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.
The messages to be sent to the agent.
Whether the server should parse specific tool call arguments (default send_message) as AssistantMessage objects.
The name of the designated message tool.
The name of the message argument in the designated message tool.
Flag to determine if individual tokens should be streamed. Set to True for token streaming (requires stream_steps = True).
Successful response
A message generated by the system. Never streamed back on a response, only used for cursor pagination.
Attributes: message (str): The message sent by the system id (str): The ID of the message date (datetime): The date the message was created in ISO format
A message sent by the user. Never streamed back on a response, only used for cursor pagination.
Attributes: message (str): The message sent by the user id (str): The ID of the message date (datetime): The date the message was created in ISO format
Representation of an agent’s internal reasoning.
Attributes: reasoning (str): The internal reasoning of the agent id (str): The ID of the message date (datetime): The date the message was created in ISO format
A message representing a request to call a tool (generated by the LLM to trigger tool execution).
Attributes: tool_call (Union[ToolCall, ToolCallDelta]): The tool call id (str): The ID of the message date (datetime): The date the message was created in ISO format
A message representing the return value of a tool call (generated by Letta executing the requested tool).
Attributes: tool_return (str): The return value of the tool status (Literal[“success”, “error”]): The status of the tool call id (str): The ID of the message date (datetime): The date the message was created in ISO format tool_call_id (str): A unique identifier for the tool call that generated this message stdout (Optional[List(str)]): Captured stdout (e.g. prints, logs) from the tool invocation stderr (Optional[List(str)]): Captured stderr from the tool invocation
Usage statistics for the agent interaction.
Attributes: completion_tokens (int): The number of tokens generated by the agent. prompt_tokens (int): The number of tokens in the prompt. total_tokens (int): The total number of tokens processed by the agent. step_count (int): The number of steps taken by the agent.