cron

A scheduling tool for reminders and recurring tasks. It can send a reminder, run a task through the agent, or schedule a one-time event in a chosen time zone.

In plain words
What is it for?
Setting break or meeting reminders, running regular checks, scheduling weekday actions, listing scheduled jobs, and removing them.
Why use it?
It prevents time-based work from being forgotten and avoids manually calculating recurring schedules.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/mathclaw-ruc/mathclaw/cron
Any agent
npx skills add MathClaw-ruc/MathClaw --skill cron
Clone the repo
git clone --depth 1 https://github.com/MathClaw-ruc/MathClaw

Made for: Claude Code, Codex.

Per session 8 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 406 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 100% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00008 $0.00406
Opus 5 $0.00004 $0.00203
Sonnet 5 $0.00002 $0.00081
Haiku 4.5 $0.00001 $0.00041

Measured 2d ago against content hash bcb13a283061, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

cron scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

100% identical to cron — 2 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

mathclaw/skills/cron/SKILL.md · 58 lines

What it actually says

Cron

Use the cron tool to schedule reminders or recurring tasks.

Three Modes

  1. Reminder - message is sent directly to user
  2. Task - message is a task description, agent executes and sends result
  3. One-time - runs once at a specific time, then auto-deletes

Examples

Fixed reminder:

cron(action="add", message="Time to take a break!", every_seconds=1200)

Dynamic task (agent executes each time):

cron(action="add", message="Check HKUDS/nanobot GitHub stars and report", every_seconds=600)

One-time scheduled task (compute ISO datetime from current time):

cron(action="add", message="Remind me about the meeting", at="<ISO datetime>")

Timezone-aware cron:

cron(action="add", message="Morning standup", cron_expr="0 9 * * 1-5", tz="America/Vancouver")

List/remove:

cron(action="list")
cron(action="remove", job_id="abc123")

Time Expressions

User says Parameters
every 20 minutes every_seconds: 1200
every hour every_seconds: 3600
every day at 8am cron_expr: "0 8 * * *"
weekdays at 5pm cron_expr: "0 17 * * 1-5"
9am Vancouver time daily cron_expr: "0 9 * * *", tz: "America/Vancouver"
at a specific time at: ISO datetime string (compute from current time)

Timezone

Use tz with cron_expr to schedule in a specific IANA timezone. Without tz, the server's local timezone is used.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 58 lines · 8 tokens per session scan A bcb13a283061

Subscribe to this mod's changes

cron is a skill published in the GitHub repository MathClaw-ruc/MathClaw (372 stars, last pushed 4mo ago), licensed MIT. It adds 8 tokens to every session and 406 once invoked, about $0.0000 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to cron, differing in 2 lines, and is treated as a copy.

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