What problem does it solve? When a bug is fixed, most workflows patch the code and move on, letting the same class of bug recur later. This Skill turns every bug, test failure, or post-mortem into a permanent specification update so the failure mode cannot silently return. ## Core Features & Use Cases - Six-step bug-to-spec protocol: Trace the root cause, analyze whether a new invariant would catch it, propose the spec edit, generate a failing test, verify the fix, and commit everything together. - Invariant quality guidance: Distinguishes testable, behavior-scoped invariants from vague rules, with concrete good and bad examples. - Scope judgment rules: Defines when not to add a new invariant (mechanical typos, one-time migrations, external dependency issues) while still logging the incident in the bug ledger. - Use Case: A refund job runs twice on retry. The Skill guides you to record the incident in the bug ledger, add an idempotency invariant to the spec, write a failing test named after that invariant, fix the code, and commit all four artifacts in one commit. ## Quick Start Ask the AI to run the backprop protocol on the failing test or bug report and update the spec with a new invariant and regression test.
