Simple Calculator MCP Server

A beginner-friendly MCP (Model Context Protocol) server built with FastMCP.

This project demonstrates how to create, run, and deploy a simple MCP server with tools and resources using FastMCP.

Features

Tools

• add — Add two numbers together.

• random_number — Generate a random number within a specified range.

Resources

• info://server — Returns server metadata and available tools.

Related MCP server: Demo MCP Server

Tech Stack

• Python 3.14+

• FastMCP 3.4.0

Installation

Install dependencies:

uv sync

or

uv add fastmcp

Run Locally

Start the MCP server:

uv run python main.py

The server will run on:

http://localhost:8000

MCP Inspector

Test the server using the FastMCP Inspector:

uv run fastmcp dev inspector main.py

Example Tools

Add Numbers

Input:

{
  "a": 10,
  "b": 20
}

Output:

30

Random Number

Input:

{
  "min_value": 1,
  "max_value": 100
}

Output:

57

Resource Example

Resource URI:

info://server

Example Response:

{
  "name": "Simple Calculator Server",
  "version": "1.0.0",
  "description": "A basic MCP server with math tools",
  "tools": ["add", "random_number"],
  "author": "Neel Contractor"
}

Deploy to FastMCP Cloud

This project was created as a learning exercise for deploying MCP servers to FastMCP Cloud.

After configuring your FastMCP account, deploy the server using the FastMCP deployment workflow.

Project Structure

.
├── main.py
├── pyproject.toml
├── uv.lock
└── README.md