What problem does it solve? Bug fixes shipped without a failing-first test can silently regress, and post-fix tests written against already-fixed code prove nothing. This Skill enforces a disciplined workflow that turns every bug report into a permanent, minimal-layer regression test before the fix is written. ## Core Features & Use Cases - Reproduce-then-test workflow: Reduce the report to a minimal trigger, write the test at the lowest layer that exhibits the bug, and watch it fail for the right reason before fixing. - Sibling sweep and escape analysis: Grep for the same defect pattern elsewhere in the codebase and record which missing test category let the bug escape. - Verification checklist: Requires captured failing output, a green post-fix suite, ticket-linked test names, and documented sibling-sweep results. - Use Case: A customer reports being charged twice on retry. You minimize the repro to an idempotency-key bug, write a unit test at the payment client layer that fails showing two charges, fix the key derivation, and grep for the same pattern in refunds. ## Quick Start Use the regression-test-from-bug skill to turn this bug report into a failing regression test before I write the fix.
