Cron Mastery 1.0.3

Master OpenClaw's timing systems. Use for scheduling reliable reminders, setting up periodic maintenance (janitor jobs), and understanding when to use Cron v...

Security Scan

The skill's instructions and requirements are coherent with a cron/scheduling helper; it does not request unrelated credentials or installs, but it does instruct modifying local scheduler state and agent memory which you should review before use.

Purpose & Capability

Name/description (cron scheduling, reminders, janitor tasks) match the SKILL.md content. No unrelated binaries, env vars, or external installs are requested.

Instruction Scope

Instructions stay focused on scheduling patterns and maintenance, but they explicitly reference and direct writing/deleting local agent files (e.g., adding timezone to MEMORY.md and deleting ~/.openclaw/state/cron/jobs.json). Those file operations are plausible for a janitor/troubleshooting guide, but they are not declared in the skill metadata and grant the agent ability to modify local state—review and permission are recommended.

Install Mechanism

Instruction-only skill with no install spec and no code files—nothing is written to disk by an installer.

Credentials

The skill requests no environment variables or credentials. It suggests using delivery channels (e.g., Telegram) but does not ask for API keys itself — it relies on the agent's existing channel integrations, which is appropriate for its purpose.

Persistence & Privilege

always is false and the skill does not request permanent/privileged presence. It recommends using the main session for maintenance because main has broader tool access — this is coherent with the janitor use case.

Assessment

This skill appears to do what it says: teach and provide templates for reliable cron jobs. Before installing/using it, note that the instructions tell the agent to (a) add timezone info to MEMORY.md and (b) potentially delete or edit ~/.openclaw/state/cron/jobs.json for troubleshooting. These file actions are reasonable for cron maintenance but give the agent permission to modify local scheduler state—only proceed if you trust the agent's existing permissions and back up those files first. Also review and replace any hard-coded delivery IDs (e.g., "1027899060") and confirm your notification channels (Telegram, etc.) are correctly configured; the skill itself does not request or store API keys, it expects the agent to already have channel access. If you want stronger safety, run templates in a sandbox or inspect the exact job payloads before scheduling them.

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):

{
  "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):

{
  "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"