What problem does it solve? Structural refactoring often introduces silent regressions because there is no proof that external behavior stayed identical. This Skill enforces a disciplined workflow—contract first, test baseline before changes, independent adversarial review, and compile-review-test loops—so every refactoring is verifiable against a frozen list of immutable items. ## Core Features & Use Cases - Contract-First SSOT: Freezes target structure, scope units, immutable items (routes, signatures, return types, annotations), and verification commands into one contract file confirmed by the user before any code changes. - Test Baseline & Contract Snapshots: Builds a rerunnable baseline from existing tests, generated contract-level tests, or a degraded fallback using contract-snapshot.py to diff public signatures, routes, and annotations before and after. - Separation of Change and Review: Modification subagents execute changes while independent read-only subagents perform adversarial method-by-method mapping reviews, with a compile-review-test loop capped at 3 rounds. - Use Case: Extract business logic from 12 Controller classes into a service layer while keeping every route, signature, and response byte-identical, then receive a graded review report and regression test evidence. ## Quick Start Ask the agent to refactor the order module by moving business logic from controllers into a service layer without changing any external behavior.
