Type: url
Original: https://martinfowler.com/articles/exploring-gen-ai/sdd-3-tools.html
Status: generated
Summary
In this October 2025 “Exploring Gen AI” article, Birgitta Böckeler examines what spec-driven development (SDD) means by trying three tools that label themselves as SDD tools — Kiro, GitHub’s spec-kit and the Tessl Framework — and proposes three implementation levels: spec-first, spec-anchored and spec-as-source. She defines a spec as a structured, behaviour-oriented natural-language artifact guiding coding agents, distinguishes it from a “memory bank” of general context documents, and describes each tool’s workflow and files. Her observations question whether one workflow fits all problem sizes, whether reviewing verbose Markdown beats reviewing code, whether the elaborate artifacts give a false sense of control, and whether spec-as-source risks repeating the downsides of model-driven development combined with LLM non-determinism, while acknowledging that the spec-first principle is valuable in many situations.