Failures That Look Like Success

The quiet agent-failure class where everything reads fine — confident answer, plausible plan, even correct internal state — but the user-facing outcome is wrong; Google's flywheel demos caught agents echoing stale values despite correct memorize calls and silently skipping self-report instructions; measured at 78% of failures in one policy-permissive tool benchmark; its read-side twin is omission, a fact that never arrives, which a nine-layer pipeline taxonomy can attribute to a locus; detectable by trace-level rubrics, not output skims — and for the deterministic layers, by a byte diff needing no grader at all