# Migration Check

> Use on any database schema or migration change: check reversibility, defaults, nullability against existing rows, and that a test exercises the new shape.

- Skill: `astarlab-s/migration-check` (Agent Skill)
- Install (CLI): `npx skillmds@latest add astarlab-s/migration-check`
- Raw SKILL.md: https://api.skillmd.com/api/skills/astarlab-s/migration-check/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: ASTARLab-s (https://skillmd.com/u/astarlab-s)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/astarlab-s/migration-check

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For any schema or migration change, verify before it merges:

1. **Reversibility** — is there a down path, or is this explicitly one-way?
   State which, and what the rollback plan is if it ships broken.
2. **Existing rows** — do new NOT NULL columns have defaults or backfills?
   Would the migration lock a large table? Check against the real row shape,
   not the ORM model.
3. **Consumers** — which queries and endpoints read the changed shape? Flag
   any that would break mid-deploy (old code, new schema).
4. **Coverage** — point at the test that exercises the new shape. If none
   exists, draft it now; a migration without a test is unverified by
   definition.

Report each of the four with a pass / fail / not-applicable and one line of
evidence.