Advanced Calculator

Unlike the basic calculator (stdio, launched by the host), this server runs over streamable HTTP as a standalone service. You start it yourself; clients connect to its URL: http://127.0.0.1:8000/mcp.

Tools

add, subtract, multiply, divide, power, sqrt, nth_root, absolute, logarithm, log10, exp, factorial, modulo, gcd, lcm, sin, cos, tan.

Setup

cd ~/Documents/Claude/advanced-calculator
uv add "mcp[cli]"

Run the server (must stay running)

uv run main.py

This time it is NOT supposed to exit or "hang silently" — it prints Uvicorn startup and keeps listening on http://127.0.0.1:8000/mcp. Leave this terminal open. (Ctrl+C to stop.)

Test it in the Inspector

In a second terminal:

cd ~/Documents/Claude/advanced-calculator
uv run mcp dev main.py

…or point the Inspector at the running HTTP URL http://127.0.0.1:8000/mcp.

Connect to Claude Desktop (via mcp-remote bridge)

Claude Desktop cannot talk to an HTTP MCP server directly, so we bridge it with mcp-remote (needs Node/npx installed). Add this to claude_desktop_config.json:

"advanced-calculator": {
  "command": "npx",
  "args": ["-y", "mcp-remote", "http://127.0.0.1:8000/mcp"]
}

Keep uv run main.py running, then fully restart Claude Desktop.

Connect from the LangChain client (transport: http)

In a MultiServerMCPClient config, this is where transport: "http" lives:

"advanced-calculator": {
    "transport": "http",
    "url": "http://127.0.0.1:8000/mcp",
}

stdio vs http — the key difference

• stdio servers (calculator, expense-tracker): the host launches them with uv --directory ... run main.py; they exit when the host disconnects.
• http server (this one): YOU run it; it stays up listening on a port, and any client connects to its URL. transport="http" is a client/bridge concept; on the server side the run transport is "streamable-http".