A2A + Roo Code: 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 Roo Code, 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 Roo Code, 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 Roo Code
• All A2A capabilities will be available for your workflows
• Access to 4 different tools

Prerequisites

Before starting, ensure you have:

• Roo Code installed and configured
• Compatible operating system (Windows, macOS, Linux)

Installation

Step 1: Install A2A

Configuration

Step 2: Configure Roo Code

1. Locate your configuration file:

   • Windows: %USERPROFILE%\.roo\mcp_settings.json
   • macOS: ~/.roo/mcp_settings.json
   • Linux: ~/.roo/mcp_settings.json

2. Add server configuration:

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

3. Restart Roo Code

Completely quit and restart Roo Code to load the new configuration.

Examples

Once configured, you can use A2A in Roo Code:

Register and Communicate with Agent

Set up communication with an A2A agent

Ask Roo Code: "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 Roo Code: "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 Roo Code: "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 Roo Code: "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. Start a new conversation in Roo Code
2. Ask Roo Code to list available tools
3. Try using A2A functionality

Test prompts:

• "Type @ and verify A2A appears in the tools list"
• "Ask: "Use A2A to help with my task""
• "Check Roo Code output panel for server connection status"

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

MCP Server Not Connecting

Symptoms: Server not appearing in tools list, Connection timeout, MCP tools unavailable

Cause: Incorrect configuration or server not starting

Solution:

• Verify mcp_settings.json syntax is correct
• Check that Node.js and npx are installed and in PATH
• View Roo Code output panel for error messages
• Test server command manually in terminal: npx -y {server_id}
• Ensure environment variables are properly set

Permission Denied Errors

Symptoms: Cannot execute commands, File access denied, Terminal commands blocked

Cause: Roo Code requires explicit permission for file and command operations

Solution:

• Review and approve permission requests when prompted
• Check VS Code workspace trust settings
• Enable necessary permissions in Roo Code settings
• Verify file and folder permissions on your system

API Key or Model Issues

Symptoms: Authentication failed, Model not responding, No AI completions

Cause: AI model API key not configured or invalid

Solution:

• Verify API key is correctly set in Roo Code settings
• Check API key has sufficient credits/quota
• Test with a different AI model provider
• Review Roo Code output panel for API error details

Custom Mode Not Working with MCP

Symptoms: MCP tools not available in custom mode, Mode cannot access server

Cause: Custom mode configuration does not include MCP tool permissions

Solution:

• Edit custom mode configuration to include MCP tools
• Add "Use MCP" to available tools in mode definition
• Ensure mode has appropriate permissions for external tools
• Test with default mode first to verify MCP server works

Extension Conflicts

Symptoms: Roo Code not responding, VS Code performance issues, Unexpected behavior

Cause: Conflicts with other AI coding extensions

Solution:

• Disable other AI coding extensions (Cline, Continue, etc.)
• Restart VS Code after disabling conflicting extensions
• Check VS Code extension logs for conflict errors
• Use only one AI coding assistant extension at a time

A2A not appearing in Roo Code

Symptoms: Server not listed, Tools not available

Cause: Configuration or installation issue

Solution:

• Verify configuration syntax
• Check A2A installation
• Restart Roo Code
• Check logs for error messages

Next Steps

Now that A2A is integrated with Roo Code:

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

Need Help?

• Search for A2A documentation
• Check the Roo Code MCP guide
• Join the MCP community discussions