Test-driven development was always more useful as a design discipline than a testing strategy. Writing the test first forced clarity about what the code was supposed to do before any implementation decisions were made. The red-green-refactor loop was valuable because it built understanding incrementally. AI-assisted development has resurfaced this distinction in an unexpected way. When code can be generated quickly from a specification, the temptation is to generate the implementation first and the tests afterward — or to generate both simultaneously and treat passing tests as evidence of correctness.