Поэтапная миграция легаси-систем

engineering

Legacy modernizer is a Claude Code skill that designs incremental migration strategies, builds dependency maps, produces phased migration roadmaps, and generates API facade designs for aging codebases. Reach for it when a monolith has grown too tangled to touch safely; when you need to replace a legacy service piece by piece without taking the business offline; when technical debt has piled up and the team wants to move to a new framework or language without a risky big-bang rewrite; or when you need to extract microservices from a monolith while keeping existing integrations intact. The skill walks through a five-step workflow: system assessment with a risk register → incremental plan with explicit per-phase rollback strategies → characterization test suite targeting 80%+ coverage of existing behavior → gradual traffic shifting through a facade with feature flags (5% → 25% → 50% → 100%) → validation and legacy retirement only after one full release cycle at 100% traffic. It produces ready-to-use Python code: an OrderServiceFacade, feature-flag wrappers, and pytest golden-master test templates. The direction is strangler fig replacement of a live system, not a one-shot rewrite — for greenfield architecture, see other catalog skills. Related skills: test-master, devops-engineer.