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Install in OpenClaw
/install cron-mastery
Description
Master OpenClaw's timing systems. Use for scheduling reliable reminders, setting up periodic maintenance (janitor jobs), and understanding when to use Cron v...
Usage Guidance
Review this skill before installing. Replace all fixed Telegram IDs and example timezones with user-confirmed placeholders, require consent before scheduling email summaries or external delivery, and do not follow the state-file deletion advice unless you have a backup and a supported recovery procedure.
Capability Analysis
Type: OpenClaw Skill
Name: cron-mastery
Version: 1.0.3
The skill demonstrates the use of `systemEvent` payloads targeting the `main` session, which grants the primary agent 'full tool access' and allows it to execute arbitrary instructions provided in the `text` field. While the example instruction in `references/templates.md` ('List all cron jobs... Delete any disabled jobs... Report results.') is for legitimate system maintenance, this mechanism represents a significant prompt injection vulnerability. A malicious actor could potentially craft a `systemEvent` payload to instruct the main agent to perform unauthorized actions (e.g., data exfiltration, arbitrary command execution) if they could inject or modify cron jobs. This is a risky capability without clear malicious intent in the provided examples, thus classified as suspicious.
Capability Assessment
Credentials
Persistent cron jobs, main-session janitor maintenance, email-reading examples, and external Telegram delivery are high-impact capabilities that need clearer scoping and confirmation than the artifact provides.
Install Mechanism
The artifact is markdown documentation only; I found no install script, executable payload, dependency installation, remote code retrieval, or tool-wrapping mechanism.
Instruction Scope
The skill presents specific, copy-ready cron payloads rather than placeholders or user-confirmed destinations, and its troubleshooting section advises deleting ~/.openclaw/state/cron/jobs.json without backup or last-resort safeguards.
Persistence & Privilege
The skill intentionally creates persistent scheduled jobs and advises storing timezone in MEMORY.md; timezone storage is low sensitivity, but persistent jobs with fixed external delivery and manual deletion of global cron state raise material review concerns.
Purpose & Capability
Cron scheduling guidance is coherent with the stated purpose, but the push-notification and morning-briefing templates hardcode Telegram recipient 1027899060, and the briefing example tells the agent to summarize unread emails before announcing results externally.
How to Use
- Make sure OpenClaw is installed (local or Docker)
- Run the install command in chat:
/install cron-mastery - After installation, invoke the skill by name or use
/cron-mastery - Provide required inputs per the skill's parameter spec and get structured output
Version History
v1.0.3
cron-mastery 1.0.3
- Updated documentation to clarify best practices for session targeting in janitor/maintenance jobs; `sessionTarget: "main"` is now emphasized as critical for system maintenance.
- Enhanced the troubleshooting section with new advice for resolving gateway timeout issues and corrupted job state.
- Modernized the legacy migration guide and examples to match OpenClaw 2026.2.15+ patterns.
- Revised internal references, replacing and consolidating template documentation files.
v1.0.2
Summary: Major update for OpenClaw 2026.2.3+ with modernized scheduling, improved reliability, and streamlined patterns.
- Standardizes all reminder setups on the new "at" ISO timestamp format and single-step cron.add (no more atMs).
- Adds explicit instructions for push notifications vs. silent logs; sub-agent must use "Strict" prompt for reliable delivery.
- Clarifies "gateway tick" timing—execution can vary by 10–60s depending on gateway, not instant at the second.
- Introduces auto-deletion of one-shot jobs after success; manual janitor now legacy unless deleteAfterRun is false.
- Updates troubleshooting for new delivery system and session targeting; removes need for most manual cleanups.
- Provides a migration guide from legacy (pre-2026.2.3) patterns to current best practices.
v1.0.1
cron-mastery v1.0.1 changelog
- Added a new "Delivery Rule (CRITICAL)" section: Always set `"deliver": true` in `agentTurn` payloads scheduled by Cron to ensure messages are visible to the user.
- Explained that without `"deliver": true`, agent messages will not be shown to the human.
- No code changes; documentation only.
v1.0.0
- Initial release of cron-mastery: a comprehensive guide to managing precise time-based tasks in OpenClaw.
- Clarifies when to use Cron (for exact schedules) vs Heartbeat (for casual checks) to ensure reliable reminders and task execution.
- Provides standardized JSON patterns for scheduling reminders and one-shot tasks using Cron.
- Introduces the “Daily Janitor”: a method to auto-clean finished one-shot cron jobs and reduce job list clutter.
- Emphasizes timezone handling for correct scheduling and offers detailed troubleshooting tips.
Metadata
Frequently Asked Questions
What is Cron Mastery?
Master OpenClaw's timing systems. Use for scheduling reliable reminders, setting up periodic maintenance (janitor jobs), and understanding when to use Cron v... It is an AI Agent Skill for Claude Code / OpenClaw, with 19118 downloads so far.
How do I install Cron Mastery?
Run "/install cron-mastery" in the OpenClaw or Claude Code chat to install it in one step — no extra setup required.
Is Cron Mastery free?
Yes, Cron Mastery is completely free (open-source). You can download, install and use it at no cost.
Which platforms does Cron Mastery support?
Cron Mastery is cross-platform and runs anywhere OpenClaw / Claude Code is available (cross-platform).
Who created Cron Mastery?
It is built and maintained by i-mw (@i-mw); the current version is v1.0.3.
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