Ask the agent to inspect the schema, migration history, deployment model, and rollback constraints before writing anything.
Prefer additive, backward-compatible steps: add fields, deploy compatible code, backfill with checkpoints, switch reads, then remove old structures later. Require explicit approval for destructive operations.
Test on representative data, estimate locks and runtime, verify idempotency, and document rollback. An agent can draft and validate a migration quickly. Humans must still own irreversible decisions and production execution.