Letta MCP Server

A Model Context Protocol (MCP) server that provides comprehensive tools for agent management, memory operations, and integration with the Letta system. This server implements the full MCP specification including tools, prompts, and resources, with enhanced descriptions, output schemas, and behavioral annotations.

View on npm | View on GitHub

Features

• 🤖 Agent Management - Create, modify, clone, and manage Letta agents
• 🧠 Memory Operations - Handle memory blocks and passages
• 🔧 Tool Integration - Attach and manage tools for agents with full MCP support
• 💬 Prompts - Interactive wizards and assistants for common workflows
• 📚 Resources - Access system information, documentation, and agent data
• 🌐 Multiple Transports - HTTP, SSE, and stdio support
• 🔗 MCP Server Integration - Integrate with other MCP servers
• 📊 Enhanced Metadata - Output schemas and behavioral annotations for all tools
• 📦 Docker Support - Easy deployment with Docker

Environment Configuration

Create a .env file with the following variables:

# Required
LETTA_BASE_URL=https://your-letta-instance.com/v1
LETTA_PASSWORD=your-secure-password

# Optional
PORT=3001
NODE_ENV=production

Installation

Install from npm

# Global installation (recommended for CLI usage)
npm install -g letta-mcp-server

# Or local installation
npm install letta-mcp-server

Use with Claude Desktop

After installing globally, add to your Claude Desktop configuration:

{
  "mcpServers": {
    "letta": {
      "command": "letta-mcp",
      "args": [],
      "env": {
        "LETTA_BASE_URL": "https://your-letta-instance.com/v1",
        "LETTA_PASSWORD": "your-secure-password"
      }
    }
  }
}

Quick Start with npm

# Install globally
npm install -g letta-mcp-server

# Set environment variables
export LETTA_BASE_URL=https://your-letta-instance.com/v1
export LETTA_PASSWORD=your-secure-password

# Run the server
letta-mcp              # stdio (for Claude Desktop)
letta-mcp --http       # HTTP transport
letta-mcp --sse        # SSE transport

Quick Setup

Option 1: Run from source

# Clone the repository
git clone https://github.com/oculairmedia/letta-MCP-server.git
cd letta-MCP-server

# Install dependencies
npm install

# Development
npm run dev         # Default (stdio) transport
npm run dev:sse     # SSE transport
npm run dev:http    # HTTP transport (recommended)

# Production
npm run start       # Default (stdio) transport
npm run start:sse   # SSE transport
npm run start:http  # HTTP transport (recommended)

Option 2: Run with Docker

Using the prebuilt image from GitHub Container Registry

Available tags:

• latest - Latest stable release
• 2.0.1, 2.0, 2 - Specific version tags
• master - Latest master branch build

# Pull the latest image
docker pull ghcr.io/oculairmedia/letta-mcp-server:latest

# Run with environment variables
docker run -d \
  -p 3001:3001 \
  -e LETTA_BASE_URL=https://your-letta-instance.com/v1 \
  -e LETTA_PASSWORD=your-secure-password \
  -e PORT=3001 \
  -e NODE_ENV=production \
  --name letta-mcp \
  ghcr.io/oculairmedia/letta-mcp-server:latest

# Or use a specific version
docker run -d \
  -p 3001:3001 \
  -e LETTA_BASE_URL=https://your-letta-instance.com/v1 \
  -e LETTA_PASSWORD=your-secure-password \
  --name letta-mcp \
  ghcr.io/oculairmedia/letta-mcp-server:2.0.1

Using Docker Compose

version: '3.8'
services:
  letta-mcp:
    image: ghcr.io/oculairmedia/letta-mcp-server:latest
    container_name: letta-mcp
    ports:
      - "3001:3001"
    environment:
      - LETTA_BASE_URL=https://your-letta-instance.com/v1
      - LETTA_PASSWORD=your-secure-password
      - PORT=3001
      - NODE_ENV=production
    restart: unless-stopped

Building from source

# Clone and build locally
git clone https://github.com/oculairmedia/letta-MCP-server.git
cd letta-MCP-server
docker build -t letta-mcp-server .
docker run -d -p 3001:3001 --env-file .env --name letta-mcp letta-mcp-server

Option 3: Run with stdio for local MCP

# Create startup script
chmod +x /opt/stacks/letta-MCP-server/start-mcp.sh

# Add to Claude
claude mcp add --transport stdio letta-tools "/opt/stacks/letta-MCP-server/start-mcp.sh"

Architecture

See the Architecture Documentation for detailed system diagrams and component relationships.

