Short answer: there isn’t a Late → TimedOut transition to configure in Prefect 3.x. - Late is a scheduled-state variant that means “this run should have started but hasn’t entered Pending yet.” It does not progress to TimedOut automatically. - The setting you can control is when a scheduled run is marked Late. That’s: -

PREFECT_API_SERVICES_LATE_RUNS_AFTER_SECONDS

(Cloud) or -

PREFECT_SERVER_SERVICES_LATE_RUNS_AFTER_SECONDS

(Server) - Default: 15 seconds - This is managed by the MarkLateRuns service (runs every 5s by default). If you’re looking for actual execution timeouts that produce TimedOut, those are controlled elsewhere (e.g., task-level

timeout_seconds

or infrastructure/runtime timeouts), not by the Late state. References: - Mark late runs service: server/services/late_runs.py - Service settings (including

late_runs.after_seconds

and

late_runs.loop_seconds

): settings/models/server/services.py - States overview: Prefect docs: States