slim the submit schemas: evidence and messages die; stringified-payload heal at the pre-validation seam

OpenRouter log diagnosis (owner, 2026-09-28): extraction time was
dominated by tool-validation retries. The failing call had the whole
propositions array emitted as ONE JSON-STRING ('propositions.0: must
be object'), a truncated placeholder artifact inside it, and
word-salad statements late in the array — payload-size collapse.
Field audit: 'evidence' was never persisted anywhere and its
faithfulness-checking consumer died with the fully-trusted ruling;
'messages' fed messageId granularity that NOTHING downstream reads,
and the model sent [] anyway (chat-level provenance in practice).
'aliases' stays (optional now): the auditor's find tool globs them.

Schema: propositions = {id, name, statement, aliases?}; edges =
{from, to, type}. Prompts lose the evidence/messages doctrine and
[id]-anchor guidance, gain a compact faithfulness line;
transcriptView renders anchorless. The auditor echo instruction
drops the evidence/messages mention, so its payload halves too.

Heal: healStringifiedArrays on the submit tool's prepareArguments
(pi-agent-core's sanctioned pre-TypeBox shim) parses a stringified
propositions/edges back into arrays — the LaTeX-restore doctrine:
heal weak-model wire behavior at the seam. Test drives the real
agent-loop seam with a stringified submit.

src/core/contracts/graph.ts

@@ -172,7 +172,7 @@ export interface CoverageEntry {
  * of work): the extractor is the ONLY stage that sees the raw source
  * (whole session as readable markdown, or raw notes) and extracts the
  * reasoning chains — propositions (lonely relevant ones included) plus
- * follows/supports edges, with verbatim evidence; the auditor NEVER sees
+ * follows/supports edges; the auditor NEVER sees
  * the source — its job is preparing the merge: identity verdicts
  * (link-or-create, merging equivalent forms of the same proposition) via
  * graph-exploration tools (find / list_sessions / list_propositions), and
@@ -187,7 +187,7 @@ export interface CoverageEntry {
 
 /** One proposed proposition — a node candidate (or a re-encounter of one). */
 export interface ExtractedProposition {
-	/** Extractor-local id ("p1", …) referenced by edges + attribution. */
+	/** Extractor-local id ("p1", …) referenced by edges. */
 	id: string;
 	/** A very short label — a few words, a compact handle like a glossary
 	 *  headword. Not a sentence, needn't be unique or self-contained: the
@@ -202,10 +202,12 @@ export interface ExtractedProposition {
 	statement: string;
 	/** Verbatim phrasings the session used. */
 	aliases: string[];
-	/** The message ids where this proposition came up — provenance. */
-	messages: string[];
-	/** Verbatim transcript quotes backing the proposition. */
-	evidence: string[];
+	/* Submit-schema slim (owner, 2026-09-28): `messages` and `evidence`
+	 * are GONE. Provenance is chat-level (the run's source key); the
+	 * verbatim-quote fields were never persisted and weak models burned
+	 * their retries on them ("propositions.0: must be object" — the
+	 * stringified-payload collapse). The extractor reports propositions
+	 * + structure, nothing else. */
 }
 
 /** One proposed relation. Endpoints are extractor-local proposition ids
@@ -219,10 +221,6 @@ export interface ExtractedEdge {
 	/** Proposition id (or graph node id) that follows / is supported. */
 	to: string;
 	type: EdgeType;
-	/** The message ids where this relation was asserted — provenance. */
-	messages: string[];
-	/** Verbatim transcript quotes backing the relation. */
-	evidence: string[];
 }
 
 /** The extractor's output shape: the raw reasoning chains. */

src/core/graph.ts

@@ -85,16 +85,11 @@ export interface MergeSource {
 	coverage?: CoverageEntry[];
 }
 
-/** (chatId, messageIds) → provenance points; order-preserving, deduped. */
-function pointsOf(chatId: string, messages: string[]): ProvenancePoint[] {
-	const seen = new Set<string>();
-	const out: ProvenancePoint[] = [];
-	for (const messageId of messages) {
-		if (messageId.length === 0 || seen.has(messageId)) continue;
-		seen.add(messageId);
-		out.push({ chatId, messageId });
-	}
-	return out;
+/** The run's chat-level provenance point (submit-schema slim, 2026-09-28:
+ *  propositions no longer carry message ids — the model never reported
+ *  them reliably anyway — so every birth from a run shares one point). */
+function pointOf(chatId: string): ProvenancePoint[] {
+	return [{ chatId, messageId: "" }];
 }
 
 const samePoint = (a: ProvenancePoint, b: ProvenancePoint): boolean =>
@@ -140,7 +135,7 @@ export function mergeFindings(chatId: string, audit: AuditResult, deps: GraphDep
 
 	for (const p of audit.propositions) {
 		if (mapping.has(p.id)) continue; // already resolved for this chat — idempotent
-		const points = pointsOf(chatId, p.messages);
+		const points = pointOf(chatId);
 		let graphNodeId: string;
 		if (p.linkTo !== undefined && existingIds.has(p.linkTo)) {
 			// Identity verdict: this proposition IS that node. Append a link
@@ -206,7 +201,10 @@ export function mergeFindings(chatId: string, audit: AuditResult, deps: GraphDep
 			from,
 			to,
 			type: edge.type,
-			provenance: bridged ? [{ chatId, messageId: "" }] : pointsOf(chatId, edge.messages),
+			// bridged vs transcript edges both carry the run's chat-level
+			// point now; the distinction lives in the endpoint resolution
+			// above (mapping vs existing node id), not in the provenance.
+			provenance: pointOf(chatId),
 		});
 		assertedByChat.add(key);
 		stats.edges++;

src/core/session-markdown.ts

@@ -4,9 +4,11 @@
  * The extractor's view of a teaching session and the future user-facing
  * session export share this engine: a session is rendered as clean,
  * readable markdown — speaker headers, quiz/check-in blocks, tool notes —
- * with the message-id anchors preserved (extraction provenance depends on
- * the extractor reporting the `[id]` tags it saw; `anchors: false` mints
- * the same document without them, for the user export).
+ * with optional message-id anchors. Since the submit-schema slim
+ * (2026-09-28) propositions no longer report message ids — the extractor
+ * renders anchorless and provenance is chat-level — so the anchors today
+ * serve only the future user-facing export; `anchors: false` mints the
+ * same document without them.
  *
  * Pure core: native messages in (LhMessage), string out. Content parity
  * with the coverage line builder (core/coverage.ts messageViewLines) is