Use for bugs, flaky behavior, crashes, broken UI, incorrect state, or inconsistent platform behavior. Investigate evidence first and fix the actual cause across Swift, Kotlin, Flutter, Tauri, Rust, and frontend code.
Installation
Installer avec Codex ou Claude Copiez ce prompt, collez-le dans Codex, Claude ou un autre assistant, puis laissez-le vérifier la page du skill et l'installer pour vous.
Use for bugs, flaky behavior, crashes, broken UI, incorrect state, or inconsistent platform behavior. Investigate evidence first and fix the actual cause across Swift, Kotlin, Flutter, Tauri, Rust, and frontend code.
Debug Root Cause
Use when
behavior is wrong, flaky, crashing, visually broken, or inconsistent
the task is to explain and fix a failure chain rather than add new product behavior
the user needs root-cause analysis, not symptom masking
Do not use when
the main task is greenfield feature implementation
there is no concrete failure to investigate
Working rules
Do not patch before you can explain the broken invariant.
Separate symptom, trigger, and root cause.
Prefer deterministic reproduction or the strongest evidence available in the repo.
Check state ownership, lifecycle, async ordering, serialization, configuration, and environment mismatches before editing.
Remove temporary debug instrumentation unless the user explicitly wants it kept.
Workflow
Define observed behavior, expected behavior, and reproduction conditions.
Gather evidence from code, logs, traces, recent changes, and platform constraints.
Rank the smallest set of plausible hypotheses.
Disprove the top hypotheses with the minimum checks needed.
Fix the root cause at the narrowest correct layer.
Add regression protection with a test or explicit validation step.
Quality bar
The final explanation names the broken invariant.
The fix restores the invariant instead of hiding the symptom.
Adjacent flows likely to regress from the same cause are checked before closeout.
Reference routing
Read references/debug-checklist.md for the investigation checklist.
Read references/release-quality-gates.md when the bug affects a user-critical or release-critical flow.
Read references/official-docs.md only when platform semantics or API guarantees matter to the diagnosis.
