visible(as_of);
+    let rows: Vec<SelectionRow> = visible.iter().map(|doc| row_of(&visible, doc)).collect();
+    let rows: Vec<&SelectionRow> = rows.iter().collect();
+    let evaluation = select(&Vocabulary, &rows, &selection, as_of, mind.cursor_key())?;
+    Mind::<S>::page(&selection, evaluation, as_of, None)
+}
+
+/// The view of one document at `as_of`, derived from the store alone.
+pub fn oracle_view<S: MindStore>(
+    mind: &Mind<S>,
+    id: &PipelineRef,
+    as_of: u64,
+) -> Result<Option<PipelineDocumentView>, MindRefusal> {
+    let fresh = Fresh::pull(mind)?;
+    let visible = fresh.visible(as_of);
+    Ok(visible.iter().find(|doc| doc.kind == id.kind && doc.key == id.id.0).map(|doc| view_of(&visible, doc)))
+}
+
+/// Every pipeline identity the store holds, in the snapshot's order.
+pub fn oracle_ids<S: MindStore>(mind: &Mind<S>, as_of: u64) -> Result<Vec<PipelineRef>, MindRefusal> {
+    let fresh = Fresh::pull(mind)?;
+    Ok(fresh.visible(as_of).iter().map(|doc| PipelineRef { kind: doc.kind, id: Short(doc.key.clone()) }).collect())
+}
+
+// ---------------------------------------------------------------------------------------------
+// The synthetic history
+// ---------------------------------------------------------------------------------------------
+
+const BATCH_RECEIPTS: usize = 700;
+
+fn pad(text: &str, bytes: usize) -> String {
+    let mut out = text.to_string();
+    while out.len() < bytes {
+        out.push_str(" padding for payload size");
+    }
+    out.truncate(bytes.max(text.len()));
+    out
+}
+
+fn range() -> CommitRange {
+    CommitRange { base: Sha("5f98228d".into()), head: Sha("a1b2c3d4".into()) }
+}
+
+fn finding(root: &str, unit: usize, n: usize) -> PipelineDocument {
+    PipelineDocument::Finding(PipelineFinding {
+        campaign: Slug(root.into()),
+        verdict: Short(format!("{root}:verdict:cut-u{unit}.s1")),
+        label: Label(format!("f{unit}-{n}")),
+        range: range(),
+        confidence: FindingConfidence::Confirmed,
+        severity: FindingSeverity::Medium,
+        claim: Line(pad("A synthetic claim.", 500)),
+        invariants: vec![Label("synthetic".into())],
+        locations: vec![CodeLocation { path: Short("crates/huginn-mind/src/query.rs".into()), line: 1, end_line: None, symbol: None }],
+        failure_scenario: Para(pad("A synthetic failure scenario.", 700)),
+        evidence: vec![Evidence { kind: EvidenceKind::Test, locator: "cargo test".into(), result: "ok".into() }],
+        precedents: vec![],
+        origin: FindingOrigin::Introduced,
+    })
+}
+
+fn cut_report(root: &str, unit: usize) -> PipelineDocument {
+    let delta = StructuralDelta {
+        lines_added: 0,
+        lines_removed: 0,
+        dependencies_added: vec![],
+        dependencies_removed: vec![],
+        formats_added: vec![],
+        formats_removed: vec![],
+        targets_added: vec![],
+        targets_removed: vec![],
+    };
+    PipelineDocument::CutReport(PipelineCutReport {
+        campaign: Slug(root.into()),
+        cut_spec: Short(format!("{root}:cut_spec:cut-u{unit}.r1")),
+        attempt: 1,
+        repo: eureka_pipeline::OrgRepo("GameCult/Huginn".into()),
+        branch: Short("hands/synthetic".into()),
+        commits: vec![ReportCommit { sha: Sha("5f98228d".into()), subject: "Land the cut".into(), builds: true }],
+        range: range(),
+        verification: (0..8)
+            .map(|n| Evidence { kind: EvidenceKind::Command, locator: Line(format!("command {n}")), result: Line(pad("passed", 1000)) })
+            .collect(),
+        mutations: vec![MutationRecord {
+            label: Label("M1".into()),
+            rule: "the rule".into(),
+            location: CodeLocation { path: Short("crates/huginn-mind/src/query.rs".into()), line: 1, end_line: None, symbol: None },
+            before: "before".into(),
+            after: "after".into(),
+            commit: Sha("5f98228d".into()),
+            failed_as_expected: true,
+        }],
+        deviations: vec![],
+        forks: vec![],
+        structural_delta: delta,
+        landed_names: vec![],
+        undone: vec![],
+        promises: vec![],
+    })
+}
+
+fn resolution(subject: PipelineRef) -> PipelineDocument {
+    PipelineDocument::Resolution(PipelineResolution {
+        subject,
+        sequence: 1,
+        outcome: ResolutionOutcome::Recorded { reason: "Synthetic.".into() },
+        rationale: Para(pad("Resolved.", 100)),
+        resolved_on: Date("2026-10-01".into()),
+    })
+}
+
+/// Grows a store to `factor` times its pipeline documents with synthetic
+/// history: findings, cut reports and the resolutions that close four records
+/// in five, about three writes a receipt, through the store's own
+/// compare-and-swap in dense receipts. `spread` puts each hundred units under
+/// its own `synth-<n>` root; otherwise everything goes under
+/// `eureka-substrate`, one root growing. Returns the documents written.
+pub fn synth_history<S: MindStore>(store: &S, instance: &Slug, factor: u32, spread: bool) -> Result<usize, MindRefusal> {
+    let pulled = store.pull_all().map_err(|error| fault(format!("{error:#}")))?;
+    let existing = pulled.iter().filter(|envelope| kind_of_type(&envelope.r#type).is_some()).count();
+    let mut ordinal = pulled.iter().filter(|envelope| envelope.r#type == HuginnCommitReceipt::TYPE).count() as u64;
+    let want = existing * factor.saturating_sub(1) as usize;
+    // A unit is five records (four findings, one cut report) and the four
+    // resolutions that close four of them.
+    let units = want / 9;
+    let cache = schema_cache()?;
+    let provenance = PipelineProvenance {
+        faculty: Faculty::Hands,
+        agent: Short("synth".into()),
+        session: Short("synth".into()),
+        tool: Short("synth".into()),
+    };
+    let now = Utc.with_ymd_and_hms(2026, 10, 1, 12, 0, 0).unwrap();
+    let mut pending: Vec<Vec<CultCacheEnvelope>> = Vec::new();
+    let mut written = 0;
+    let flush = |groups: &mut Vec<Vec<CultCacheEnvelope>>, ordinal: &mut u64| -> Result<(), MindRefusal> {
+        if groups.is_empty() {
+            return Ok(());
+        }
+        let mut replacements = Vec::new();
+        for writes in groups.drain(..) {
+            *ordinal += 1;
+            let receipt = receipt::candidate(instance, provenance.clone(), &[], &writes, *ordinal, now)?;
+            let (envelope, _) = cache.prepare_entry_named(&receipt.receipt_id, &receipt).map_err(|error| fault(format!("{error:#}")))?;
+            replacements.extend(writes);
+            replacements.push(envelope);
+        }
+        if !store.compare_and_swap_batch(&[], replacements).map_err(|error| fault(format!("{error:#}")))? {
+            return Err(fault("the synthetic batch lost its swap".into()));
+        }
+        Ok(())
+    };
+    let prepare = |document: &PipelineDocument| -> Result<(PipelineRef, CultCacheEnvelope), MindRefusal> {
+        let key = pipeline_key(document)?;
+        let envelope = document.prepare(&cache).map_err(|error| fault(format!("{error:#}")))?;
+        Ok((PipelineRef { kind: document.kind(), id: Short(key) }, envelope))
+    };
+    for unit in 0..units {
+        let root = if spread { format!("synth-{}", unit / 100) } else { "eureka-substrate".to_string() };
+        let mut records = Vec::new();
+        for n in 0..4 {
+            records.push(prepare(&finding(&root, unit, n))?);
+        }
+        records.push(prepare(&cut_report(&root, unit))?);
+        let mut closers = Vec::new();
+        for (subject, _) in records.iter().take(4) {
+            closers.push(prepare(&resolution(subject.clone()))?);
+        }
+        let mut all = records.into_iter().chain(closers).map(|(_, envelope)| envelope).collect::<Vec<_>>();
+        written += all.len();
+        let tail = all.split_off(6);
+        let middle = all.split_off(3);
+        pending.extend([all, middle, tail]);
+        if pending.len() >= BATCH_RECEIPTS {
+            flush(&mut pending, &mut ordinal)?;
+        }
+    }
+    flush(&mut pending, &mut ordinal)?;
+    Ok(written)
+}
+
+/// Opens the store at `path` under its exclusive lock, grows it, and lets go
+/// of the lock, so a `Mind::open` can follow.
+pub fn synth_history_at(path: &Path, instance: &Slug, factor: u32, spread: bool) -> Result<usize, MindRefusal> {
+    let store = crate::store::OwnedRedbMessagePackBackingStore::new(path).map_err(|error| fault(format!("{error:#}")))?;
+    synth_history(&store, instance, factor, spread)
+}

crates/huginn-mind/src/persona.rs

@@ -19,7 +19,10 @@ use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
 use serde_json::Value;
 
+use eureka_pipeline::Slug;
+
 use crate::mind::Mind;
+use crate::receipt::HuginnCommitReceipt;
 use crate::refusal::MindRefusal;
 use crate::store::MindStore;
 
@@ -124,6 +127,15 @@ pub(crate) fn updated_at(value: &Value) -> Option<&str> {
     value.get("updatedAt").and_then(Value::as_str)
 }
 
+/// The receipt that wrote the persona's stored bytes: the newest receipt whose writes name it.
+pub(crate) fn persona_receipt_of(receipts: &[HuginnCommitReceipt], instance: &Slug) -> Option<String> {
+    receipts
+        .iter()
+        .filter(|receipt| receipt.writes.iter().any(|write| write.document_type == HuginnPersonaEntry::TYPE && write.document_key == instance.0))
+        .max_by_key(|receipt| receipt.ordinal)
+        .map(|receipt| receipt.receipt_id.clone())
+}
+
 impl<S: MindStore> Mind<S> {
     /// This mind's persona envelope, if one is stored.
     pub(crate) fn persona_envelope(&self) -> Option<&CultCacheEnvelope> {
@@ -146,14 +158,7 @@ impl<S: MindStore> Mind<S> {
         let value = decode(envelope)?;
         let integrity = |detail: &str| MindRefusal::Unavailable { detail: detail.into() };
         let updated_at = updated_at(&value).ok_or_else(|| integrity("the stored persona has no updatedAt"))?.to_string();
-        let identity = (envelope.r#type.as_str(), envelope.key.as_str());
-        let receipt_id = self
-            .receipts()?
-            .into_iter()
-            .filter(|receipt| receipt.writes.iter().any(|write| write.identity() == identity))
-            .max_by_key(|receipt| receipt.ordinal)
-            .ok_or_else(|| integrity("the stored persona has no receipt"))?
-            .receipt_id;
+        let receipt_id = self.persona_receipt.clone()?.ok_or_else(|| integrity("the stored persona has no receipt"))?;
         Ok(Some(PersonaStateView { value, updated_at, receipt_id }))
     }
 }
@@ -585,7 +590,7 @@ mod tests {
         let mut with_one = base();
         with_one.push(entry(INSTANCE, persona(INSTANCE, T1)));
         let mind = Mind::open_with(planted(with_one.clone()), &yggdrasil).unwrap();
-        assert_eq!(mind.envelopes().len(), 3);
+        assert_eq!(mind.envelopes().count(), 3);
         assert_eq!(persona_in_status(&mind), crate::wire::PersonaStatus::Unreadable);
         assert!(mind.persona().is_err());
 
@@ -606,6 +611,31 @@ mod tests {
     /// Status answers in the door's own terms: a stored persona the door
     /// cannot read is `Unreadable`, not the `Absent` of a mind with none, while
     /// `PersonaGet` answers `Unavailable` for the same bytes.
+    /// The persona's receipt is the newest put that wrote it, advanced with each put and the same
+    /// after a restart.
+    #[test]
+    fn the_persona_receipt_is_the_newest_put_held_and_after_a_restart() {
+        let store = MemoryStore::new();
+        let mut mind = seeded_over(&store);
+        committed(put(&mut mind, persona(INSTANCE, T1), None));
+        let first = mind.persona().unwrap().unwrap().receipt_id;
+        committed(put(&mut mind, persona(INSTANCE, T2), Some(T1)));
+        let second = mind.persona().unwrap().unwrap().receipt_id;
+        assert_ne!(first, second);
+        let newest = mind
+            .receipts()
+            .unwrap()
+            .into_iter()
+            .filter(|receipt| receipt.writes.iter().any(|write| write.document_type == HuginnPersonaEntry::TYPE))
+            .max_by_key(|receipt| receipt.ordinal)
+            .unwrap()
+            .receipt_id;
+        assert_eq!(second, newest);
+        let reopened = Mind::open_with(store, &slug(INSTANCE)).unwrap();
+        assert_eq!(reopened.persona().unwrap().unwrap().receipt_id, second);
+        assert_eq!(reopened.persona_receipt, mind.persona_receipt);
+    }
+
     #[test]
     fn status_says_unreadable_where_the_door_says_unavailable() {
         let yggdrasil = slug(INSTANCE);

crates/huginn-mind/src/query.rs

@@ -1,9 +1,12 @@
 //! The read side of a mind: a document with the facts of its admission and
 //! its status, and one typed selection over them.
 //!
-//! Nothing here is stored. Status is derived per call through the same
-//! `docs::Docs` the admission rules use, so a withdrawn resolution reopens its
-//! subject for a reader exactly when it reopens it for a rule. The facts come
+//! Nothing derived here is stored in a document. The rows come from the mind's
+//! held `image::Image`, a fold of the receipts; status is derived through the
+//! same `docs::Docs` the admission rules use, at the head when the image was
+//! advanced and at an old snapshot when a reader asks, so a withdrawn
+//! resolution reopens its subject for a reader exactly when it reopens it for
+//! a rule. The facts come
 //! from the commit receipts, from their `writes` and from nothing else: a
 //! document's `admitted_at` is the `now` its batch was admitted at
 //! (`committed_at`), never the store's `stored_at` stamp. A pipeline document
@@ -13,18 +16,19 @@
 //! `query` is CultNet's selection over rows this crate supplies (`rows.rs`).
 //! The substrate owns the filter, the order, the hop, the cursor and the
 //! paging; this module owns the snapshot (`Reader::at`: every derivation runs
-//! over the documents admitted at or before the page's `asOf`), the
+//! over the documents admitted at or before the page's `asOf`, and the image
+//! only narrows which of its rows the substrate is handed), the
 //! projection to a header or a whole view, and the typing of the edges.
 //!
 //! `rank` is the semantic read: the daemon's index supplies candidate ids and
 //! scores, and this module joins them back through the mind and lets the
 //! selection decide. No clock, no store handle, no network.
 
