Why PRD Alone Is Not Enough: What the Tech Spec Must Cover in AI-Assisted Development
in the “Taming AI Coding Agents with TDD” series. The first covered test-driven requirements anchoring, the second covered the GEAR protocol for requirements disambiguation. This one fills the gap between them: after the PRD is done, what must the tech spec cover? Requirements Locked, Code Still Wrong Before the second Aristotle refactor, I spent two full days writing requirements. Following the structured approach from the previous article, I captured every acceptance criterion, boundary condition, error path, and platform constraint[1]. The AI consumed the document, passed all 37 static assertions plus end-to-end tests. The codebase was split into four files by responsibility. Information flow was switched from push to pull. ...