A2A + mcphub.nvim: Complete MCP Integration

A2A is a MCP server that An MCP server that bridges the Model Context Protocol (MCP) with the Agent-to-Agent (A2A) protocol, enabling MCP-compatible AI assistants (like Claude) to seamlessly interact with A2A agents..

When integrated with mcphub.nvim, you can:

• Register and manage A2A agents for communication
• Send messages to A2A agents and handle responses
• Manage asynchronous tasks and retrieve results

This guide provides step-by-step instructions to set up A2A in mcphub.nvim, including configuration, examples, and troubleshooting.

What You'll Achieve

After completing this setup:

• A2A will be fully integrated and operational
• You can use A2A tools directly in mcphub.nvim
• All A2A capabilities will be available for your workflows
• Access to 4 different tools

Prerequisites

Before starting, ensure you have:

• mcphub.nvim installed and configured
• Compatible operating system (Neovim)

Installation

Step 1: Install A2A

Configuration

Step 2: Configure mcphub.nvim

1. Locate your configuration file:

   • Windows: %LOCALAPPDATA%\mcphub\servers.json
   • macOS: ~/.config/mcphub/servers.json
   • Linux: ~/.config/mcphub/servers.json

2. Add server configuration:

{
  "mcpServers": {
    "a2a": {
      "command": "a2a",
      "args": [],
      "env": {
        "MCP_TRANSPORT": "streamable-http",
        "MCP_HOST": "0.0.0.0",
        "MCP_PORT": "8080",
        "MCP_PATH": "/api/mcp",
        "MCP_DEBUG": "true"
      }
    }
  }
}

3. Restart mcphub.nvim

Completely quit and restart mcphub.nvim to load the new configuration.

Examples

Once configured, you can use A2A in mcphub.nvim:

Register and Communicate with Agent

Set up communication with an A2A agent

Ask mcphub.nvim: "Register an agent for data analysis tasks and send it a dataset processing request"

Expected Result: Agent registered, task submitted, and task_id returned for tracking

Stream Real-Time Data

Use streaming to get real-time updates from agent

Ask mcphub.nvim: "Stream live updates from the monitoring agent about system metrics"

Expected Result: Continuous stream of system metrics and status updates

Manage Multiple Agents

Coordinate tasks across multiple A2A agents

Ask mcphub.nvim: "List all available agents and distribute parallel processing tasks"

Expected Result: Agent list displayed, tasks distributed, and progress tracked

Handle Task Results

Retrieve and process completed task results

Ask mcphub.nvim: "Get the results from the data analysis task I submitted earlier"

Expected Result: Task results retrieved with processed data and analysis findings

Testing Your Setup

1. Launch mcphub.nvim
2. Verify A2A is available in the tools list
3. Test basic A2A functionality

Troubleshooting

Common Issues

Agent Registration Failed

Symptoms: Registration errors, Agent not found, Connection timeouts

Cause: Network connectivity issues or invalid agent configuration

Solution:

• Check internet connectivity to A2A network
• Verify agent endpoint URLs are correct
• Ensure agent is online and accepting connections
• Check firewall settings and port accessibility

Task Never Completes

Symptoms: Task stuck in pending state, No response from agent

Cause: Agent overload, network issues, or task complexity

Solution:

• Check agent status and availability
• Cancel and resubmit the task
• Break complex tasks into smaller parts
• Try different agent if available

Transport Protocol Errors

Symptoms: Connection refused, Protocol mismatch errors

Cause: Incorrect transport configuration or port conflicts

Solution:

• Verify MCP_TRANSPORT setting matches client expectations
• Check MCP_HOST and MCP_PORT are accessible
• Ensure no port conflicts with other services
• Try different transport mode (stdio, http, sse)

Message Streaming Issues

Symptoms: Broken streams, Incomplete messages, Timeout errors

Cause: Network instability or buffer overflow

Solution:

• Check network stability and bandwidth
• Reduce message frequency or size
• Enable debug logging to trace issues
• Use appropriate buffer sizes for streaming

Servers not showing in :McpHub

Symptoms: Empty server list, Configuration not loaded

Cause: Incorrect configuration file path or JSON syntax error

Solution:

• Verify servers.json exists in ~/.config/mcphub/ or .vscode/mcp.json in project root
• Check JSON syntax for errors (trailing commas, missing quotes)
• Run :checkhealth mcphub to diagnose issues

Tool execution fails

Symptoms: Error message when AI tries to use tool, No response

Cause: Server command failed or environment variables missing

Solution:

• Check server logs in :McpHub
• Verify "command" path is correct and executable
• Ensure required environment variables are set in the config

Chat plugin not recognizing tools

Symptoms: AI says it cannot perform the action, Tools not listed in chat

Cause: Integration issue with the specific chat plugin

Solution:

• Ensure you are using a supported version of the chat plugin
• Check mcphub.nvim documentation for plugin-specific setup instructions
• Restart Neovim to reload the integration

A2A not appearing in mcphub.nvim

Symptoms: Server not listed, Tools not available

Cause: Configuration or installation issue

Solution:

• Verify configuration syntax
• Check A2A installation
• Restart mcphub.nvim
• Check logs for error messages

Next Steps

Now that A2A is integrated with mcphub.nvim:

• Explore all A2A capabilities through mcphub.nvim
• Check out other MCP servers that work with mcphub.nvim
• Join the MCP community for tips and support
• Consider contributing to A2A development

Need Help?

• Search for A2A documentation
• Check the mcphub.nvim MCP guide
• Join the MCP community discussions