-use std::collections::{BTreeMap, BTreeSet};
+use std::collections::{BTreeMap, BTreeSet, HashMap, HashSet};
 
 use cultcache_rs::DatabaseEntry;
 use cultnet_rs::{
-    Cursor, EdgeAnchor, EdgeMatch, Evaluation, LIMIT_MAX, LIMIT_MIN, PROJECTION_DOCUMENT, Row, Selection, select, validate,
+    Cursor, EdgeAnchor, EdgeMatch, Evaluation, LIMIT_MAX, LIMIT_MIN, PROJECTION_DOCUMENT, Selection, select, validate,
 };
 use eureka_pipeline::{
     ClaimOutcome, CommitRange, Date, FindingConfidence, FindingOrigin, FindingSeverity, Label, Line, MemoryOrigin, MemorySort, OrgRepo,
@@ -34,12 +38,13 @@ use eureka_pipeline::{
 use schemars::JsonSchema;
 use serde::{Deserialize, Serialize};
 
-use crate::docs::{CitationRole, Docs, Held, citations, kind_of_type};
+use crate::docs::{CitationRole, Docs, kind_of_type};
+use crate::image::{Image, status_of};
 use crate::mind::{Mind, schema_cache};
 use crate::persona::HuginnPersonaEntry;
-use crate::receipt::{self, PipelineProvenance};
+use crate::receipt::{HuginnCommitReceipt, PipelineProvenance};
 use crate::refusal::MindRefusal;
-use crate::rows::{SelectionRow, Vocabulary, refuse_values, root_and_local};
+use crate::rows::{SelectionRow, Vocabulary, refuse_values};
 use crate::store::MindStore;
 
 /// What admission recorded about a document when it landed: the receipt that
@@ -325,57 +330,51 @@ pub struct Ranked {
     pub dropped: Vec<PipelineRef>,
 }
 
-/// The admission facts of every stored document, built once per read call from
-/// the receipts. `writes` only: a document a later batch cited as a strong read
-/// keeps the receipt that wrote it. A10 admits one write per pipeline identity,
-/// so two receipts naming one pipeline document is an integrity fault, not a
-/// choice to make. The persona document is the one identity replaced by design
-/// (`put_persona` is a compare-and-swap on `updatedAt`) and is not a pipeline
-/// document: it has no admission facts here, and `Mind::persona` reads its own
-/// receipt.
-pub(crate) struct AdmissionIndex(BTreeMap<(String, String), AdmissionFacts>);
+impl AdmissionFacts {
+    /// What a receipt records about every document it wrote.
+    pub(crate) fn of(receipt: &HuginnCommitReceipt) -> Self {
+        Self {
+            receipt_id: receipt.receipt_id.clone(),
+            admitted_at: receipt.committed_at.clone(),
+            provenance: receipt.provenance.clone(),
+            ordinal: receipt.ordinal,
+        }
+    }
+}
+
+/// The identities the receipts wrote, checked once per build. A chain that is not exactly
+/// `{1..=N}` refuses before a single ordinal is trusted. `writes` only: a document a later batch
+/// cited as a strong read keeps the receipt that wrote it. A10 admits one write per pipeline
+/// identity, so two receipts naming one pipeline document is an integrity fault, not a choice to
+/// make. The persona document is the one identity replaced by design (`put_persona` is a
+/// compare-and-swap on `updatedAt`) and is not a pipeline document: it has no admission facts
+/// here, and the mind holds its receipt apart.
+pub(crate) struct AdmissionIndex(HashSet<(String, String)>);
 
 impl AdmissionIndex {
-    pub(crate) fn build<S: MindStore>(mind: &Mind<S>) -> Result<Self, MindRefusal> {
-        // Every reader of the ordinal asks the same density check admission
-        // does, through `head`: a chain that is not exactly `{1..=N}` refuses
-        // here before a single ordinal is copied out, not only when admission
-        // happens to be the caller.
-        receipt::head(mind)?;
-        let mut facts = BTreeMap::new();
-        for receipt in mind.receipts()? {
+    pub(crate) fn build(receipts: &[HuginnCommitReceipt]) -> Result<Self, MindRefusal> {
+        let mut ordinals = receipts.iter().map(|receipt| receipt.ordinal).collect::<Vec<_>>();
+        ordinals.sort_unstable();
+        if !ordinals.iter().copied().eq(1..=ordinals.len() as u64) {
+            return Err(MindRefusal::Unavailable { detail: "receipt ordinals are not 1..=N: found a duplicate or a gap".into() });
+        }
+        let mut identities = HashSet::new();
+        for receipt in receipts {
             for write in receipt.writes.iter().filter(|write| write.document_type != HuginnPersonaEntry::TYPE) {
-                let identity = (write.document_type.clone(), write.document_key.clone());
-                let landed = AdmissionFacts {
-                    receipt_id: receipt.receipt_id.clone(),
-                    admitted_at: receipt.committed_at.clone(),
-                    provenance: receipt.provenance.clone(),
-                    ordinal: receipt.ordinal,
-                };
-                if facts.insert(identity, landed).is_some() {
+                if !identities.insert((write.document_type.clone(), write.document_key.clone())) {
                     return Err(integrity(&write.document_type, &write.document_key, "is written by two receipts"));
                 }
             }
         }
-        Ok(Self(facts))
+        Ok(Self(identities))
     }
 
-    fn of(&self, held: &Held) -> Result<AdmissionFacts, MindRefusal> {
-        self.facts_of(held.kind, &held.key)
+    pub(crate) fn contains(&self, type_id: &str, key: &str) -> bool {
+        self.0.contains(&(type_id.to_string(), key.to_string()))
     }
 
-    fn facts_of(&self, kind: PipelineKind, key: &str) -> Result<AdmissionFacts, MindRefusal> {
-        let type_id = kind.type_id();
-        self.0
-            .get(&(type_id.to_string(), key.to_string()))
-            .cloned()
-            .ok_or_else(|| integrity(type_id, key, "has no commit receipt"))
-    }
-
-    /// The ordinal of the receipt that wrote a document: the projection's
-    /// position for it.
-    pub(crate) fn ordinal_of(&self, kind: PipelineKind, key: &str) -> Result<u64, MindRefusal> {
-        self.facts_of(kind, key).map(|facts| facts.ordinal)
+    pub(crate) fn identities(&self) -> impl Iterator<Item = &(String, String)> {
+        self.0.iter()
     }
 }
 
@@ -400,89 +399,75 @@ impl RootTouched {
     }
 }
 
-/// One read call's working set: the image as of one snapshot and the facts it
-/// was built from. Built once per call and thrown away with it; nothing here
-/// outlives the answer.
-struct Reader {
-    docs: Docs,
-    facts: AdmissionIndex,
+/// One read call's view of the held image at one snapshot. Nothing is decoded or built here: a row
+/// is the image's own, unless its status changed after `as_of`, in which case it is rebuilt once
+/// with the status the closing resolutions give at `as_of`.
+pub(crate) struct Reader<'i> {
+    docs: Docs<'i>,
+    image: &'i Image,
+    as_of: u64,
+    patched: HashMap<u32, SelectionRow>,
 }
 
-impl Reader {
-    /// The mind as it stood when receipt `as_of` landed: the documents whose
-    /// writing receipt has `ordinal <= as_of`, and every derivation (in
-    /// force, the closing resolution, `base`, citations) over that image
-    /// alone. The facts are built over all receipts, and every held document
-    /// must have its receipt whatever `as_of` is, so an orphan or a double
-    /// write refuses at any snapshot.
-    fn at<S: MindStore>(mind: &Mind<S>, as_of: u64) -> Result<Self, MindRefusal> {
-        let mut docs = Docs::from_image(mind.envelopes())?;
-        let facts = AdmissionIndex::build(mind)?;
-        let mut visible = Vec::with_capacity(docs.image.len());
-        for held in docs.image {
-            if facts.of(&held)?.ordinal <= as_of {
-                visible.push(held);
-            }
-        }
-        docs.image = visible;
-        Ok(Self { docs, facts })
+impl<'i> Reader<'i> {
+    /// The mind as it stood when receipt `as_of` landed. The held fault, if the store has one, is
+    /// answered at any snapshot.
+    pub(crate) fn at<S: MindStore>(mind: &'i Mind<S>, as_of: u64) -> Result<Self, MindRefusal> {
+        let image = mind.image()?;
+        Ok(Self { docs: Docs::at(image, as_of), image, as_of, patched: HashMap::new() })
     }
 
-    fn held(&self, kind: PipelineKind, key: &str) -> Option<&Held> {
-        self.docs.image.iter().find(|held| held.kind == kind && held.key == key)
+    fn status_at(&self, id: u32) -> PipelineStatus {
+        let row = self.image.row(id);
+        status_of(self.docs.closing_resolution(row.kind, &row.key))
+    }
+
+    /// Whether the row exists at `as_of`; when it does, its snapshot row is ready for `row`.
+    pub(crate) fn prepare(&mut self, id: u32) -> bool {
+        if self.image.row(id).ordinal > self.as_of {
+            return false;
+        }
+        if self.image.status_changed[id as usize] > self.as_of && !self.patched.contains_key(&id) {
+            let row = self.image.make_row(id, self.status_at(id));
+            self.patched.insert(id, row);
+        }
+        true
+    }
+
+    /// A prepared row.
+    pub(crate) fn row(&self, id: u32) -> &SelectionRow {
+        if self.image.status_changed[id as usize] > self.as_of { &self.patched[&id] } else { self.image.row(id) }
+    }
+
+    /// The rows a selection can match at this snapshot: a superset the substrate then decides over.
+    pub(crate) fn universe(&mut self, selection: &Selection) -> Vec<u32> {
+        let ids = self.image.universe(selection, self.as_of);
+        ids.into_iter().filter(|id| self.prepare(*id)).collect()
+    }
+
+    pub(crate) fn rows(&self, ids: &[u32]) -> Vec<&SelectionRow> {
+        ids.iter().map(|id| self.row(*id)).collect()
     }
 
     /// The lookup `Mind::view` answers through, so a caller holding one `Reader`
     /// views many documents from one snapshot.
-    fn view(&self, id: &PipelineRef) -> Result<Option<PipelineDocumentView>, MindRefusal> {
-        self.held(id.kind, &id.id.0).map(|held| self.view_of(held)).transpose()
+    pub(crate) fn id_of(&self, kind: PipelineKind, key: &str) -> Option<u32> {
+        self.image.id_of(kind, key)
     }
 
-    fn view_of(&self, held: &Held) -> Result<PipelineDocumentView, MindRefusal> {
-        let admission = self.facts.of(held)?;
-        let status = match self.docs.closing_resolution(held.kind, &held.key) {
-            Some((key, record)) => PipelineStatus::Resolved {
-                resolution: PipelineRef { kind: PipelineKind::Resolution, id: Short(key.to_string()) },
-                record: record.clone(),
-            },
-            None => PipelineStatus::InForce,
-        };
-        Ok(PipelineDocumentView {
-            id: PipelineRef { kind: held.kind, id: Short(held.key.clone()) },
-            document: held.document.clone(),
-            admission,
-            status,
-        })
-    }
-
-    /// The document `repo` and `cut` are read through: a resolution's
-    /// subject, and its subject's subject when that is a resolution too (the
-    /// Q19 cap stops the chain at two). A7 puts every subject in the image,
-    /// and a resolution key is strictly longer than the id it resolves, so
-    /// this walks down and stops. Anything that is not a resolution is its
-    /// own base.
-    fn base<'b>(&'b self, held: &'b Held) -> &'b Held {
-        let mut current = held;
-        while let PipelineDocument::Resolution(resolution) = &current.document {
-            let Some(subject) = self.held(resolution.subject.kind, &resolution.subject.id.0) else {
-                return current;
-            };
-            current = subject;
+    pub(crate) fn view(&self, id: &PipelineRef) -> Result<Option<PipelineDocumentView>, MindRefusal> {
+        let Some(row) = self.image.id_of(id.kind, &id.id.0) else { return Ok(None) };
+        let held = self.image.row(row);
+        if held.ordinal > self.as_of {
+            return Ok(None);
         }
-        current
+        if self.image.status_changed[row as usize] <= self.as_of {
+            return Ok(Some(held.view.clone()));
+        }
+        Ok(Some(self.image.make_row(row, self.status_at(row)).view))
     }
 
     fn roots_touched(&self) -> Vec<RootTouched> {
-        let mut newest: BTreeMap<&str, &AdmissionFacts> = BTreeMap::new();
-        for ((type_id, key), facts) in &self.facts.0 {
-            if kind_of_type(type_id).is_none() {
-                continue;
-            }
-            let root = root_and_local(key).0;
-            if newest.get(root).is_none_or(|seen| seen.ordinal < facts.ordinal) {
-                newest.insert(root, facts);
-            }
-        }
         let docs = &self.docs;
         let campaigns: BTreeMap<&str, &PipelineCampaign> = docs
             .of_kind(PipelineKind::Campaign)
@@ -491,19 +476,9 @@ impl Reader {
                 _ => None,
             })
             .collect();
-        newest
-            .into_iter()
-            .map(|(root, facts)| RootTouched::of(root, facts, campaigns.get(root).map_or(&[][..], |campaign| docs.repos_in_force(campaign))))
-            .collect()
-    }
-
-    fn rows(&self) -> Result<Vec<SelectionRow>, MindRefusal> {
-        self.docs
-            .image
-            .iter()
-            .map(|held| {
-                Ok(SelectionRow::new(held, self.base(held), self.view_of(held)?, citations(&held.document)))
-            })
+        self.image
+            .roots()
+            .map(|(root, newest)| RootTouched::of(root, &newest.view.admission, campaigns.get(root).map_or(&[][..], |campaign| docs.repos_in_force(campaign))))
             .collect()
     }
 }
@@ -524,7 +499,7 @@ impl<S: MindStore> Mind<S> {
     /// vocabulary for one rule.
     pub fn view(&self, id: &PipelineRef) -> Result<Option<PipelineDocumentView>, MindRefusal> {
         id.validate_ref()?;
-        Reader::at(self, receipt::head(self)?)?.view(id)
+        Reader::at(self, self.image()?.head)?.view(id)
     }
 
