| name | systematic-debugging |
| description | Applies a modified Fagan Inspection methodology to resolve persistent bugs and complex issues. Use when several fix or debugging attempts have already failed and a methodical root-cause analysis warranting a Fagan inspection is needed. For first-pass diagnosis of a reproducible bug or regression use diagnose-hard-problem. Do not use for simple troubleshooting. |
Systematic Debugging with Fagan Inspection
This skill applies a modified Fagan Inspection methodology for systematic problem resolution when facing complex problems or stubborn bugs that have resisted multiple fix attempts.
Process Overview
Create tasks for each of the four phases, then work them to completion, marking each done before starting the next.
Follow these four phases sequentially. Do not skip phases or attempt fixes before completing the inspection.
Phase 1: Initial Overview
Establish a clear understanding of the problem before analysis:
- Explain the problem in plain language without technical jargon
- State expected behaviour - what should happen
- State actual behaviour - what is happening instead
- Document symptoms - error messages, logs, observable failures
- Context - when does it occur, how often, under what conditions
- Prior fix attempts - list each attempt, what it changed, and why it failed; treat these as eliminated hypotheses that Phase 3 must account for
Output: A clear problem statement that anyone could understand.
Phase 2: Systematic Inspection
Perform a line-by-line walkthrough as the "Reader" role in Fagan Inspection. Identify defects without attempting to fix them yet - this is pure inspection.
Check against these defect categories:
- Logic Errors
