Cron Manager

Cron manager

A scheduled task is a PROMPT the agent will run on its own, later, with nobody watching. Use this when the user says "every morning", "each Monday", "in two hours", "remind me on the 3rd". Three tools do everything: cron_create, cron_list, cron_delete.

There is no update tool and no run-now tool. Both are compositions, written out below. The headings that describe them are procedure names, not callable tools: the only names you may call are the three above.

A cron task fires a prompt on a clock. A watcher fires on a CONDITION becoming true, and costs nothing while the condition is false. "Every hour, check whether the site is down" is a watcher, not a cron: see watcher-design. A mission is an objective pursued across iterations, sometimes on a cadence: see long-running-work.

Creating one

cron_create requires name and prompt, plus one way of saying when:

Passing neither returns Specify either 'cron_expr' or 'fire_at'. Passing both is not an error and not a merge: fire_at wins and the cron expression is never evaluated.

Two further arguments are read but absent from the tool's published schema, so you have to know they exist:

• skills, an array of skill names loaded into the scheduled run's prompt. A task whose prompt says "check the feeds" will not find blogwatcher on its own; name it here.
• channel, where the answer is delivered. Left out, the task inherits the channel it was created from, which is usually what the user wants.

Procedure:

1. cron_list first. A task with the same intent already existing means the user gets told twice, on a schedule, forever. There is no duplicate protection in the tool.
2. cron_create with name, prompt, and one of cron_expr or fire_at.
3. Read the answer. It ends with Cron task created with ID <uuid>. Keep that id: it is the only handle for deleting the task.
4. cron_list again and confirm the entry is there with the schedule you intended.
5. Tell the user, in local time, when it will next run.

Write prompt as a complete instruction for an agent with no conversation behind it. It runs cold, weeks later. "Do the thing we discussed" schedules a failure.

The cron expression, exactly as this scheduler reads it

Five fields, separated by spaces: MIN HOUR DOM MON DOW. Any other count never fires, and nothing reports it. Six-field expressions with seconds, @daily, @hourly, and MON or SUN day names are all rejected this way, silently.

Each field accepts *, an exact number, a comma list (1,3,5), a range (1-5), or a step (*/15). Names, a range with a step (1-5/2), L and # are not implemented.

Two things differ from the cron you know, and both produce a task that looks correct and never fires:

• Day of week is 1 to 7, Monday to Sunday. 0 is not Sunday here, it matches nothing. 0 9 * * 0 never runs. Sunday is 7.
• Times are LOCAL to the machine running the node, not UTC. Do not convert. 0 8 * * 1-5 is 08:00 local, Monday to Friday.

fire_at is the opposite: it is parsed as RFC3339 and is therefore UTC when it ends in Z. A fire_at string RFC3339 cannot parse is silently dropped, so a malformed one with no cron_expr surfaces as Specify either 'cron_expr' or 'fire_at'.

0 8 * * 1-5        08:00 local, Monday to Friday
*/15 * * * *       every quarter hour
0 9 1 * *          09:00 local on the 1st of every month
30 20 * * 7        20:30 local on Sunday

Listing

cron_list takes no arguments and returns a JSON array. Each entry carries id, name, cron_expr, fire_at and enabled. It does not return the prompt.

It also lists mission cadences, which are not cron tasks. Those entries carry "kind": "mission" and an id shaped mission:<slug>. This is deliberate, so that "what is scheduled?" has one truthful answer. But cron_delete cannot remove them: a mission goes through mission_delete with its slug.

Present the result as a table: name, schedule, enabled. Read the raw JSON before extracting anything; do not assume field names from this document alone.

Deleting

cron_delete with id, the UUID from cron_list. There is no deletion by name and none by position: list order is not stable, so deleting "the second one" eventually deletes something else.

1. cron_list, find the entry, read its id.
2. Not found: stop and say so. Do not delete the closest match.
3. The id starts with mission:: this is a mission. Use mission_delete with the part after the colon.
4. cron_delete with the id.
5. cron_list again. A schedule that survives a deletion you reported keeps firing long after everyone has forgotten it exists.

Updating one, without an update tool

Replace it, in this order, so a failure cannot leave the user with nothing scheduled:

1. cron_list, find the entry, read its id.
2. Recover the prompt. cron_list does not return it, so it comes from this conversation or from the user. Do not guess it.
3. cron_create with the new schedule and that prompt.
4. Confirm the new one exists with cron_list.
5. cron_delete the OLD id.

Creating before deleting means a crash between the two leaves a duplicate, which the user can see and remove. Deleting first means a crash leaves silence, which nobody notices.

Running one now, without a run-now tool

cron_list returns the schedule but NOT the prompt, so there is nothing to replay unless you already have it.

1. If the task was created in this session, you have the prompt. Execute it directly as an instruction.
2. Otherwise ask the user what it was meant to do, or read it from the Cron page of the dashboard. Do not invent a plausible prompt and run it: a scheduled task can send messages and write files.

Traps

• A one-shot task disables itself after firing and stays in the list. enabled: false next to a fire_at in the past is a task that already ran, not a broken one. Delete it if the user wants the list clean.
• A fire_at in the past fires on the next tick, within a minute, not never.
• The same task never fires twice inside one minute, so * * * * * gives one run per minute whatever the polling rate.
• The prompt runs with no conversation around it. Absolute paths, full context, an explicit success criterion.
• A schedule is a standing commitment. Confirm the cadence with the user before creating anything recurring, and say what it will do each time it fires.
• Never schedule anything that spends money, writes to a third party, or deletes data unless the user asked for exactly that.

Failure modes

Created, listed, enabled, never fires. In order of likelihood: the expression does not have exactly five fields; day of week was written 0 for Sunday; the time was converted to UTC when the scheduler reads local; a day name or @daily was used. Re-read the expression against the rules above, then cron_list to see what was actually stored.

Specify either 'cron_expr' or 'fire_at'. Neither was given, or fire_at was not valid RFC3339 and was dropped. RFC3339 wants the T and an offset: 2026-12-31T23:59:00Z, not 2026-12-31 23:59.

cron_delete reports the id was not found. The id came from a mission entry, or from an earlier listing that has since changed. cron_list again and take the current id.

The user gets the same notification twice. Two tasks with the same intent, or a cron task duplicating a mission cadence. cron_list shows both; delete each with the tool that matches its kind.

It fires but the answer goes nowhere. The origin channel no longer exists. Recreate the task with an explicit channel.