     /// The upgrade gate (ruling readback-gate-and-materialized-image): every
@@ -532,21 +507,29 @@ impl<S: MindStore> Mind<S> {
     /// stored key, type and payload bytes, and views back unchanged through the
     /// read path `view` uses; every pipeline write a receipt names is stored,
     /// and every stored document has its receipt. Returns how many documents
-    /// it read back; an empty store is a fault. One `Reader` serves every view,
-    /// because `Reader::at` is the expensive build. Admits nothing. A fault
-    /// names the document's key and what failed, never its content.
+    /// it read back; an empty store is a fault. The held image is first set beside a
+    /// fresh fold of the store and must equal it. That clause proves the holder's advance
+    /// only for a mind that has committed since it opened; on the just-opened mind the
+    /// upgrade reads, both sides are one fold of the same bytes, so a wrong fold passes
+    /// it. What the gate proves today is the per-document read-back below. One pass over
+    /// the mind, O(N). Admits nothing. A fault names the document's key and what failed,
+    /// never its content.
     pub fn read_back(&self) -> Result<usize, MindRefusal> {
-        self.read_back_through(Reader::view)
+        self.read_back_through(|reader, id| reader.view(id))
     }
 
     /// The gate's one body; `lookup` is the read path under test, which tests
     /// replace with a lying one to prove the view comparison refuses.
     fn read_back_through(
         &self,
-        lookup: impl Fn(&Reader, &PipelineRef) -> Result<Option<PipelineDocumentView>, MindRefusal>,
+        lookup: impl Fn(&Reader<'_>, &PipelineRef) -> Result<Option<PipelineDocumentView>, MindRefusal>,
     ) -> Result<usize, MindRefusal> {
         let cache = schema_cache()?;
-        let reader = Reader::at(self, receipt::head(self)?)?;
+        let image = self.image()?;
+        if *image != self.fresh_image()? {
+            return Err(MindRefusal::Unavailable { detail: "the held image differs from a fresh fold".into() });
+        }
+        let reader = Reader::at(self, image.head)?;
         let mut count = 0;
         for envelope in self.envelopes() {
             let Some(kind) = kind_of_type(&envelope.r#type) else { continue };
@@ -566,10 +549,14 @@ impl<S: MindStore> Mind<S> {
             }
             count += 1;
         }
-        for (type_id, key) in reader.facts.0.keys() {
-            if kind_of_type(type_id).is_some() && self.raw_envelope(type_id, key).is_none() {
-                return Err(integrity(type_id, key, "is named by a receipt but not stored"));
-            }
+        let receipted = AdmissionIndex::build(&self.receipts()?)?;
+        let mut missing: Vec<&(String, String)> = receipted
+            .identities()
+            .filter(|(type_id, key)| kind_of_type(type_id).is_some() && self.raw_envelope(type_id, key).is_none())
+            .collect();
+        missing.sort();
+        if let Some((type_id, key)) = missing.first() {
+            return Err(integrity(type_id, key, "is named by a receipt but not stored"));
         }
         if count == 0 {
             return Err(MindRefusal::Unavailable { detail: "the store holds no pipeline document".into() });
@@ -587,7 +574,7 @@ impl<S: MindStore> Mind<S> {
     pub fn query(&self, selection: &Selection) -> Result<PipelineSelectionPage, MindRefusal> {
         validate(selection, &Vocabulary).map_err(cultnet_rs::SelectionRefusal::Invalid)?;
         let selection = refuse_values(selection)?;
-        let head = receipt::head(self)?;
+        let head = self.image()?.head;
         let as_of = match selection.cursor.as_deref().filter(|cursor| !cursor.is_empty()) {
             Some(cursor) => {
                 let as_of = Cursor::parse(cursor)?.as_of;
@@ -600,17 +587,31 @@ impl<S: MindStore> Mind<S> {
             }
             None => head,
         };
-        let rows = Reader::at(self, as_of)?.rows()?;
-        let evaluation = select(&Vocabulary, &rows, &selection, as_of, self.cursor_key())?;
-        Self::page(&selection, evaluation, as_of, None)
+        self.select_at(&selection, as_of)
+    }
+
+    #[cfg(test)]
+    /// The doors `query` passes, then the one body at a snapshot the caller names: the entry the
+    /// oracle tests set against the oracle at every `as_of`.
+    pub(crate) fn query_at(&self, selection: &Selection, as_of: u64) -> Result<PipelineSelectionPage, MindRefusal> {
+        validate(selection, &Vocabulary).map_err(cultnet_rs::SelectionRefusal::Invalid)?;
+        let selection = refuse_values(selection)?;
+        self.select_at(&selection, as_of)
+    }
+
+    fn select_at(&self, selection: &Selection, as_of: u64) -> Result<PipelineSelectionPage, MindRefusal> {
+        let mut reader = Reader::at(self, as_of)?;
+        let ids = reader.universe(selection);
+        let rows = reader.rows(&ids);
+        let evaluation = select(&Vocabulary, &rows, selection, as_of, self.cursor_key())?;
+        Self::page(selection, evaluation, as_of, None)
     }
 
     /// Every root this mind holds a document under, with its newest admission and, for a root that is an in-force
     /// campaign, the repos in force (`Docs::repos_in_force`, never the campaign row's opening set). A resolution's
     /// key carries its subject's root, so a later resolution is a touch of that root. One pass at the head, no rows.
     pub fn roots_touched(&self) -> Result<Vec<RootTouched>, MindRefusal> {
-        let head = receipt::head(self)?;
-        Ok(Reader::at(self, head)?.roots_touched())
+        Ok(Reader::at(self, self.image()?.head)?.roots_touched())
     }
 
     /// What a semantic query must satisfy before anything is embedded: the
@@ -655,8 +656,8 @@ impl<S: MindStore> Mind<S> {
     /// ids this returns.
     pub fn members(&self, selection: &Selection, semantic: &SemanticQuery) -> Result<Members, MindRefusal> {
         let selection = Self::semantic_selection(selection, semantic)?;
-        let head = receipt::head(self)?;
-        let rows = Reader::at(self, head)?.rows()?;
+        let head = self.image()?.head;
+        let mut reader = Reader::at(self, head)?;
         // The walk is built here, field by field, from the caller's filters
         // alone and never spread from the caller's selection: the page size
         // is ours (the caller's `limit` shapes an answer, not the walk's cost:
@@ -675,9 +676,11 @@ impl<S: MindStore> Mind<S> {
         let mut ids = Vec::new();
         let mut pages = 0;
         loop {
+            let universe = reader.universe(&walk);
+            let rows = reader.rows(&universe);
             let evaluation = select(&Vocabulary, &rows, &walk, head, self.cursor_key())?;
             pages += 1;
-            ids.extend(evaluation.rows.iter().map(ref_of));
+            ids.extend(evaluation.rows.iter().map(|row| ref_of(row)));
             match evaluation.next_cursor {
                 Some(next) => walk.cursor = Some(next),
                 None => return Ok(Members { as_of: head, ids, pages }),
@@ -713,18 +716,19 @@ impl<S: MindStore> Mind<S> {
     ) -> Result<Ranked, MindRefusal> {
         let selection = Self::semantic_selection(selection, semantic)?;
         let as_of = members.as_of;
-        let rows = Reader::at(self, as_of)?.rows()?;
-
-        let held: BTreeMap<(PipelineKind, &str), i64> =
-            rows.iter().map(|row| ((row.kind, row.key.as_str()), row.ordinal())).collect();
+        let mut reader = Reader::at(self, as_of)?;
         let member: BTreeSet<(PipelineKind, &str)> =
             members.ids.iter().map(|id| (id.kind, id.id.0.as_str())).collect();
         let mut candidates: Vec<(&str, f32, i64)> = Vec::new();
         let mut dropped = Vec::new();
         for (hit, score) in hits {
             let id = (hit.kind, hit.id.0.as_str());
-            match held.get(&id) {
-                Some(&ordinal) if member.contains(&id) => candidates.push((id.1, *score, ordinal)),
+            let ordinal = match reader.id_of(hit.kind, id.1) {
+                Some(row) if reader.prepare(row) => Some(reader.row(row).ordinal as i64),
+                _ => None,
+            };
+            match ordinal {
+                Some(ordinal) if member.contains(&id) => candidates.push((id.1, *score, ordinal)),
                 _ => dropped.push(hit.clone()),
             }
         }
@@ -744,16 +748,18 @@ impl<S: MindStore> Mind<S> {
             Evaluation { rows: Vec::new(), matched: 0, edges: Vec::new(), next_cursor: None }
         } else {
             let narrowed = Selection { keys: Some(keys), limit: Some(LIMIT_MAX), ..selection.clone() };
+            let ids = reader.universe(&narrowed);
+            let rows = reader.rows(&ids);
             select(&Vocabulary, &rows, &narrowed, as_of, self.cursor_key())?
         };
         let score = |row: &SelectionRow| scores.get(row.key.as_str()).copied().unwrap_or(f32::NEG_INFINITY);
-        evaluation.rows.sort_by(|a, b| score(b).total_cmp(&score(a)).then(a.ordinal().cmp(&b.ordinal())));
+        evaluation.rows.sort_by(|a, b| score(b).total_cmp(&score(a)).then(a.ordinal.cmp(&b.ordinal)));
         evaluation.rows.truncate(limit);
         evaluation.next_cursor = None;
-        let row_scores: Vec<f32> = evaluation.rows.iter().map(score).collect();
+        let row_scores: Vec<f32> = evaluation.rows.iter().map(|row| score(row)).collect();
         let position =
             |kind: PipelineKind, key: &str| evaluation.rows.iter().position(|row| row.kind == kind && row.key == key);
-        let mut kept: Vec<(usize, EdgeMatch<SelectionRow>)> = std::mem::take(&mut evaluation.edges)
+        let mut kept: Vec<(usize, EdgeMatch<&SelectionRow>)> = std::mem::take(&mut evaluation.edges)
             .into_iter()
             .filter_map(|edge| {
                 let owner = match edge.anchor {
@@ -771,9 +777,9 @@ impl<S: MindStore> Mind<S> {
 
     /// The projection of an evaluation: a header or a whole view per row, and
     /// the typed edges a hop traversed.
-    fn page(
+    pub(crate) fn page(
         selection: &Selection,
-        evaluation: Evaluation<SelectionRow>,
+        evaluation: Evaluation<&SelectionRow>,
         as_of: u64,
         scores: Option<Vec<f32>>,
     ) -> Result<PipelineSelectionPage, MindRefusal> {
@@ -788,7 +794,7 @@ impl<S: MindStore> Mind<S> {
                 let role = CitationRole::from_name(&edge.role).ok_or_else(|| MindRefusal::Unavailable {
                     detail: format!("the evaluator returned an edge in role {:?}, which is not a citation role", edge.role),
                 })?;
-                typed.push(PipelineEdge { from: ref_of(&edge.from), role, to: ref_of(&edge.to) });
+                typed.push(PipelineEdge { from: ref_of(edge.from), role, to: ref_of(edge.to) });
             }
             Some(typed)
         } else {
@@ -802,8 +808,15 @@ impl<S: MindStore> Mind<S> {
 mod tests {
     use super::*;
     use crate::fixtures::*;
-    use crate::receipt::Faculty;
+    use crate::receipt::{self, Faculty};
     use cultnet_rs::{Citation, FieldPredicate, Incoming, RecordRef};
+
+    /// Every row the mind holds at `as_of`, as the substrate is handed them.
+    fn all_rows(mind: &Mind<MemoryStore>, as_of: u64) -> Vec<SelectionRow> {
+        let mut reader = Reader::at(mind, as_of).unwrap();
+        let ids = reader.universe(&Selection::default());
+        reader.rows(&ids).into_iter().cloned().collect()
+    }
     use crate::store::test_stores::MemoryStore;
     use chrono::{TimeZone, Utc};
     use eureka_pipeline::{
@@ -1339,7 +1352,7 @@ mod tests {
         committed(admit(&mut mind, vec![question_n(1), question_n(2)]));
         let selection = of_kinds(&[K::Question]);
         let head = 2;
-        let rows = Reader::at(&mind, head).unwrap().rows().unwrap();
+        let rows = all_rows(&mind, head);
         let at = |as_of: u64| Selection {
             cursor: Some(Cursor::mint(as_of, &rows[0], &selection, mind.cursor_key())),
             ..selection.clone()
@@ -1393,7 +1406,7 @@ mod tests {
     #[test]
     fn every_emitted_closed_value_passes_the_door() {
         let mind = worked();
-        let rows = Reader::at(&mind, 100).unwrap().rows().unwrap();
+        let rows = all_rows(&mind, 100);
         for row in &rows {
             for alias in ["root", "in_force", "faculty", "repo", "cut", "severity", "confidence", "origin", "authority", "claim_outcome", "outcome"] {
                 for value in cultnet_rs::Row::values(row, alias) {
@@ -2022,6 +2035,44 @@ mod tests {
         assert_eq!((ids(&page), page.matched), (vec![shelf.r4.clone()], plain_matched(&shelf.mind, &standing(Selection::default()))), "top_k bounds the page too");
     }
 
