Checks that a control can actually fail before you trust it passing. Use when writing or reviewing a test, lint rule, CI gate, feature flag, ignore rule, or runbook check, or when a QA pass, audit, or review comes back clean. Covers the check that greps for a string that never appears, the gate that never closes, the assertion too weak to tell two bugs apart, the fixture neutered before the code sees it, and the documented control with no implementation.
