The QA Lookback Loop: Milestone Retros at Agentic Scale

Conventional postmortem discipline catches failures after they ship; it cannot catch the operational learning that fires on success cases or the drift that accumulates across many sessions. This paper specifies the QA Lookback Loop: a three-layer architecture with daily lookbacks (Klaus-curated, semi-automated), milestone retros (per story-close and epic-close, three-section format — Lessons Learned, Microbreakthroughs, Problem Set), and a continuously growing compendium (Klaus-gatekept, sprint-planning-readable). A meta-failure case study (the 2026-04-29 stale-state INFERENCE-FAILURE lookback) demonstrates the lookback-of-lookback discipline. This is Paper Five of the Managing Agentics Ops decalogy.