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Letta

API reference

Python SDK

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.

Send Message Streaming

Letta's internal representation of a message. Includes methods to convert to/from LLM provider formats.

Attributes:
    id (str): The unique identifier of the message.
    role (MessageRole): The role of the participant.
    text (str): The text of the message.
    user_id (str): The unique identifier of the user.
    agent_id (str): The unique identifier of the agent.
    model (str): The model used to make the function call.
    name (str): The name of the participant.
    created_at (datetime): The time the message was created.
    tool_calls (List[ToolCall]): The list of tool calls requested.
    tool_call_id (str): The id of the tool call.

Agent Id

Created At

The model used to make the function call.

Model

Name

Text

Tool Call Id

Tool Calls

User Id

Message

Role

MessageCreate

MessageRole

Location

Error Type

ValidationError

Type

ToolCall

The arguments to pass to the function (JSON dump)

Arguments

ToolCallFunction

LettaStreamingRequest

bearerAuth

HTTPValidationError

Letta is an AI platform for building stateful LLM applications.

Overview

Welcome to Letta

Quickstart

Developer quickstart

Install and setup Letta to run the server & ADE

Run with pip

Run Letta server with pip

Run with Docker

Run Letta server with Docker

OpenAI

OpenAI proxy

OpenAI-compatible endpoint

Anthropic

Groq

Together

Google AI (Gemini)

Ollama

vLLM

Azure OpenAI

Letta concepts

Key concepts

MemGPT concepts

MemGPT

Tools

Memory

Messaging agents

Message streaming

Streaming support

Understanding the concept of LLM memory management introduced in MemGPT

Memory management

Understanding memory management

Learn how to create custom memory classes

Custom memory

Creating custom memory classes

Get Tool

Delete Tool

Update Tool

Get Tool Id

Get a list of all tools available to agents belonging to the org of the user

List Tools

Upsert Tool

Create Tool

Add Base Tools

Get Source

Delete Source

Update the name or documentation of an existing data source.

Update Source

Get Source Id By Name

List Sources

Create Source

Attach a data source to an existing agent.

Attach Source To Agent

Detach a data source from an existing agent.

Detach Source From Agent

Upload File To Source

List all passages associated with a data source.

List Passages

List paginated files associated with a data source.

List Files From Source

Delete File From Source

List all agents associated with a given user.
This endpoint retrieves a list of all agents and their configurations associated with the specified user ID.

List Agents

Create a new agent with the specified configuration.

Create Agent

Retrieve the context window of a specific agent.

Get Agent Context Window

Get Agent State

Delete Agent

Update Agent

Get Tools From Agent

Add Tool To Agent

Remove Tool From Agent

Get the sources associated with an agent.

Get Agent Sources

Retrieve the messages in the context of a specific agent.

Get Agent In Context Messages

Retrieve the memory state of a specific agent.
This endpoint fetches the current memory state of the agent identified by the user ID and agent ID.

Get Agent Memory

Update the core memory of a specific agent.
    This endpoint accepts new memory contents (labels as keys, and values as values) and updates the core memory of the agent identified by the user ID and agent ID.
This endpoint accepts new memory contents to update the core memory of the agent.
This endpoint only supports modifying existing blocks; it does not support deleting/unlinking or creating/linking blocks.

Update Agent Memory

Update the label of a block in an agent's memory.

Update Agent Memory Label

Creates a memory block and links it to the agent.

Add Agent Memory Block

Removes a memory block from an agent by unlnking it. If the block is not linked to any other agent, it is deleted.

Remove Agent Memory Block

Update the limit of a block in an agent's memory.

Update Agent Memory Limit

Retrieve the summary of the recall memory of a specific agent.

Get Agent Recall Memory Summary

Retrieve the summary of the archival memory of a specific agent.

Get Agent Archival Memory Summary

Retrieve the memories in an agent's archival memory store (paginated query).

Get Agent Archival Memory

Insert a memory into an agent's archival memory store.

Insert Agent Archival Memory

Delete a memory from an agent's archival memory store.

Delete Agent Archival Memory

Get Agent Messages

Process a user message and return the agent's response.
This endpoint accepts a message from a user and processes it through the agent.

tools

sources

agents

models

blocks

jobs

health

Send Message Streaming

Authorizations

Path Parameters

Body

Response