5-whys-skill

The 5-Whys Root Cause Analysis skill brings Toyota Production System methodology to Claude Code, enabling teams to trace problems back to their fundamental causes through iterative questioning. It automatically triggers when you ask about root causes, debugging issues, or incident analysis, then applies a structured 5-phase process: defining the problem, asking why iteratively, identifying the root cause, validating the causal chain, and defining countermeasures. The skill outputs a formatted analysis showing the problem statement, why chain with evidence, root cause classification, and recommended actions. Operations teams, incident response leaders, and engineers benefit from fact-based analysis that avoids blame and focuses on preventable, systemic causes rather than symptoms.

Clone the skill repository and copy it to your Claude Code skills directory, or create a symlink. The skill activates automatically when you use trigger phrases like 'find the root cause,' 'debug this issue,' 'analyze this bug,' or 'dig deeper' in English, or equivalent phrases in Chinese. It structures your analysis into a problem statement, iterative why chain with evidence, root cause identification, and countermeasures.