Simple Calculator MCP Server

A simple Model Context Protocol (MCP) server built with FastMCP that demonstrates how to create MCP Tools and Resources. This project exposes basic arithmetic operations, random number generation, and server metadata over the HTTP transport.

Features

• ➕ Add two integers

• 🎲 Generate a random number within a specified range

• 📄 Expose server information as an MCP Resource

• 🌐 HTTP transport support

Related MCP server: API MCP Server

Project Structure

SimpleCalculatorMCPServer/
│
├── main.py
├── pyproject.toml
├── README.md
└── .venv/

Requirements

• Python 3.10+

• uv

• FastMCP

Installation

1. Clone the repository

git clone <repository-url>
cd SimpleCalculatorMCPServer

2. Create a virtual environment

uv venv

3. Activate the environment

Linux/macOS

source .venv/bin/activate

Windows

.venv\Scripts\activate

4. Install FastMCP

uv add fastmcp

Running the Server

Start the MCP server:

python main.py

or

uv run python main.py

The server will start on:

http://localhost:8000

Available Tools

1. add

Adds two integers.

Parameters

Example

Input

{
  "a": 15,
  "b": 25
}

Output

40

2. random_number

Generates a random integer within a given range.

Parameters

Example

Input

{
  "min_val": 10,
  "max_val": 50
}

Output

27

Available Resource

info://server

Returns metadata about the MCP server.

Example Response

{
  "name": "Simple Calculator Server",
  "Version": "1.0.0",
  "Description": "A basic MCP server with math tools and random number generation.",
  "tools": [
    "add",
    "random_number"
  ],
  "authors": "BinishaChapagain"
}

Transport

The server runs using the HTTP transport.

Configuration:

mcp.run(
    transport="http",
    host="0.0.0.0",
    port=8000
)

Testing

You can test the server using:

• FastMCP Inspector

• OpenCode

• Any MCP-compatible client

Available endpoints:

• Tool: add

• Tool: random_number

• Resource: info://server

Technologies Used

• Python

• FastMCP

• Model Context Protocol (MCP)

Learning Objectives

This project demonstrates how to:

• Create an MCP server using FastMCP.

• Register MCP tools.

• Register MCP resources.

• Expose an MCP server over HTTP.

• Interact with the server using an MCP client.