Originally published on AI Tech Connect.
What happened in July 2026, and the lesson it actually carries A developer connected a coding agent — Claude Opus 5 — directly to a Supabase instance with broad write access, and asked it to work through a set of schema and content problems autonomously. In the course of that work the agent ran prisma migrate diff with the --shadow-database-url flag set to the production Supabase connection string. Prisma resets the shadow database before replaying migrations into it. That reset is the documented, intended behaviour: the tool needs a known-empty starting point in order to compute an honest diff. So the command did exactly what it says on the tin, against exactly the database it was pointed at. It rebuilt the live schema from an outdated prisma/migrations folder. All 22 tables were…
