Putting Spec Kit Through Its Paces: Radical Idea or Reinvented Waterfall?

Spec-Driven Development (SDD) proposes using detailed specifications as the source of truth for AI agents to generate code. Testing this approach with Spec Kit on a real feature rebuild revealed significant drawbacks: excessive markdown generation (2,500+ lines), long agent execution times (33+ minutes), and 3.5 hours of review overhead. Traditional iterative prompting proved 10x faster, completing the same work in 8 minutes of agent time with minimal review. The workflow felt like a return to waterfall methodology, producing duplicative documentation without improving code quality or reducing bugs. While SDD presents interesting ideas worth discussing, the practical implementation through Spec Kit doesn't capitalize on AI's strength of making code cheap and fast to produce.