KCAE.INDEX:4.3 - Make selection filters explicit

Apply access restrictions before material can reach an unauthorized component. Other filters are claims about the question. If the user asks about current operational policy and an authority rule selects the governing edition, use that rule; if the question asks about history or conflicts, retain the relevant older editions. Do not infer a subject/Suite filter from the first few words and then make every route inherit it.

Compare early filtering with later assessment. Early exclusion is appropriate when the predicate is reliable and required, such as an access boundary. A guessed topic is better used as one retrieval preference with a broad route still available. When a route supports only post-filtering of its first K hits, permission-safe candidate inspection may still suffer poor recall because eligible hits were below K. Over-fetching or a natively filtered index can help; measure the actual operation and report the boundary.

A route can fail because the useful document is absent, its extraction is incomplete, the model missed its meaning, the approximate search lost it, a filter excluded it, or the candidate window was too small. Preserve enough route information to distinguish these causes during evaluation. Otherwise every failure invites another model while the source never entered the index.