A vibe coder I follow lost two days of customer data last weekend. Not from a hack. Not from a hardware failure. From a single AI-generated migration that a senior engineer would have caught in 10 seconds. If you're shipping with Claude, Cursor, Copilot, or any agent that touches your schema, you need to read this before you run another migrate command. What actually goes wrong AI is genuinely good at writing application code. It pattern-matches against millions of similar codebases and produces plausible code fast. For most things — components, handlers, glue logic — that's enough. If it's wrong, you re-render. You re-run. You ship a fix. Database migrations are different. They have one property the AI quietly ignores: they execute exactly once, and the wrong sequence is unrecoverable without a backup. Three failure modes I've now seen in the wild: 1. Silent column drops. The AI "improves" a migration by removing what it thinks is a dead column. The column had three months of customer data.…