Endpoint Trust Score

Objective, reproducible reliability scoring for x402 / agent-payable endpoints.

Thousands of paid endpoints are appearing with no independent record of which are actually up, fast, honestly priced, and stable over time. The Trust Score measures that continuously so an agent can consult a signal before it pays. GET /v1/trust/score?url=<endpoint> — $0.005; /v1/trust/report adds history detail for $0.02.

We measure endpoints; we do not rank, endorse, or accept payment from the endpoints we measure. Metrics are mechanical and every score ships with its underlying counts.

Methodology

Scores are computed by a pure function over an append-only history of periodic probes. Weights, bands, and windows are frozen and versioned (thresholdsVersion: p2t-score-1.0.0) and stamped on every score, so any third party holding a history slice can recompute any score. Ratings that can't be audited are marketing.

What we measure

Most signals come from the endpoint's unpaid protocol handshake (the HTTP 402 challenge), which costs nothing and reveals the advertised terms:

Component	Weight	What it captures
Availability	0.50	Does it respond over time (confirmed observations only).
Latency	0.15	p50/p95/p99 from raw timings — the tail an agent pipeline actually feels.
Terms stability	0.20	Price drift; a change of payment recipient (custody) is flagged, never averaged away.
Challenge integrity	0.15	Does it present a well-formed, parseable payment challenge.

A rare, capped, fully-paid spot-check verifies that a paid call is actually honored — we pay the advertised price like any customer.

Verdicts

reliable (≥80) · mixed (≥50) · unreliable · and unrated — an endpoint with too little history is unrated with no score, never a fake-neutral number.

Principles we hold ourselves to

Our failures are never charged to you. A probe failure on our side (network, timeout, rate-limiting) is recorded as ours and excluded — an endpoint is never marked down for our infrastructure. Ambiguous single failures are excluded until confirmed.
No lookahead. A score dated T uses only history up to T; it is reproducible forever.
Objective metrics, raw counts attached. Verdict words are defined mechanically; every score carries the counts behind it so you can re-judge.
Query privacy. We never sell, profile, or build a product from which endpoints a consumer asked about.
Known limitation. Latency is measured from a single region (us-east-1) and labeled as such; multi-vantage is future work.

For endpoint operators

Our monitor identifies itself honestly (User-Agent portico-trust-prober) and is a good citizen: conservative cadence, exponential backoff, and it honors 429 / Retry-After. We probe only endpoints publicly listed on public directories, in the manner they advertise for consumption.

Re-probe, correction, or opt-out: email ops@forum-labs.com. Opt-outs are honored within 24 hours; corrections are appended to the record (append-only — we never silently edit it).

Forum Labs · ops@forum-labs.com · @shopforumlabs
Not financial advice. Metrics are informational and mechanical.