Overview
deprecation-and-migration is an open-source backend skill for Claude Code and compatible agents, published by addyosmani. Its author describes it as: “Manages deprecation and migration. Use when removing old systems, APIs, or features. Use when migrating users from one implementation to another. Use when migrating a database schema in production, such as renaming or…”. The project has 98k stars on GitHub and is available under the MIT license. Add it to your setup with `/plugin marketplace add addyosmani/agent-skills`.
What deprecation-and-migration does
Code is a liability, not an asset. Every line of code has ongoing maintenance cost — bugs to fix, dependencies to update, security patches to apply, and new engineers to onboard. Deprecation is the discipline of removing code that no longer earns its keep, and migration is the process of moving users safely from the old to the new.
Best for
What’s inside
The SKILL.md for deprecation-and-migration is organised into these sections:
- Overview
- When to Use
- Core Principles
- Code Is a Liability
- Hyrum's Law Makes Removal Hard
- Deprecation Planning Starts at Design Time
- The Deprecation Decision
- Compulsory vs Advisory Deprecation
- The Migration Process
- Step 1: Build the Replacement
- Step 2: Announce and Document
- Step 3: Migrate Incrementally
Installation
Add deprecation-and-migration to your agent with:
/plugin marketplace add addyosmani/agent-skillsReview a skill’s source before installing it — skills can instruct your agent to run commands. This command comes from the skill’s public repository, which is the source of truth for setup steps. New to skills? Read how to install Claude Code skills.
Supported agents
- Claude Code — ships a claude code plugin marketplace
- Codex — declared in the repository topics
- Cursor — declared in the repository topics
- Antigravity — declared in the repository topics
License
deprecation-and-migration is published under the MIT license.
Strengths
- Clear MIT license — safe to read and adapt within its terms
- Ships in addyosmani/agent-skills, an established project with 97,992 GitHub stars
- Works with Claude Code, Codex, Cursor, Antigravity
- Actively maintained — repository updated in the last 30 days
- Its repository gained 16,916 GitHub stars over the last 52 days
Author
Topics
Frequently asked questions
- What does deprecation-and-migration do?
- Manages deprecation and migration. Use when removing old systems, APIs, or features. Use when migrating users from one implementation to another. Use when migrating a database schema in production, such as renaming or dropping a column without downtime (expand/contract). Use when deciding whether to maintain or sunset existing code.
- How do I install deprecation-and-migration?
- Run /plugin marketplace add addyosmani/agent-skills in your agent, then reload your skills. Review the source at https://github.com/addyosmani/agent-skills before installing.
- Is deprecation-and-migration free to use?
- Yes. deprecation-and-migration is free and open source under the MIT license, so you can read, run, and adapt it within that license's terms.
- Which agents does deprecation-and-migration work with?
- deprecation-and-migration lists Claude Code, Codex, Cursor, and Antigravity — named in its SKILL.md, its plugin marketplace or its repository topics. Skills use the portable SKILL.md format, so other agents that read that format may load it too.
- Where does deprecation-and-migration come from?
- deprecation-and-migration ships inside addyosmani/agent-skills, a repository that contains 26 catalogued skills in total. The repository's 97,992 GitHub stars apply to that whole collection, not to this skill on its own.
