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

A2A_ENDPOINT_URL: URL of the A2A agent to connect to (default: "http://localhost:41241")

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

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

This server cannot be installed

security - not tested

license - not tested

quality - not tested

hybrid server

The server is able to function both locally and remotely, depending on the configuration or use case.

An MCP server that enables LLMs to interact with Agent-to-Agent (A2A) protocol compatible agents, allowing for sending messages, tracking tasks, and receiving streaming responses.

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