The MCP paywall, in Python

The Python equivalent of the Weather MCP server, built on FastMCP with the payments-py SDK — same tool, resource and prompt, same x402 v2 in-band transport.

mcp-examples/weather-mcp-py/

1 What you'll learn

Everything the TypeScript MCP tutorial teaches, on FastMCP and payments-py.

Protect a Python MCP server with Nevermined using FastMCP
Serve full OAuth 2.1 discovery (RFC 8414 / 9728) endpoints
Pay per use with credits via x402 tokens
Optionally enrich forecasts with OpenAI gpt-4o-mini

2 How it works

Same protocol surface as the TypeScript server — weather.today tool, weather://today resource, weather.ensureCity prompt — with the Bearer-authenticated session and in-band _meta payment. Requires payments-py[fastapi] ≥ 1.15.

Bearer sessionOAuth 2.1

call tool_meta x402/payment

check + deductcredits

resultweather

3 Under the hood

Python 3.10+FastMCPpayments-py[fastapi] ≥ 1.15PoetryOpenAI

# MCP surface

weather.today       # tool — current weather for any city
weather://today      # resource — static weather data
weather.ensureCity   # prompt — guide the LLM to request weather

src/	FastMCP server with Nevermined payments + OAuth discovery
README.md	installation and configuration

4 See it run

The MCP paywall, in Python

Sandbox agent — real payment round-trips (402 → authorize → settle) with a per-session credit balance, no external service and no real money. Same MCP flow on FastMCP (Python); the sandbox runs the exchange locally. See the README to connect a hosted weather-mcp-py server.