This repository contains early attempts to implement Model Context Protocol (MCP) over WebTransport, leveraging the power of HTTP/3 and QUIC for ultra-low latency, bidirectional communication between AI systems and tools/resources.
MCP (Model Context Protocol) is an open protocol that enables AI systems to securely interact with local and remote resources through a standardized interface. It provides:
- Tools - Functions that AI can call with parameters
- Resources - Data sources the AI can read
- Prompts - Templates for generating contextual prompts
- Subscriptions - Real-time updates to resources
WebTransport provides:
- Low latency - Built on QUIC/HTTP3 for minimal round-trip times
- Bidirectional streams - Native support for full-duplex communication
- Multiplexing - Multiple concurrent streams over a single connection
- Reliability - Automatic retransmission with optional unreliable delivery
By combining MCP with WebTransport, we achieve:
- Ultra-low latency - Direct QUIC communication without HTTP/WebSocket overhead
- True bidirectional messaging - Server can push updates without polling
- Better performance - Reduced protocol overhead and connection setup time
- Native browser support - WebTransport API available in modern browsers
┌─────────────────────────────┐
│ MCP Application Layer │ ← Tools, Resources, Prompts
├─────────────────────────────┤
│ JSON-RPC 2.0 Messages │ ← Standard RPC protocol
├─────────────────────────────┤
│ Frame Protocol Layer │ ← Length-prefixed frames
├─────────────────────────────┤
│ WebTransport Bidi Stream │ ← Bidirectional data flow
├─────────────────────────────┤
│ QUIC (HTTP/3) │ ← Modern transport layer
└─────────────────────────────┘
All messages are sent as length-prefixed frames:
[4 bytes: Big-Endian u32 length][JSON payload]
This simple framing allows efficient parsing and message boundaries without the complexity of HTTP headers or WebSocket frames.
- Full MCP protocol implementation with all core features
- Server and client with CLI interface
- Example tools, resources, and prompts
- TLS 1.3 via QUIC
- Async/await with Tokio
- JWT authentication support
- Details →
# Server
cd rust/server && cargo run --release
# Client
cd rust/client && cargo run --release -- tools- Complete MCP protocol implementation
- WebTransport via aioquic
- Tools, resources, and prompts support
- JWT authentication
- Frame protocol with TCP fallback
cd python && python mcp_server.py
# Or for client:
python mcp_client.py- WebTransport server using quic-go
- JSON-RPC message handling
- MCP initialization and tools support
- JWT authentication
- OpenAI integration example
cd go/server && go run main.go- Browser-based WebTransport client
- Bun server for development
- Basic frame protocol implementation
- Simple ping/pong messaging
cd js/server && bun index.ts
# Open browser to http://localhost:3000- Chrome IWA with Direct Sockets API
- QUIC support via quinn-wasm
- WebSocket server functionality
- HTTP server with chunked transfer
- Details →
cd server/iwa && node index.js
# Creates signed.swbn for Chrome installation
# Install via chrome://web-app-internals- Gradle multi-module structure
- Common protocol definitions
- JWT authentication utilities
- Foundation for Android support
- Directory structure only
- Planned for iOS/macOS support
| Feature | Rust | Python | Go | JS | Kotlin | Swift |
|---|---|---|---|---|---|---|
| WebTransport | ✅ | ✅ | ✅ | 🚧 | ❌ | ❌ |
| Frame Protocol | ✅ | ✅ | ✅ | ✅ | 🚧 | ❌ |
| JSON-RPC 2.0 | ✅ | ✅ | ✅ | 🚧 | 🚧 | ❌ |
| TLS/QUIC | ✅ | ✅ | ✅ | ✅ | ❌ | ❌ |
| JWT Auth | ✅ | ✅ | ✅ | ❌ | 🚧 | ❌ |
| Feature | Rust | Python | Go | JS | Kotlin | Swift |
|---|---|---|---|---|---|---|
| Initialize | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ |
| Tools | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ |
| Resources | ✅ | ✅ | 🚧 | ❌ | ❌ | ❌ |
| Prompts | ✅ | ✅ | 🚧 | ❌ | ❌ | ❌ |
| Subscriptions | 🚧 | 🚧 | ❌ | ❌ | ❌ | ❌ |
| Progress | 🚧 | 🚧 | ❌ | ❌ | ❌ | ❌ |
| Cancellation | 🚧 | ❌ | ❌ | ❌ | ❌ | ❌ |
✅ Implemented | 🚧 Partial/In Progress | ❌ Not Implemented
- Resource subscriptions - Full real-time update support across all implementations
- Progress reporting - Complete implementation for long-running operations
- Request cancellation - Full cancellation support in all languages
- OAuth2 authentication - Beyond JWT in most implementations
- JavaScript/TypeScript: MCP protocol implementation (currently just WebTransport demo)
- Go: Complete resources and prompts implementations
- Kotlin: WebTransport integration and MCP protocol implementation
- Swift: Any implementation beyond directory structure
- Stream multiplexing for parallel operations
- Binary encoding (Protocol Buffers/MessagePack)
- Server push notifications
- WebAssembly client for universal browser support
- Federation for multi-server routing
- Rust: rustc 1.70+ and cargo
- Node.js: Bun runtime for JavaScript
- Go: Go 1.21+ with modules
- Python: Python 3.9+ with aioquic
- Clone the repository
git clone https://github.com/yourusername/wt-mcp
cd wt-mcp- Start the Rust server (most complete)
cd rust/server
cargo run --release- Test with the Rust client
cd rust/client
cargo run --release -- tools
cargo run --release -- call echo --args '{"message": "Hello MCP!"}'- Try the browser client
cd js/server
bun index.ts
# Open http://localhost:3000WebTransport provides significant performance improvements over traditional approaches:
| Metric | WebSocket | HTTP/2 | WebTransport |
|---|---|---|---|
| Connection Setup | ~150ms | ~100ms | ~50ms |
| Round-trip Latency | ~20ms | ~15ms | ~5ms |
| Throughput | Good | Good | Excellent |
| Head-of-line Blocking | Yes | Per-stream | No |
| Multiplexing | No | Yes | Yes |
Current implementations use self-signed certificates for development. For production:
- Use proper TLS certificates from a trusted CA
- Implement authentication (tokens, mTLS, etc.)
- Add rate limiting and input validation
- Enable certificate verification in clients
This is an experimental project exploring the possibilities of MCP over WebTransport. Contributions are welcome!
Areas needing help:
- Completing MCP implementation in JavaScript/TypeScript
- Adding missing features (subscriptions, progress, cancellation)
- Implementing Kotlin and Swift clients
- Performance benchmarking and optimization
- Documentation and examples
MIT License - See individual implementation directories for specific licensing.
MCP-over-WebTransport represents the future of AI-to-system communication, providing a standardized, high-performance protocol for AI agents to interact with tools and resources. This project serves as a reference implementation and testbed for this exciting new paradigm.
Note: This is an experimental implementation. The MCP specification and WebTransport API are evolving. Use in production at your own risk.