cron-scheduler

---
name: cron-scheduler
version: 1.0.0
description: |
  Schedule management with staggering, quiet hours, and wake-up override.
  Validates schedules, prevents collisions, and gates delivery during quiet hours.
triggers:
  - "schedule a job"
  - "cron"
  - "quiet hours"
  - "what jobs are running"
tools:
  - search
  - get_page
  - put_page
mutating: true
---

# Cron Scheduler

> **Convention:** See `skills/conventions/test-before-bulk.md` — test every cron job on 3-5 items first.

## Contract

This skill guarantees:
- Schedule staggering: max 1 job per 5-minute slot, no collisions
- Quiet hours gating: timezone-aware, with user-awake override
- Thin job prompts: jobs say "Read skills/X/SKILL.md and run it" (no inline 3000-word prompts)
- Idempotency: jobs can run twice without duplicate side effects
- Results saved as reports: `reports/{job-name}/{YYYY-MM-DD-HHMM}.md`

## Phases

1. **Define job.** Name, schedule (cron expression), skill to run, timeout.
2. **Validate schedule.** Check no collision with existing jobs (5-minute offset rule).
   - Slots: :05, :10, :15, :20, :25, :30, :35, :40, :45, :50
   - If collision detected, suggest the next available slot
3. **Check quiet hours.** Default: 11 PM - 8 AM local time.
   - Override: user-awake flag (if user is active, quiet hours suspended)
   - During quiet hours: save output to held queue
   - Morning contact releases the backlog
4. **Register with host scheduler.** OpenClaw cron, Railway cron, crontab, or process manager. **Each registered entry should execute via Minions, not `agentTurn`.** See `skills/conventions/cron-via-minions.md` for the rewrite pattern (PGLite uses `--follow`, Postgres uses fire-and-forget + `--idempotency-key` on the cycle slot). GBrain's v0.11.0 migration auto-rewrites entries for built-in handlers; host-specific handlers need a code-level registration per `docs/guides/plugin-handlers.md`.
5. **Write thin prompt.** Job prompt is one line: "Read skills/{name}/SKILL.md and run it."

## Idempotency Requirement

Every cron job MUST be idempotent:
- Running the same job twice produces the same result (no duplicate pages, no duplicate timeline entries)
- Use checkpoint state files to track progress and resume interrupted runs
- Check for existing output before creating new output

## Output Format

Job configuration saved. Report: "Job '{name}' scheduled at {cron expression}. Next run: {time}."

## Multi-source brains: use `sync --all`, not per-source entries

When the brain has 2+ active sources (anything `gbrain sources list` shows
with a non-null `local_path` that isn't archived), use one consolidated
cron line instead of N per-source entries.

**Preferred (multi-source)**:

```cron
*/5 * * * * gbrain sync --all --parallel 4 --workers 4 --skip-failed
```

This replaces N per-source lines AND auto-picks-up future sources without
a crontab edit. Concurrency budget: `parallel × workers × 2 ≈ 32`
connections during the wave (each per-file worker opens its own
2-connection pool). Stay under your Postgres `max_connections` setting.

**Avoid (legacy)**: separate `gbrain sync --source default` and
`gbrain sync --source zion-brain` entries staggered by 5 minutes. They
require manual deconfliction every time a new source is added, and a
slow source can race a fast source on the legacy global `gbrain-sync`
lock (v0.40.3.0+ uses per-source `gbrain-sync:<sourceId>` locks but the
per-source cron pattern doesn't benefit from the parallelism that
`--all --parallel` actually delivers).

`gbrain doctor` surfaces the recommended line as a `sync_consolidation`
check whenever it detects 2+ active sources. Paste-ready from there.

### Managed brain

A managed brain refuses the line above: managed sync needs `--no-pull` and
rejects `--skip-failed` (`writer_coordinator_required`). Check the mode first:
`gbrain sources writer status --json` reports `"mode": "managed"` or
`"mode": "classic"`, and its `bindings` name each source's owner host.

On a managed brain, install this line instead, on the host that owns the
sources:

```cron
*/15 * * * * gbrain sources refresh <id>; gbrain sync --all --no-pull --hard-deadline 13m
```

- `gbrain sources refresh <id>` is the only way a managed checkout takes
  upstream commits (a fetch and `git merge --ff-only`, then a managed sync of
  the sources on that checkout). Add one refresh per checkout that tracks a
  remote, with its real source id; drop it for checkouts with no remote. The
  `;` is deliberate: the sync still runs when a refresh refuses.
- `--hard-deadline 13m` stays under the 15-minute interval. Managed sync takes
  no per-source lock, so a run that outlives the interval would overlap the
  next tick. A run stopped at its deadline ends `resumable` and the next tick
  continues it. Sources drain one at a time, so `--parallel` does not apply.
- `owner_unavailable` for a source: read its `detail`. `unbound_source` on a
  classic Postgres brain is normal and does not stop classic sync; keep the
  sync line. Any other detail means another host owns the source: install a
  per-source line on that host (`gbrain sync --source <id> --no-pull
  --hard-deadline 13m`, plus its refresh) instead of claiming it here.
- Failed files: after fixing the files and committing them, rerun the plain
  `gbrain sync --source <id> --no-pull …` with the failed run's options; the
  next sync retries what the last one recorded. Never add `--skip-failed`
  (`--retry-failed` is a deprecated alias of the plain sync on a managed
  brain).

`gbrain doctor` prints this managed line in `sync_consolidation` on a managed
brain with 2+ active sources.

## When it fails

Follow the [agent operator protocol](../conventions/agent-operator-protocol.md) for any gbrain error `code`, exit code, `[AGENT]` block or notice block. Specific to this skill:

- A scheduled `gbrain sync` hits `sync_in_progress` / `lock_busy`: an earlier tick still runs. Widen the interval or stagger the job; never add a second overlapping schedule.
- Doctor reports a stale source after the cron change: check `gbrain sources status <id>` for held items or errors before changing the schedule again.
- `checkpoint_validation_timeout` in a sync log: run the retry command the error prints; do not cancel the request.
- `writer_coordinator_required` from a scheduled sync: the brain is managed. Replace the line with the [managed brain](#managed-brain) recipe; never retry with `--skip-failed` or without `--no-pull`.
- `sync_in_progress` from `gbrain sources refresh`: a managed sync cursor is unfinished, and the refresh never waits on it. Run the `gbrain sync --source <id> --no-pull …` command the refusal prints; the next tick's refresh then runs.
- `worktree_refreshing` from a sync: a refresh is draining or merging that checkout. Leave it; the next tick syncs it.

## Anti-Patterns

- Scheduling jobs at the same minute (:00 for everything)
- Inline 3000-word prompts in cron jobs (use skill file references)
- Running cron jobs without testing on 3-5 items first
- Jobs that produce different output on re-run (not idempotent)
- Sending notifications during quiet hours (save to held queue instead)
- Separate per-source `gbrain sync --source <id>` cron entries when
  `gbrain sync --all --parallel N --workers N` would replace them with
  one line that auto-picks-up future sources.

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