AI agent skill · by @Archive228

Migration Writer

Write safe, reversible database migrations for this repo's conventions. Use for any schema change.

Archived 2026-10-23 · Source updated 2026-07-14 · License: MIT. Check the original repository for the latest version.

SKILL.md instructions

# Migration Writer
1. Read the current schema first. Match the repo's migration tool and naming (`NNN_<verb>_<noun>`).
2. Write BOTH up and down. A migration you can't reverse is a migration you can't deploy safely.
3. **Live-safe**: on a hot table, adding a NOT NULL column with no default, or an index without CONCURRENTLY, takes a blocking lock. Split into steps: add nullable → backfill → add constraint.
4. Backfill large tables in batches, not one statement.
5. Never edit an already-merged migration — add a new one.
Test with a dry-run before committing. Output the migration + the exact deploy order.