Send Message Streaming
Process a user message and return the agent’s response. This endpoint accepts a message from a user and processes it through the agent. It will stream the steps of the response always, and stream the tokens if ‘stream_tokens’ is set to True.
Authentication
Header authentication of the form Bearer <token>
Path Parameters
The ID of the agent in the format ‘agent-<uuid4>’
Request
Syntactic sugar for a single user message. Equivalent to messages=[{‘role’: ‘user’, ‘content’: input}].
Only return specified message types in the response. If None (default) returns all messages.
If True, returns a streaming response (Server-Sent Events). If False (default), returns a complete response.
Flag to determine if individual tokens should be streamed, rather than streaming per step (only used when streaming=true).
Whether to include periodic keepalive ping messages in the stream to prevent connection timeouts (only used when streaming=true).
Whether to process the request in the background (only used when streaming=true).
Whether the server should parse specific tool call arguments (default send_message) as AssistantMessage objects. Still supported for legacy agent types, but deprecated for letta_v1_agent onward.
The name of the designated message tool. Still supported for legacy agent types, but deprecated for letta_v1_agent onward.
The name of the message argument in the designated message tool. Still supported for legacy agent types, but deprecated for letta_v1_agent onward.
