Deprecation And Migration

Most teams are better at building systems than removing them, which is how you end up maintaining three authentication flows and two logging libraries. This skill helps you decide whether to sunset old code, plan compulsory versus advisory deprecations, and actually migrate users without leaving zombie code that nobody owns but everybody depends on. The core insight is that code is a liability with ongoing maintenance costs, and Hyrum's Law means you can't just announce deprecation and expect users to switch. It includes the strangler pattern for gradual cutover, the churn rule (if you deprecate infrastructure, you migrate the users), and a decision framework for weighing migration cost against maintenance burden. Use this when replacing APIs, consolidating duplicate implementations, or deciding if that legacy service earns its keep.

Install to Claude Code

npx -y skills add addyosmani/agent-skills --skill deprecation-and-migration --agent claude-code