Streaming

Streaming lets your agent send responses token-by-token as the LLM generates them. Users see text appear in real-time instead of waiting for the full response.

StreamSession API

Start a stream with agent.stream():

interface StreamSession {
  delta(chunk: string): Promise<void>;  // Send a chunk
  done(finalPayload: SendPayload): Promise<void>;  // Complete the stream
  abort(): void;  // Cancel the stream
}

Basic Usage

const session = agent.stream(conversationId);
// SDK sends a stream.start frame with an idempotency key

for await (const chunk of llmStream) {
  await session.delta(chunk);
  // Each delta is independently encrypted and sent
}

await session.done({
  type: "text",
  content: fullText,
});
// SDK sends stream.done with the full encrypted payload for persistence

With OpenAI

agent.onMessage(async (msg) => {
  const session = agent.stream(msg.conversation_id);

  const stream = await openai.chat.completions.create({
    model: "gpt-4o",
    messages: [{ role: "user", content: msg.content }],
    stream: true,
  });

  let fullText = "";

  for await (const chunk of stream) {
    const delta = chunk.choices[0]?.delta?.content ?? "";
    if (delta) {
      fullText += delta;
      await session.delta(delta);
    }
  }

  await session.done({
    type: "text",
    content: fullText,
  });
});

Aborting a Stream

Cancel a stream if the user sends a new message or an error occurs:

session.abort();
// SDK sends a stream.abort frame; the client discards partial content

Encryption

Each delta frame is independently encrypted. This means each chunk is a self-contained encrypted payload. The final done frame carries the complete encrypted message for server-side persistence.

Limits

Constraint	Value
Maximum stream duration	5 minutes
Orphan detection timeout	30 seconds (no delta)
Large groups (201-500 members)	Streaming disabled

If the server detects a stream timeout, it sends a stream.error frame. The SDK aborts the session and emits the error via onEvent. The agent decides whether to restart.

Next Steps

• Artifacts — Send structured interactions
• Sending Messages — Non-streaming message types
• WebSocket Events — Stream event frame reference