Calculator MCP Server

A Model Context Protocol (MCP) server that provides mathematical calculation tools for AI assistants.

Features

This MCP server provides three core mathematical operations:

• Add - Add two numbers together with calculation history tracking
• Multiply - Multiply two numbers with optimized performance
• Divide - Divide numbers with comprehensive zero-division protection

The server maintains a calculation history and provides robust error handling for all mathematical operations.

Prerequisites

• Node.js (version 14 or higher)
• npm or yarn package manager

Installation

1. Clone or download this repository

2. Navigate to the project directory:

   cd my-first-mcp-server
   

3. Install dependencies:

   npm install
   

4. Build the TypeScript code:

   npm run build
   

Running the Server

Development Mode

For development and testing:

npm run dev

Production Mode

For production use:

npm run start

Testing the Server

You can test if the server is working by sending an MCP request:

echo '{"jsonrpc": "2.0", "id": 1, "method": "tools/list"}' | node dist/server.js

This should return a JSON response listing the available tools.

Integration with AI Clients

Cursor IDE

1. Create a .cursor/mcp.json file in your project root:

   {
     "mcpServers": {
       "calculator": {
         "command": "node",
         "args": [
           "/absolute/path/to/my-first-mcp-server/dist/server.js"
         ],
         "env": {}
       }
     }
   }
   

2. Replace /absolute/path/to/my-first-mcp-server/ with the actual path to this directory

3. Restart Cursor IDE

4. The calculator tools will be available to the AI assistant

Claude Desktop

1. Create or edit ~/Library/Application Support/Claude/claude_desktop_config.json:

   {
     "mcpServers": {
       "calculator": {
         "command": "node",
         "args": ["/absolute/path/to/my-first-mcp-server/dist/server.js"]
       }
     }
   }
   

2. Replace the path with your actual directory path

3. Restart Claude Desktop

Development

To modify or extend the calculator functionality:

1. Edit the source files in the src/ directory
2. Rebuild the project: npm run build
3. Test your changes: npm run dev

Configuration

The server can be configured using environment variables. Copy .env.example to .env and modify as needed.

Available configuration options:

• NODE_ENV: Environment mode (development/production)
• PORT: Server port (default: 3000)
• LOG_LEVEL: Logging verbosity
• DB_*: Database connection settings

Docker Support

You can run the entire stack using Docker Compose:

docker-compose up -d

This will start:

• Calculator MCP Server
• PostgreSQL database (for calculation history)
• Redis cache
• Database administration interface

Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests for new functionality
5. Submit a pull request

License

This project is licensed under the ISC License.

Available Tools

add

Adds two numbers together.

Parameters:

• a (number): First number
• b (number): Second number

Example: add(25, 17) returns 42

multiply

Multiplies two numbers.

Parameters:

• a (number): First number
• b (number): Second number

Example: multiply(6, 7) returns 42

divide

Divides the first number by the second number.

Parameters:

• a (number): Dividend (number to divide)
• b (number): Divisor (divide by this)

Example: divide(84, 2) returns 42

Note: Division by zero will return an error.

Using in Other Projects

Option 1: Absolute Path Reference

In any project where you want to use this calculator:

1. Create .cursor/mcp.json in that project's root
2. Reference the absolute path to this server's dist/server.js
3. Restart your IDE

Option 2: Copy to Project

# Copy the entire MCP server to your project
cp -r /path/to/my-first-mcp-server /path/to/your-project/mcp-servers/calculator

# Update .cursor/mcp.json to use relative path:
{
  "mcpServers": {
    "calculator": {
      "command": "node",
      "args": ["./mcp-servers/calculator/dist/server.js"],
      "env": {}
    }
  }
}

Option 3: NPM Package (Advanced)

You can publish this as an npm package for easier distribution:

1. Update package.json with your package details
2. Run npm publish
3. In other projects: npm install your-calculator-mcp
4. Use npx your-calculator-mcp in MCP configuration

Development

Scripts

• npm run build - Compile TypeScript to JavaScript
• npm run dev - Run in development mode with tsx
• npm run start - Run the compiled server

File Structure

my-first-mcp-server/
├── src/
│   └── server.ts          # Main server implementation
├── dist/
│   └── server.js          # Compiled JavaScript (generated)
├── .cursor/
│   └── mcp.json          # Local MCP configuration
├── package.json          # Node.js dependencies and scripts
├── tsconfig.json         # TypeScript configuration
└── README.md            # This file

Troubleshooting

Server Not Connecting

1. Ensure the path in .cursor/mcp.json is correct and absolute
2. Verify the server builds successfully: npm run build
3. Test the server manually: echo '{"jsonrpc": "2.0", "id": 1, "method": "tools/list"}' | node dist/server.js
4. Restart your IDE after configuration changes

Tools Not Available

1. Check that .cursor/mcp.json is in the root of your working project
2. Ensure you're opening the correct project in your IDE
3. Wait a few seconds after opening for MCP to initialize
4. Check IDE developer console for MCP-related errors

Permission Issues

# Make sure the server file is executable
chmod +x dist/server.js

Server Details

• Protocol: Model Context Protocol (MCP)
• Transport: Standard I/O (stdio)
• Language: TypeScript/Node.js
• Framework: @modelcontextprotocol/sdk

License

ISC

Contributing

Feel free to extend this server with additional mathematical operations or features!