performing-systematic-debugging-for-stubborn-problems

This skill provides a structured framework for systematic debugging by applying a modified Fagan Inspection methodology. It is specifically designed for developers facing complex, persistent issues that have resisted multiple standard fix attempts. By moving away from trial-and-error 'quick fixes' and toward a methodical, multi-phase analysis, this tool ensures that root causes are identified through logical rigor rather than conjecture.

The process is divided into four distinct phases: Initial Overview, Systematic Inspection, Root Cause Analysis using the Five Whys technique, and Solution & Verification. During the inspection phase, the agent acts as a reader, performing a line-by-line code walkthrough to detect logic errors, boundary condition failures, incorrect error handling, data flow inconsistencies, and integration point defects. It requires explicit reasoning, where the agent must document every assumption, flag unclear segments for deeper analysis, and think aloud to maintain transparency.

• Performs line-by-line inspection to identify logic errors, control flow issues, and boundary condition defects.

• Implements the Five Whys technique to trace symptoms back to fundamental root causes in environmental, concurrency, or design contexts.

• Facilitates detailed documentation of expected vs. actual behavior to clarify complex system interactions.

• Generates structured verification plans, including specific test cases, manual steps, and monitoring strategies to ensure permanent resolution.

• Operates as a gatekeeper against 'shotgun debugging,' requiring completion of analysis before implementation.

• Best suited for stubborn bugs, complex distributed system failures, or legacy code defects that require deep architectural understanding.

• Not intended for simple syntax errors, environmental configuration issues that don't involve code, or initial troubleshooting efforts.

• Input requires the problem context, codebase, and history of failed attempts; outputs a categorised defect list, root cause report, and verification roadmap.

• Users must provide explicit approval between phases to ensure quality and alignment with system design constraints.

• Employs 'ultrathink' capabilities for complex sections where logic or integration points are highly obscure.