Value: Feedback -- systematic investigation produces understanding. Understanding produces correct fixes. Correct fixes prevent recurrence. Skipping investigation produces symptom fixes that hide bugs.
Teaches a disciplined 4-phase debugging process that enforces root cause analysis before any fix attempt. Prevents the most common debugging failure mode: jumping to a fix without understanding why the problem exists.
Never change code to fix a bug until you have completed root cause investigation. When you see an error and immediately know the fix, that is exactly when you are most likely to be wrong. Investigate first.
Systematic 4-phase debugging: understand the failure, form hypotheses, test one change at a time, fix with confidence. Activate when tests fail unexpectedly, errors occur, behavior is wrong, or something that worked before is now broken. Triggers on: "debug", "why is this failing", "test failure", "unexpected error", "bug", "broken". Source: jwilger/agent-skills.