Skill: lean-zhouchao/cron-mastery-zc (version 1.0.0)

--- name: cron-mastery-zc description: Master OpenClaw's timing systems. Use for scheduling reliable reminders, setting up periodic maintenance (janitor jobs), and understanding when to use Cron vs Heartbeat for time-sensitive tasks. --- # Cron Mastery **Rule #1: Heartbeats drift. Cron is precise.** This skill provides the definitive guide for managing time in OpenClaw 2026.2.15+. It solves the "I missed my reminder" problem by enforcing a strict separation between casual checks (heartbeat) and hard schedules (cron). ## The Core Principle | System | Behavior | Best For | Risk | | :--- | :--- | :--- | :--- | | **Heartbeat** | "I'll check in when I can" (e.g., every 30-60m) | Email checks, casual news summaries, low-priority polling. | **Drift:** A "remind me in 10m" task will fail if the heartbeat is 30m. | | **Cron** | "I will run at exactly X time" | Reminders ("in 5 mins"), daily reports, system maintenance. | **Clutter:** Creates one-off jobs that need cleanup. | ## 1. Setting Reliable Reminders (2026.2.15+ Standard) **Rule:** Never use `act:wait` or internal loops for long delays (>1 min). Use `cron:add` with a one-shot `at` schedule. ### Precision & The "Scheduler Tick" While Cron is precise, execution depends on the **Gateway Heartbeat** (typically every 10-60s). A job set for `:00` seconds will fire on the first "tick" after that time. Expect up to ~30s of variance depending on your gateway config. ### Modern One-Shot Reminder Pattern Use this payload structure for "remind me in X minutes" tasks. **Key Features (v2026.2.15+):** - **Payload Choice:** Use **AgentTurn** with **Strict Instructions** for push notifications (reminders that ping your phone). Use **systemEvent** only for silent logs or background state updates. - **Reliability:** `nextRunAtMs` corruption and "Add-then-Update" deadlocks are resolved. - **Auto-Cleanup:** One-shot jobs auto-delete after success (`deleteAfterRun: true`). **CRITICAL: Push Notifications vs. Silent Logs** - **systemEvent (Silent):** Injects text into the chat history. Great for background logs, but **WILL NOT** ping the user's phone on Telegram/WhatsApp. - **AgentTurn (Proactive):** Wakes an agent to deliver the message. **REQUIRED** for push notifications. Use the "Strict" prompt to avoid AI chatter. **For push-notification reminders (Reliable):** ```json { "name": "Remind: Water", "schedule": { "kind": "at", "at": "2026-02-06T01:30:00Z" }, "payload": { "kind": "agentTurn", "message": "DELIVER THIS EXACT MESSAGE TO THE USER WITHOUT MODIFICATION OR COMMENTARY:\n\n💧 Drink water, Momo!" }, "sessionTarget": "isolated", "delivery": { "mode": "announce", "channel": "telegram", "to": "1027899060" } } ``` **For background logs (Silent):** ```json { "name": "Log: System Pulse", "schedule": { "kind": "every", "everyMs": 3600000 }, "payload": { "kind": "systemEvent", "text": "[PULSE] System healthy." }, "sessionTarget": "main" } ``` ### Cron Concurrency Rule (Stabilized) Pre-2026.2.15, the "Add-then-Update" pattern caused deadlocks. While this is now stabilized, it is still **best practice** to pass all parameters (including `wakeMode: "now"`) directly in the initial `cron.add` call for maximum efficiency. ## 2. The Janitor (Auto-Cleanup) - LEGACY **Note:** As of v2026.2.14, OpenClaw includes **maintenance recompute semantics**. The gateway now automatically cleans up stuck jobs and repairs corrupted schedules. **Manual cleanup is only needed for:** - One-shot jobs created with `deleteAfterRun: false`. - Stale recurring jobs you no longer want. ### Why use `sessionTarget: "main"`? (CRITICAL) Sub-agents (`isolated`) often have restricted tool policies and cannot call `gateway` or delete other `cron` jobs. For system maintenance like the Janitor, **always** target the `main` session via `systemEvent` so the primary agent (with full tool access) performs the cleanup. ## 3. Reference: Timezone Lock For cron to work, the agent **must** know its time. * **Action:** Add the user's timezone to `MEMORY.md`. * **Example:** `Timezone: Cairo (GMT+2)` * **Validation:** If a user says "remind me at 9 PM," confirm: "9 PM Cairo time?" before scheduling. ## 4. The Self-Wake Rule (Behavioral) **Problem:** If you say "I'll wait 30 seconds" and end your turn, you go to sleep. You cannot wake up without an event. **Solution:** If you need to "wait" across turns, you **MUST** schedule a Cron job. * **Wait < 1 minute (interactive):** Only allowed if you keep the tool loop open (using `act:wait`). * **Wait > 1 minute (async):** Use Cron with `wakeMode: "now"`. ## 5. Legacy Migration Guide If you have old cron jobs using these patterns, update them: | Legacy (Pre-2026.2.3) | Modern (2026.2.15+) | | :--- | :--- | | `"schedule": {"kind": "at", "atMs": 1234567890}` | `"schedule": {"kind": "at", "at": "2026-02-06T01:30:00Z"}` | | `"deliver": true` in payload | Not needed - `announce` mode handles delivery | | `"sessionTarget": "main"` | `"sessionTarget": "isolated"` (default behavior) | | Manual ghost cleanup required | One-shots auto-delete (`deleteAfterRun: true`) | | `cron.update` after `cron.add` | Single-step `cron.add` with all properties | ## Troubleshooting * **"My reminder didn't fire":** Check `cron:list`. Verify the `at` timestamp is in the future (ISO 8601 format). Ensure `wakeMode: "now"` is set. * **"Gateway Timeout (10000ms)":** This happens if the `cron` tool takes too long (huge job list or file lock). - **Fix 1:** Manually delete `~/.openclaw/state/cron/jobs.json` and restart the gateway if it's corrupted. - **Fix 2:** Run a manual sweep to reduce the job count. * **"Job ran but I didn't get the message":** Ensure you are using the **Strict Instruction Pattern** with `agentTurn` + `announce` mode for proactive pings. * **"The reminder message has extra commentary":** The subagent is being conversational. Use the strict prompt pattern: `"DELIVER THIS EXACT MESSAGE TO THE USER WITHOUT MODIFICATION OR COMMENTARY:\n\n💧 Your message here"`

