Claude Arithmetic MCP Server

A simple Model Context Protocol (MCP) project built with Python andFastMCP. The server exposes basic arithmetic operations as MCP tools andcan be used locally with Claude Desktop or deployed as a remote MCPserver.

Project Overview

This project demonstrates the basic MCP client-server architecture:

Claude Desktop
      |
      | MCP
      v
Arithmetic MCP Server
      |
      +-- add()
      +-- subtract()
      +-- multiply()
      +-- divide()

The server was tested using MCP Inspector and deployed remotely usingPrefect Horizon.

Features

Addition

Subtraction

Multiplication

Division

MCP tool registration using FastMCP

Local testing with MCP Inspector

Claude Desktop integration

Remote deployment through Prefect Horizon

Tech Stack

Python

MCP

FastMCP

MCP Inspector

Claude Desktop

Prefect Horizon

Git & GitHub

MCP Tools

Tool         Description

add        Adds two numberssubtract   Subtracts the second number from the firstmultiply   Multiplies two numbersdivide     Divides the first number by the second

The divide tool also handles division by zero.

Project Structure

MCP-Client-Server-Integration/
│
├── server.py
├── fastmcp.json
├── pyproject.toml
├── uv.lock
├── README.md
├── .gitignore
└── src/

Running Locally

Create and activate a virtual environment, then install the projectdependencies.

Run the MCP server:

fastmcp run server.py

The server uses the MCP stdio transport for local client connections.

Testing with MCP Inspector

The server can be inspected with FastMCP:

fastmcp inspect server.py

MCP Inspector can also be used to connect to the server and test theregistered tools.

Claude Desktop

The server can be connected to Claude Desktop as an MCP server.

Claude Desktop acts as the MCP client and can discover and invoke thearithmetic tools when required.

Example:

User: Calculate 25 × 8

Claude Desktop
      |
      v
multiply(a=25, b=8)
      |
      v
200

Remote Deployment

The MCP server was deployed using Prefect Horizon.

Remote MCP endpoint:

https://claude-arithmetic-mcp.fastmcp.app/mcp

The deployed server provides the same four arithmetic tools through aremote MCP endpoint.

What I Learned

Basic MCP architecture and client-server communication

How to create and register MCP tools with FastMCP

How MCP clients discover and call tools

Testing MCP servers with MCP Inspector

Connecting an MCP server with Claude Desktop

Deploying a remote MCP server