Type Alias: WorkflowEvent

type WorkflowEvent = 
  | {
  audience?: string;
  runId: string;
  threadId?: string;
  ts: number;
  type: "RUN_STARTED";
}
  | {
  audience?: string;
  output: unknown;
  runId: string;
  ts: number;
  type: "RUN_FINISHED";
}
  | {
  audience?: string;
  code: string;
  error: SerializedError;
  runId: string;
  ts: number;
  type: "RUN_ERRORED";
}
  | {
  audience?: string;
  meta?: WorkflowMetadata;
  stepId: string;
  ts: number;
  type: "STEP_STARTED";
}
  | {
  attempts?: ReadonlyArray<StepAttempt>;
  audience?: string;
  meta?: WorkflowMetadata;
  result: unknown;
  stepId: string;
  ts: number;
  type: "STEP_FINISHED";
}
  | {
  attempts?: ReadonlyArray<StepAttempt>;
  audience?: string;
  error: SerializedError;
  meta?: WorkflowMetadata;
  stepId: string;
  ts: number;
  type: "STEP_FAILED";
}
  | {
  audience?: string;
  deadline?: number;
  meta?: Record<string, unknown>;
  name: string;
  stepId: string;
  ts: number;
  type: "SIGNAL_AWAITED";
}
  | {
  audience?: string;
  meta?: WorkflowMetadata;
  name: string;
  payload: unknown;
  signalId?: string;
  stepId: string;
  ts: number;
  type: "SIGNAL_RESOLVED";
}
  | {
  approvalId: string;
  audience?: string;
  description?: string;
  meta?: WorkflowMetadata;
  stepId: string;
  title: string;
  ts: number;
  type: "APPROVAL_REQUESTED";
}
  | {
  approvalId: string;
  approved: boolean;
  audience?: string;
  feedback?: string;
  meta?: WorkflowMetadata;
  stepId: string;
  ts: number;
  type: "APPROVAL_RESOLVED";
}
  | {
  audience?: string;
  meta?: WorkflowMetadata;
  stepId: string;
  ts: number;
  type: "NOW_RECORDED";
  value: number;
}
  | {
  audience?: string;
  meta?: WorkflowMetadata;
  stepId: string;
  ts: number;
  type: "UUID_RECORDED";
  value: string;
}
  | {
  audience?: string;
  delta: ReadonlyArray<Operation>;
  ts: number;
  type: "STATE_DELTA";
}
  | {
  audience?: string;
  name: string;
  ts: number;
  type: "CUSTOM";
  value: Record<string, unknown>;
};

Defined in: packages/workflow-core/src/types.ts:70

The shape of every event the engine appends to a run's log.

Two consumers, one shape:

Durability: the engine appends events to the run's log. Replay reads the log and short-circuits primitives that have a matching CHECKPOINT event by stepId.
Observability: the engine emits the same events through runWorkflow's AsyncIterable<WorkflowEvent> and (if wired) through stream subscribers. A browser/UI subscribes to the same log a Durable Streams URL would expose.

Events fall into two categories internally:

Checkpoint events — replay uses these to skip already- completed work. Indexed by stepId. STEP_FINISHED, STEP_FAILED, SIGNAL_RESOLVED, APPROVAL_RESOLVED, NOW_RECORDED, UUID_RECORDED, RUN_FINISHED, RUN_ERRORED.
Coordination events — persisted so hosts and resume calls can identify the pending wait. SIGNAL_AWAITED, APPROVAL_REQUESTED.
Observability events — engine emits but replay ignores. RUN_STARTED, STEP_STARTED, STATE_DELTA, CUSTOM.

The optional audience field is engine-ignored. Adapters/views (e.g., a Durable Streams projection layer) may filter on it to produce internal vs client vs admin views of the same log.

Type Declaration

{
  audience?: string;
  runId: string;
  threadId?: string;
  ts: number;
  type: "RUN_STARTED";
}

audience?

optional audience: string;

runId

runId: string;

threadId?

optional threadId: string;

ts

ts: number;

type

type: "RUN_STARTED";

{
  audience?: string;
  output: unknown;
  runId: string;
  ts: number;
  type: "RUN_FINISHED";
}

audience?

optional audience: string;

output

output: unknown;

runId

runId: string;

ts

ts: number;

type

type: "RUN_FINISHED";

{
  audience?: string;
  code: string;
  error: SerializedError;
  runId: string;
  ts: number;
  type: "RUN_ERRORED";
}

audience?

optional audience: string;

code

code: string;

error

error: SerializedError;

runId

runId: string;

ts

ts: number;

type

type: "RUN_ERRORED";

