Sanctum Letta MCP (SSE Edition)

Version: 2.2.0

A powerful, modular orchestration server designed to securely expose and manage command-line tools and automation scripts within your internal infrastructure. Built for the Letta Agentic AI framework, MCP operates as a Server-Sent Events (SSE) server using aiohttp for real-time communication and is now fully compliant with the Model Context Protocol (MCP).

🚀 Letta/MCP Compliance

• MCP-Compliant SSE/JSON-RPC: Implements the Model Context Protocol event and message contract for seamless Letta integration.
• Dynamic Plugin Discovery: Auto-discovers all plugins in mcp/plugins/ at startup. No static registration—just drop in a new plugin with a cli.py and it will be available after a server restart.
• Immediate Tools Manifest: On SSE connect, emits a JSON-RPC 2.0 tools manifest event as required by Letta and MCP.
• JSON-RPC 2.0 Everywhere: All requests and responses (including errors) use the JSON-RPC 2.0 format.
• Production-Ready Testing: Comprehensive test suite with unit, integration, and end-to-end tests.

✨ Key Features

• SSE Server: Real-time communication via Server-Sent Events over HTTP using aiohttp
• Dynamic Plugin Architecture: Plugins are auto-discovered at startup; no code changes needed to add new tools
• Comprehensive Testing: Full test suite with coverage reporting and timeout protection
• Single Worker Thread: Serializes all plugin execution for safety
• Comprehensive Audit Logging: All requests and results are logged (no sensitive data)
• Docker-Ready: Designed for container deployment with Letta
• Sanctum Stack Compatible: Uses aiohttp, pydantic, and other Sanctum-standard libraries

🧪 Testing

The project includes a comprehensive testing infrastructure:

bash
Run all tests
python run_tests.py --type all
Run specific test types
python run_tests.py --type unit      # Unit tests
python run_tests.py --type integration  # Integration tests  
python run_tests.py --type e2e       # End-to-end tests
Run with coverage
python run_tests.py --type all --coverage
Run individual test files
python -m pytest tests/unit/
python -m pytest tests/integration/
python -m pytest tests/e2e/

Test Coverage:

• Unit Tests: Plugin discovery, tool manifest building, execution logic
• Integration Tests: HTTP endpoints, SSE connections, JSON-RPC handling
• E2E Tests: Complete workflows with multiple plugins and concurrent operations

🚀 Quick Start

1. Clone the repository and install dependencies:

bash
   git clone https://github.com/actuallyrizzn/sanctum-letta-mcp.git
   cd sanctum-letta-mcp
   python -m venv venv
   source venv/bin/activate  # On Windows: venv\Scripts\activate
   pip install -r requirements.txt
   

2. Run the MCP SSE server:

bash
   python -m mcp.mcp_server
   

or (if running as a service):

bash
   python mcp/mcp_server.py
   

3. Run tests to verify everything works:

bash
   python run_tests.py --type all
   

📡 Example SSE Communication

HTTP Request:

http
POST /message HTTP/1.1
Content-Type: application/json
{
  "jsonrpc": "2.0",
  "id": "req-1",
  "method": "tools/call",
  "params": {
    "name": "botfather.click-button",
    "arguments": {"button-text": "Payments", "msg-id": 12345678}
  }
}

SSE Response Stream (on connect):

data: {"jsonrpc":"2.0","method":"notifications/tools/list","params":{"tools":[...]}}

Tool Call Response:

json
{
  "jsonrpc": "2.0",
  "id": "req-1",
  "result": {
    "content": [
      {"type": "text", "text": "Clicked button Payments on message 12345678"}
    ]
  }
}

🔌 API Endpoints

• GET /sse - SSE connection for real-time events (emits tools manifest on connect)
• POST /message - Tool invocation endpoint (JSON-RPC 2.0)
• GET /health - Health check with plugin and session counts

📚 Documentation

• Getting Started - Installation and basic usage (SSE)
• API Reference - SSE message protocol
• Plugin Development - Guide for creating plugins
• Testing Guide - Comprehensive testing documentation
• Security Guide - Security best practices
• Monitoring Guide - Logging and observability

🏗️ Project Structure

letta-internal-mcp/
├── mcp/                    # Main package
│   ├── mcp_server.py      # aiohttp SSE server entrypoint
│   ├── plugins/           # Plugin implementations (auto-discovered)
│   │   ├── botfather/     # BotFather automation plugin
│   │   └── devops/        # DevOps automation plugin
│   └── __init__.py        # Package metadata
├── tests/                 # Comprehensive test suite
│   ├── unit/             # Unit tests for core functions
│   ├── integration/      # HTTP/SSE integration tests
│   ├── e2e/              # End-to-end workflow tests
│   └── conftest.py       # Test fixtures and configuration
├── docs/                 # Documentation
├── run_tests.py          # Test runner with coverage
├── requirements.txt      # Dependencies
└── pytest.ini           # Pytest configuration

🔧 Configuration

Environment Variables:

• MCP_PORT - Server port (default: 8000)
• MCP_HOST - Server host (default: 0.0.0.0)
• MCP_PLUGINS_DIR - Custom plugins directory (default: mcp/plugins/)

📦 Dependencies

Core:

• aiohttp==3.9.1 - Async HTTP server
• aiohttp-cors==0.7.0 - CORS support
• pydantic==2.6.1 - Data validation

Testing:

• pytest==7.4.3 - Testing framework
• pytest-asyncio==0.21.1 - Async test support
• pytest-cov==4.1.0 - Coverage reporting
• pytest-mock==3.12.0 - Mocking utilities
• pytest-timeout==2.1.0 - Test timeout protection

📄 License

This project is licensed under the Creative Commons Attribution-ShareAlike (CC BY-SA) license. See LICENSE for details.

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Note:

• The legacy STDIO protocol and references have been archived. This implementation is HTTP/SSE-only and fully MCP/Letta compatible.
• Version 2.2.0 includes comprehensive testing infrastructure and improved plugin discovery.
• For advanced plugin schema extraction or hot-reload, see future roadmap.