Systematic Debugging

WHEN: A bug fix has failed two or more times, the same test keeps failing for different reasons, or the symptom keeps moving when fixes are applied. Also use proactively for any type:bug that touches more than one file or crosses a module boundary.

When to Use This Skill

Load this skill when:

• Two or more fixes for the same bug have not held
• The failing test now fails in a different way after each attempt
• A type:bug issue is non-trivial (more than a single-file typo)
• A Reviewer has issued CHANGES REQUESTED twice on the same defect
• You feel the urge to "try one more thing" instead of investigating

Skip when:

• The bug is a single-line obvious typo with no dependencies
• The failure mode is fully understood and the fix is mechanical