# Calculator MCP Server
[](https://www.python.org/downloads/)
[](https://modelcontextprotocol.io/)
[](https://opensource.org/licenses/MIT)
A simple calculator MCP (Model Context Protocol) server that exposes arithmetic operations as tools for AI assistants like Claude.
## What is MCP?
[Model Context Protocol (MCP)](https://modelcontextprotocol.io/) is an open protocol that enables AI assistants to interact with external tools and data sources. This server demonstrates how to build MCP tools using Python.
## Features
| Tool | Description | Example |
|------|-------------|---------|
| `add` | Add two numbers | `add(5, 3)` → `8` |
| `subtract` | Subtract numbers | `subtract(10, 4)` → `6` |
| `multiply` | Multiply numbers | `multiply(6, 7)` → `42` |
| `divide` | Divide with zero-check | `divide(15, 3)` → `5.0` |
| `power` | Exponentiation | `power(2, 3)` → `8.0` |
| `modulo` | Remainder operation | `modulo(17, 5)` → `2` |
| `square_root` | Square root | `square_root(16)` → `4.0` |
| `absolute` | Absolute value | `absolute(-5)` → `5` |
| `percentage` | Calculate percentage | `percentage(200, 15)` → `30.0` |
## Installation
### Prerequisites
- Python 3.10 or higher
- pip package manager
### Install from source
```bash
git clone https://github.com/Sathiya-Moorthi/MCP.git
cd calculator-mcp
pip install -e .
```
### Install dependencies only
```bash
pip install mcp
```
## Usage
### With Claude Desktop
Add to your Claude Desktop configuration file:
**Windows:** `%APPDATA%\Claude\claude_desktop_config.json`
**macOS:** `~/Library/Application Support/Claude/claude_desktop_config.json`
```json
{
"mcpServers": {
"calculator": {
"command": "python",
"args": ["/path/to/calculator-mcp/calculator_server.py"]
}
}
}
```
Restart Claude Desktop, then ask Claude to perform calculations!
### With Cursor IDE
Add to your Cursor MCP configuration (`~/.cursor/mcp.json`):
```json
{
"mcpServers": {
"calculator": {
"command": "python",
"args": ["/path/to/calculator-mcp/calculator_server.py"]
}
}
}
```
### Standalone Testing
```bash
python calculator_server.py
```
The server communicates via stdio (standard input/output) using the MCP protocol.
## Development
### Setup development environment
```bash
# Clone the repository
git clone https://github.com/Sathiya-Moorthi/MCP.git
cd calculator-mcp
# Create virtual environment
python -m venv venv
source venv/bin/activate # On Windows: venv\Scripts\activate
# Install dependencies
pip install -e ".[dev]"
```
### Run tests
```bash
pytest
```
### Project Structure
```
calculator-mcp/
├── calculator_server.py # Main MCP server implementation
├── pyproject.toml # Project configuration
├── tests/
│ └── test_calculator.py # Unit tests
├── .github/
│ └── workflows/
│ └── ci.yml # GitHub Actions CI
├── README.md
├── LICENSE
└── .gitignore
```
## How It Works
This server uses **FastMCP**, a high-level API from the official MCP Python SDK:
```python
from mcp.server.fastmcp import FastMCP
mcp = FastMCP(name="calculator")
@mcp.tool()
def add(a: float, b: float) -> float:
"""Add two numbers together."""
return a + b
if __name__ == "__main__":
mcp.run()
```
Key concepts:
- **`@mcp.tool()` decorator** - Registers functions as MCP tools
- **Type hints** - Define parameter types for validation
- **Docstrings** - Become tool descriptions visible to AI
- **`mcp.run()`** - Starts the server with stdio transport
## Contributing
Contributions are welcome! Please feel free to submit a Pull Request.
1. Fork the repository
2. Create your feature branch (`git checkout -b feature/amazing-feature`)
3. Commit your changes (`git commit -m 'Add amazing feature'`)
4. Push to the branch (`git push origin feature/amazing-feature`)
5. Open a Pull Request
## Acknowledgments
- [Anthropic](https://www.anthropic.com/) for the MCP protocol
- [MCP Python SDK](https://github.com/modelcontextprotocol/python-sdk)