{
  audience?: string;
  meta?: WorkflowMetadata;
  stepId: string;
  ts: number;
  type: "STEP_STARTED";
}

audience?

optional audience: string;

meta?

optional meta: WorkflowMetadata;

stepId

stepId: string;

ts

ts: number;

type

type: "STEP_STARTED";

{
  attempts?: ReadonlyArray<StepAttempt>;
  audience?: string;
  meta?: WorkflowMetadata;
  result: unknown;
  stepId: string;
  ts: number;
  type: "STEP_FINISHED";
}

attempts?

optional attempts: ReadonlyArray<StepAttempt>;

audience?

optional audience: string;

meta?

optional meta: WorkflowMetadata;

result

result: unknown;

stepId

stepId: string;

ts

ts: number;

type

type: "STEP_FINISHED";

{
  attempts?: ReadonlyArray<StepAttempt>;
  audience?: string;
  error: SerializedError;
  meta?: WorkflowMetadata;
  stepId: string;
  ts: number;
  type: "STEP_FAILED";
}

attempts?

optional attempts: ReadonlyArray<StepAttempt>;

audience?

optional audience: string;

error

error: SerializedError;

meta?

optional meta: WorkflowMetadata;

stepId

stepId: string;

ts

ts: number;

type

type: "STEP_FAILED";

{
  audience?: string;
  deadline?: number;
  meta?: Record<string, unknown>;
  name: string;
  stepId: string;
  ts: number;
  type: "SIGNAL_AWAITED";
}

audience?

optional audience: string;

deadline?

optional deadline: number;

meta?

optional meta: Record<string, unknown>;

name

name: string;

stepId

stepId: string;

ts

ts: number;

type

type: "SIGNAL_AWAITED";

{
  audience?: string;
  meta?: WorkflowMetadata;
  name: string;
  payload: unknown;
  signalId?: string;
  stepId: string;
  ts: number;
  type: "SIGNAL_RESOLVED";
}

audience?

optional audience: string;

meta?

optional meta: WorkflowMetadata;

name

name: string;

payload

payload: unknown;

signalId?

optional signalId: string;

Host-supplied idempotency token. Same signalId at the same stepId is a no-op (idempotent retry); different signalId is a lost race.

stepId

stepId: string;

ts

ts: number;

type

type: "SIGNAL_RESOLVED";

{
  approvalId: string;
  audience?: string;
  description?: string;
  meta?: WorkflowMetadata;
  stepId: string;
  title: string;
  ts: number;
  type: "APPROVAL_REQUESTED";
}

approvalId

approvalId: string;

audience?

optional audience: string;

description?

optional description: string;

meta?

optional meta: WorkflowMetadata;

stepId

stepId: string;

title

title: string;

ts

ts: number;

type

type: "APPROVAL_REQUESTED";

{
  approvalId: string;
  approved: boolean;
  audience?: string;
  feedback?: string;
  meta?: WorkflowMetadata;
  stepId: string;
  ts: number;
  type: "APPROVAL_RESOLVED";
}

approvalId

approvalId: string;

approved

approved: boolean;

audience?

optional audience: string;

feedback?

optional feedback: string;

meta?

optional meta: WorkflowMetadata;

stepId

stepId: string;

ts

ts: number;

type

type: "APPROVAL_RESOLVED";

{
  audience?: string;
  meta?: WorkflowMetadata;
  stepId: string;
  ts: number;
  type: "NOW_RECORDED";
  value: number;
}

audience?

optional audience: string;

meta?

optional meta: WorkflowMetadata;

stepId

stepId: string;

ts

ts: number;

type

type: "NOW_RECORDED";

value

value: number;

{
  audience?: string;
  meta?: WorkflowMetadata;
  stepId: string;
  ts: number;
  type: "UUID_RECORDED";
  value: string;
}

audience?

optional audience: string;

meta?

optional meta: WorkflowMetadata;

stepId

stepId: string;

ts

ts: number;

type

type: "UUID_RECORDED";

value

value: string;

{
  audience?: string;
  delta: ReadonlyArray<Operation>;
  ts: number;
  type: "STATE_DELTA";
}

audience?

optional audience: string;

delta

delta: ReadonlyArray<Operation>;

ts

ts: number;

type

type: "STATE_DELTA";

{
  audience?: string;
  name: string;
  ts: number;
  type: "CUSTOM";
  value: Record<string, unknown>;
}

audience?

optional audience: string;

name

name: string;

ts

ts: number;

type

type: "CUSTOM";

value

value: Record<string, unknown>;