Streaming

Live chat uses Server-Sent Events with a versioned, ordered event protocol rather than an unstructured text socket.

Transport

POST /chat returns:

Content-Type: text/event-stream
Cache-Control: no-cache, no-transform
X-Accel-Buffering: no

The route requires an authenticated account session and is protected by the chat rate limiter.

Protocol version

Current stream events carry protocol_version: 1, a turn identifier, and a monotonically ordered sequence field. Part-level events add a part identifier; tool events add a tool identifier.

Clients should treat the protocol version as part of the compatibility contract rather than assuming event payloads can change without coordination.

Event families

The current stream model includes typed events for:

• turn start and routing;
• activity progress;
• answer start, delta, and completion;
• code start, delta, and completion;
• tool start, progress, state transitions, and completion;
• additional bounded platform events as documented by their public contract.

Backpressure and intermediaries

The API disables response buffering and transformation for the stream. Clients should consume events incrementally and should not depend on intermediaries coalescing chunks.

Durable state is separate

Streaming transports live execution. Conversation persistence is a separate durable boundary. A robust client should not assume that the presence or absence of one network chunk is itself the durable conversation record.