Building sdd: A Spec-Driven Workflow That Enforces Itself

Almost every project I’ve written about this year, Codex, Tsundoku, Kiln, Mnemo, was built the same way: a PRD, broken into phase specs, broken into task files, implemented one task at a time with Claude Code doing most of the typing. That workflow started as a handful of personal slash commands, and it’s now a proper Claude Code plugin called sdd. This post is about what it does, and about the part that took the most work: making it enforce itself. ...

September 27, 2026 · 5 min · 1032 words · Sylvain Cau