skillsight

How to safely add, edit, and verify Drizzle migrations in the skills-observability backend (PostgreSQL + Drizzle ORM). Covers the schema-first generation flow, the strict monotonicity invariant of `_journal.json` `when` timestamps (whose violation has silently skipped migrations in production), idempotent SQL patterns, and how to verify on a fresh DB before merging. Use this skill whenever the user edits `backend/src/db/schema.ts`, runs `bun run migrate:generate` or `bun run migrate:run`, hand-edits anything under `backend/src/db/migrations/` (including `meta/_journal.json`), asks about adding or altering a database column / table / index / constraint, debugs a migration that "didn't apply" or "ran in dev but not prod", or resolves a merge conflict in the migration journal. Trigger this even if the user only mentions a small schema tweak — the journal pitfall is the kind of bug where everything looks fine until production silently diverges, and the right time to apply this guidance is before the schema edit,