use-context-root-cause-analysis

name	use-context-root-cause-analysis
description	Root cause analysis with 5 Whys.
when_to_use	root cause, 5 Whys, なぜなぜ分析, 根本原因, 原因分析, symptom fix, 対症療法
allowed-tools	Read Task Bash(ugrep:*) Bash(bfs:*)
context	fork
background	false
user-invocable	false

Root Cause Analysis - 5 Whys

Principle

Fix the root cause, not the symptom. Symptom fixes add complexity; root-cause fixes prevent recurrence.

5 Whys Process

Ask "why" five times, descending through abstraction levels.

Step	Level
1	Observable fact
2	Implementation detail
3	Design decision
4	Architectural constraint
5	Root cause

Tips

Tip	Description
Stay factual	Evidence, not assumptions
Don't stop early	First "why" is rarely root cause
Don't go deep	Stop when actionable
Validate	"Because [5], therefore [4]..."
Verify fix	"Will this prevent the problem?"
Watch complexity signals	When intermittent / multiple independent changes overlap / behavior unexplained, enumerate ≥3 cause-layer candidates before converging

Output Format

Field	Description
Symptom	User-facing failure
Root cause	Why the failure occurred (5 Whys result)
Pattern	Isolated / Recurring / Systematic

Pattern Enum

Consumers such as the /fix Non-obvious flow branch on the Pattern field to decide whether to apply defense-in-depth or escalate.

Value	Meaning
Isolated	Single location, no recurrence path
Recurring	Similar code exists nearby, recurrence possible
Systematic	Design-rooted, architecture-level recurrence risk

References

Topic	File
Worked examples	${CLAUDE_SKILL_DIR}/references/five-whys.md
Symptom → Root Cause	${CLAUDE_SKILL_DIR}/references/symptom-patterns.md