# Spot Check


What the observatory already knows about an x402 host, signed.

## At a glance

- **Attests:** Name a host and get what this observatory already holds on it, signed: corpus rounds and verdicts as recorded, when we last actually knocked, our coverage of the window since we met it, and the gaps with their reasons. Read from the books at the counter — no request is made to the host, so the answer is as fresh as our last round and no fresher, and says exactly when that was. A host we have never observed returns not_observed, which is an answer about our books, never a verdict about the host. The same facts serve free at /corpus/host/{host}.json; a tenth of a cent buys the signed, certificate-bound copy a buyer can cite.
- **Input:** host (query parameters; input schema and checkout: https://scvd.store/menu/spot_check?view=compact)
- **Output:** The deliverable as JSON, plus a signed certificate Every artifact carries a cert_id and verifies free at https://scvd.store/api/verify/{cert_id}.
- **Cryptography:** ed25519 signature by this store's key, published at https://scvd.store/.well-known/scvd-signing-key and carried inside every 402
- **Verify:** GET https://scvd.store/api/verify/{cert_id} — free, no account, no rate limit, checkable offline with the published key
- **Price and fulfilment:** $0.001 USDC fixed, one-off; nothing here charges again by itself, ever — there is no mechanism that could; delivered instantly
- **Does not attest:** fitness for your particular task; future protocol compatibility beyond stated interfaces; human-labor turnaround faster than posted SLA

## About this item

Name a host and get what this observatory already holds on it, signed: corpus rounds and verdicts as recorded, when we last actually knocked, our coverage of the window since we met it, and the gaps with their reasons. Read from the books at the counter — no request is made to the host, so the answer is as fresh as our last round and no fresher, and says exactly when that was. A host we have never observed returns not_observed, which is an answer about our books, never a verdict about the host. The same facts serve free at /corpus/host/{host}.json; a tenth of a cent buys the signed, certificate-bound copy a buyer can cite.

- **id:** `spot_check`
- **price:** $0.001 fixed, one-off; nothing here charges again by itself, ever — there is no mechanism that could
- **fulfillment:** delivered instantly
- **buy:** `GET https://scvd.store/api/buy/spot_check?host=<host>` (USDC over x402 v2 on Base, Polygon, Arbitrum, World, Solana, or USDC over MPP (evm/charge) on Base for every shelf item, every publication page and the commission desk)
- **required inputs:** `host` — fill the `<host>` slot above before paying. The bare door `GET https://scvd.store/api/buy/spot_check` quotes free and refuses the paid request without it; no money moves.
- **sample:** https://scvd.store/samples/spot-check.json

House rules: give the host in the host query parameter: a bare hostname, e.g. example.com (a url is read for its hostname); reads what we already recorded — no request is made to the subject; a host we've never met returns not_observed, which is an answer; never a ranking, and never a verdict without its derivation and denominator beside it.; want a live read instead? the preflight at /api/preflight/v3 is free and knocks right now.

> A tenth of a cent for whatever's already on the card. We don't go and look — this is what the shop already saw, dated, with the blanks left blank.

Optional next work: You operate the endpoint and a single reading is not enough to see what changes after deployment. [Watch your endpoint after a change — scope, price and free starting point](https://scvd.store/operators#endpoint-watch).