SkillMedev/legacy-modernization
Skill Claude CodeCodex
Ports a codebase across a breaking language or runtime version with compatibility shims, batched automated transforms, dual-runtime CI, and old-vs-new output diffing, ending in a flag-flip cutover with a rollback rule. Use when someone says "migrate us from Python 2 to 3", "we're jumping Node majors", "move to the…