Debug failing, flaky, slow, or incorrect behavior with a reproducible feedback loop. Use when something is broken, throwing, failing tests, behaving unexpectedly, or showing a performance regression.
Installation
Install with Codex or Claude Copy this prompt, paste it into Codex, Claude, or another assistant, and let it review the skill page and install it for you.
Debug failing, flaky, slow, or incorrect behavior with a reproducible feedback loop. Use when something is broken, throwing, failing tests, behaving unexpectedly, or showing a performance regression.
Debug
Input
A bug report, failing command, test, error, performance complaint, repro steps, or affected area.
Use explicit input first; otherwise infer from context, recent edits, selected files, or branch.
Safest default: find an agent-runnable repro before patching.
Workflow
Build a feedback loop. Reproduce the issue with a runnable command, test, script, request, or browser flow.
Confirm the symptom. Verify the repro matches the user's reported behavior, not a nearby failure.
Minimize the repro. Reduce inputs, state, or steps until the failing behavior is clear.
Form hypotheses. List 2-4 falsifiable causes and test one at a time.
Instrument narrowly. Add targeted logs, assertions, debugger probes, or measurements only where they distinguish hypotheses.
Fix the root cause. Keep the change scoped to the proven cause.
Add regression coverage. Add or update a test when there is a suitable behavior-facing seam.
Clean up. Remove temporary probes, scripts, and logs.
Output
Repro used
Root cause
Fix applied
Regression coverage added or skipped
Validation run
Guardrails
Do not patch before reproducing unless reproduction is impossible.
If no repro is possible, state what was tried and what artifact or access is needed.
Do not leave temporary debug logs, scripts, or instrumentation behind.
