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

Prerequisites

Before starting, ensure you have:

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

Installation

Step 1: Install A2A

Configuration

Step 2: Configure OpenCode

1. Locate your configuration file:

2. Add server configuration:

Configure MCP servers in your `opencode.json` or `opencode.jsonc`:

```json
{
  "mcp": {
    "my-mcp": {
      "type": "local",
      "command": ["npx", "-y", "@modelcontextprotocol/server-everything"],
      "environment": {
        "API_KEY": "$API_KEY"
      },
      "timeout": 5000
    },
    "remote-server": {
      "type": "remote",
      "url": "https://mcp.example.com/sse",
      "headers": {
        "Authorization": "Bearer $API_TOKEN"
      }
    }
  }
}

Disable a server temporarily:

{
  "mcp": {
    "my-mcp": {
      "type": "local",
      "command": ["npx", "-y", "mcp-server"],
      "enabled": false
    }
  }
}

3. **Restart OpenCode**

Completely quit and restart OpenCode to load the new configuration.



## Examples

Once configured, you can use A2A in OpenCode:

### Register and Communicate with Agent

Set up communication with an A2A agent

**Ask OpenCode:** "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 OpenCode:** "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 OpenCode:** "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 OpenCode:** "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. Run opencode in terminal
2. Add "use the mcp_name tool" to your prompts
3. Verify tool execution and response



## 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 Loading

**Symptoms:** Server not appearing in tools, Timeout errors, Command not found

**Cause:** Invalid configuration, missing dependencies, or timeout too short

**Solution:**
- Verify command array is correct in opencode.json
- Check environment variables are set properly
- Increase timeout value if server takes longer to start
- Test MCP server command independently in terminal

#### Context Limit Exceeded

**Symptoms:** Context too large errors, Slow responses, Truncated output

**Cause:** Too many MCP servers adding to context

**Solution:**
- Disable unused MCP servers with enabled: false
- Use per-agent tool configuration to limit active MCPs
- Avoid MCP servers that add many tokens (e.g., GitHub MCP)

#### Remote Server Connection Failed

**Symptoms:** Cannot connect to remote MCP, Authentication errors

**Cause:** Invalid URL, missing headers, or network issues

**Solution:**
- Verify remote server URL is correct
- Check authorization headers are properly configured
- Ensure environment variables for tokens are set

#### A2A not appearing in OpenCode

**Symptoms:** Server not listed, Tools not available

**Cause:** Configuration or installation issue

**Solution:**
- Verify configuration syntax
- Check A2A installation
- Restart OpenCode
- Check logs for error messages



## Next Steps

Now that A2A is integrated with OpenCode:

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

## Need Help?

- Search for [A2A documentation](https://www.mcpstack.org)
- Check the [OpenCode MCP guide](https://www.mcpstack.org/clients)
- Join the MCP community discussions