CronCreate

A built-in definition supplied to the request when the tools option was omitted.

Captured description

Schedule a prompt to be enqueued at a future time. Use for both recurring schedules and one-shot reminders.

Uses standard 5-field cron in the user’s local timezone: minute hour day-of-month month day-of-week. “0 9 * * *” means 9am local — no timezone conversion needed.

One-shot tasks (recurring: false)

For “remind me at X” or “at <time>, do Y” requests — fire once then auto-delete. Pin minute/hour/day-of-month/month to specific values: “remind me at 2:30pm today to check the deploy” → cron: “30 14 <today_dom> <today_month> *”, recurring: false “tomorrow morning, run the smoke test” → cron: “57 8 <tomorrow_dom> <tomorrow_month> *”, recurring: false

Recurring jobs (recurring: true, the default)

For “every N minutes” / “every hour” / “weekdays at 9am” requests: ”*/5 * * * *” (every 5 min), “0 * * * *” (hourly), “0 9 * * 1-5” (weekdays at 9am local)

Avoid the :00 and :30 minute marks when the task allows it

Every user who asks for “9am” gets 0 9, and every user who asks for “hourly” gets 0 * — which means requests from across the planet land on the API at the same instant. When the user’s request is approximate, pick a minute that is NOT 0 or 30: “every morning around 9” → “57 8 * * *” or “3 9 * * *” (not “0 9 * * *”) “hourly” → “7 * * * *” (not “0 * * * *”) “in an hour or so, remind me to…” → pick whatever minute you land on, don’t round

Only use minute 0 or 30 when the user names that exact time and clearly means it (“at 9:00 sharp”, “at half past”, coordinating with a meeting). When in doubt, nudge a few minutes early or late — the user will not notice, and the fleet will.

Session-only

Jobs live only in this Claude session — nothing is written to disk, and the job is gone when Claude exits.

Not for live watching

CronCreate re-runs a prompt at fixed wall-clock intervals. To watch a log file, process, or command output and be notified the moment something changes, use the Monitor tool instead — Monitor streams events as they happen; cron polls on a schedule.

Runtime behavior

Jobs only fire while the REPL is idle (not mid-query). The scheduler adds a small deterministic jitter on top of whatever you pick: recurring tasks fire up to 10% of their period late (max 15 min); one-shot tasks landing on :00 or :30 fire up to 90 s early. Picking an off-minute is still the bigger lever.

Recurring tasks auto-expire after 7 days — they fire one final time, then are deleted. This bounds session lifetime. Tell the user about the 7-day limit when scheduling recurring jobs.

Returns a job ID you can pass to CronDelete.

Input schema

JSON 
{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "type": "object",
  "properties": {
    "cron": {
      "description": "Standard 5-field cron expression in local time: \"M H DoM Mon DoW\" (e.g. \"*/5 * * * *\" = every 5 minutes, \"30 14 28 2 *\" = Feb 28 at 2:30pm local once).",
      "type": "string"
    },
    "prompt": {
      "description": "The prompt to enqueue at each fire time.",
      "type": "string"
    },
    "recurring": {
      "description": "true (default) = fire on every cron match until deleted or auto-expired after 7 days. false = fire once at the next match, then auto-delete. Use false for \"remind me at X\" one-shot requests with pinned minute/hour/dom/month.",
      "type": "boolean"
    },
    "durable": {
      "description": "true = persist to .claude/scheduled_tasks.json and survive restarts. false (default) = in-memory only, dies when this Claude session ends. Use true only when the user asks the task to survive across sessions.",
      "type": "boolean"
    }
  },
  "required": [
    "cron",
    "prompt"
  ],
  "additionalProperties": false
}

Independent estimate

~1,519 tokens

The captured tool object was counted against the common baseline. This value supports comparison and is not additive.