Spec-Driven Development

Overview

SDD makes specifications the source of truth — code serves specs, not the other way around. Instead of prompting an AI with vague descriptions and hoping for the right output, you define precise specifications first, then let AI generate code strictly constrained by those specs.

Core principle: "When specifications drive implementation, pivots become systematic regenerations rather than manual rewrites."

Why it works: without a spec, AI makes thousands of micro-decisions silently. With a spec, those decisions are made by you — explicitly, before any code is written.

Spec Levels