Prisma Safe Migrations

Use this skill to perform schema evolution safely with minimal production risk.

When to Use

• Editing prisma/schema.prisma.
• Creating migration files in prisma/migrations.
• Changing constraints, enums, indexes, or relation fields.
• Reviewing migration risk before release.

Safety Strategy

• Prefer expand-contract migrations for breaking changes.
• Avoid one-step destructive changes in active production paths.
• Verify generated SQL before applying.

Procedure

1. Read only relevant files:
   • prisma/schema.prisma
   • recent prisma/migrations/*/migration.sql
   • feature service/repository files affected by schema change
2. Classify change risk:
   • Low: add nullable columns, add non-blocking indexes
   • Medium: add required fields with defaults, enum extension
   • High: drop/rename columns, incompatible type changes, unique constraints on dirty data