MCP Toolkit Gleam

Production-ready Model Context Protocol (MCP) Toolkit implementation in Gleam with comprehensive transport support, bidirectional communication, and enterprise-grade features.

🎯 Features

Multi-Transport Support

• stdio: Standard input/output transport
• WebSocket: Real-time bidirectional communication on ws://localhost:8080/mcp
• Server-Sent Events (SSE): Server-to-client streaming on http://localhost:8081/mcp
• Transport Bridging: Connect any two transports with filtering and transformation

Production-Ready Architecture

• Latest MCP Specification: Implements MCP 2025-06-18 with backward compatibility
• Comprehensive Testing: Full test coverage with birdie snapshots and gleunit
• Type Safety: Strong typing throughout with comprehensive error handling
• Modular Design: Clean separation between core protocol and transport layers
• Production-Ready: Comprehensive error handling and logging throughout

Enterprise Features

• Bidirectional communication with server-initiated requests
• Resource/tool/prompt change notifications
• Request/response correlation with unique IDs
• Client capability tracking and message routing
• Comprehensive logging and error reporting

🚀 Quick Start

Prerequisites

• Erlang/OTP 28+: For optimal performance and compatibility
• Gleam 1.11.1+: Latest Gleam compiler with modern language features
• Git: For version control and dependency management

Installation

gleam deps download
gleam build

Usage Examples

# Lightweight stdio transport (dependency-free)
gleam run -m mcp_stdio_server

# Full server with WebSocket support
gleam run -m mcp_full_server websocket

# Full server with Server-Sent Events
gleam run -m mcp_full_server sse

# Transport bridging between different protocols
gleam run -m mcp_full_server bridge

# Comprehensive server with all transports
gleam run -m mcp_full_server full

📁 Project Structure

src/
├── mcp_stdio_server.gleam        # Lightweight stdio executable
├── mcp_full_server.gleam         # Comprehensive server executable  
└── mcp_toolkit_gleam/
    ├── core/                   # Core protocol implementation
    │   ├── protocol.gleam      # MCP protocol types and functions
    │   ├── server.gleam        # Server implementation
    │   ├── method.gleam        # MCP method constants
    │   └── json_schema*.gleam  # JSON schema handling
    ├── transport/              # Core transports
    │   └── stdio.gleam         # Standard I/O transport
    └── transport_optional/     # HTTP/WebSocket transports
        ├── websocket.gleam     # WebSocket transport
        ├── sse.gleam          # Server-Sent Events transport
        ├── bidirectional.gleam # Bidirectional communication
        └── bridge.gleam        # Transport bridging

test/
├── mcp_toolkit_gleam/
│   ├── core/                   # Core functionality tests