# Migration

> Implement reversible compatibility-safe transitions. Use for schema, data, API, protocol, configuration, or dependency migrations requiring rollback and preservation proof.

- Skill: `juliusbrussee/migration` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add juliusbrussee/migration`
- Raw SKILL.md: https://api.skillmd.com/api/skills/juliusbrussee/migration/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Integrations & APIs
- Author: Julius Brussee (https://skillmd.com/u/juliusbrussee)
- Updated: 2026-09-09
- Page: https://skillmd.com/skills/juliusbrussee/migration

---


# Migration

Map current readers, writers, data shape, compatibility window, and ownership before editing.

- Define forward path and rollback path.
- Preserve existing data; make destructive steps explicit and separately authorized.
- Keep mixed-version operation safe where rollout can overlap.
- Sequence expand, migrate, verify, then contract when applicable.
- Make retries idempotent and partial failure observable.
- Verify old and new paths at required transition stages.

Stop after requested stage passes; do not perform later destructive contraction implicitly.