Seed Idempotency Guide

Seed data must be deterministic and safe to rerun.

Use unique seed-owned keys, upsert, or skip-if-exists behavior. Do not truncate tables or delete user-created data. The Sprint 20 verification command is pnpm db:seed:verify, which runs the seed twice and checks known seed-owned records stay stable.

The current verification checks Sprint 19 communication outbox items, templates, reviews, manual send logs, communication permissions, and the Sprint 16B staff usage metric seed row.