Stream chat replies with the TypeScript SDK

Talk to your Darwin agent from your own app, Slack, WhatsApp or a voice bot. The key needs the chat:write scope. Darwin keeps the transcript; you send only what the visitor said. How sessions, actions and allowances work: Chat API.

const session = await darwin.chat.sessions.create({
  visitor: { email: "ada@example.com", name: "Ada" }, // treated as verified: you hold the key
  channel: "app",
  context: { plan: "enterprise", seats: 40 },
});

// Wait for the whole reply.
const reply = await darwin.chat.sessions.send(session.id, { text: "Can I book a demo?" });
console.log(reply.message.text);
for (const action of reply.actions) {
  if (action.type === "booking_offered") showBookingButton(action.booking_url);
}

// Or stream it as it is written.
const stream = await darwin.chat.sessions.sendStream(session.id, { text: "What does it cost?" });
for await (const delta of stream.textDeltas()) process.stdout.write(delta);

A ChatStream can also be iterated for every parsed chunk of the AI SDK UI message stream (start, text-delta, tool-input-available, tool-output-available, finish, error…), or read in one go with await stream.finalText(). Call stream.abort() to stop. sendStream sends no automatic Idempotency-Key, because the API holds an idempotent response back until it is complete in order to store it. For the same reason it is retried only after a 429. send gets a key and the usual retries.