deprecation-and-migration SKILL.md skillA

deprecation-and-migration from addyosmani/agent-skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.

mdr add addyosmani/agent-skills/deprecation-and-migration@git:20261017.9f91cc4

Pins git:20261017.9f91cc4 in mdr.lock. Pin the fingerprint instead.

Audit grade

A, 17 of 17 checks passed

Kind

SKILL.md skill

Repository

addyosmani/agent-skills

Path

skills/deprecation-and-migration/SKILL.md

Versions recorded

6

Latest version

git:20261017.9f91cc4, committed Oct 17, 2026

First version recorded

Mar 28, 2026

Size

12,839 bytes

Repository stars

112,362

License

MIT

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.

Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.

What the file says

# Deprecation and Migration

## Overview

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.

Most engineering organizations are good at building things. Few are good at removing them. This skill addresses that gap.

## When to Use

- Replacing an old system, API, or library with a new one
- Sunsetting a feature that's no longer needed
- Consolidating duplicate implementations
- Removing dead code that nobody owns but everybody depends on
- Planning the lifecycle of a new system (deprecation planning starts at design time)
- Deciding whether to maintain a legacy system or invest in migration

## Core Principles

### Code Is a Liability
…

Read the whole file at its exact version.

How to install

mdr add addyosmani/agent-skills/deprecation-and-migration@sha256:1896d7db836fc067

[![mdr](https://markdownregistry.com/badge/art_ggkgxpa5t26dtful.svg)](https://markdownregistry.com/a/art_ggkgxpa5t26dtful)

Versions

The registry has recorded 6 versions of this file, between Mar 28, 2026 and Oct 17, 2026, about one every 41 days.

Audit of the latest version

Source

API

GET https://markdownregistry.com/api/v1/artifacts/art_ggkgxpa5t26dtful
GET https://markdownregistry.com/api/v1/resolve?ref=addyosmani/agent-skills/deprecation-and-migration
GET https://markdownregistry.com/api/v1/blob/1896d7db836fc067e2856739664db9ff5bb642526fdff2126d08ec0d588da4b7

Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.

Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.

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