Dev Guide: Use a Mini Evidence Card to Catch State-Change Bugs at Release

A software development practice proposes attaching a small 'evidence card' to pull requests when releasing features that involve shared state, such as booking reschedules. The card documents intended behavior, adjacent paths tested, production signals to monitor, and a named rollback owner with a clear decision threshold. The approach addresses a common gap where a passing CI test confirms the changed feature but leaves adjacent behaviors — like reminders tied to an old appointment time — unverified. A pure-function JavaScript example illustrates how targeted unit tests can surface forgotten state updates, while the author notes that integration and production checks remain separately necessary. The goal is to make the scope of verification explicit and to record what was actually observed after deployment, rather than treating a green build as full proof of correctness.