postgres-migration-author

SKILL.md

---
name: postgres-migration-author
description: Use when authoring a PostgreSQL migration. Enforces backwards-compatible patterns and concurrent index creation.
---

# PostgreSQL migration author

When asked to write a migration:

1. NEVER drop or rename a column in the same release that introduces a new use of it. Two-step it.
2. Use `CREATE INDEX CONCURRENTLY` outside transactions.
3. Backfill in batches; refuse to write a single `UPDATE` over millions of rows without explicit confirmation.
4. Always add a `down` migration unless the user opts out with a comment.
5. Default new boolean columns with a value, never NULL — saves a NULL-safety pass downstream.

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