# Things happen twice, or not at all

Prompts to start with when a codebase shows this problem.

- [Safe to run twice?](https://atlasscope.dev/prompts/safe-to-run-twice): Finds actions that do damage when they run twice: double sends, double charges, duplicate rows.
- [Updates that overwrite each other](https://atlasscope.dev/prompts/updates-that-overwrite-each-other): Finds updates that overwrite newer data because two things wrote at once.
- [Imports that fail quietly](https://atlasscope.dev/prompts/imports-that-fail-quietly): Finds rows that go missing or land on the wrong record during import, with no error.
- [Background jobs that hang or stop halfway](https://atlasscope.dev/prompts/background-jobs-that-hang-or-stop-halfway): Finds scheduled jobs and background workers that can hang, overlap or stop halfway.

Source: https://atlasscope.dev/fix/things-happen-twice-or-not-at-all