cron-scheduler

cron-scheduler is a skill for Claude Code, Codex from JayRHa/AgentSkills. It costs 137 tokens per session (1,995 once invoked), scanned A, original, MIT.

A scheduling assistant for cron expressions, which are compact rules that tell computers when to run jobs. It also covers related formats used by systemd, cloud services, Kubernetes, and GitHub Actions.

In plain words
What is it for?
Use it to write, explain, validate, and preview scheduled tasks, including their next run times and timing behavior.
Why use it?
It reduces mistakes caused by different scheduler formats, time zones, daylight-saving changes, missed runs, and overlapping jobs.

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/jayrha/agentskills/cron-scheduler
Any agent
npx skills add JayRHa/AgentSkills --skill cron-scheduler
Clone the repo
git clone --depth 1 https://github.com/JayRHa/AgentSkills

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for cron-scheduler

README.md
[![agentmods](https://agentmods.dev/badge/skills/jayrha/agentskills/cron-scheduler.svg)](https://agentmods.dev/skills/jayrha/agentskills/cron-scheduler)
Your own site
<a href="https://agentmods.dev/skills/jayrha/agentskills/cron-scheduler"><img src="https://agentmods.dev/badge/skills/jayrha/agentskills/cron-scheduler.svg" alt="Measured on agentmods" height="20"></a>
Per session 137 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,995 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found 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 $0.00137 $0.01995
Opus 5 $0.00068 $0.00997
Sonnet 5 $0.00027 $0.00399
Haiku 4.5 $0.00014 $0.00199

Measured 4d ago against content hash 686e020d4296, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

cron-scheduler 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 4d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/cronlint.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

cron-scheduler/SKILL.md · 82 lines

How it starts

The opening of the file, as written. The whole thing — 82 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Cron Scheduler

Overview

Translate human scheduling intent into correct cron expressions, explain existing expressions in plain language, preview the next fire times, and avoid the subtle traps (DOM/DOW OR-logic, timezone/DST drift, overlapping long-running jobs, missed runs on downtime). Covers classic Vixie/POSIX cron, plus the dialects used by systemd timers, Quartz, AWS EventBridge, Kubernetes CronJobs, and GitHub Actions.

Keywords: cron, crontab, cron expression, schedule, scheduler, scheduled job, */5, 0 9 * * 1-5, timezone, TZ, DST, daylight saving, day-of-week, day-of-month, systemd timer, OnCalendar, Quartz, EventBridge rate/cron, Kubernetes CronJob, GitHub Actions schedule, every N minutes, weekday, next run, overlap, concurrencyPolicy, flock.

Workflow

  1. Identify the target system. Cron dialects differ. Ask or infer: classic crontab (5 fields), systemd OnCalendar, Quartz/Spring (6-7 fields with seconds + ?), AWS EventBridge (6 fields, year, requires ?), Kubernetes CronJob (5 fields, UTC by default), or GitHub Actions (5 fields, UTC only). See references/cron-syntax.md for the field tables per dialect.
  2. Pin down the timezone. Determine where the schedule should fire in wall-clock terms and which TZ the runner uses. Most engines run in UTC or the daemon's local TZ — not the user's. Decide and state explicitly. See references/timezones-and-dst.md.
  3. Build the expression field by field using references/cron-syntax.md. Prefer ranges and steps (9-17, */15) over enumerations when they read clearly.
  4. Check the OR-logic trap. If BOTH day-of-month and day-of-week are restricted (neither is *), Vixie cron fires when EITHER matches, not both. This is the #1 silent bug. See the worked example in examples/build-and-explain.md.
  5. Validate and preview. Run scripts/cronlint.py "<expr>" -n 5 to confirm it parses, see a plain-language breakdown, and list the next fire times. Always preview before delivering.
  6. Audit operational pitfalls: DST gaps/doubles, jobs slower than their interval (overlap), missed runs after downtime, and the difference between "every 5 minutes" and "every hour at minute 5." See references/scheduling-pitfalls.md.
  7. Deliver the expression, a one-line plain-English explanation, the assumed timezone, and the next 3-5 fire times.

Read the full file on GitHub · 82 lines

Files

What ships with it

5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 4d ago First seen · 82 lines · 137 tokens per session scan A 686e020d4296

Subscribe to this mod's changes

cron-scheduler is a skill published in the GitHub repository JayRHa/AgentSkills (4 stars, last pushed 1mo ago), licensed MIT. It adds 137 tokens to every session and 1,995 once invoked, about $0.0007 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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