practice bug fix — the boot sweep stamped a LIVE run (owner live test 2026-09-29)

Owner report: created a set, 'Interrupted (server restarted)' showed
on list + set views, generation proceeded and overwrote it. The
sweep's 'generating + no registry row' test had a false-positive
mode: it ran at EVERY pipeline instantiation, and an instance could
evaluate against a registry whose fresh row it couldn't observe.

Three guards, per ruling:

1. HEARTBEAT: ProblemSet.updatedAt? (contract + doc) — bumped on
   every store write; createSet stamps it = createdAt; saveSet
   re-stamps (validator tolerates absence for legacy rows).

2. ONCE PER PROCESS: the sweep guards on globalThis
   .__lhPracticeSweepDone — no instance re-evaluates after the
   process's first sweep.

3. GRACE WINDOW: only sets whose heartbeat (updatedAt ?? createdAt)
   is older than 120s are stamped. A live run saves at every phase/
   problem transition, so it is structurally unreachable; a true
   orphan is minutes stale at next boot. One [practice <id>] log
   line per stamped set (the extraction/jobs console.error idiom).

Tests: stale orphan stamped; FRESH generating set untouched (grace);
once-guard (second factory instantiation never re-sweeps); live-row
protection re-armed via resetSweep() test seam; store pins for
updatedAt birth-stamp + re-stamp + legacy tolerance. Architecture.md
sweep sentence updated (once-per-process + grace semantics).

1142/1142, tsc 0, lint 0, build 0.

src/agent/subagents/practice-pipeline.ts

@@ -264,15 +264,29 @@ export interface PracticePipelineDeps extends PracticeModels {
 export function createPracticePipeline(deps: PracticePipelineDeps) {
 	const agents = createPracticeAgents(deps);
 
-	// BOOT SWEEP: a persisted partitioning/generating set with no live row
-	// is a crash/restart orphan (the registry is memory-only) — mark it,
-	// idempotently. Runs at every pipeline instantiation (dev route
-	// entries re-run it; live rows are globalThis-shared and skipped).
-	for (const set of deps.practiceStore.listSets()) {
-		if (
-			(set.status === "partitioning" || set.status === "generating") &&
-			!practiceRuns().has(`${set.id}:generation`)
-		) {
+	// BOOT SWEEP (owner bug fix, live test 2026-09-29 — the sweep once
+	// stamped a LIVE run): a persisted partitioning/generating set with no
+	// live row AND a heartbeat older than the grace window is a crash/
+	// restart orphan (the registry is memory-only) — mark it, idempotently.
+	// THREE guards against stamping the living:
+	//   1. ONCE PER PROCESS (globalThis flag) — an instance could otherwise
+	//      evaluate against a registry whose fresh row it can't observe
+	//      (dev route bundles, restart paths).
+	//   2. GRACE WINDOW (120s over updatedAt ?? createdAt) — a live run
+	//      saves at every phase/problem transition, so its heartbeat is
+	//      structurally never 120s stale; a true orphan is minutes stale at
+	//      the next boot.
+	//   3. Live-row check (globalThis-shared registry) as before.
+	const sweepFlag = globalThis as { __lhPracticeSweepDone?: boolean };
+	if (!sweepFlag.__lhPracticeSweepDone) {
+		sweepFlag.__lhPracticeSweepDone = true;
+		const staleBefore = Date.now() - 120_000;
+		for (const set of deps.practiceStore.listSets()) {
+			if (set.status !== "partitioning" && set.status !== "generating") continue;
+			if (practiceRuns().has(`${set.id}:generation`)) continue;
+			const heartbeat = Date.parse(set.updatedAt ?? set.createdAt);
+			if (Number.isFinite(heartbeat) && heartbeat > staleBefore) continue; // grace
+			console.error(`[practice ${set.id}] boot sweep: stale ${set.status} set marked interrupted`);
 			set.status = "error";
 			set.error = "Interrupted (server restarted)";
 			deps.practiceStore.saveSet(set);

src/core/contracts/practice.ts

@@ -163,6 +163,12 @@ export interface ProblemSet {
 	 *  default. */
 	title: string;
 	createdAt: string;
+	/** Bumped on every store write — the live-run heartbeat the boot
+	 *  sweep's grace window reads (a live run saves at every phase or
+	 *  problem transition, so it is structurally never 120s stale).
+	 *  Absent on legacy rows (validator tolerates; readers fall back
+	 *  to createdAt). */
+	updatedAt?: string;
 	params: PracticeParams;
 	/** The selected node ids — the raw selection record. The chain
 	 *  decomposition derives from these + the follows-edges among them at

src/store/practice.ts

@@ -133,6 +133,7 @@ function createSet(init: Omit<ProblemSet, "id">): ProblemSet {
 	const set: ProblemSet = {
 		...init,
 		id: `ps_${Date.now().toString(36)}_${crypto.randomUUID().slice(0, 8)}`,
+		updatedAt: init.updatedAt ?? init.createdAt,
 	};
 	writeSetFile(set);
 	return set;
@@ -164,6 +165,9 @@ function listSets(): ProblemSet[] {
 
 function saveSet(set: ProblemSet): void {
 	if (!isProblemSet(set)) throw new Error("problem set record failed validation");
+	// The heartbeat: every write re-stamps (the boot sweep's grace window
+	// reads this — a live run is structurally never 120s stale).
+	set.updatedAt = new Date().toISOString();
 	writeSetFile(set);
 }