One Sume schedule on a clock and on call: api_trigger_enabled

Most teams want both: a Monday 09:00 run, and a way to fire it by hand when a launch moves. Sume's Scheduled model allows that, with one rule you must get right at create time.

Two trigger types, one flag

trigger_type is cron or api and is fixed when you create the schedule. An API-only schedule can never get a cadence, and a cron schedule can never become API-only. But a cron schedule can also set api_trigger_enabled to true, which permits POST /v1/actions/{action_id}/runs in addition to the clock (Create a schedule).

What an API run needs

The schedule must be active, the flag must be on, and the key needs actions:read and actions:write. An inactive schedule answers 409 action_inactive. Run history labels each run API or Cron, so a manual fire is visible afterwards.

Overlap

Only one run of a schedule is active at a time. on_active_run is skip by default: a fire during a run returns 200 with a receipt whose status is skipped and skip_reason is previous_run_active. reject returns 409 action_run_in_progress instead. Use skip when an overlap is harmless, as the API trigger page says.

Pick the clock-plus-manual setup if there is any chance you will want to fire early. It costs nothing to enable, and it is the one choice you cannot change later.