Calculator MCP Server

A simple Model Context Protocol (MCP) server that provides basic calculator functionality through MCP tools.

Features

This MCP server provides the following calculator tools:

add: Add two numbers together
subtract: Subtract second number from first number
multiply: Multiply two numbers together
divide: Divide first number by second number (with zero-division protection)
power: Raise first number to the power of second number
sqrt: Calculate square root of a number (with negative number protection)

Installation

Install dependencies:

npm install

Build the TypeScript code:

npm run build

Usage

Running the Server

Start the MCP server:

npm start

Or run in development mode:

npm run dev

MCP Client Configuration

To use this calculator MCP server with an MCP client (like Claude Desktop), add it to your MCP configuration:

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

Available Tools

add

Adds two numbers together.

Parameters: a (number), b (number)
Example: add(5, 3) returns 5 + 3 = 8

subtract

Subtracts the second number from the first.

Parameters: a (number), b (number)
Example: subtract(10, 4) returns 10 - 4 = 6

multiply

Multiplies two numbers together.

Parameters: a (number), b (number)
Example: multiply(6, 7) returns 6 × 7 = 42

divide

Divides the first number by the second.

Parameters: a (number), b (number)
Example: divide(15, 3) returns 15 ÷ 3 = 5
Error handling: Returns error for division by zero

power

Raises the base to the power of the exponent.

Parameters: base (number), exponent (number)
Example: power(2, 8) returns 2^8 = 256

sqrt

Calculates the square root of a number.

Parameters: number (number)
Example: sqrt(16) returns √16 = 4
Error handling: Returns error for negative numbers

Development

Project Structure

calculator-mcp/
├── src/
│   └── index.ts          # Main MCP server implementation
├── dist/                 # Compiled JavaScript output
├── package.json          # Dependencies and scripts
├── tsconfig.json         # TypeScript configuration
└── README.md            # This file

Building

npm run build

Development Mode

npm run dev

Error Handling

The calculator includes proper error handling for:

Division by zero
Square root of negative numbers
Invalid tool names
General execution errors

All errors are returned with appropriate error messages and the isError flag set to true.

License

MIT

calculator-mcp

Documentation