MCP Server (FastMCP)

A minimal Model Context Protocol server using FastMCP, with one tool, one prompt, and one resource.

Requirements

• Python 3.10+

• pip

Related MCP server: MCP Weather Server

Setup

1. Create and activate a virtual environment

python3 -m venv .venv
source .venv/bin/activate   # Windows: .venv\Scripts\activate

2. Install dependencies

pip install -r requirements.txt

3. Run the server

MCP servers use stdio by default. Your MCP client launches the process. To verify it starts:

python server.py
# Blocks waiting for MCP messages. Press Ctrl+C to quit.

Connecting to Claude Desktop

Add to your Claude Desktop config:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json

• Windows: %APPDATA%\Claude\claude_desktop_config.json

{
  "mcpServers": {
    "example-server": {
      "command": "/absolute/path/to/MCP-Server/.venv/bin/python",
      "args": ["/absolute/path/to/MCP-Server/server.py"]
    }
  }
}

Use your actual paths and restart Claude Desktop.

Using with MCP Dashboard

The MCP Dashboard launches this server as a subprocess and talks to it over stdio, so tools, resources, and prompts all appear in the UI.

From the MCP-Dashboard directory (with Flask installed), run:

# Unbuffered (-u) so the dashboard receives list responses immediately
python app.py -- python -u path/to/MCP-Server/server.py

Windows:

python app.py -- python -u path\to\MCP-Server\server.py

Use a Python that has both flask and fastmcp installed (or use the full path to this repo's venv Python if you use one).

The dashboard will open at http://localhost:8080 and show the calculate tool, app://info resource, and explain prompt. You can try the tool, read the resource, and get the prompt from the browser.

Reference

Tool: calculate

• Input: { "expression": "sqrt(2) * pi" }

• Output: "4.442882938158366"

• Supports: +, -, *, /, **, %, //, and functions like abs, round, sqrt, ceil, floor, log, log10, sin, cos, tan; constants pi, e.

Prompt: explain

• Input: { "topic": "recursion" }

• Returns a user message asking the model to explain the topic in simple terms.

Resource: app://info

• Read-only. Returns JSON: {"name": "mcp-server", "capabilities": ["calculate", "prompts", "resources"]}.

Project structure

MCP-Server/
├── server.py
├── requirements.txt
└── README.md

To add more tools, prompts, or resources, use the @mcp.tool, @mcp.prompt, and @mcp.resource(...) decorators in server.py.