agent.stream() should provide access to structured response

[dremnik]

Problem

When using agent.stream() with structured output, there's no way to get the final parsed response from the stream.

Options

Option 1: Yield as final event

for await (const event of agent.stream(prompt, options)) {
  if (event.kind === "tool-call") console.log(event.toolId);
  if (event.kind === "text-delta") process.stdout.write(event.text);
  if (event.kind === "response") {
    const result = event.response;
    // { needs_updating: boolean, reason: string }
  }
}

Option 2: Property on stream object

const stream = agent.stream(prompt, options);

for await (const event of stream) {
  if (event.kind === "tool-call") console.log(event.toolId);
  if (event.kind === "text-delta") process.stdout.write(event.text);
}

const result = await stream.response;
// { needs_updating: boolean, reason: string }

Type signature:

interface AgentStreamResult<TResult> extends AsyncIterable<ThreadStreamEvent> {
  response: Promise<TResult>;
}

Recommendation

Option 2 - the response isn't really a stream "event", it's the final output. Keeping it separate makes types cleaner.