Drill into root cause with a 5-Why why chain, why analysis, or structured root cause investigation. Builds a Why chain from symptom to systemic root cause, validates each step with evidence, and detects circular reasoning. Use for 8D D4, CAPA, FMEA cause analysis, or any quality investigation requiring confirmed root cause identification.
Install
npx skills add RBraga01/Quality-Engineering-Skills --skill 5why-root-causenpx skills add RBraga01/Quality-Engineering-Skills --skill 5why-root-cause -a claude-code -gnpx skills add RBraga01/Quality-Engineering-Skills --skill 5why-root-cause -a codex -ggemini skills install https://github.com/RBraga01/Quality-Engineering-Skills.git --path skills/problem-solving/5why-root-causegh skill install RBraga01/Quality-Engineering-Skills 5why-root-causegit clone --depth 1 https://github.com/RBraga01/Quality-Engineering-Skills /tmp/RBraga01__Quality-Engineering-Skills
mkdir -p ~/.claude/skills ~/.agents/skills
cp -R /tmp/RBraga01__Quality-Engineering-Skills/skills/problem-solving/5why-root-cause ~/.claude/skills/5why-root-cause # Claude Code
cp -R /tmp/RBraga01__Quality-Engineering-Skills/skills/problem-solving/5why-root-cause ~/.agents/skills/5why-root-cause # Codex, Cursor, Gemini CLI, Copilot, OpenCode