+    /// Three equal scores in every arrival order rank by ordinal alone, so a lookup that gives
+    /// every hit the same row (or the wrong one) is seen.
+    #[test]
+    fn equal_scores_rank_by_each_documents_own_ordinal_in_any_arrival_order() {
+        let shelf = shelf();
+        let image = shelf.mind.image().unwrap();
+        let named = [(K::Question, shelf.q2.clone()), (K::Ruling, shelf.r4.clone()), (K::Resolution, shelf.withdrawn_resolution.clone())];
+        let ordinal = |(kind, key): &(K, String)| image.row(image.id_of(*kind, key).unwrap()).ordinal;
+        let mut expected: Vec<(K, String)> = named.to_vec();
+        expected.sort_by_key(ordinal);
+        assert!(ordinal(&expected[0]) < ordinal(&expected[1]) && ordinal(&expected[1]) < ordinal(&expected[2]), "the fixture's ordinals are distinct");
+        for order in [[0, 1, 2], [0, 2, 1], [1, 0, 2], [1, 2, 0], [2, 0, 1], [2, 1, 0]] {
+            let hits: Vec<_> = order.iter().map(|at| hit(named[*at].0, &named[*at].1, 0.5)).collect();
+            let page = rank_all(&shelf.mind, &Selection::default(), &asking(10), &hits).page;
+            assert_eq!(ids(&page), expected.iter().map(|(_, key)| key.clone()).collect::<Vec<_>>(), "arrival order {order:?}");
+            // The cut is where the tie-break decides: the page keeps the earliest ordinals.
+            let keys: Vec<String> = expected.iter().map(|(_, key)| key.clone()).collect();
+            let limited = Selection { limit: Some(1), ..Selection::default() };
+            assert_eq!(ids(&rank_all(&shelf.mind, &limited, &asking(10), &hits).page), keys[..1].to_vec(), "limit 1, arrival order {order:?}");
+            assert_eq!(ids(&rank_all(&shelf.mind, &Selection::default(), &asking(2), &hits).page), keys[..2].to_vec(), "top_k 2, arrival order {order:?}");
+        }
+    }
+
+    /// Past the candidate cut the tie-break decides who is kept: equal scores arriving in reverse
+    /// keep the earliest ordinals, which a lookup that gives every hit one row does not.
+    #[test]
+    fn equal_scores_past_the_cut_keep_the_earliest_ordinals() {
+        let mut mind = seeded();
+        let total = LIMIT_MAX + 3;
+        for n in 1..=total {
+            committed(admit(&mut mind, vec![question_n(n)]));
+        }
+        let key = |n: u32| id("question", &format!("Q{n}"));
+        let hits: Vec<_> = (1..=total).rev().map(|n| hit(K::Question, &key(n), 0.5)).collect();
+        let page = rank_all(&mind, &Selection::default(), &asking(LIMIT_MAX), &hits).page;
+        assert_eq!(ids(&page), (1..=LIMIT_MAX).map(key).collect::<Vec<_>>());
+    }
+
     /// Membership is the selection's alone: a kind, a key allowlist and a
     /// citation predicate each cut the candidates exactly as they cut a plain
     /// query, and the citation predicate sees the whole mind, not only the
@@ -2533,8 +2584,8 @@ mod tests {
         let absent = mind(gate_rows()).read_back_through(|_, _| Ok(None));
         assert!(matches!(&absent, Err(MindRefusal::Unavailable { detail }) if detail.contains("does not view back")), "{absent:?}");
         let other = mind(gate_rows()).read_back_through(|reader, id| {
-            let first = reader.docs.image.iter().find(|held| held.kind == id.kind).unwrap();
-            reader.view_of(first).map(Some)
+            let (first, _) = reader.image.of_kind(id.kind).next().unwrap();
+            reader.view(&PipelineRef { kind: id.kind, id: Short(first.to_string()) })
         });
         assert!(matches!(&other, Err(MindRefusal::Unavailable { detail }) if detail.contains("does not view back")), "{other:?}");
     }
@@ -2648,30 +2699,18 @@ mod tests {
     /// close a campaign, so the image is built by hand.
     #[test]
     fn a_closed_campaign_answers_no_repos() {
-        let held = |kind: K, key: String, document: D| Held { kind, key, document };
         let (open_key, closed_key, closing_key) = ("open:campaign:open".to_string(), "closed:campaign:closed".to_string(), "closed:resolution:campaign.n1".to_string());
         let named = |slug: &str, repo_name: &str| {
             let D::Campaign(mut c) = campaign(&[repo_name]) else { panic!("a campaign") };
             c.slug = slug.into();
             D::Campaign(c)
         };
-        let image = vec![
-            held(K::Campaign, open_key.clone(), named("open", REPO)),
-            held(K::Campaign, closed_key.clone(), named("closed", OTHER_REPO)),
-            held(K::Resolution, closing_key.clone(), resolution(r(K::Campaign, &closed_key), withdrawn())),
-        ];
-        let landed = |ordinal: u64| AdmissionFacts {
-            receipt_id: format!("receipt-{ordinal}"),
-            admitted_at: "2026-09-16T12:00:00Z".into(),
-            provenance: provenance(Faculty::Hands),
-            ordinal,
-        };
-        let facts = AdmissionIndex(BTreeMap::from([
-            ((K::Campaign.type_id().to_string(), open_key), landed(1)),
-            ((K::Campaign.type_id().to_string(), closed_key), landed(2)),
-            ((K::Resolution.type_id().to_string(), closing_key), landed(3)),
-        ]));
-        let roots = Reader { docs: Docs { image, batch: Vec::new() }, facts }.roots_touched();
+        let image = Image::of_documents(vec![
+            (K::Campaign, open_key.clone(), named("open", REPO)),
+            (K::Campaign, closed_key.clone(), named("closed", OTHER_REPO)),
+            (K::Resolution, closing_key.clone(), resolution(r(K::Campaign, &closed_key), withdrawn())),
+        ]);
+        let roots = Reader { docs: Docs::at(&image, image.head), image: &image, as_of: image.head, patched: HashMap::new() }.roots_touched();
         let by_root: BTreeMap<&str, &RootTouched> = roots.iter().map(|root| (root.root.0.as_str(), root)).collect();
         assert_eq!(by_root["open"].repos, [repo(REPO)]);
         assert!(by_root["closed"].repos.is_empty(), "{roots:?}");

