Explain and check cron schedules

--- name: explain-and-check-cron-schedules description: "Translates cron expressions into plain English, shows upcoming run times and flags common mistakes. Use when someone shares a cron line or asks for a schedule to be written or reviewed." --- Apply this whenever someone pastes a cron expression, a crontab line, a scheduled job definition, or asks you to write a recurring schedule. When explaining an existing schedule 1. Identify the format first: five fields (minute, hour, day of month, month, day of week) or six or seven with seconds or year. Say which one you assume if it is not stated. 2. Restate it in one plain sentence, for example "Every weekday at 02:30". 3. List the next five run times as a small table. Ask for the time zone and the current date if you need them; never guess silently. 4. Name the specific traps that apply: - When both day of month and day of week are set, most implementations run on either match, not both. - Dates that never occur, such as the 31st in a short month or February 30. - Daylight saving changes: a local time can be skipped or run twice. - The job runs in the server time zone, which may differ from the team's. - Step values like */7 restart each hour or day and do not give an even interval. - Runs that overlap because the job can take longer than the interval, and runs so frequent they may overload a system. 5. Suggest a corrected expression when you find a problem and explain the difference in one sentence. When writing a new schedule 1. Ask for any missing detail: how often, which days, which time zone, and what should happen if a run is missed. 2. Give the expression, its plain-English reading and the next five run times. 3. Mention any variations between schedulers that could change the meaning. Output shape Use short headings: Meaning, Next runs, Warnings, Suggested change. Keep each warning to one or two lines. Avoid - Claiming a run time is certain when time zone or daylight saving is unknown. - Running together expressions from different schedulers without saying so. - Long background lessons; answer the question asked.

Meaning: at minute 0 of 09:00 and 17:00, Monday to Friday (assuming a standard five-field format). Next runs (assuming time zone America/New_York, from Tue 3 Mar): 1. Tue 3 Mar 17:00 2. Wed 4 Mar 09:00 3. Wed 4 Mar 17:00 4. Thu 5 Mar 09:00 5. Thu 5 Mar 17:00 Warnings - If the server runs in UTC, these fire at 04:00 and 12:00 local time in winter. - On the spring clock change, nothing is skipped at these hours, but a 02:30 job would be. Suggested change: none needed. If you want only the first business day of each month, use a separate rule rather than adding day-of-month, because setting both fields runs on either match.