A CI check that failed the build when someone forgot a DB migration

At a mid-size SaaS company, a recurring annoyance was that someone would change a database model in a pull request but forget to include the migration file, and staging would break after merge. It happened enough that it had a nickname. As an intern I asked if I could try to catch it in CI. My first idea was naive — just check that if any model file changed, a migration file also changed — but that had false positives, like renaming a comment or editing a docstring shouldn't require a migration. So I leaned on the ORM's own tooling: I added a CI step that ran the framework's 'check for missing migrations' command in a throwaway database and failed the build if it reported pending schema changes with no migration. That was authoritative because it asked the framework itself rather than guessing from file diffs. The hard part was making the failure message useful — a red X with no explanation just annoys people — so I had it print the exact command to generate the missing migration. I tested it by intentionally opening a PR with a model change and no migration to confirm it went red, and one with both to confirm it stayed green. It cut the 'forgot the migration' breakages to basically zero on our team.