MCP Protocol Support

This server implements the full MCP specification with all three capabilities:

🔧 Tools

All tools include:

• Enhanced Descriptions: Detailed explanations with use cases and best practices
• Output Schemas: Structured response definitions for predictable outputs
• Behavioral Annotations: Hints about tool behavior (readOnly, costLevel, executionTime, etc.)

💬 Prompts

Interactive prompts for common workflows:

• letta_agent_wizard - Guided agent creation with memory and tool setup
• letta_memory_optimizer - Analyze and optimize agent memory usage
• letta_debug_assistant - Troubleshoot agent issues
• letta_tool_config - Discover, attach, create, or audit tools
• letta_migration - Export, import, upgrade, or clone agents

📚 Resources

Access system information and documentation:

• letta://system/status - System health and version info
• letta://system/models - Available LLM and embedding models
• letta://agents/list - Overview of all agents
• letta://tools/all/docs - Complete tool documentation with examples
• letta://docs/mcp-integration - Integration guide
• letta://docs/api-reference - API quick reference

Resource templates for dynamic content:

• letta://agents/{agent_id}/config - Agent configuration
• letta://agents/{agent_id}/memory/{block_id} - Memory block content
• letta://tools/{tool_name}/docs - Individual tool documentation

Available Tools

Agent Management

Tool	Description	Annotations
create_agent	Create a new Letta agent	💰 Medium cost, ⚡ Fast
list_agents	List all available agents	👁️ Read-only, 💰 Low cost
prompt_agent	Send a message to an agent	💰 High cost, ⏱️ Variable time, 🔒 Rate limited
retrieve_agent	Get agent details by ID	👁️ Read-only, ⚡ Fast
get_agent_summary	Get agent summary information	👁️ Read-only, ⚡ Fast
modify_agent	Update an existing agent	✏️ Modifies state, ⚡ Fast
delete_agent	Delete an agent	⚠️ Dangerous, 🗑️ Permanent
clone_agent	Clone an existing agent	💰 Medium cost, ⏱️ Medium time
bulk_delete_agents	Delete multiple agents	⚠️ Dangerous, 📦 Bulk operation
export_agent	Export agent configuration and memory	👁️ Read-only, ⚡ Fast, 📦 Full backup
import_agent	Import agent from backup	💰 High cost, ⏱️ Slow, ✏️ Creates state

Memory Management

Tool	Description	Annotations
list_memory_blocks	List all memory blocks	👁️ Read-only, ⚡ Fast
create_memory_block	Create a new memory block	✏️ Creates state, ⚡ Fast
read_memory_block	Read a memory block	👁️ Read-only, ⚡ Fast
update_memory_block	Update a memory block	✏️ Modifies state, ⚡ Fast
attach_memory_block	Attach memory to an agent	✏️ Links resources, ⚡ Fast

Passage Management

Tool	Description	Annotations
list_passages	Search archival memory	👁️ Read-only, ⚡ Fast
create_passage	Create archival memory	💰 Medium cost (embeddings), ⚡ Fast
modify_passage	Update archival memory	💰 Medium cost (re-embedding), ⚡ Fast
delete_passage	Delete archival memory	🗑️ Permanent, ⚡ Fast

Tool Management

Tool	Description	Annotations
list_agent_tools	List tools for an agent	👁️ Read-only, ⚡ Fast
attach_tool	Attach tools to an agent	✏️ Modifies capabilities, ⚡ Fast
upload_tool	Upload a custom tool	🔒 Security: Executes code, ⚡ Fast
bulk_attach_tool_to_agents	Attach tool to multiple agents	📦 Bulk operation, ⏱️ Slow

Model Management

Tool	Description	Annotations
list_llm_models	List available LLM models	👁️ Read-only, ⚡ Fast
list_embedding_models	List available embedding models	👁️ Read-only, ⚡ Fast

