bsafronov Fix Bug
Correct the established mechanism at the boundary that owns the behavior, with credible regression evidence.
- Check that the supplied cause explains the failing path and that the expected result has an independent basis. Reuse credible diagnostic evidence; reopen only the uncertainty that would change the repair. If the mechanism remains unknown, resolving it is a separate outcome.
- Repair the owning behavior rather than masking its symptom in a caller. The responsible change may span files or layers; the fewest changed lines is not the goal. Account for callers that share the mechanism and preserve their valid behavior, including consequential boundaries and failure paths.
- Choose regression proof that distinguishes the defect from the correction. Reuse an existing check when it already detects the defect. Add a focused test when recurrence risk warrants it; otherwise preserve a concrete reproduction, before/after observation, or equivalent evidence. Derive the expected result from the contract, not from the changed algorithm. A check that passes on the faulty version cannot alone prove this repair.
- Verify the correction and affected behavior through the relevant boundary. Distinguish an unavailable check, an unrelated baseline failure, and a failure caused by the change. A mock or unit result does not establish an external integration guarantee. Report the remaining limit instead of weakening the expected behavior to make a check pass.
Complete when the established failure is corrected and the available regression and affected-behavior evidence supports that claim; state any material unverified part precisely. This Skill does not prescribe test-before-code ordering. Compose requested test-first work when that sequence matters; independent interface choices, new features, structural refactoring, and compatibility transitions keep their own outcomes.