crates/huginn-mind/src/read_tests.rs

@@ -0,0 +1,768 @@
+//! The held image against the oracle. The oracle derives every answer from the store alone, per
+//! call, by the linear derivation the read side had before it held an image; these tests set the
+//! two side by side over a history with withdrawal chains, a re-resolution, hand-offs, a run and
+//! its closure, at every snapshot, across a restart, and across the commit paths that do not
+//! land. They fail when a held answer differs from a fresh one, not when a particular structure
+//! changes.
+
+use std::collections::BTreeSet;
+use std::sync::{Arc, atomic::{AtomicBool, Ordering}};
+
+use anyhow::{Result, anyhow};
+use cultcache_rs::{CacheBackingStore, CultCacheEnvelope, DatabaseEntry, PushAllOptions};
+use cultnet_rs::{Citation, FieldPredicate, Incoming, RecordRef, Row, Selection};
+use eureka_pipeline::{ClaimOutcome, FindingConfidence, PipelineDocument as D, PipelineKind as K, RunTurn, pipeline_key};
+
+use crate::docs::{CitationRole, kind_of_id};
+use crate::fixtures::*;
+use crate::image::Image;
+use crate::mind::{Mind, schema_cache};
+use crate::oracle::{oracle_ids, oracle_page, oracle_view};
+use crate::query::{AdmissionIndex, PipelineSelectionPage, Reader};
+use crate::receipt::{self, Faculty, HuginnCommitReceipt};
+use crate::refusal::MindRefusal;
+use crate::rows::{Alias, STATUS_ALIASES, SelectionRow};
+use crate::store::MindStore;
+use crate::store::test_stores::{MemoryStore, RefusingStore, SwapCommand};
+
+fn answering(label: &str, question: &str) -> D {
+    let mut ruling = ruling(label);
+    ruling.answers = Some(s(question));
+    ruling.choice = Some(l("A"));
+    D::Ruling(ruling)
+}
+
+fn key_of(document: &D) -> String {
+    pipeline_key(document).unwrap()
+}
+
+/// The batches of a history, each with the faculty that admits it.
+fn history() -> Vec<(Faculty, Vec<D>)> {
+    let spec = |cut: &str, revision: u32| id("cut_spec", &format!("cut-{cut}.r{revision}"));
+    let run_a = mind_run("a", RunTurn::SelfRun, &[r(K::CutSpec, &spec("1", 1))]);
+    let run_key = key_of(&run_a);
+    let mut back = match hand_off(OTHER_INSTANCE, INSTANCE, REPO, &[]) {
+        D::HandOff(back) => back,
+        _ => unreachable!(),
+    };
+    back.handed_on = eureka_pipeline::Date("2026-09-17".into());
+    vec![
+        (Faculty::Hands, vec![
+            question("Q1", &["A", "B"], "A"),
+            D::Ruling(ruling("R1")),
+            D::CutSpec(cut_spec("1", 1)),
+            D::CutSpec(cut_spec("9", 1)),
+            D::CutSpec(cut_spec("10", 1)),
+            follow_up("FU-1", r(K::Question, &id("question", "Q1"))),
+        ]),
+        (Faculty::Hands, vec![D::CutReport(cut_report("9", 1)), D::CutReport(cut_report("10", 1))]),
+        (Faculty::Hands, vec![
+            verdict("9", 1, vec![claim(ClaimOutcome::Falsified, &[&id("finding", "cut-9.s1.F1")], Some("P1"), &["M1"])]),
+            D::Finding(finding("9", 1, "F1", FindingConfidence::Confirmed)),
+        ]),
+        // A resolution that sorts before its subject's superseder in the batch it arrives in.
+        (Faculty::Hands, vec![
+            D::CutSpec(cut_spec("9", 2)),
+            resolution(r(K::CutSpec, &spec("9", 1)), superseded(&[r(K::CutSpec, &spec("9", 2))])),
+        ]),
+        // The withdrawal of a resolution, and its withdrawal: the spec closes and reopens.
+        (Faculty::Hands, vec![resolution(r(K::CutSpec, &spec("10", 1)), withdrawn())]),
+        (Faculty::Hands, vec![resolution(r(K::Resolution, &id("resolution", "cut_spec.cut-10.r1.n1")), withdrawn())]),
+        (Faculty::Soul, vec![D::Ruling(ruling("R2"))]),
+        (Faculty::Hands, vec![answering("R3", &id("question", "Q1"))]),
+        // A hand-off away and back: a stewardship closes, its closure is withdrawn, a new one opens.
+        (Faculty::Hands, vec![hand_off(INSTANCE, OTHER_INSTANCE, REPO, &[])]),
+        (Faculty::Hands, vec![D::HandOff(back)]),
+        // A run that claims a spec, then is withdrawn unrun.
+        (Faculty::Hands, vec![run_a]),
+        (Faculty::Hands, vec![resolution(r(K::Run, &run_key), withdrawn())]),
+        (Faculty::Life, vec![question_n(2)]),
+    ]
+}
+
+fn apply<S: MindStore>(mind: &mut Mind<S>, faculty: Faculty, documents: Vec<D>) {
+    committed(admit_as(mind, faculty, documents));
+}
+
+fn history_mind() -> Mind<MemoryStore> {
+    let mut mind = seeded();
+    for (faculty, documents) in history() {
+        apply(&mut mind, faculty, documents);
+    }
+    mind
+}
+
+fn held_equals_fresh<S: MindStore>(mind: &Mind<S>) {
+    let held = mind.image().unwrap();
+    let fresh = mind.fresh_image().unwrap();
+    assert!(*held == fresh, "the held image differs from a fresh fold at head {}", held.head);
+}
+
+fn of_kinds(kinds: &[K]) -> Selection {
+    Selection { schemas: Some(kinds.iter().map(|kind| kind.type_id().to_string()).collect()), ..Selection::default() }
+}
+
+fn any_of(index: &str, values: &[&str]) -> FieldPredicate {
+    FieldPredicate { index: index.into(), op: "any_of".into(), values: Some(values.iter().map(|v| v.to_string()).collect()), number: None }
+}
+
+fn with(mut selection: Selection, predicate: FieldPredicate) -> Selection {
+    selection.fields.get_or_insert_with(Vec::new).push(predicate);
+    selection
+}
+
+fn all_rows<S: MindStore>(mind: &Mind<S>, as_of: u64) -> Vec<SelectionRow> {
+    let mut reader = Reader::at(mind, as_of).unwrap();
+    let ids = reader.universe(&Selection::default());
+    reader.rows(&ids).into_iter().cloned().collect()
+}
+
+/// Selections that between them touch every kind, every alias value the history emits, keys, both
+/// hops on every role with both `exists`, combinations, the other order and the smallest page.
+fn corpus<S: MindStore>(mind: &Mind<S>) -> Vec<Selection> {
+    let head = mind.image().unwrap().head;
+    let rows = all_rows(mind, head);
+    let mut out = vec![Selection::default()];
+    for kind in K::ALL.iter().copied() {
+        out.push(of_kinds(&[kind]));
+        out.push(Selection { descending: true, limit: Some(1), ..of_kinds(&[kind]) });
+        for alias in ["in_force", "root", "faculty"] {
+            for value in ["true", "false", CAMPAIGN, "Hands"] {
+                out.push(with(of_kinds(&[kind]), any_of(alias, &[value])));
+            }
+        }
+    }
+    let (mut pairs, mut edges) = (BTreeSet::new(), BTreeSet::new());
+    for row in &rows {
+        for alias in Alias::ALL {
+            for value in Row::values(row, alias.name()) {
+                pairs.insert((alias.name(), value));
+            }
+        }
+        for (role, target, _) in Row::references(row) {
+            edges.insert((role, target));
+        }
+        out.push(Selection { keys: Some(vec![row.key.clone()]), projection: "document".into(), ..Selection::default() });
+    }
+    out.push(Selection { keys: Some(vec!["nobody:question:nothing".into()]), ..Selection::default() });
+    for (alias, value) in &pairs {
+        out.push(with(Selection::default(), any_of(alias, &[value])));
+    }
+    for (role, target) in &edges {
+        let schema = kind_of_id(target).map_or("epiphany.pipeline.question.v1".to_string(), |kind| kind.type_id().to_string());
+        for role_filter in [Some(role.clone()), None] {
+            let citation = Citation { target: RecordRef::new(schema.clone(), target.clone()), role: role_filter };
+            out.push(Selection { cites: Some(citation.clone()), ..Selection::default() });
+            out.push(with(Selection { cites: Some(citation), ..Selection::default() }, any_of("in_force", &["true"])));
+        }
+    }
+    for role in CitationRole::ALL {
+        for exists in [true, false] {
+            let incoming = Incoming { role: role.name().into(), exists };
+            out.push(Selection { cited: Some(incoming.clone()), ..Selection::default() });
+            out.push(with(Selection { cited: Some(incoming.clone()), ..Selection::default() }, any_of("in_force", &["true"])));
+            out.push(Selection { cited: Some(incoming), descending: true, limit: Some(1), ..of_kinds(&[K::CutSpec, K::Question]) });
+        }
+    }
+    if let Some((role, target)) = edges.iter().next() {
+        let citation = Citation { target: RecordRef::new(K::Question.type_id(), target.clone()), role: Some(role.clone()) };
+        out.push(Selection { cites: Some(citation), cited: Some(Incoming { role: "subject".into(), exists: false }), ..Selection::default() });
+    }
+    out
+}
+
+/// One page, both ways, whole page or whole refusal.
+fn agree<S: MindStore>(mind: &Mind<S>, selection: &Selection, as_of: u64) -> Result<PipelineSelectionPage, MindRefusal> {
+    let held = mind.query_at(selection, as_of);
+    let fresh = oracle_page(mind, selection, as_of);
+    assert_eq!(held, fresh, "as_of {as_of}: {selection:?}");
+    held
+}
+
+fn walk<S: MindStore>(mind: &Mind<S>, selection: &Selection, as_of: u64) {
+    let mut selection = Selection { limit: Some(1), ..selection.clone() };
+    let mut at = as_of;
+    for _ in 0..80 {
+        let Ok(page) = agree(mind, &selection, at) else { return };
+        let Some(next) = page.next else { return };
+        at = page.as_of;
+        selection.cursor = Some(next);
+    }
+    panic!("a limit-1 walk did not end");
+}
+
+#[test]
+fn held_image_equals_a_fresh_fold_after_every_commit() {
+    let mut mind = seeded();
+    held_equals_fresh(&mind);
+    for (faculty, documents) in history() {
+        apply(&mut mind, faculty, documents);
+        held_equals_fresh(&mind);
+    }
+    let image = mind.image().unwrap();
+    assert!(image.status_changed.iter().any(|at| *at > 1), "the history changes a status after the row was written");
+    assert_eq!(image.head, history().len() as u64 + 1);
+}
+
+#[test]
+fn every_read_agrees_with_the_oracle_at_every_snapshot() {
+    let mind = history_mind();
+    let head = mind.image().unwrap().head;
+    let corpus = corpus(&mind);
+    assert!(corpus.len() > 300, "the corpus is {}", corpus.len());
+    let mut differs_from_head = 0;
+    for as_of in 1..=head {
+        for selection in &corpus {
+            let _ = agree(&mind, selection, as_of);
+        }
+        let open = Selection { fields: Some(vec![any_of("in_force", &["true"])]), ..Selection::default() };
+        if mind.query_at(&open, as_of).unwrap().matched != mind.query_at(&open, head).unwrap().matched {
+            differs_from_head += 1;
+        }
+    }
+    assert!(differs_from_head > 0, "a status reversed by a later withdrawal shows at an old snapshot");
+    for kind in K::ALL.iter().copied() {
+        walk(&mind, &of_kinds(&[kind]), head);
+        walk(&mind, &of_kinds(&[kind]), head - 3);
+    }
+    walk(&mind, &Selection::default(), head);
+    walk(&mind, &Selection { descending: true, ..Selection::default() }, 4);
+}
+
+#[test]
+fn views_and_status_agree_with_the_oracle_at_every_snapshot() {
+    let mind = history_mind();
+    let head = mind.image().unwrap().head;
+    let every = oracle_ids(&mind, head).unwrap();
+    assert_eq!(every.len(), mind.image().unwrap().rows.len(), "the oracle names every document, or the loop below proves nothing");
+    for as_of in 1..=head {
+        let reader = Reader::at(&mind, as_of).unwrap();
+        for id in &every {
+            assert_eq!(reader.view(id).unwrap(), oracle_view(&mind, id, as_of).unwrap(), "{} at {as_of}", id.id.0);
+        }
+    }
+    let spec = r(K::CutSpec, &id("cut_spec", "cut-10.r1"));
+    assert_eq!(mind.view(&spec).unwrap().unwrap().status, crate::query::PipelineStatus::InForce, "the reopened spec stands at the head");
+    let closed = Reader::at(&mind, 6).unwrap().view(&spec).unwrap().unwrap();
+    assert!(matches!(closed.status, crate::query::PipelineStatus::Resolved { .. }), "and is closed while its withdrawal is the head");
+    let reopened = Mind::open_with(mind.store().clone(), &slug(INSTANCE)).unwrap();
+    assert_eq!(reopened.status(crate::wire::IndexStatus::Current), mind.status(crate::wire::IndexStatus::Current));
+    assert_eq!(reopened.persona().unwrap(), mind.persona().unwrap());
+}
+
+#[test]
+fn a_restart_answers_what_the_held_image_answered() {
+    let dir = tempfile::tempdir().unwrap();
+    let instance = slug(INSTANCE);
+    let mut mind = Mind::open(dir.path(), &instance).unwrap();
+    seed(&mut mind);
+    for (faculty, documents) in history() {
+        apply(&mut mind, faculty, documents);
+    }
+    let head = mind.image().unwrap().head;
+    let corpus = corpus(&mind);
+    // A cursor is minted under the process's own key, so the answers are compared without it.
+    let plain = |page: Result<PipelineSelectionPage, MindRefusal>| page.map(|page| PipelineSelectionPage { next: None, ..page });
+    let answers: Vec<_> = corpus.iter().map(|selection| plain(mind.query_at(selection, head))).collect();
+    let cursor = mind.query(&Selection { limit: Some(1), ..of_kinds(&[K::Question]) }).unwrap().next.unwrap();
+    let held = mind.image().unwrap().clone();
+    drop(mind);
+    let reopened = Mind::open(dir.path(), &instance).unwrap();
+    assert!(*reopened.image().unwrap() == held, "the image a restart folds is the image the holder held");
+    for (selection, before) in corpus.iter().zip(&answers) {
+        assert_eq!(&plain(reopened.query_at(selection, head)), before, "{selection:?}");
+    }
+    let stale = Selection { limit: Some(1), cursor: Some(cursor), ..of_kinds(&[K::Question]) };
+    assert!(matches!(reopened.query(&stale), Err(MindRefusal::CursorInvalid { .. })), "a cursor does not survive a restart");
+}
+
+#[test]
+fn a_lost_swap_rebuilds_from_what_the_store_holds() {
+    let store = MemoryStore::new();
+    let mut holder = opened(store.clone(), INSTANCE);
+    seed(&mut holder);
+    let mut other = Mind::open_with(store.clone(), &slug(INSTANCE)).unwrap();
+    committed(admit(&mut other, vec![question_n(7)]));
+    let planted = r(K::Question, &id("question", "Q7"));
+    assert!(holder.view(&planted).unwrap().is_none(), "without a lost swap the plant stays unseen until restart: the stated contract");
+    assert_eq!(Mind::open_with(store.clone(), &slug(INSTANCE)).unwrap().view(&planted).unwrap().map(|v| v.id), Some(planted.clone()));
+    let outcome = admit(&mut holder, vec![question_n(7)]);
+    assert!(matches!(outcome, crate::admission::PipelineAdmissionOutcome::Conflict { .. }), "{outcome:?}");
+    held_equals_fresh(&holder);
+    assert!(holder.view(&planted).unwrap().is_some(), "the lost swap looked at the store");
+    committed(admit(&mut holder, vec![question_n(8)]));
+    held_equals_fresh(&holder);
+}
+
+/// A store that lands the swap and then reports an error, so the holder cannot know.
+#[derive(Clone)]
+struct LandsThenFails {
+    inner: MemoryStore,
+    armed: Arc<AtomicBool>,
+}
+
+impl CacheBackingStore for LandsThenFails {
+    fn pull_all(&self) -> Result<Vec<CultCacheEnvelope>> {
+        self.inner.pull_all()
+    }
+    fn push(&mut self, entry: &CultCacheEnvelope) -> Result<()> {
+        self.inner.push(entry)
+    }
+    fn delete(&mut self, entry: &CultCacheEnvelope) -> Result<()> {
+        self.inner.delete(entry)
+    }
+    fn push_all(&mut self, entries: &[CultCacheEnvelope], options: PushAllOptions) -> Result<()> {
+        self.inner.push_all(entries, options)
+    }
+}
+
+impl MindStore for LandsThenFails {
+    fn compare_and_swap_batch(&self, expected: &[CultCacheEnvelope], replacements: Vec<CultCacheEnvelope>) -> Result<bool> {
+        let landed = self.inner.compare_and_swap_batch(expected, replacements)?;
+        if self.armed.swap(false, Ordering::SeqCst) {
+            return Err(anyhow!("the store failed after landing"));
+        }
+        Ok(landed)
+    }
+}
+
+#[test]
+fn a_store_error_during_commit_rebuilds() {
+    let inner = MemoryStore::new();
+    let armed = Arc::new(AtomicBool::new(false));
+    let mut mind = opened(LandsThenFails { inner: inner.clone(), armed: armed.clone() }, INSTANCE);
+    seed(&mut mind);
+    armed.store(true, Ordering::SeqCst);
+    let outcome = admit(&mut mind, vec![question_n(1)]);
+    assert!(matches!(outcome, crate::admission::PipelineAdmissionOutcome::Refused(MindRefusal::Unavailable { .. })), "{outcome:?}");
+    held_equals_fresh(&mind);
+    assert!(mind.view(&r(K::Question, &id("question", "Q1"))).unwrap().is_some(), "the batch that landed is held");
+    committed(admit(&mut mind, vec![question_n(2)]));
+    held_equals_fresh(&mind);
+
+    let refusing = RefusingStore::new();
+    let mut mind = opened(refusing.clone(), INSTANCE);
+    seed(&mut mind);
+    refusing.command(SwapCommand::Fail);
+    let before = mind.image().unwrap().clone();
+    assert!(matches!(admit(&mut mind, vec![question_n(1)]), crate::admission::PipelineAdmissionOutcome::Refused(_)));
+    held_equals_fresh(&mind);
+    assert!(*mind.image().unwrap() == before, "a store that did not land leaves the image as it was");
+    refusing.command(SwapCommand::Delegate);
+    committed(admit(&mut mind, vec![question_n(1)]));
+    held_equals_fresh(&mind);
+}
+
+/// The rows of a healthy two-step mind, to be broken one way at a time.
+fn healthy_rows() -> Vec<CultCacheEnvelope> {
+    let mut mind = seeded();
+    committed(admit(&mut mind, vec![question_n(1)]));
+    mind.store().rows()
+}
+
+fn receipt_of(rows: &[CultCacheEnvelope], ordinal: u64) -> HuginnCommitReceipt {
+    rows.iter()
+        .filter(|row| row.r#type == HuginnCommitReceipt::TYPE)
+        .map(|row| rmp_serde::from_slice::<HuginnCommitReceipt>(&row.payload).unwrap())
+        .find(|receipt| receipt.ordinal == ordinal)
+        .unwrap()
+}
+
+fn faulted_mind(rows: Vec<CultCacheEnvelope>) -> (Mind<MemoryStore>, MemoryStore) {
+    let store = MemoryStore::new();
+    rows.into_iter().for_each(|row| store.plant(row));
+    (Mind::open_with(store.clone(), &slug(INSTANCE)).unwrap(), store)
+}
+
+#[test]
+fn a_faulted_store_refuses_alike_at_every_snapshot() {
+    let cache = schema_cache().unwrap();
+    let mut cases: Vec<(&str, Vec<CultCacheEnvelope>)> = Vec::new();
+
+    let mut rows = healthy_rows();
+    let at = rows.iter().position(|row| row.key == id("question", "Q1")).unwrap();
+    rows[at].payload = vec![0xc1];
+    cases.push(("an undecodable document", rows));
+
+    let mut rows = healthy_rows();
+    let at = rows.iter().position(|row| row.r#type == HuginnCommitReceipt::TYPE).unwrap();
+    rows[at].payload = vec![0xc1];
+    cases.push(("an undecodable receipt", rows));
