New: 98,000+ skills indexed from GitHub repos with 100+ stars · every skill safety-checkedBrowse top skillsTop skills
Esc to closeBrowse all skills
Submit a skillBrowse skills
Submit a skillBrowse skills

Agent skill

Cron

by HKUDS in HKUDS/OpenOPC

Schedule reminders, recurring tasks, and one-time jobs using system crontab.

MITAuto-check passedProductivity & Automation

Install Cron

skills CLI
$ npx skills add HKUDS/OpenOPC --skill cron -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install HKUDS/OpenOPC cron --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/HKUDS/OpenOPC.git skills-src && mkdir -p .claude/skills && cp -r skills-src/.opc/skills/cron .claude/skills/cron && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
cron
GitHub stars
1.8k
Token cost
~323 tokens
SKILL.md length
111 words
Files
1
Skills in repo
7
Repo updated
First seen
Licence
MIT

At a glance

Schedule reminders, recurring tasks, and one-time jobs using system crontab.

  • Tasks that involve Scheduled and recurring tasks
  • SKILL.md covers List current cron jobs, Add a recurring job, Common schedules and One-time scheduled task, plus 2 more sections
  • Calls apt

What it does

Cron is an agent skill from HKUDS/OpenOPC. Schedule reminders, recurring tasks, and one-time jobs using system crontab.

Its SKILL.md is about 320 tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.

It sits in Productivity & Automation, covering Scheduled and recurring tasks. The repository describes itself as: OpenOPC: Build Your Personal AI-Native Company — Self-Built, Self-Run, Self-Grown. The licence is MIT.

When your agent uses it

  • Tasks that involve Scheduled and recurring tasks

Example prompts

  • “/cron”

What it can do on your machine

Read from SKILL.md and the folder at commit b14e85d. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    Shell commands in SKILL.md call:

    • apt

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    No URLs in SKILL.md.

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Cron loads about 323 tokens when it runs. Until then it costs about 20 tokens; SKILL.md has 111 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~20
When it runs · the whole SKILL.md, loaded when a task matches
~323

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from HKUDS/OpenOPC at commit b14e85d, republished under its MIT licence (© HKUDS). 111 words, ~323 tokens.

Download SKILL.mdSave it as .claude/skills/cron/SKILL.md (or your agent's skills folder).
name
cron
description
Schedule reminders, recurring tasks, and one-time jobs using system crontab.

Cron

Schedule tasks using the system crontab via shell_exec.

List current cron jobs

bash
crontab -l

Add a recurring job

bash
(crontab -l 2>/dev/null; echo "*/20 * * * * echo 'Time to take a break!' >> /tmp/opc-reminders.log") | crontab -

Common schedules

ScheduleCron expression
Every 20 minutes*/20 * * * *
Every hour0 * * * *
Every day at 8am0 8 * * *
Weekdays at 5pm0 17 * * 1-5
Every Monday at 9am0 9 * * 1

One-time scheduled task

Use at for one-time jobs:

bash
echo "echo 'Meeting reminder' >> /tmp/opc-reminders.log" | at 14:30

Or schedule with a specific date:

bash
echo "echo 'Deadline reminder' >> /tmp/opc-reminders.log" | at 10:00 2026-03-20

Remove a job

Edit the crontab directly:

bash
crontab -e

Or filter out a specific job:

bash
crontab -l | grep -v 'pattern-to-remove' | crontab -

Notes

  • Use full paths in cron commands (cron has a minimal $PATH).
  • Redirect output to a log file or /dev/null to avoid mail noise.
  • Check at availability: which at (install with apt install at if missing).

© HKUDS, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

Just SKILL.md in .opc/skills/cron of HKUDS/OpenOPC.

Open the folder on GitHubat commit b14e85d

Compare with similar skills

Cron next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Cron compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Cron this skillHKUDS/OpenOPC1.8k—~323Automated safety check: PassMIT
ScheduleTinyAGI/tinyagi3.6k—~1.4kAutomated safety check: PassMIT
Send User MessageTinyAGI/tinyagi3.6k—~829Automated safety check: PassMIT
Cron Opsczl9707/build-your-own-openclaw1.9k—~593Automated safety check: PassMIT
X Bookmarkssharbelxyz/x-bookmarks289—~2kAutomated safety check: NotesNone
Jobsphysiclaw/PhysiClaw3861 repos~1.1kAutomated safety check: PassMIT

Similar skills

  • Schedule

    TinyAGI/tinyagi

    Create, list, and delete scheduled tasks (recurring or one-time) that send messages to agents.

    3.6k GitHub stars~1.4k tokensUpdated 6 mo ago
    Productivity & AutomationAuto-check passed

  • Send User Message

    TinyAGI/tinyagi

    Send a proactive message to a paired user via their channel (Discord, Telegram, or WhatsApp).

