At every pipeline stage boundary, an empty result is byte-identical to a failed scan - auth expired, wrong path, swallowed exception, truncated pagination. This service issues a signed receipt at the boundary so a downstream stage can tell a proven zero from an unknown.
The receipt's signed body carries the scan parameters, the scanned count, a SHA-256 hash of the canonical listing, a Merkle root, the full listing itself, the matched set, and the explicit missing list (expected - scanned). Completeness is computed by the issuer, never asserted by the caller: an auth-failed or error scan can only be UNKNOWN, a truncated or missing-bearing scan PARTIAL at best, and only a clean scan with an empty missing list is COMPLETE. A downstream stage concludes EMPTY only from a verified, fresh, COMPLETE receipt; every other state is UNKNOWN.
The coverage probe, stated plainly: an independent re-scan of a sampled slice, hard-capped at 5% of the claimed set. It is a coarse-fault tripwire only - measured at a 5% sample: wrong-path 1.00, truncated-50% 1.00, 10%-missing 1.00, 3%-missing 0.80, 0.3%-missing 0.15. It does not reliably detect small holes; small-hole completeness is carried by the listing hash + explicit missing list, not by sampling. This product is not represented as FTO-cleared (its freedom-to-operate screen is AMBER, screen-level).
Prices: Receipt issuance $0.02/receipt · Verification $0.005/check · Coverage probe $0.25/probe (sample capped at 5%). One free receipt per operator, ever.
API: https://textforagents.com/products/stage-completeness-receipts/ · Docs: https://textforagents.com/products/stage-completeness-receipts/docs · OpenAPI: https://textforagents.com/products/stage-completeness-receipts/openapi.json · Support: support@textforagents.com