# Cron Audit

> Parses a crontab, expands every schedule into concrete values, explains each job in plain words, and flags invalid lines, impossible schedules, and over-frequent jobs. Crontab syntax is write-only for most humans; this makes it readable. Stdlib-only, deterministic.

- Skill: `trac3r00/cron-audit` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add trac3r00/cron-audit`
- Raw SKILL.md: https://api.skillmd.com/api/skills/trac3r00/cron-audit/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Security
- License: MIT
- Author: trac3r00 (https://skillmd.com/u/trac3r00)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/trac3r00/cron-audit

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# Cron Audit

Crontab lines are write-only for most humans. This reads them back.

## Commands

```bash
python3 scripts/cron_audit.py /etc/crontab
crontab -l | python3 scripts/cron_audit.py -
python3 scripts/cron_audit.py deploy/crontab.txt --max-freq-min 5 --json
```

## Reports

Per line: parsed schedule values (`hour [2], minute [0], weekday [1,2,3,4,5]`),
a plain-words explanation ("every weekday, hour 9-17, every 15 minutes"),
and the command. Invalid lines get the exact parse error
(`range 25-30 outside hour 0-23`).

Exit 1 on any invalid line — a CI gate for committed crontabs.

## Catches

- Wrong field count (5 fields + command required)
- Values/ranges outside field bounds (minute>59, month>12)
- Bad steps (`*/0`), unparseable tokens
- Jobs more frequent than `--max-freq-min` minutes (runaway polling)

## Pairs with

`apple-suite` (the GUI-app automation layer; cron is the headless layer),
`sys-health` (is the box those jobs run on healthy).