A2A Client MCP Server

An MCP server client for the Agent-to-Agent (A2A) protocol, enabling LLMs to interact with A2A agents.

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A2A Client MCP Server

An MCP server that acts as a client to the Agent-to-Agent (A2A) protocol, allowing LLMs to interact with A2A agents through the Model Context Protocol (MCP).

Features

  • Connect to any A2A-compatible agent
  • Send and receive messages
  • Track and manage tasks
  • Support for streaming responses
  • Query agent capabilities and metadata

Installation

Install globally

npm install -g a2a-client-mcp-server

Or run directly with npx

npx a2a-client-mcp-server

Configuration

Environment Variables

Usage with Claude Desktop

Add this to your claude_desktop_config.json:

NPX

npm run build npm link

{ "mcpServers": { "a2a-client": { "command": "npx", "args": ["-y", "a2a-client-mcp-server"], "env": { "A2A_ENDPOINT_URL": "http://localhost:41241" } } } }

Docker

Build the Docker image:

docker build -t a2a-client-mcp-server .

Configure Claude Desktop:

{ "mcpServers": { "a2a-client": { "command": "docker", "args": [ "run", "-i", "--rm", "-e", "A2A_ENDPOINT_URL", "a2a-client-mcp-server" ], "env": { "A2A_ENDPOINT_URL": "http://localhost:41241" } } } }

Available Tools

a2a_send_task

Send a task to an A2A agent

  • message (string): Message to send to the agent
  • taskId (string, optional): Task ID (generated if not provided)

a2a_get_task

Get the current state of a task

  • taskId (string): ID of the task to retrieve

a2a_cancel_task

Cancel a running task

  • taskId (string): ID of the task to cancel

a2a_send_task_subscribe

Send a task and subscribe to updates (streaming)

  • message (string): Message to send to the agent
  • taskId (string, optional): Task ID (generated if not provided)
  • maxUpdates (number, optional): Maximum updates to receive (default: 10)

a2a_agent_info

Get information about the connected A2A agent

  • No parameters required

Resources

The server provides access to two MCP resources:

  • a2a://agent-card: Information about the connected A2A agent
  • a2a://tasks: List of recent A2A tasks

Example Usage

This example shows how to use A2A Client MCP Server to interact with a Coder Agent:

First, let me explore what A2A agent we're connected to.

I'll use the a2a_agent_info tool to check the agent details.

The agent provides a coding service that can generate files based on natural language instructions. Let's create a simple Python script.

I'll use the a2a_send_task tool to send a request:

Task: "Create a Python function that calculates the Fibonacci sequence"

Now I can check the task status using a2a_get_task with the task ID from the previous response.

The agent has created the requested Python code. I can now retrieve and use this code in my project.

Development

Install dependencies

npm install

Build the project

npm run build

Run in development mode

npm run watch

License

MIT

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