Specs Aren't Waterfall When the Rebuild Takes 15 Minutes
The HN Crowd Has a Point
The Hacker News post titled "Spec-Driven Development: The Waterfall Strikes Back" hit roughly 332 points and dragged the same debate onto the front page three separate times in a month. The receipts piled up fast. François Zaninotto argued specs eat more than half of project time. A widely-shared Medium piece coined "Waterfall in Markdown." Someone posted screenshots of an agent generating 1,300 lines of markdown to render a date.
If you have watched a founder try to ship through a planning-heavy AI workflow, none of this is shocking. You write a spec. The agent half-reads it. You discover the constraint that actually matters two weeks in. You rewrite the spec. The agent forgets. The "spec-driven" part of the workflow starts to feel like every shoulder-tap meeting you have ever sat through, only now the meeting writes itself.
The critics are not wrong about what they are seeing. They are wrong about what is actually broken.
