MCPFax Reliability

Creditworthiness grade for one x402 endpoint or MCP server: letter grade A-E (or NR when unrated), a 0-1000 score, per-component subscores, a confidence level, flags, and the dated evidence each figure rests on. Use this before trusting or paying an unfamiliar endpoint. The grade ranks observed risk; it is not a calibrated probability of failure, not validated over any forward horizon, and not a s

What changed under an x402 endpoint or MCP server you have ALREADY integrated: payTo rotations, price, asset and network changes, terms added or removed, and tool-schema changes. This is not a discovery tool and will not help you choose a server; it tells you whether the one you wired in still matches what you wired in. Pass up to 50 subjects and the `since` watermark returned by your last call, a

Payer-concentration and wash-risk assessment for a receiving wallet: how concentrated its observed payers are, the measured coverage of that observation, an explicit wash-risk haircut ONLY when coverage is sufficient, how many listings declare the same address, and observed USDC inflow. Use this to judge whether a seller's apparent revenue reflects real independent demand. The haircut and the adju

Observed on-chain revenue signals for one listing: total USDC inflow, how many distinct payers, the modal transfer size, payment rate, 7- and 30-day trend windows, and where it sits in its cohort by percentile. Use this to size a seller's real traction. Inflow is observed on-chain and is not proven to be x402 sales revenue. Trend windows are only as wide as the wallet's real scanned span, which th

Know-your-agent profile for a paying wallet: how many distinct services it pays, total observed spend, whether the address is a contract or an externally owned account, and coverage-gated screening signals. Use this to vet a counterparty that is paying you. Screening signals are withheld with status "not_rated" until the observed record for the address clears the published coverage floor (14 days,

Chronological feed of rating actions since a date: grade upgrades and downgrades, payTo wallet changes (a seller redirecting payment), listing removals, and returns. Use this to monitor a portfolio of endpoints for adverse changes rather than re-scoring each one. The feed cannot return events from before the observatory archive started; the response reports coverage.archive_since, coverage.rating_

Check that an endpoint is live and that its terms have not changed, BEFORE you send it an expensive request. A $15 call with a hypothetical 2% loss rate carries $0.30 of expected loss; a reachability check cannot promise to prevent it. Compare the quoted fee with the value of the pending call and the failures this check can actually detect. For a cheap $0.001 lookup, the $0.008 fee is eight times