n8n-nodes-mcp-client

Please note, This package is not working yet, I will set the version to 1.0.0 when it is working. ( 90% chance I will forget to update this readme when I do )

This package provides an n8n node for interacting with Model Context Protocol (MCP) tools. It allows you to integrate MCP-compatible AI tools into your n8n workflows.

Installation

To install this package in your n8n instance:

npm install @coulee-tech/n8n-nodes-mcp-client

Features

• List available MCP tools
• Call specific MCP tools with custom arguments
• Full integration with n8n workflows
• Support for standard MCP protocol communication

MCP Protocol Requirements

Your MCP client must:

1. Accept JSON-RPC style messages via stdin
2. Output responses via stdout
3. Support the following methods:
   • tools/list: Lists available tools
   • tools/call: Calls a specific tool with arguments

Example MCP message format:

// Request
{
  "method": "tools/call",
  "params": {
    "name": "tool-name",
    "arguments": {
      // tool-specific arguments
    }
  }
}

// Response
{
  "result": {
    // tool-specific response
  }
}

Configuration

Credentials

To use the MCP Client node, you need to configure the following credentials:

1. Command: The command to execute for the MCP client (e.g., the path to your MCP-compatible tool)
2. Arguments: Command-line arguments for the MCP client (comma-separated)

Node Configuration

The node provides two operations:

1. List Tools

   • Lists all available MCP tools from your configured client
   • No additional parameters required

2. Call Tool

   • Calls a specific MCP tool with custom arguments
   • Required parameters:
     • Tool Name: The name of the tool to call
     • Tool Arguments: JSON object containing the arguments for the tool

Usage Example

Here's an example of how to use the MCP Client node in your workflow:

1. Add the MCP Client node to your workflow
2. Configure the credentials with your MCP client command and arguments
3. Choose an operation:
   • To list tools: Select "List Tools" operation
   • To call a tool: Select "Call Tool" operation and provide:

     {
       "toolName": "your-tool-name",
       "toolArguments": {
         "param1": "value1",
         "param2": "value2"
       }
     }

Error Handling

The node includes comprehensive error handling:

• Invalid command or arguments
• Tool execution failures
• MCP protocol communication errors
• JSON parsing errors

Development

To contribute to this package:

1. Clone the repository
2. Install dependencies:

   npm install

3. Build the package:

   npm run build

4. Run tests:

   npm test

License

This project is licensed under the MIT License - see the LICENSE file for details.

Support

For issues and feature requests, please use the GitHub issue tracker.