KB completeness has a formal toolkit beyond obligatory attributes — cardinality assertions, the No-Change Assumption, and text-extraction recall

The same survey that grounds claim-obligatory-attributes-as-gap-signal offers three further completeness instruments, each mappable to vault practice:

1. Cardinality assertions — comparing a relation's recorded cardinality against its real one is the formal primitive of completeness measurement. Vault analogue: "this cluster should have N members" claims (a MOC that names five clusters but links four is measurably incomplete).
2. No-Change Assumption (NCA) — if repeated observations stop adding new facts, treat the region as converged: a lightweight temporal completeness signal. Vault analogue: a topic whose captures stop yielding new claims has stopped growing — the loop-until-dry intuition, formalized.
3. Text-extraction-based recall — compare what a source document mentions against what the KB extracted from it. Vault analogue: the promotion accounting's not_promoted lists exist precisely so recall against a capture is auditable.

One quantitative boundary from the paper stays flagged per the capture: the LM-KBC 2023 best-system figure (69% F1 on cardinality prediction) is cited within the survey from shared-task proceedings — [unverified-quant — needs primary] until read there. See question-gap-detection, moc-machine-self-knowledge.