+
+    let mut rows = healthy_rows();
+    let gone = receipt_of(&rows, 1).receipt_id;
+    rows.retain(|row| row.key != gone);
+    cases.push(("an undense chain", rows));
+
+    let mut rows = healthy_rows();
+    let orphan = prepare(&question_n(5));
+    rows.push(orphan);
+    cases.push(("an orphan", rows));
+
+    let mut rows = healthy_rows();
+    let mut twice = receipt_of(&rows, 2);
+    twice.ordinal = 3;
+    twice.receipt_id = "mind-commit-twice".into();
+    rows.push(cache.prepare_entry_named(&twice.receipt_id, &twice).unwrap().0);
+    cases.push(("a document written by two receipts", rows));
+
+    for (name, rows) in cases {
+        let (mind, store) = faulted_mind(rows);
+        let before = store.rows();
+        let probe = of_kinds(&[K::Question]);
+        let seen = mind.query_at(&probe, 1);
+        let fault = seen.clone().expect_err(name);
+        for as_of in [1, 2, 5] {
+            assert_eq!(mind.query_at(&probe, as_of), seen, "{name} at {as_of}");
+            assert_eq!(oracle_page(&mind, &probe, as_of).expect_err(name), fault, "{name}: the oracle names the same fault");
+        }
+        assert_eq!(mind.query(&probe), seen, "{name}: query answers the held fault");
+        assert_eq!(mind.view(&r(K::Question, &id("question", "Q1"))), Err(fault.clone()), "{name}");
+        let outcome = admit(&mut Mind::open_with(store.clone(), &slug(INSTANCE)).unwrap(), vec![question_n(9)]);
+        assert!(matches!(outcome, crate::admission::PipelineAdmissionOutcome::Refused(ref refusal) if *refusal == fault), "{name}: admit refuses with the fault, {outcome:?}");
+        assert_eq!(store.rows(), before, "{name}: a refused admission writes nothing");
+        let status = mind.status(crate::wire::IndexStatus::Current);
+        assert_eq!(status.persona, crate::wire::PersonaStatus::Absent, "{name}: status stays total");
+        assert_eq!(mind.persona().unwrap(), None, "{name}");
+    }
+}
+
+#[test]
+fn an_edge_outside_its_target_falls_back_to_the_whole_universe() {
+    let mut rows = healthy_rows();
+    let cache = schema_cache().unwrap();
+    // A run claims a question: the role claims cut specs, findings and follow-ups. Admission would
+    // refuse it, so it is planted with its receipt.
+    let planted = mind_run("planted", RunTurn::SelfRun, &[r(K::Question, &id("question", "Q1"))]);
+    let envelope = planted.prepare(&cache).unwrap();
+    let mut receipt = receipt::candidate(&slug(INSTANCE), provenance(Faculty::Hands), &[], std::slice::from_ref(&envelope), 3, now()).unwrap();
+    receipt.receipt_id = receipt.digest().unwrap();
+    rows.push(cache.prepare_entry_named(&receipt.receipt_id, &receipt).unwrap().0);
+    rows.push(envelope);
+    let (mind, _) = faulted_mind(rows);
+    assert!(!mind.image().unwrap().edges_in_target, "the planted edge is outside its role's kinds");
+    let healthy = seeded();
+    assert!(healthy.image().unwrap().edges_in_target);
+    let refused = MindRefusal::from(cultnet_rs::SelectionRefusal::ReferenceOutsideTarget {
+        from_schema_id: K::Run.type_id().into(),
+        from_key: key_of(&planted),
+        role: "claims".into(),
+        to_schema_id: K::Question.type_id().into(),
+        to_key: id("question", "Q1"),
+    });
+    let elsewhere = Citation { target: RecordRef::new(K::CutSpec.type_id(), id("cut_spec", "cut-1.r1")), role: Some("claims".into()) };
+    for selection in [
+        Selection { cited: Some(Incoming { role: "claims".into(), exists: true }), ..Selection::default() },
+        Selection { cites: Some(elsewhere), ..Selection::default() },
+    ] {
+        assert_eq!(agree(&mind, &selection, 3), Err(refused.clone()), "the substrate refuses the edge exactly as it would over the whole mind");
+    }
+}
+
+#[test]
+fn status_aliases_are_the_declared_ones() {
+    let mut mind = seeded();
+    let mut before = all_rows(&mind, 1);
+    let mut status_changes = 0;
+    for (faculty, documents) in history() {
+        apply(&mut mind, faculty, documents);
+        let after = all_rows(&mind, mind.image().unwrap().head);
+        for (old, new) in before.iter().zip(&after) {
+            if old.view.status != new.view.status {
+                status_changes += 1;
+            }
+            for alias in Alias::ALL {
+                if !STATUS_ALIASES.contains(&alias) {
+                    assert_eq!(Row::values(old, alias.name()), Row::values(new, alias.name()), "{} changed under a status change", alias.name());
+                }
+            }
+        }
+        before = after;
+    }
+    assert!(status_changes >= 3, "the history changes statuses ({status_changes})");
+}
+
+#[test]
+fn read_back_refuses_a_held_image_that_differs_from_a_fresh_fold() {
+    let store = MemoryStore::new();
+    let mut holder = opened(store.clone(), INSTANCE);
+    seed(&mut holder);
+    assert_eq!(holder.read_back().unwrap(), 4, "a clean store counts every document");
+    let mut other = Mind::open_with(store, &slug(INSTANCE)).unwrap();
+    committed(admit(&mut other, vec![question_n(1)]));
+    let refused = holder.read_back();
+    assert!(matches!(&refused, Err(MindRefusal::Unavailable { detail }) if detail.contains("held image differs from a fresh fold")), "{refused:?}");
+    assert_eq!(other.read_back().unwrap(), 5);
+}
+
+#[test]
+fn the_admission_index_names_what_receipts_wrote() {
+    let mind = history_mind();
+    let index = AdmissionIndex::build(&mind.receipts().unwrap()).unwrap();
+    let image: &Image = mind.image().unwrap();
+    for row in &image.rows {
+        assert!(index.contains(row.kind.type_id(), &row.key));
+    }
+}
+
+/// A store whose swap can land then err, be lost, and whose next pull can fail: a look that fails
+/// after a store fault.
+#[derive(Clone)]
+struct FailsTheLook {
+    inner: MemoryStore,
+    land_then_err: Arc<AtomicBool>,
+    lose: Arc<AtomicBool>,
+    pull_err: Arc<AtomicBool>,
+}
+
+impl CacheBackingStore for FailsTheLook {
+    fn pull_all(&self) -> Result<Vec<CultCacheEnvelope>> {
+        if self.pull_err.swap(false, Ordering::SeqCst) {
+            return Err(anyhow!("the look failed"));
+        }
+        self.inner.pull_all()
+    }
+    fn push(&mut self, entry: &CultCacheEnvelope) -> Result<()> {
+        self.inner.push(entry)
+    }
+    fn delete(&mut self, entry: &CultCacheEnvelope) -> Result<()> {
+        self.inner.delete(entry)
+    }
+    fn push_all(&mut self, entries: &[CultCacheEnvelope], options: PushAllOptions) -> Result<()> {
+        self.inner.push_all(entries, options)
+    }
+}
+
+impl MindStore for FailsTheLook {
+    fn compare_and_swap_batch(&self, expected: &[CultCacheEnvelope], replacements: Vec<CultCacheEnvelope>) -> Result<bool> {
+        if self.lose.swap(false, Ordering::SeqCst) {
+            return Ok(false);
+        }
+        let landed = self.inner.compare_and_swap_batch(expected, replacements)?;
+        if self.land_then_err.swap(false, Ordering::SeqCst) {
+            return Err(anyhow!("the store failed after landing"));
+        }
+        Ok(landed)
+    }
+}
+
+fn fails_the_look() -> (Mind<FailsTheLook>, FailsTheLook) {
+    let store = FailsTheLook { inner: MemoryStore::new(), land_then_err: Default::default(), lose: Default::default(), pull_err: Default::default() };
+    let mut mind = opened(store.clone(), INSTANCE);
+    seed(&mut mind);
+    (mind, store)
+}
+
+/// One rule for a failed look: the fault is held, reads and admission refuse with it, nothing is
+/// written, and a restart holds what the store holds and admits at the next ordinal.
+fn assert_fault_is_held(mind: &mut Mind<FailsTheLook>, store: &FailsTheLook, landed: &[&str]) {
+    assert!(matches!(mind.image(), Err(MindRefusal::Unavailable { .. })));
+    assert!(matches!(mind.query(&of_kinds(&[K::Question])), Err(MindRefusal::Unavailable { .. })));
+    let rows = store.inner.rows();
+    let next = admit(mind, vec![question_n(50)]);
+    assert!(matches!(next, crate::admission::PipelineAdmissionOutcome::Refused(MindRefusal::Unavailable { .. })), "{next:?}");
+    assert_eq!(store.inner.rows(), rows, "a held fault writes nothing");
+    let mut reopened = opened(store.clone(), INSTANCE);
+    held_equals_fresh(&reopened);
+    assert_eq!(reopened.query(&of_kinds(&[K::Question])).unwrap().matched, landed.len() as u32);
+    committed(admit(&mut reopened, vec![question_n(51)]));
+    held_equals_fresh(&reopened);
+    reopened.read_back().unwrap();
+}
+
+#[test]
+fn a_failed_look_after_a_landed_error_holds_the_fault() {
+    let (mut mind, store) = fails_the_look();
+    store.land_then_err.store(true, Ordering::SeqCst);
+    store.pull_err.store(true, Ordering::SeqCst);
+    let first = admit(&mut mind, vec![question_n(1)]);
+    assert!(matches!(first, crate::admission::PipelineAdmissionOutcome::Refused(MindRefusal::Unavailable { .. })), "{first:?}");
+    assert_fault_is_held(&mut mind, &store, &["Q1"]);
+}
+
+#[test]
+fn a_failed_look_after_a_lost_swap_holds_the_fault() {
+    let (mut mind, store) = fails_the_look();
+    let mut other = opened(store.clone(), INSTANCE);
+    committed(admit(&mut other, vec![question_n(7)]));
+    store.lose.store(true, Ordering::SeqCst);
+    store.pull_err.store(true, Ordering::SeqCst);
+    let lost = admit(&mut mind, vec![question_n(8)]);
+    assert!(matches!(lost, crate::admission::PipelineAdmissionOutcome::Refused(MindRefusal::Unavailable { .. })), "{lost:?}");
+    assert_fault_is_held(&mut mind, &store, &["Q7"]);
+}
+
+// ---- the floor: what a read and a landed commit may cost, counted ----
+
+/// Reads and a landed admission never pull the store: a pull is a decode of the whole mind.
+#[test]
+fn reads_and_landed_admissions_pull_the_store_zero_times() {
+    let mut mind = history_mind();
+    let pulls = mind.store().pull_count();
+    let head = mind.image().unwrap().head;
+    mind.query(&Selection::default()).unwrap();
+    mind.query_at(&of_kinds(&[K::Question]), head / 2).unwrap();
+    mind.view(&r(K::Question, &id("question", "Q1"))).unwrap();
+    let _ = mind.status(crate::wire::IndexStatus::Current);
+    let _ = mind.persona();
+    assert_eq!(mind.store().pull_count(), pulls, "a read pulled the store");
+    committed(admit(&mut mind, vec![question_n(99)]));
+    committed(admit(&mut mind, vec![resolution(r(K::Question, &id("question", "Q99")), withdrawn())]));
+    assert_eq!(mind.store().pull_count(), pulls, "a landed swap pulled the store");
+    held_equals_fresh(&mind);
+}
+
+/// A lost swap and a store error each look at the store exactly once.
+#[test]
+fn a_lost_swap_and_a_store_error_pull_the_store_once_each() {
+    let (mut mind, store) = fails_the_look();
+    let mut other = opened(store.clone(), INSTANCE);
+    committed(admit(&mut other, vec![question_n(7)]));
+    let pulls = store.inner.pull_count();
+    store.lose.store(true, Ordering::SeqCst);
+    admit(&mut mind, vec![question_n(8)]);
+    assert_eq!(store.inner.pull_count(), pulls + 1, "a lost swap looks once");
+    store.land_then_err.store(true, Ordering::SeqCst);
+    admit(&mut mind, vec![question_n(9)]);
+    assert_eq!(store.inner.pull_count(), pulls + 2, "a store error looks once");
+}
+
+/// A history of many questions, one of them the only Soul's, one follow-up citing Q1.
+fn many_rows_mind() -> Mind<MemoryStore> {
+    let mut mind = seeded();
+    for chunk in (1..=40).collect::<Vec<u32>>().chunks(10) {
+        committed(admit(&mut mind, chunk.iter().map(|n| question_n(*n)).collect()));
+    }
+    committed(admit_as(&mut mind, Faculty::Soul, vec![question_n(41)]));
+    committed(admit(&mut mind, vec![follow_up("FU-1", r(K::Question, &id("question", "Q1")))]));
+    mind
+}
+
+/// The universe is the narrowing: a selection that names a key, a rare field value or a cited
+/// target hands the match only its candidates, never the mind.
+#[test]
+fn a_selection_reads_its_candidates_and_not_the_mind() {
+    let mind = many_rows_mind();
+    let image = mind.image().unwrap();
+    let (head, total) = (image.head, image.rows.len());
+    assert!(total > 40);
+    assert_eq!(image.universe(&Selection::default(), head).len(), total, "the unfiltered selection is the whole mind");
+    let keyed = Selection { keys: Some(vec![id("question", "Q3")]), ..Selection::default() };
+    assert_eq!(image.universe(&keyed, head).len(), 1, "keys");
+    let rare = with(of_kinds(&[K::Question]), any_of("faculty", &["Soul"]));
+    assert_eq!(image.universe(&rare, head).len(), 1, "a rare field value");
+    assert_eq!(image.universe(&of_kinds(&[K::Question]), head).len(), 41, "a kind is its own rows");
+    let citation = Citation { target: RecordRef::new(K::Question.type_id(), id("question", "Q1")), role: None };
+    let citers = Selection { cites: Some(citation), ..Selection::default() };
+    let universe = image.universe(&citers, head);
+    assert!(universe.len() <= 3 && !universe.is_empty(), "a hop starts from the target's citers: {}", universe.len());
+    assert!(total > 10 * universe.len());
+    assert!(mind.query(&citers).unwrap().matched >= 1);
+}
+
+// ---- the narrowing lines the oracle corpus must reach ----
+
+/// Both hops with the citer's schema excluding the target's: the target row is handed to the
+/// match only by the line that adds the cites target to a both-hop universe.
+#[test]
+fn both_hops_with_a_schema_excluding_the_target_agree() {
+    let mind = history_mind();
+    let head = mind.image().unwrap().head;
+    let rows = all_rows(&mind, head);
+    let mut edges = BTreeSet::new();
+    for row in &rows {
+        for (role, target, _) in Row::references(row) {
+            edges.insert((row.kind, role, target));
+        }
+    }
+    let (mut pages, mut hits) = (0, 0);
+    for (carrier, role, target) in &edges {
+        let schema = kind_of_id(target).map_or(K::Question.type_id().to_string(), |kind| kind.type_id().to_string());
+        let citation = Citation { target: RecordRef::new(schema, target.clone()), role: Some(role.clone()) };
+        for exists in [true, false] {
+            let incoming = Incoming { role: "subject".into(), exists };
+            let plain = Selection { cites: Some(citation.clone()), cited: Some(incoming.clone()), ..of_kinds(&[*carrier]) };
+            let narrowed = with(Selection { projection: "document".into(), ..plain.clone() }, any_of("in_force", &["true"]));
+            for as_of in [head, head / 2] {
+                for selection in [&plain, &narrowed] {
+                    if let Ok(page) = agree(&mind, selection, as_of) {
+                        pages += 1;
+                        hits += usize::from(page.matched > 0);
+                    }
+                }
+            }
+        }
+    }
+    assert!(pages > 0 && hits > 0, "no both-hop selection with a schema matched anything ({pages} pages)");
+}
+
+/// A resolution withdrawn by another: the Resolution schema excludes the cut spec it cites.
+#[test]
+fn a_both_hop_selection_finds_a_citer_whose_target_the_schema_excludes() {
+    let mind = history_mind();
+    let selection = Selection {
+        cites: Some(Citation { target: RecordRef::new(K::CutSpec.type_id(), id("cut_spec", "cut-10.r1")), role: None }),
+        cited: Some(Incoming { role: "subject".into(), exists: true }),
+        ..of_kinds(&[K::Resolution])
+    };
+    let head = mind.image().unwrap().head;
+    let page = agree(&mind, &selection, head).unwrap();
+    assert_eq!(page.matched, 1, "{page:?}");
+}
+
+fn planted_rows(rows: &mut Vec<CultCacheEnvelope>, ordinal: u64, document: &D) {
+    let cache = schema_cache().unwrap();
+    let envelope = document.prepare(&cache).unwrap();
+    let mut receipt = receipt::candidate(&slug(INSTANCE), provenance(Faculty::Hands), &[], std::slice::from_ref(&envelope), ordinal, now()).unwrap();
+    receipt.receipt_id = receipt.digest().unwrap();
+    rows.push(cache.prepare_entry_named(&receipt.receipt_id, &receipt).unwrap().0);
+    rows.push(envelope);
+}
+
+/// Two closures in force over one subject, the later sequence arriving first. Admission refuses
+/// this; a store that holds it must still answer as the oracle does, closers in key order.
+#[test]
+fn planted_double_closers_keep_key_order() {
+    let q = r(K::Question, &id("question", "Q1"));
+    let mut rows = healthy_rows();
+    planted_rows(&mut rows, 3, &resolution_n(q.clone(), 2, withdrawn()));
+    planted_rows(&mut rows, 4, &resolution_n(q.clone(), 1, withdrawn()));
+    let (mind, _) = faulted_mind(rows);
+    for as_of in 1..=4 {
+        assert_eq!(Reader::at(&mind, as_of).unwrap().view(&q).unwrap(), oracle_view(&mind, &q, as_of).unwrap(), "at {as_of}");
+    }
+}
+
+// ---- Hands' own gaps ----
+
+/// A lost swap names the identities that moved beneath it: a written key already stored, a read
+/// document that changed, and not a read document that is the same.
+#[test]
+fn a_conflict_names_the_identities_that_changed() {
+    let (mut mind, store) = fails_the_look();
+    let mut other = opened(store.clone(), INSTANCE);
+    committed(admit(&mut other, vec![question_n(7)]));
+    store.lose.store(true, Ordering::SeqCst);
+    let outcome = admit(&mut mind, vec![question_n(7)]);
+    let crate::admission::PipelineAdmissionOutcome::Conflict { identities } = outcome else { panic!("{outcome:?}") };
+    assert_eq!(identities, vec![r(K::Question, &id("question", "Q7"))], "the written key that was already stored");
+
+    let cited = |mind: &mut Mind<FailsTheLook>| {
+        let mut spec = cut_spec("1", 1);
+        spec.rulings = vec![s(&id("ruling", "R1"))];
+        admit(mind, vec![D::CutSpec(spec)])
+    };
+    committed(admit(&mut mind, vec![D::Ruling(ruling("R1"))]));
+    store.lose.store(true, Ordering::SeqCst);
+    let outcome = cited(&mut mind);
+    let crate::admission::PipelineAdmissionOutcome::Conflict { identities } = outcome else { panic!("{outcome:?}") };
+    assert!(identities.is_empty(), "a read document that did not change is not named: {identities:?}");
+
+    let mut bent = ruling("R1");
+    bent.ruling = "A ruling that moved beneath the holder.".into();
+    store.inner.plant(prepare(&D::Ruling(bent)));
+    store.lose.store(true, Ordering::SeqCst);
+    let outcome = cited(&mut mind);
+    let crate::admission::PipelineAdmissionOutcome::Conflict { identities } = outcome else { panic!("{outcome:?}") };
+    assert_eq!(identities, vec![r(K::Ruling, &id("ruling", "R1"))], "the read document that changed");
+}

