Type Alias: StructuredOutputStream<T>

type StructuredOutputStream<T> = AsyncIterable<
  | Exclude<StreamChunk, CustomEvent>
  | StructuredOutputStartEvent
  | StructuredOutputCompleteEvent<T>
  | ApprovalRequestedEvent
| ToolInputAvailableEvent>;

Defined in: packages/ai/src/types.ts:1554

Public type for streams returned by chat({ outputSchema, stream: true }).

Yields all standard StreamChunk lifecycle events plus the three tagged CUSTOM events the orchestrator can emit through this path:

structured-output.complete — terminal event with typed value.object: T
approval-requested — server tool needs approval (pauses the run)
tool-input-available — client tool invocation (pauses the run)

Each variant has a literal name, so a single discriminated narrow gives you a typed value with no helper or cast:

for await (const chunk of stream) {
  if (chunk.type === 'CUSTOM' && chunk.name === 'structured-output.complete') {
    chunk.value.object // typed as T
  } else if (chunk.type === 'CUSTOM' && chunk.name === 'approval-requested') {
    chunk.value.toolCallId // typed as string
  }
}

Caveat: tools can emit arbitrary user-defined custom events via the emitCustomEvent(name, value) context API. Those flow through this stream at runtime but are intentionally absent from this type — including a bare CustomEvent (whose value: any would poison the union) would collapse chunk.value back to any after the narrow. If you rely on emitCustomEvent plus outputSchema + stream: true, branch on CUSTOM outside the literal-name narrows or cast explicitly.