Simple MCP Server

A simple Model Context Protocol (MCP) server example that demonstrates basic MCP functionality.

What it does

This MCP server provides three basic tools:

1. echo - Echoes back a message you provide

2. calculator - Performs basic mathematical operations (add, subtract, multiply, divide)

3. current_time - Returns the current date and time

Related MCP server: Echo MCP Server

Prerequisites

• Node.js 16 or higher

• npm

Installation

1. Clone this repository

2. Install dependencies:

   npm install

Building

Build the TypeScript code:

npm run build

Running the Server

Start the server in development mode:

npm run dev

Or run the built version:

npm start

Testing with Claude Desktop

To test this MCP server with Claude Desktop, add the following configuration to your claude_desktop_config.json:

Windows

Location: %APPDATA%\Claude\claude_desktop_config.json

macOS/Linux

Location: ~/Library/Application Support/Claude/claude_desktop_config.json

Configuration:

{
  "mcpServers": {
    "simple-mcp-server": {
      "command": "node",
      "args": ["/absolute/path/to/your/project/build/index.js"]
    }
  }
}

Replace /absolute/path/to/your/project/ with the actual path to your project directory.

Project Structure

├── src/
│   └── index.ts          # Main server implementation
├── build/                # Compiled JavaScript (generated)
├── .github/
│   └── copilot-instructions.md  # Copilot instructions
├── .vscode/
│   └── mcp.json          # VS Code MCP configuration
├── package.json          # Project configuration
├── tsconfig.json         # TypeScript configuration
└── README.md            # This file

Tools Available

echo

• Description: Echo back the provided message

• Parameters:

  • message (string): The message to echo back

calculator

• Description: Perform basic mathematical operations

• Parameters:

  • operation (enum): One of 'add', 'subtract', 'multiply', 'divide'

  • a (number): The first number

  • b (number): The second number

current_time

• Description: Get the current date and time

• Parameters: None

Example Usage

Once connected to an MCP client like Claude Desktop, you can use commands like:

• "Echo back the message 'Hello World'"

• "Calculate 15 plus 25"

• "What's the current time?"

Development

This project is set up with:

• TypeScript for type safety

• Zod for runtime type validation

• MCP SDK for protocol compliance

• ES modules support