crates/huginn-mind/src/receipt.rs

@@ -190,26 +190,13 @@ pub(crate) fn candidate(
     Ok(receipt)
 }
 
-/// This mind's admission order: `N`, the count of receipts, when their
-/// ordinals are exactly `{1..=N}`. Every reader of the ordinal asks here,
-/// never by counting receipts itself: admission takes `head(self)? + 1` for
-/// the next one, and `AdmissionIndex::build` (`query.rs`) calls it too, so
-/// `query` and `view` carry the same density check rather than trusting a
-/// stored ordinal unchecked. `Mind::receipts` is `pub(crate)`, so this crate
-/// is the only place raw ordinals can be read at all; that keeps this the
-/// one door, rather than something a doc comment merely asks callers to
-/// respect. `ordinal` stays display-only on the read side until RS-3 makes
-/// it the order. A chain that is not dense refuses rather than guessing, on
-/// both sides alike.
+/// This mind's admission order: `N`, the count of receipts, when their ordinals are exactly
+/// `{1..=N}`, read from the held image, which checked the chain once when it was built and
+/// extends it by one with each commit. Every reader of the ordinal asks here, never by counting
+/// receipts itself: admission takes `head(self)? + 1` for the next one. A chain that is not dense
+/// is a held fault that refuses on both sides alike.
 pub(crate) fn head<S: MindStore>(mind: &Mind<S>) -> Result<u64, MindRefusal> {
-    let mut ordinals = mind.receipts()?.into_iter().map(|receipt| receipt.ordinal).collect::<Vec<_>>();
-    ordinals.sort_unstable();
-    let n = ordinals.len() as u64;
-    if ordinals.into_iter().eq(1..=n) {
-        Ok(n)
-    } else {
-        Err(MindRefusal::Unavailable { detail: "receipt ordinals are not 1..=N: found a duplicate or a gap".into() })
-    }
+    Ok(mind.image()?.head)
 }
 
 /// The versions of a set of envelopes in identity order, so the digest does
@@ -265,24 +252,34 @@ pub(crate) fn commit<S: MindStore>(
             .filter(|read| !writes.iter().any(|write| write.r#type == read.r#type && write.key == read.key))
             .cloned(),
     );
-    replacements.push(receipt_envelope);
+    replacements.push(receipt_envelope.clone());
     let expected: &[CultCacheEnvelope] = &strong_reads;
-    let landed = MindStore::compare_and_swap_batch(mind.store(), expected, replacements).map_err(unavailable)?;
-    mind.refresh()?;
-    if !landed {
-        let changed = strong_reads
-            .iter()
-            .filter(|read| mind.raw_envelope(&read.r#type, &read.key) != Some(read))
-            .chain(writes.iter().filter(|write| mind.raw_envelope(&write.r#type, &write.key).is_some()));
-        let identities = changed
-            .filter_map(|envelope| {
-                let kind = PipelineKind::ALL.iter().find(|kind| kind.type_id() == envelope.r#type)?;
-                Some(PipelineRef { kind: *kind, id: Short(envelope.key.clone()) })
-            })
-            .collect();
-        return Ok(CommitOutcome::Conflict(identities));
+    let landed = match MindStore::compare_and_swap_batch(mind.store(), expected, replacements) {
+        Ok(landed) => landed,
+        // Whether the batch landed is unknown, so the holder looks at the store before it answers
+        // anything else; a failed look holds the fault (Mind::refresh), so nothing answers or
+        // writes on a stale image.
+        Err(error) => {
+            let _ = mind.refresh();
+            return Err(unavailable(error));
+        }
+    };
+    if landed {
+        mind.advance(&receipt, receipt_envelope, &writes);
+        return Ok(CommitOutcome::Committed(receipt));
     }
-    Ok(CommitOutcome::Committed(receipt))
+    mind.refresh()?;
+    let changed = strong_reads
+        .iter()
+        .filter(|read| mind.raw_envelope(&read.r#type, &read.key) != Some(read))
+        .chain(writes.iter().filter(|write| mind.raw_envelope(&write.r#type, &write.key).is_some()));
+    let identities = changed
+        .filter_map(|envelope| {
+            let kind = PipelineKind::ALL.iter().find(|kind| kind.type_id() == envelope.r#type)?;
+            Some(PipelineRef { kind: *kind, id: Short(envelope.key.clone()) })
+        })
+        .collect();
+    Ok(CommitOutcome::Conflict(identities))
 }
 
 fn unique_identities(versions: &[DocumentVersion]) -> bool {

crates/huginn-mind/src/rows.rs

@@ -17,7 +17,7 @@ use eureka_pipeline::{
     RulingAuthority, RunOperator, RunTurn, Slug,
 };
 
-use crate::docs::{CitationRole, Held, kind_of_id, kind_of_type};
+use crate::docs::{CitationRole, kind_of_id, kind_of_type};
 use crate::query::PipelineDocumentView;
 use crate::refusal::MindRefusal;
 
@@ -68,8 +68,14 @@ const MEMORY_ORIGINS: [&str; 4] = ["Room", "Direct", "Wake", "SelfRun"];
 /// The one value a presence alias answers with; a row without it answers nothing.
 const PRESENT: [&str; 1] = ["true"];
 
+/// The aliases whose values follow a row's status. Every other alias's values are
+/// fixed when the row is written, so the held image may narrow by them at any
+/// snapshot and by these only at the head. A test pins that no other alias
+/// changes across a status change.
+pub(crate) const STATUS_ALIASES: [Alias; 2] = [Alias::InForce, Alias::Ran];
+
 impl Alias {
-    const ALL: [Alias; 19] = [
+    pub(crate) const ALL: [Alias; 19] = [
         Self::Root,
         Self::InForce,
         Self::Faculty,
@@ -91,7 +97,7 @@ impl Alias {
         Self::MemoryOrigin,
     ];
 
-    fn name(self) -> &'static str {
+    pub(crate) fn name(self) -> &'static str {
         match self {
             Self::Root => "root",
             Self::InForce => "in_force",
@@ -115,7 +121,7 @@ impl Alias {
         }
     }
 
-    fn from_name(name: &str) -> Option<Self> {
+    pub(crate) fn from_name(name: &str) -> Option<Self> {
         Self::ALL.into_iter().find(|alias| alias.name() == name)
     }
 
@@ -193,11 +199,11 @@ fn outcome_name(outcome: &ResolutionOutcome) -> &'static str {
 
