# A2A MCP Bridge

> An MCP (Model Context Protocol) server that bridges AI agents to A2A (Agent-to-Agent) agents.

## What this service does

This is a publicly accessible MCP server running on Cloudflare Workers. It exposes two tools that let any MCP-compatible AI agent (Claude, ChatGPT, Cursor, etc.) connect to and communicate with any A2A-protocol agent:

1. **connect_to_a2a** — Send a message to any A2A agent by URL. Discovers the agent card from /.well-known/agent.json, sends the message via JSON-RPC 2.0 tasks/send, and returns the agent response.

2. **discover_a2a_agent** — Fetch an A2A agent capability card from its /.well-known/agent.json endpoint to inspect its name, skills, and endpoint URL.

## How to connect

### MCP endpoint
Connect any MCP client to:
```
https://a2a-mcp-bridge.bodyforagents.workers.dev/mcp
```

### A2A agent card
This service also publishes an A2A agent card at:
```
https://a2a-mcp-bridge.bodyforagents.workers.dev/.well-known/agent.json
```

### Example: connect from Claude Code
```
claude mcp add --transport http a2a-bridge https://a2a-mcp-bridge.bodyforagents.workers.dev/mcp
```

### Example: MCP initialize request
```
curl -X POST https://a2a-mcp-bridge.bodyforagents.workers.dev/mcp \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","id":1,"method":"initialize","params":{"protocolVersion":"2025-06-18","capabilities":{},"clientInfo":{"name":"test","version":"1.0"}}}'
```

### Example: call connect_to_a2a tool
```
curl -X POST https://a2a-mcp-bridge.bodyforagents.workers.dev/mcp \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","id":3,"method":"tools/call","params":{"name":"connect_to_a2a","arguments":{"agent_url":"https://example-agent.com","message":"Hello!"}}}'
```

## Protocols supported
- **MCP** (Model Context Protocol) — Streamable HTTP transport, JSON-RPC 2.0
- **A2A** (Agent-to-Agent) — JSON-RPC 2.0 tasks/send, agent card discovery

## Use cases
- Let any AI agent talk to any other A2A-compatible agent
- Bridge MCP-only clients to A2A-only agents
- Discover A2A agent capabilities before sending messages
- Multi-agent orchestration via a single MCP endpoint

## No authentication required
This MCP server is open and public. No API key or OAuth needed.