Small live x402 fixture for docs/tests?

[Bortlesboat]

Hi Apify team -- I maintain Satoshi API, a small Bitcoin fee-intelligence API with x402 enabled on Base.

I noticed mcpc has solid x402 support already, including signing a PAYMENT-REQUIRED header and retrying with PAYMENT-SIGNATURE. If useful, Satoshi API can be a tiny live fixture for docs or tests because it has both a no-payment first call and a very cheap paid call:

• Free first value: GET https://bitcoinsapi.com/api/v1/fees/recommended
• Paid x402 resource: GET https://bitcoinsapi.com/api/v1/fees/landscape ($0.005 USDC on Base)
• Discovery: https://bitcoinsapi.com/.well-known/x402
• Paid OpenAPI: https://bitcoinsapi.com/openapi.json
• Agent card: https://bitcoinsapi.com/.well-known/agent-card.json

The demo task is simple: ask whether to send Bitcoin now or wait. The free endpoint returns a useful recommendation; the paid endpoint exercises the full 402 challenge and retry flow.

I can open a small docs PR or test fixture if third-party live resources are welcome. If you prefer to keep examples entirely self-contained, no worries -- I mostly wanted to offer a real endpoint that is small enough to be practical for people testing mcpc x402.