Connecting Letta to MCP Servers

Danger

Letta no longer supports legacy .json configuration files. Use the ADE or API/SDK.

Letta supports three MCP transport types depending on your deployment and use case.

Connection Methods

• ADE: Point-and-click server management via web interface
• API/SDK: Programmatic integration for production

Transport Types

• Streamable HTTP (Recommended): Production-ready with auth support. Works on Cloud + self-hosted.
• SSE (Legacy): Deprecated but supported for compatibility.
• stdio (Self-hosted only): Local development and testing.

Transport	Cloud	Self-hosted
Streamable HTTP	✅	✅
SSE	✅	✅
stdio	❌	✅

Tool Execution Flow

sequenceDiagram
    participant A as Letta Agent
    participant L as Letta Server
    participant S as MCP Server

    A->>L: Tool request
    L->>S: MCP execute
    S-->>L: Result
    L-->>A: Response

Quick Start

1. Choose transport type based on your deployment
2. Connect via ADE: Tool Manager → Add MCP Server
3. Attach tools to agents

See remote servers or local servers for detailed setup.