rca

Conduct a root-cause analysis on a bug, incident, or regression — reproduce the failure, reconstruct the timeline, run a 5-whys chain, distinguish symptom from proximate cause from root cause, sweep for siblings, and propose a fix that addresses the cause (not the symptom). Use when the user says "/rca", "root cause", "5 whys", "why is this failing", "investigate this regression", or after any failure the team wants to learn from rather than just patch.