git:20260528.67ddbec to git:20260529.53de3c2

---

name: async-worker-recovery

description: Background worker, heartbeat, stale-run, crash-recovery, and deadletter workflow. Use when debugging stuck/dead workers or changing async run reliability.

---

# async-worker-recovery

Use this skill when a pi-crew run is stuck, stale, interrupted, or has dead workers.

## Source patterns distilled

- pi-subagents async patterns: detached runner, status files, result watcher, stale PID reconciler

- pi-crew runtime: `src/runtime/background-runner.ts`, `async-runner.ts`, `heartbeat-watcher.ts`, `worker-heartbeat.ts`, `crash-recovery.ts`, `stale-reconciler.ts`, `deadletter.ts`, `delivery-coordinator.ts`

- UI recovery controls: `src/ui/run-dashboard.ts`, `src/ui/dashboard-panes/health-pane.ts`, `src/ui/run-action-dispatcher.ts`

## Rules

- Distinguish historical dead-heartbeat events from current active failures. Check manifest/task status and event timestamps.

- Heartbeat warnings should only apply to currently running/waiting work, never terminal runs/tasks.

- Stale reconciliation order: result/terminal evidence → PID liveness → stale threshold/active evidence.

- Reconcile state under run lock and re-read inside the lock before repair.

- Deadletter entries are evidence, not automatic proof of permanent failure; inspect attempts and later completion events.

- For background runs, verify PID liveness and background log before declaring stuck.

- Session delivery should queue while inactive and flush only to the current generation/session.

- Do not poll in sleep loops waiting for async completion if the system has a watcher/result notification path.

## Operator checklist

1. Load manifest/tasks and recent events.

2. Check `manifest.async.pid` and process liveness.

3. Check heartbeat `lastSeenAt`, progress `lastActivityAt`, and terminal status.

4. Inspect deadletter and diagnostic report.

5. Choose recovery: resume, retry, kill stale, diagnostic, or no-op historical notification.

## Enforcement — Worker Recovery Gate

**Before taking recovery action, verify:**

- [ ] Run status is not terminal (completed/failed/cancelled)

- [ ] Heartbeat is genuinely stale (not just delayed polling)

- [ ] PID is dead or stale threshold exceeded

- [ ] Recovery action matches run state (resume vs retry vs kill)

- [ ] Session generation matches before state modification

If ANY answer is NO → Stop. Re-check status. Do not apply stale recovery to active runs.

## Verification

```bash

cd pi-crew

npx tsc --noEmit

node --experimental-strip-types --test test/unit/heartbeat-watcher.test.ts test/unit/stale-reconciler.test.ts test/unit/deadletter.test.ts test/integration/async-restart-recovery.test.ts

npm test

```