Lumière PayCheck MCP server

Lumière PayCheck

Check an x402 endpoint before your agent pays it.

AI agents now pay for APIs on their own with x402: an endpoint answers 402 Payment Required with a price, the agent pays in USDC, and gets the data. Nothing in that flow tells the agent whether the endpoint works, whether the price is right, or whether the payout wallet is the real one.

Lumière PayCheck answers those questions. It monitors every endpoint listed in the x402 Bazaar, grades each one, and gives your agent a plain verdict: proceed, caution, or avoid.

🌐 Live: https://lumierepaycheck.org · 🔌 MCP: https://lumierepaycheck.org/mcp · 📜 Terms

This repository is the public home for docs, examples, and feedback. The monitoring service itself is hosted and closed-source; the scoring formula is public (below).

What it does

• Monitors every endpoint in the x402 Bazaar (the badge above shows the live count, which grows as new endpoints are listed) every 30 minutes: price quote, payout wallet, uptime, response time.
• Flags hijack risk, without punishing normal rotations. Every payout-wallet change is checked against the seller's own wallet declaration, the seller's earlier wallets, and direct transfers between the old and new wallet. Confirmed rotations don't affect the grade; unexplained changes are avoid, then caution with human review. Sellers that use a new address per request are recognized automatically. How it works.
• Spending rules for agents. Before paying, an agent asks "may I pay this endpoint this amount to this wallet?" and gets allow or deny with reasons.
• Plans for teams (new). Scoped agent keys, daily/monthly spend limits, signed receipts your wallet verifies before paying, a replayable audit trail, and human review for anomalies. Details.
• Alerts. Watch an endpoint and get signed webhook alerts when it breaks, changes wallet, or raises its price.
• Paid delivery checks: small real payments that confirm an endpoint returns what it advertises. A failure only counts if a re-test about two hours later fails too, and requests an endpoint rejects for missing input never count.
• Known-answer tests: values, not just shape. Uptime and schema checks can pass while an API returns the wrong number. For endpoints with a knowable answer, the verifier pays for a call with a known correct result, or compares against an independent live source, and checks the value itself. Sellers can add their own tests. How it works.
• Real usage from on-chain data: actual x402 payments (USDC on Base and Solana) into each endpoint's payout wallet over 30 days: volume, distinct buyers, typical and largest payment, trend, and how concentrated the buyers are, counting only payments submitted by recognized facilitators.
• Community outcome reports: agents that pay through us report whether calls worked. Reports only point our re-tests at problems; grades change only when our own paid test confirms. On by default, easy to opt out.

No accounts, no API keys. Free checks are free; paid features are paid per call with x402, the same way agents pay everything else.

Quick start

1. From Claude, Cursor, or any MCP client

Add the remote MCP server:

https://lumierepaycheck.org/mcp

Shortened. The full README is on GitHub.