Trust data for agents that pay agents.
MCPFax joins endpoint reliability, declared payment terms, dated rating actions, and observed USDC payer graphs. It returns evidence you can dispute—not a black-box “safe” badge.
Observation archive: 11 day(s), measured from 2026-08-11 through 2026-08-21. Every window we report is bounded by that archive: nothing here is a 30- or 90-day record until the archive covers 30 or 90 days. Live figures: GET /health → coverage.
Paid endpoints
| Route | USDC / call | Returns |
|---|---|---|
GET /score | $0.002 | MCPFax credit grade, subscores, confidence, and cited evidence |
GET /authenticity | $0.01 | Payer concentration, wash-risk haircut, and authenticity-adjusted inflow for one wallet. Refuses with HTTP 422 and charges nothing when the address's own observed record does not clear the published coverage floor, rather than billing for a guaranteed not_rated. |
GET /revenue | $0.01 | Observed USDC inflow, payer breadth, trend, and cohort rank |
GET /drift | $0.002 | What changed under an integration you already wired in: payTo rotations, price and asset and network changes, terms removed, tool schemas changed. Pass up to 50 subjects and the watermark from your last call; receive the changes since it and a new watermark. Subjects MCPFax has never observed are named as unobserved rather than reported clear. |
GET /payer | $0.002 | Know-your-agent payer graph and coverage-gated screening signals |
GET /payto-change-feed | $0.001 | Observed change feed for listed x402 sellers: declared payTo changes with before/after values, other declared-terms changes (price, facilitator, fee payer), registry removals and returns, rating actions, and grade downgrades. Every response reports measured per-category coverage for the requested window. |
GET /preflight | $0.002 | Advisory preflight on one endpoint before a consequential call: a bounded live probe (reachable, status, latency, MCP initialize, current x402 price and payTo) joined to our observed history (reliability over a stated window, payTo and price changes, first seen). Returns ALLOW, WARN or UNKNOWN. Never a guarantee. No evidence, no charge. |
One request
curl 'https://YOUR_HOST/score?endpoint=host:api.example.com' # → 402 plus PAYMENT-REQUIRED (x402 v1, network "base") # Retry with X-PAYMENT, or the equivalent alias PAYMENT-SIGNATURE.
Free surfaces
GET /health readiness and coverage · GET /llms.txt agent-readable docs · POST /mcp MCP initialize and tool discovery. Tool calls use the same x402 prices. Licensees use GET /feed/reliability with a bearer key and cursor pagination.
What the numbers do not prove. A wallet balance is not revenue. Incoming USDC is observed on-chain but is not yet guaranteed to be an x402 sale. HHI measures concentration, not common control. Funding-source edges are still missing, so observed organic/wash percentages remain null. Wash-risk and payer-concentration verdicts are withheld as “insufficient payer observations — not rated” until a subject’s own observed payment record covers at least 14 days and 20 payments—so a thin record is reported as thin, never as a finding against a named party.
MCPFax Credit Model 1.0 is ordinal, not a calibrated probability of default, and it is not validated over any forward horizon. Observation archive: 11 day(s), measured from 2026-08-11 through 2026-08-21. See the response’s evidence citations and coverage block before acting.