Debugging
When to use
Use this skill for debugging when you need to locate the actual cause of a reproducible failure. The expected result is a root-cause note and verified fix.
Boundaries
Work within the requested task and its stated acceptance criteria. Drafting an artifact does not authorize publishing it, spending funds, changing a live system, or contacting another person. Identify any such action separately before taking it.
Inputs
Inspect the relevant code, tests, interfaces, dependency graph, and failure report. Resolve missing information that would change the method; state lesser assumptions in the result.
Method
- Diagnose. Reproduce the behavior, inspect the call graph and tests, and identify the contract that a fix must preserve.
- Decide. Isolate the behavior, compare implementation options, and make a reversible change.
- Produce. Build a root-cause note and verified fix from the inspected material; keep assumptions distinguishable from observed facts.
Decision rules
- Write the smallest maintainable change that addresses the cause. Include an edge case that would fail with a superficial patch.
- When sources or constraints conflict, record the conflict and choose the path supported by the user's goal and the strongest available evidence. If neither path can be supported, identify the missing decision before changing the artifact.
Domain rules
- Preserve public contracts or document a migration.
- Record the failure case that the change prevents.
Verification
Reproduce first, then confirm the original failure is gone. Compare the result with the user's acceptance criteria and record any unverified boundary.
Return changed files, test evidence, complexity or performance notes when relevant, and any follow-up migration.
Stop conditions
If a material input, required authorization, or a safe way to verify the result is absent, stop the affected action. Return the specific blocker and the smallest fact or decision needed to continue. Do not report an unrun check as passed.
Output
Provide a root-cause note and verified fix. Include the decisive evidence and actual verification result. Name any artifact location and unresolved issue that affects its use.
