Cron Helper

Explain, generate, and validate cron expressions. Convert plain English schedules to cron syntax and back. Show next run times. Works with standard 5-field and 6-field (with seconds) cron.

Explain, generate, validate, and preview cron expressions — all from plain English or raw cron syntax.

Trigger phrases

• "What does this cron mean: * * * * *"
• "Explain this cron expression"
• "Generate a cron for every weekday at 9am"
• "When does 0 9 * * 1-5 run next?"
• "Is this cron valid?"
• "Convert to cron: every 15 minutes"
• "Show me the next runs for this cron"

Usage

Run the script with uv run (handles dependencies automatically):

# Explain a cron expression
uv run scripts/cron.py explain "0 9 * * 1-5"

# Generate cron from plain English
uv run scripts/cron.py generate "every weekday at 9am"
uv run scripts/cron.py generate "every 15 minutes"
uv run scripts/cron.py generate "first day of month at midnight"

# Show next N run times (default 5)
uv run scripts/cron.py next "0 9 * * 1-5"
uv run scripts/cron.py next "*/15 * * * *" --count 10

# Validate a cron expression
uv run scripts/cron.py validate "0 9 * * 1-5"
uv run scripts/cron.py validate "60 9 * * *"

Instructions for the agent

1. Parse the user's request to determine the command: explain, generate, next, or validate.
2. Run the appropriate uv run scripts/cron.py <command> "<expression or description>" command.
3. Present the output to the user, adding any clarifying context.
4. If the user provides a cron expression, always offer to explain it AND show next runs.

Reference

See references/cron-syntax.md for field ranges, special characters, and common examples.