MCP Integration

Tool	Description	Annotations
list_mcp_servers	List configured MCP servers	👁️ Read-only, ⚡ Fast
list_mcp_tools_by_server	List tools from an MCP server	👁️ Read-only, ⚡ Fast
add_mcp_tool_to_letta	Import MCP tool to Letta	✏️ Creates tool, ⚡ Fast

Prompt Tools

Tool	Description	Annotations
list_prompts	List available prompt templates	👁️ Read-only, ⚡ Fast
use_prompt	Execute a prompt template	💰 Variable cost, ⏱️ Variable time

Directory Structure

• src/index.js - Main entry point
• src/core/ - Core server functionality
• src/handlers/ - Prompt and resource handlers
• src/examples/ - Example prompts and resources
• src/tools/ - Tool implementations organized by category:
  • agents/ - Agent management tools
  • memory/ - Memory block tools
  • passages/ - Passage management tools
  • tools/ - Tool attachment and management
  • mcp/ - MCP server integration tools
  • models/ - Model listing tools
  • enhanced-descriptions.js - Detailed tool descriptions
  • output-schemas.js - Structured output definitions
  • annotations.js - Behavioral hints
• src/transports/ - Server transport implementations

Transport Protocols

The server supports three transport protocols:

1. HTTP (Recommended) - Streamable HTTP transport with full duplex communication

   • Endpoint: http://your-server:3001/mcp
   • Best for production use and remote connections
   • Supports health checks at /health

2. SSE (Server-Sent Events) - Real-time event streaming

   • Endpoint: http://your-server:3001/sse
   • Good for unidirectional server-to-client updates

3. stdio - Standard input/output

   • Direct process communication
   • Best for local development and Claude integration

Configuration with MCP Settings

Add the server to your mcp_settings.json:

"letta": {
  "command": "node",
  "args": [
    "--no-warnings",
    "--experimental-modules",
    "path/to/letta-server/src/index.js"
  ],
  "env": {
    "LETTA_BASE_URL": "https://your-letta-instance.com",
    "LETTA_PASSWORD": "yourPassword"
  },
  "disabled": false,
  "alwaysAllow": [
    "upload_tool",
    "attach_tool",
    "list_agents",
    "list_memory_blocks"
  ],
  "timeout": 300
}

For remote instances with HTTP transport (recommended):

"remote_letta_tools": {
  "url": "http://your-server:3001/mcp",
  "transport": "http",
  "disabled": false,
  "alwaysAllow": [
    "attach_tool", 
    "list_agents",
    "list_tools",
    "get_agent"
  ],
  "timeout": 120
}

Docker Operations

# View container logs
docker logs -f letta-mcp

# Stop the container
docker stop letta-mcp

# Update to latest version
docker pull ghcr.io/oculairmedia/letta-mcp-server:latest
docker stop letta-mcp
docker rm letta-mcp
docker run -d -p 3001:3001 -e PORT=3001 -e NODE_ENV=production --name letta-mcp ghcr.io/oculairmedia/letta-mcp-server:latest

Troubleshooting

Common Issues

1. Connection refused errors

   • Ensure the server is running and accessible
   • Check firewall settings for port 3001
   • Verify the correct transport protocol is being used

2. Authentication failures

   • Verify LETTA_BASE_URL includes /v1 suffix
   • Check LETTA_PASSWORD is correct
   • Ensure environment variables are loaded
   • When self-hosting the Letta-Server, set environment variables accordingly:

     "env": {
        "LETTA_BASE_URL": "http://localhost:8283",
        "LETTA_PASSWORD": "",
        "LOG_LEVEL": "info"
      }

3. Tool execution timeouts

   • Increase timeout values in MCP configuration
   • Check network latency for remote connections
   • Consider using HTTP transport for better reliability

Health Check

The HTTP transport provides a health endpoint:

curl http://your-server:3001/health

Response:

{
  "status": "healthy",
  "transport": "streamable_http",
  "protocol_version": "2025-06-18",
  "sessions": 0,
  "uptime": 12345.678
}

Development

Testing

# Run tests
npm test

# Run tests with coverage
npm run test:coverage

# Run linter
npm run lint

Contributing

We welcome contributions! Please see our Contributing Guide for details on:

• Development setup
• Code style and standards
• Adding new tools
• Testing requirements
• Pull request process

Security

For security vulnerabilities, please see our Security Policy.

License

MIT License - see LICENSE file for details