 /// One document as the evaluator sees it: its identity, its ordinal, what it
 /// answers for each alias, its citation edges, and the view a page projects.
-#[derive(Clone, Debug)]
+#[derive(Clone, Debug, PartialEq)]
 pub(crate) struct SelectionRow {
     pub(crate) kind: PipelineKind,
     pub(crate) key: String,
-    ordinal: u64,
+    pub(crate) ordinal: u64,
     values: BTreeMap<&'static str, Vec<String>>,
     refs: Vec<(CitationRole, PipelineRef)>,
     pub(crate) view: PipelineDocumentView,
@@ -205,24 +211,28 @@ pub(crate) struct SelectionRow {
 
 impl SelectionRow {
     /// `base` is the first non-resolution the document reaches through its
-    /// subjects: the row a resolution's `repo` and `cut` are read from.
+    /// subjects: the row a resolution's `repo` and `cut` are read from; `None`
+    /// is a document that is its own base. The row is the only decoded copy of
+    /// its document: it lives in `view`.
     pub(crate) fn new(
-        held: &Held,
-        base: &Held,
+        kind: PipelineKind,
+        key: &str,
+        base: Option<(&str, &PipelineDocument)>,
         view: PipelineDocumentView,
         refs: Vec<(CitationRole, PipelineRef)>,
     ) -> Self {
         use PipelineDocument as D;
+        let (base_key, base_document) = base.unwrap_or((key, &view.document));
         let mut values: BTreeMap<&'static str, Vec<String>> = BTreeMap::new();
         let mut put = |alias: Alias, found: Vec<String>| {
             values.insert(alias.name(), found);
         };
-        put(Alias::Root, vec![root_and_local(&held.key).0.to_string()]);
+        put(Alias::Root, vec![root_and_local(key).0.to_string()]);
         put(Alias::InForce, vec![matches!(view.status, crate::query::PipelineStatus::InForce).to_string()]);
         put(Alias::Faculty, vec![format!("{:?}", view.admission.provenance.faculty)]);
         put(
             Alias::Repo,
-            match &base.document {
+            match base_document {
                 D::Campaign(campaign) => campaign.repos.iter().map(OrgRepo::identity).collect(),
                 D::CutSpec(spec) => vec![spec.repo.identity()],
                 D::CutReport(report) => vec![report.repo.identity()],
@@ -236,7 +246,7 @@ impl SelectionRow {
         );
         put(
             Alias::Cut,
-            root_and_local(&base.key)
+            root_and_local(base_key)
                 .1
                 .strip_prefix("cut-")
                 .and_then(|rest| rest.split_once('.'))
@@ -244,7 +254,7 @@ impl SelectionRow {
                 .into_iter()
                 .collect(),
         );
-        match &held.document {
+        match &view.document {
             D::Finding(finding) => {
                 put(Alias::Severity, vec![format!("{:?}", finding.severity)]);
                 put(Alias::Confidence, vec![format!("{:?}", finding.confidence)]);
@@ -277,7 +287,12 @@ impl SelectionRow {
             }
             _ => {}
         }
-        Self { kind: held.kind, key: held.key.clone(), ordinal: view.admission.ordinal, values, refs, view }
+        Self { kind, key: key.to_string(), ordinal: view.admission.ordinal, values, refs, view }
+    }
+
+    /// Each alias this row answers, with its values: what the held image indexes.
+    pub(crate) fn alias_values(&self) -> impl Iterator<Item = (&'static str, &[String])> {
+        self.values.iter().map(|(alias, values)| (*alias, values.as_slice()))
     }
 }
 

crates/huginn-mind/src/wire.rs

@@ -370,15 +370,9 @@ impl<S: MindStore> Mind<S> {
     /// `whoami`, derived from the image every time it is asked, and from the
     /// index status the caller holds: the mind stores neither.
     pub fn status(&self, index: IndexStatus) -> MindStatus {
-        let mut documents = 0_u32;
-        let mut receipts = 0_u32;
-        for envelope in self.envelopes() {
-            if envelope.r#type == HuginnCommitReceipt::TYPE {
-                receipts += 1;
-            } else if PipelineKind::ALL.iter().any(|kind| kind.type_id() == envelope.r#type) {
-                documents += 1;
-            }
-        }
+        let count = |type_id: &str| self.envelopes.get(type_id).map_or(0, |keyed| keyed.len() as u32);
+        let receipts = count(HuginnCommitReceipt::TYPE);
+        let documents = PipelineKind::ALL.iter().map(|kind| count(kind.type_id())).sum();
         MindStatus {
             instance: self.instance().clone(),
             schema_epoch: PIPELINE_SCHEMA_EPOCH.to_string(),

crates/huginn-mind/tests/read_floor.rs

@@ -0,0 +1,172 @@
+//! What a read costs, measured through the public API alone so the same file
+//! runs at the base and at the branch. Ignored: it wants a copy of a real
+//! store and says what it measured instead of asserting.
+//!
+//! `FLOOR_STATE` is a directory holding `minds/<instance>/mind.redb`. It is
+//! copied to a temp dir and never opened in place. `FLOOR_SCALE` (default 1)
+//! grows the copy with synthetic history to that multiple of its documents;
+//! `FLOOR_ROOTS` is `spread` (each hundred units under its own root) or
+//! `same` (one root grows). `FLOOR_INSTANCE` defaults to `eureka`; `FLOOR_SAMPLES` (default 7) is how many times each read is timed, for a base too slow to sample 7 times.
+//!
+//! cargo test --release -p huginn-mind --features test-support --test read_floor -- --ignored --nocapture
+#![cfg(feature = "test-support")]
+
+use std::path::PathBuf;
+use std::time::{Duration, Instant};
+
+use chrono::Utc;
+use cultnet_rs::{Citation, FieldPredicate, Incoming, RecordRef, Selection};
+use huginn_mind::eureka_pipeline::{PipelineDocument, PipelineKind, PipelinePulse, PipelineRef, Short, Slug};
+use huginn_mind::oracle::synth_history_at;
+use huginn_mind::{Faculty, IndexStatus, Mind, PipelineAdmissionBatch, PipelinePageItems, PipelineProvenance};
+
+fn env(name: &str, default: &str) -> String {
+    std::env::var(name).unwrap_or_else(|_| default.to_string())
+}
+
+fn rss_kib() -> u64 {
+    std::fs::read_to_string("/proc/self/status")
+        .ok()
+        .and_then(|status| {
+            status.lines().find_map(|line| line.strip_prefix("VmRSS:")?.split_whitespace().next()?.parse().ok())
+        })
+        .unwrap_or(0)
+}
+
+fn any_of(index: &str, values: &[&str]) -> FieldPredicate {
+    FieldPredicate { index: index.into(), op: "any_of".into(), values: Some(values.iter().map(|v| v.to_string()).collect()), number: None }
+}
+
+fn of(kind: PipelineKind, fields: Vec<FieldPredicate>) -> Selection {
+    Selection { schemas: Some(vec![kind.type_id().to_string()]), fields: Some(fields), ..Selection::default() }
+}
+
+fn median(mut samples: Vec<Duration>) -> Duration {
+    samples.sort();
+    samples[samples.len() / 2]
+}
+
+fn time<T>(mut read: impl FnMut() -> T) -> Duration {
+    let samples: usize = env("FLOOR_SAMPLES", "7").parse().unwrap();
+    median(
+        (0..samples)
+            .map(|_| {
+                let started = Instant::now();
+                std::hint::black_box(read());
+                started.elapsed()
+            })
+            .collect(),
+    )
+}
+
+fn keys_of(mind: &Mind<huginn_mind::OwnedRedbMessagePackBackingStore>, kind: PipelineKind) -> Vec<PipelineRef> {
+    let page = mind.query(&Selection { schemas: Some(vec![kind.type_id().to_string()]), limit: Some(5), ..Selection::default() }).unwrap();
+    match page.items {
+        PipelinePageItems::Headers(headers) => headers.into_iter().map(|header| header.id).collect(),
+        PipelinePageItems::Documents(views) => views.into_iter().map(|view| view.id).collect(),
+    }
+}
+
+#[test]
+#[ignore]
+fn read_floor() {
+    let instance = Slug(env("FLOOR_INSTANCE", "eureka"));
+    let scale: u32 = env("FLOOR_SCALE", "1").parse().unwrap();
+    let spread = env("FLOOR_ROOTS", "spread") == "spread";
+    let source = PathBuf::from(env("FLOOR_STATE", "/state")).join("minds").join(&instance.0).join("mind.redb");
+    let temp = tempfile::tempdir().unwrap();
+    let target = temp.path().join("minds").join(&instance.0);
+    std::fs::create_dir_all(&target).unwrap();
+    std::fs::copy(&source, target.join("mind.redb")).unwrap();
+    let path = target.join("mind.redb");
+
+    let synthetic = if scale > 1 { synth_history_at(&path, &instance, scale, spread).unwrap() } else { 0 };
+    let size_mib = std::fs::metadata(&path).unwrap().len() / (1024 * 1024);
+
+    let started = Instant::now();
+    let mut mind = Mind::open(temp.path(), &instance).unwrap();
+    let open = started.elapsed();
+    let rss = rss_kib() / 1024;
+    let status = mind.status(IndexStatus::Current);
+
+    let findings = keys_of(&mind, PipelineKind::Finding);
+    let finding = findings.first().expect("the store holds a finding").clone();
+    let root = finding.id.0.split(':').next().unwrap().to_string();
+    let mut one = Selection { keys: Some(vec![finding.id.0.clone()]), projection: "document".into(), ..Selection::default() };
+    one.schemas = Some(vec![PipelineKind::Finding.type_id().to_string()]);
+
+    let run_desc = Selection { descending: true, limit: Some(3), ..of(PipelineKind::Run, vec![any_of("root", &[&root]), any_of("operated_by", &["Mind"])]) };
+    let cites = Selection {
+        cites: Some(Citation { target: RecordRef::new(PipelineKind::Finding.type_id(), finding.id.0.clone()), role: Some("subject".into()) }),
+        ..of(PipelineKind::Resolution, vec![])
+    };
+    let stewardship = of(PipelineKind::Stewardship, vec![any_of("root", &[&root])]);
+    let memory = of(PipelineKind::Memory, vec![any_of("root", &[&root]), any_of("memory_origin", &["Room"])]);
+    let follow_up = Selection { limit: Some(20), ..of(PipelineKind::FollowUp, vec![any_of("in_force", &["true"])]) };
+    let three = of(
+        PipelineKind::Finding,
+        vec![any_of("severity", &["High"]), any_of("confidence", &["Confirmed"]), any_of("origin", &["Introduced"])],
+    );
+    let unreported = Selection {
+        cited: Some(Incoming { role: "cut_spec".into(), exists: false }),
+        ..of(PipelineKind::CutSpec, vec![any_of("in_force", &["true"])])
+    };
+
+    let paged = |selection: &Selection| {
+        let mut selection = selection.clone();
+        let mut pages = 0;
+        loop {
+            let page = mind.query(&selection).unwrap();
+            pages += 1;
+            match page.next {
+                Some(next) if pages < 3 => selection.cursor = Some(next),
+                _ => return pages,
+            }
+        }
+    };
+
+    let mut rows: Vec<(&str, Duration)> = vec![
+        ("whoami/status", time(|| mind.status(IndexStatus::Current))),
+        ("persona", time(|| mind.persona().unwrap())),
+        ("view", time(|| mind.view(&finding).unwrap())),
+        ("keys=1 document", time(|| mind.query(&one).unwrap())),
+        ("run root+operated_by desc", time(|| mind.query(&run_desc).unwrap())),
+        ("resolution cites subject", time(|| mind.query(&cites).unwrap())),
+        ("stewardship root", time(|| mind.query(&stewardship).unwrap())),
+        ("memory two fields", time(|| mind.query(&memory).unwrap())),
+        ("follow_up in_force paged", time(|| paged(&follow_up))),
+        ("finding three fields", time(|| mind.query(&three).unwrap())),
+        ("cut_spec in_force cited", time(|| mind.query(&unreported).unwrap())),
+    ];
+    let line = [&run_desc, &cites, &stewardship, &memory, &follow_up, &three, &unreported, &one];
+    let first_line = time(|| {
+        for n in 0..25 {
+            let _ = mind.query(line[n % line.len()]);
+        }
+    });
+    rows.push(("first line (25 reads)", first_line));
+
+    let pulse = PipelineDocument::Pulse(PipelinePulse {
+        instance: instance.clone(),
+        label: format!("floor-{}", Utc::now().timestamp_nanos_opt().unwrap_or_default()).as_str().into(),
+        note: "read floor".into(),
+        tempo_vote_beat_s: None,
+        tempo_vote_withdrawn: false,
+        urgency_permille: Some(1),
+    });
+    let provenance = PipelineProvenance { faculty: Faculty::Hands, agent: Short("floor".into()), session: Short("floor".into()), tool: Short("floor".into()) };
+    let started = Instant::now();
+    let outcome = mind.admit(PipelineAdmissionBatch { instance: instance.clone(), provenance, documents: vec![pulse] }, Utc::now());
+    let admit = started.elapsed();
+    let started = Instant::now();
+    let read_back = mind.read_back();
+    let read_back_time = started.elapsed();
+
+    println!("\nFLOOR documents={} receipts={} store_mib={} synthetic_docs={} scale={} roots={}", status.documents, status.receipts, size_mib, synthetic, scale, if spread { "spread" } else { "same" });
+    println!("FLOOR open_ms={:.0} rss_mib={}", open.as_secs_f64() * 1e3, rss);
+    for (name, took) in rows {
+        println!("FLOOR read {:<28} {:>10.1} us", name, took.as_secs_f64() * 1e6);
+    }
+    println!("FLOOR admit_ms={:.0} ({})", admit.as_secs_f64() * 1e3, if matches!(outcome, huginn_mind::PipelineAdmissionOutcome::Committed { .. }) { "committed".to_string() } else { format!("{outcome:?}") });
+    println!("FLOOR read_back_ms={:.0} ({:?})", read_back_time.as_secs_f64() * 1e3, read_back);
+}