Type Alias: EngineEvent {#type-alias-engineevent}

EngineEvent = { run: Run; type: "run:start"; } | { durationMs: number; run: Run; type: "run:complete"; } | { durationMs: number; error: string; run: Run; type: "run:error"; } | { attempt: number; error: string; run: Run; type: "run:retry"; } | { error: string; run: Run; type: "run:dead"; } | { childRuns: Run[]; resumedRun: Run; type: "run:resume"; } | { durationMs: number; effectKey: string; runId: string; type: "effect:complete"; } | { durationMs: number; effectKey: string; error: string; runId: string; type: "effect:error"; } | { effectKey: string; runId: string; type: "effect:replay"; } | { run: Run; type: "lease:reclaim"; } | { context: string; error: unknown; type: "internal:error"; }

Discriminated union of all engine lifecycle events emitted via EngineOptions.onEvent.

• run:start, run claimed by dispatcher and about to execute.
• run:complete, handler returned { success: true }. durationMs is current-attempt execution time.
• run:error, run reached errored state (handler threw, returned { success: false }, or failed validation). durationMs is current-attempt execution time (0 if no handler ran).
• run:retry, handler threw but retries remain; run returns to idle.
• run:dead, retry budget exhausted; always followed by run:error.
• run:resume, a deferred run was resumed, creating child runs.
• effect:complete, durable effect executed successfully. durationMs is effect function wall-clock time.
• effect:error, durable effect threw. durationMs is time until the throw.
• effect:replay, durable effect replayed from store (no re-execution).
• lease:reclaim, a stale lease was reclaimed (one event per run).
• internal:error, an internal error was caught that would otherwise be swallowed.