mcp-a2a-bridge

# MCP-A2A Bridge > A lightweight Model Context Protocol (MCP) **server** that proxies requests to one or more remote **A2A** agents. > > It lets tools that natively speak MCP – such as Claude, Cursor AI, or any other MCP-aware client – interact with agents that expose the [A2A protocol](https://github.com/modelcontextprotocol/a2a). > In short: **MCP on the front-end, A2A on the back-end.** --- ## Why would I want this? * **Use your existing AI client as an A2A Client** Use Claude Desktop, Cursor, etc. as a client that can connect to and use A2A servers --- ### MCP config in Claude / Cursor To integrate with an MCP client that supports local servers (like Claude Desktop or Cursor), configure it to run the bridge using `npx`. **Example `claude_desktop_config.json`:** ```jsonc { "mcpServers": { "MCP-A2A Bridge": { "command": "npx", "args": [ "-y", "@agentopolis/mcp-a2a-bridge@latest", "--a2a-server-config-dir=/Users/ryan/.config/mcp-a2a-bridge/servers" // Replace with your desired absolute path ] } } } ``` **Important:** * Replace `/Users/ryan/.config/mcp-a2a-bridge/servers` with the actual **absolute path** you want to use on your system. Restart or refresh your application after adding this configuration. The bridge should appear as a new tool provider. --- ## Usage **Example:** Send these prompts to your AI client: 1. Add an A2A server using its url ``` add this a2a server: https://a2a-demos.agentopolis.ai/bella-restaurant ``` 2. Ask what skills the A2A server has: ``` what skills does Bella have? ``` 3. Use the skills ``` What kind of specials are they running? ``` and ``` Make a reservation for two for thursday at 8pm, under the name Ryan ``` ## Screenshots using Claude Desktop 1. Adding an A2A server  2. Checking the MCP Tools  4. Asking about specials  5. Making a reservation  6. Listing servers  ## Configuration Directory The bridge stores A2A server registrations as JSON files. The location is determined as follows: 1. `--a2a-server-config-dir=/your/absolute/path` (CLI flag - **Recommended**) 2. `./.mcp-a2a-servers` (Relative to the current working directory of the bridge process – default if the CLI flag is not set. This may be unpredictable when run by other tools.) A typical entry lives at `<config_dir>/<serverId>.json`. --- ## Available MCP tools | Tool name | Purpose | Input schema | |-----------|---------|-------------| | `a2a_register_server` | Fetches an A2A agent's card from `<url>/.well-known/agent.json` and saves it. | `{ url: string }` | | `a2a_reload_servers` | Re-reads all JSON files in the config directory. | _none_ | | `a2a_list_servers` | Lists registered servers. | _none_ | | `a2a_get_server_details` | Full card for a given server. | `{ serverId: string }` | | `a2a_remove_server` | Delete a registration. | `{ serverId: string }` | | `a2a_send_task` | Generic escape hatch – call any A2A agent with an arbitrary message. | `{ serverId: string; taskId: string; message?: string | Message }` | | _`<serverId>_<skillId>`_ | **Auto-generated**. One tool per skill on every registered agent. Accepts `{ message: string }`. | — | > A `<serverId>_<skillId>` tool name is slugified (`my-agent` + `provide-restaurant-info` → `my-agent_provide-restaurant-info`). --- Released under the MIT license.