Spec-driven development

AI Spec-Driven Development (AI-SDD) in 2026: Why SDD Is Back and Docs Become Code

Since GitHub's Spec Kit and AWS's Kiro arrived in autumn 2025, spec-driven development (SDD) has become the standard discipline for AI coding. Written for corporate new-business teams, this article explains why "fix the documents before writing code" made a comeback, how to write the four documents (requirements, specification, basic design, detailed design) with a coding agent, and why development docs, progress docs and memory docs now play a role close to code, quoting Andrej Karpathy's statements along the way. A full rewrite of the March 2026 original. Part 3 of the AI-native new business development series.