What problem does it solve? Modernizing aging codebases without disrupting production is risky and complex. This Skill provides structured workflows for assessing legacy systems, planning incremental migrations, and executing them safely with rollback strategies, eliminating the danger of big-bang rewrites. ## Core Features & Use Cases - System Assessment: Analyze codebases for dependencies, code smells, technical debt, and risk areas before touching production code. - Incremental Migration Patterns: Apply strangler fig, branch by abstraction, dual-write database migration, and facade patterns with feature-flag-controlled rollouts. - Safety Net Construction: Build characterization tests, golden master tests, and parallel-run comparisons to preserve existing business behavior. - Use Case: When decomposing a monolith into microservices, use this Skill to extract a payment service behind a facade, route traffic gradually (10% → 50% → 100%), and validate error rates at each phase before retiring legacy code. ## Quick Start Use the legacy-modernizer skill to assess my monolithic application and design a phased migration plan to extract the payment module into a separate service.