path: _meta.json
content: ownerId: kn77tqkcm269sx2m1yqg1ja83n8090mv
slug: cron-mastery
version: 1.0.3
publishedAt: 1771282970279

path: references/templates.md
content: # Cron Examples & Templates

## One-Shot Reminder (Push Notification / Reliable)

**Context:** User says "Remind me to check the oven in 15 mins."
**Best for:** Timers that MUST ping the user's phone.

```json
{
  "action": "add",
  "job": {
    "name": "Oven Timer",
    "schedule": {
      "kind": "at",
      "at": "2026-02-16T21:15:00+02:00"
    },
    "payload": {
      "kind": "agentTurn",
      "message": "DELIVER THIS EXACT MESSAGE TO THE USER WITHOUT MODIFICATION OR COMMENTARY:\n\n🔥 OVEN CHECK! It's been 15 minutes."
    },
    "sessionTarget": "isolated",
    "delivery": {
      "mode": "announce",
      "channel": "telegram",
      "to": "1027899060"
    },
    "wakeMode": "now"
  }
}
```

## The Janitor (System Maintenance)

**Context:** Cleaning up finished one-shot jobs daily.
**Best for:** Running with full tool access in the main session.

```json
{
  "action": "add",
  "job": {
    "name": "Daily Cron Sweep",
    "schedule": {
      "kind": "every",
      "everyMs": 86400000
    },
    "payload": {
      "kind": "systemEvent",
      "text": "Time for the 24-hour cron sweep. List all cron jobs (includeDisabled: true). Delete any disabled jobs with lastStatus: ok. Report results."
    },
    "sessionTarget": "main",
    "wakeMode": "now"
  }
}
```

## Complex Task (Recurring/Async)

**Context:** User says "Summarize my emails every morning at 8 AM."

```json
{
  "action": "add",
  "job": {
    "name": "Morning Briefing",
    "schedule": {
      "kind": "cron",
      "expr": "0 8 * * *",
      "tz": "Africa/Cairo"
    },
    "payload": {
      "kind": "agentTurn",
      "message": "Good morning! Search for unread emails and top tech news, then summarize them."
    },
    "sessionTarget": "isolated",
    "wakeMode": "now",
    "delivery": {
      "mode": "announce",
      "channel": "telegram",
      "to": "1027899060"
    }
  }
}
```


Security scan verdicts — ClawScan: suspicious | static analysis: clean | VirusTotal: clean | SkillSpector: suspicious (CRITICAL)