Detective-style investigation that follows evidence trails to find root causes, bugs, inconsistencies, and hidden problems. Works on code, performance, architecture, data, and systems. Three investigative lenses: Sherlock (deduction), Poirot (psychology/intent), Columbo (what's missing). Triggers: investigate, debug, detective, find bug, root cause, what's wrong, diagnose, trace, why is this broken, what happened.
