Help us improve
Share bugs, ideas, or general feedback.
From grimoire
Investigates root causes of defects or incidents by iteratively asking 'why' to trace failures from symptoms to systemic causes. Useful for postmortems and recurring failures.
npx claudepluginhub jeffreytse/grimoire --plugin grimoireHow this skill is triggered — by the user, by Claude, or both
Slash command
/grimoire:apply-five-whysThe summary Claude sees in its skill listing — used to decide when to auto-load this skill
Iteratively ask "why?" five times to trace a failure from its surface symptom to its root systemic cause.
Chains 'why' questions with evidence to find systemic root causes after a fault is localized and proximate cause is known. Includes counterfactual test and stop condition.
Five Whys, fishbone diagrams, identifying systemic causes not just symptoms.
Conducts root cause analysis using 5-Why methodology for errors, bugs, build/test failures, performance issues, and integration problems.
Share bugs, ideas, or general feedback.
Iteratively ask "why?" five times to trace a failure from its surface symptom to its root systemic cause.
Adopted by: Toyota (originator), Google SRE, Amazon, every organization operating under ISO 9001 quality management, and standard practice in lean manufacturing globally. Impact: Toyota's implementation of Five Whys reduced defect recurrence rates by 70%+ by shifting focus from symptom suppression to systemic fix. Google SRE teams credit iterative root cause analysis as the primary driver of reducing repeat incidents; the Google SRE workbook mandates it as part of postmortem procedure. Why best: Most incident responses fix the immediate symptom — the server that crashed, the query that timed out. Without root cause analysis, the same failure recurs in a different form weeks later. Five Whys breaks the symptom–fix–recurrence loop by forcing every investigation to reach a systemic or process-level cause before closing.
Sources: Taiichi Ohno "Toyota Production System" (1978); Google SRE Workbook Chapter 10; ISO 9001:2015 §10.2