What can start a workflow?

Three things. A schedule, an event, or you.

A schedule is a time and a timezone: every weekday at nine, the first of the month. A manual workflow has no schedule and waits until somebody presses run.

An event trigger is where the work is. There is no menu of supported services, so the trigger gets written for your workflow during the interview: the agent authors the small piece of code that subscribes to the service and reads its events, and the platform handles the signature check, the registration handshake and the delivery identity itself. Events then arrive at a URL that belongs to that one registration and nothing else. A service that only offers polling is reached the same way, on a schedule the platform runs.

If you would rather just have the URL, you can. A service whose whole integration is a box asking for a webhook URL, a Framer form or a Zapier step or your own script, gets one you paste in yourself: the assistant mints it during the interview, hands it to you with a copy button, and a two minute listen window lets you send a real delivery through it and keep the payload before anything is published. See webhook URL triggers.

A registration is desired state rather than a setup step you perform once. The platform checks the subscription is still there, re-arms it when it vanishes, tells you when it cannot, and takes it down cleanly when you pause the workflow. If it keeps failing, that reopens the interview so the code can be repaired instead of quietly going dead. The same event delivered twice still does the job once.

Every event-driven workflow keeps sample payloads, so you can fire it against the real shape of the event before anything real arrives.