cron-mastery

Original：🇺🇸 English

Translated

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.

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Sourcesundial-org/awesome-openclaw-skills

Added on2026-02-15

NPX Install

npx skill4agent add sundial-org/awesome-openclaw-skills cron-mastery

SKILL.md Content

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Cron Mastery

Rule #1: Heartbeats drift. Cron is precise.

This skill provides the definitive guide for managing time in OpenClaw. 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

Never use

act:wait

or internal loops for long delays (>1 min). Use

cron:add

with a one-shot

at

schedule.

Standard Reminder Pattern (JSON)

Use this payload structure for "remind me in X minutes" tasks:

json

{
  "name": "Remind: Drink Water",
  "schedule": {
    "kind": "at",
    "atMs": <CURRENT_MS + DELAY_MS>
  },
  "payload": {
    "kind": "agentTurn",
    "message": "⏰ Reminder: Drink water!",
    "deliver": true
  },
  "sessionTarget": "isolated",
  "wakeMode": "next-heartbeat"
}

Note: Even with
wakeMode: "next-heartbeat"
, the cron system forces an event injection at
atMs
. Use
mode: "now"
in the
cron:wake
tool if you need to force an immediate wake outside of a job payload.

2. The Janitor (Auto-Cleanup)

One-shot cron jobs (kind:

at

) disable themselves after running but stay in the list as "ghosts" (

enabled: false

,

lastStatus: ok

). To prevent clutter, install the Daily Janitor.

Setup Instructions

Check current jobs:
```
cron:list
```
(includeDisabled: true)
Create the Janitor:
- Name:
```
Daily Cron Cleanup
```
- Schedule: Every 24 hours (
```
everyMs: 86400000
```
  )
- Payload: An agent turn that runs a specific prompt.

The Janitor Prompt (Agent Turn)

"Time for the 24-hour cron sweep. List all cron jobs including disabled ones. If you find any jobs that are
enabled: false
and have
lastStatus: ok
(finished one-shots), delete them to keep the list clean. Do not delete active recurring jobs. Log what you deleted."

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"
```
.

Example Payload for "Checking back in 30s":