    3.6k GitHub stars~829 tokensUpdated 6 mo ago
    Productivity & AutomationAuto-check passed

  • Cron Ops

    czl9707/build-your-own-openclaw

    Create, list, and delete scheduled cron jobs. An agent skill from czl9707/build-your-own-openclaw.

    1.9k GitHub stars~593 tokensUpdated 3 mo ago
    Productivity & AutomationAuto-check passed

  • X Bookmarks

    sharbelxyz/x-bookmarks

    Fetch, summarize, and manage X/Twitter bookmarks via bird CLI or X API v2.

    289 GitHub stars~2k tokensUpdated 7 mo ago
    Productivity & AutomationAuto-check: notes

  • Jobs

    physiclaw/PhysiClaw

    A skill your agent uses when the task involves scheduling future work — any "remind me at …", "every weekday …", "check again in 30 min", or closing a fired cron job.

    386 GitHub starsUsed in 1 repo~1.1k tokens
    Productivity & AutomationAuto-check passed

  • Wp Wpcli And Ops

    Automattic/agent-skills

    A skill your agent uses when working with WP-CLI (wp) for WordPress operations: safe search-replace, db export/import, plugin/theme/user/content management, cron, cache flushing, multisite, and…

    211 GitHub starsUsed in 2 repos~988 tokens
    Productivity & AutomationAuto-check passed

More from HKUDS/OpenOPC

  • Skill Creator

    HKUDS/OpenOPC

    Create or update skills. An agent skill from HKUDS/OpenOPC.

    1.8k GitHub stars~980 tokensUpdated 27 days ago
    Auto-check passed

  • Clawhub

    HKUDS/OpenOPC

    Search and install agent skills from ClawHub, the public skill registry.

    1.8k GitHub stars~467 tokensUpdated 27 days ago
    Auto-check passed

  • Skill Evolution

    HKUDS/OpenOPC

    Evolve new skills from project experience. An agent skill from HKUDS/OpenOPC.

    1.8k GitHub stars~641 tokensUpdated 27 days ago
    Auto-check passed

  • Collaboration Playbook

    HKUDS/OpenOPC

    Standing rules for how any role in an OpenOPC company coordinates with its peers — work-item discipline, messaging, meetings, and blocking collaboration.

    1.8k GitHub stars~1.6k tokensUpdated 27 days ago
    Auto-check passed

  • Opc Collab

    HKUDS/OpenOPC

    Collaborate with other agents in OpenOPC company mode via the opc-collab CLI — send messages, request user input, delegate work, read the manager board, respond in meetings, propose task adjustments.

    1.8k GitHub stars~3.8k tokensUpdated 27 days ago
    Auto-check passed

  • Memory

    HKUDS/OpenOPC

    Manage durable global/project memory in .opc/memory/global.md and .opc/memory/projects/<currentprojectid.md.

    1.8k GitHub stars~304 tokensUpdated 27 days ago
    Auto-check passed

Categories

Questions about Cron

What does Cron do?

Schedule reminders, recurring tasks, and one-time jobs using system crontab. Cron is an agent skill from HKUDS/OpenOPC. Schedule reminders, recurring tasks, and one-time jobs using system crontab.

When should I use Cron?

Cron fits situations like: tasks that involve Scheduled and recurring tasks.

How do I install Cron in Claude Code?

Run `npx skills add HKUDS/OpenOPC --skill cron -a claude-code`. Or copy the skill folder (.opc/skills/cron in HKUDS/OpenOPC) into .claude/skills/cron in your project. Claude Code loads it when a task matches its description.

How do I install Cron in Codex?

Run `npx skills add HKUDS/OpenOPC --skill cron -a codex`. Or copy the skill folder (.opc/skills/cron in HKUDS/OpenOPC) into .agents/skills/cron in your project. Codex loads it when a task matches its description.

Can I use Cron in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add HKUDS/OpenOPC --skill cron -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/cron, .gemini/skills/cron, .github/skills/cron and .opencode/skills/cron in your project.

What does Cron need to run?

Going by SKILL.md and its folder, Cron needs the command-line tools its instructions call (apt).

Does Cron access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Cron safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Cron use?

Cron is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does Cron use?

About 323 tokens (SKILL.md is roughly 1.3k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.

What are the alternatives to Cron?

Skills that share tags, products or a category with Cron: Schedule (TinyAGI/tinyagi, 3.6k stars), Send User Message (TinyAGI/tinyagi, 3.6k stars), Cron Ops (czl9707/build-your-own-openclaw, 1.9k stars) and X Bookmarks (sharbelxyz/x-bookmarks, 289 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Cron?

HKUDS (a GitHub organization) maintains it in HKUDS/OpenOPC, which has 1,815 GitHub stars. The repository holds 7 skills in this directory. The repository was last updated on September 11, 2026.

Source: HKUDS/OpenOPC on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.