A2A + MCPHub (mcp.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 (mcp.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 (mcp.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 (mcp.nvim)
• All A2A capabilities will be available for your workflows
• Access to 4 different tools

Prerequisites

Before starting, ensure you have:

• MCPHub (mcp.nvim) installed and configured
• Compatible operating system (Neovim 0.9+, Windows, macOS, Linux)

Installation

Step 1: Install A2A

Configuration

Step 2: Configure MCPHub (mcp.nvim)

1. Open MCPHub (mcp.nvim) settings
2. Navigate to MCP server configuration
3. Add A2A server with appropriate settings
4. Save and restart if needed

Examples

Once configured, you can use A2A in MCPHub (mcp.nvim):

Register and Communicate with Agent

Set up communication with an A2A agent

Ask MCPHub (mcp.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 (mcp.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 (mcp.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 (mcp.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 (mcp.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

Plugin Not Loading or Command Not Found

Symptoms: :MCPHub command not recognized, Plugin not appearing in :PlugStatus, No errors but plugin inactive

Cause: Plugin not properly installed or configuration error

Solution:

• Verify plugin is added to plugin manager configuration
• Run plugin manager install command (:PackerInstall, :PlugInstall, or Lazy auto-install)
• Check for errors in :messages after sourcing config
• Ensure dependencies (plenary.nvim, nui.nvim) are installed
• Restart Neovim completely

MCP Server Won't Start

Symptoms: Server status shows "Error", Red indicator on server, Server immediately stops after starting

Cause: Invalid server configuration or missing dependencies

Solution:

• Verify npx is installed and in PATH: npx --version
• Check MCP server package exists: npx -y @modelcontextprotocol/server-filesystem --help
• Review server configuration in setup() - verify command and args
• Check server logs in MCPHub interface for detailed error messages
• Ensure required environment variables are set (e.g., GITHUB_TOKEN)
• Test server manually in terminal: npx -y @modelcontextprotocol/server-filesystem /path

UI Not Displaying Correctly

Symptoms: Blank window, Garbled text, Layout issues, Missing borders

Cause: Terminal or Neovim rendering issues

Solution:

• Verify Neovim version is 0.9 or higher: nvim --version
• Try different border style in ui.border config ("single", "double", "rounded")
• Check terminal supports Unicode and 256 colors
• Update nui.nvim dependency to latest version
• Test with different colorscheme to rule out theme conflicts

Integration with Avante/CodeCompanion Not Working

Symptoms: AI assistant not seeing MCP tools, Tool calls failing, Integration not recognized

Cause: Integration not enabled or incompatible versions

Solution:

• Verify integration is enabled in config: integrations.avante = true
• Ensure Avante.nvim/CodeCompanion.nvim is installed and loaded
• Check versions are compatible - update both plugins to latest
• Restart Neovim after enabling integration
• Check :checkhealth for integration-specific warnings

Marketplace Not Loading

Symptoms: :MCPHubMarketplace shows empty list, Network error in marketplace, Timeout loading servers

Cause: Network connectivity issues or marketplace service unavailable

Solution:

• Verify internet connectivity
• Check firewall allows HTTPS connections
• Try again later if marketplace service is temporarily down
• Review proxy settings if behind corporate firewall
• Check :messages for detailed network error messages

Project-Local Config Not Loading

Symptoms: .mcphub.json ignored, Project servers not appearing, Only global config loaded

Cause: Config file location or format issues

Solution:

• Verify .mcphub.json is in project root (same directory as .git)
• Check JSON syntax is valid using jsonlint or similar tool
• Ensure file name is exactly .mcphub.json (case-sensitive)
• Restart Neovim after creating/modifying project config
• Check file permissions are readable

A2A not appearing in MCPHub (mcp.nvim)

Symptoms: Server not listed, Tools not available

Cause: Configuration or installation issue

Solution:

• Verify configuration syntax
• Check A2A installation
• Restart MCPHub (mcp.nvim)
• Check logs for error messages

Next Steps

Now that A2A is integrated with MCPHub (mcp.nvim):

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

Need Help?

• Search for A2A documentation
• Check the MCPHub (mcp.nvim) MCP guide
• Join the MCP community discussions