Version: 2.1.0 Last Updated: 2026-01-26 Applicability: All projects adopting Spec-Driven Development Scope: universal Industry Standards: None (Emerging 2025+ methodology) References: specmatic.io
Spec-Driven Development (SDD) is an AI-era methodology (2025+) distinct from traditional TDD/BDD/ATDD. It ensures that changes are planned, documented, and approved via specifications before implementation. The core principle is "Spec First, Code Second" - no functional code changes without a corresponding approved specification.
SDD operates at different maturity levels: Spec-first (discard after completion), Spec-anchored (maintain throughout evolution), and Spec-as-source (spec is only source, code auto-generated). The methodology uses Forward Derivation to generate test artifacts (BDD scenarios, TDD skeletons, contracts) from specifications.
Full Guide: SDD Guide
| Aspect | Description |
|---|---|
| Core Workflow | Proposal → Review → Implementation → Verification → Archive |
| Key Principle | Spec First, Code Second |
| Test Generation | Forward Derivation (/derive-bdd, /derive-tdd, /derive-all) |
| Maturity Levels | Spec-first, Spec-anchored, Spec-as-source |
| Tools | OpenSpec, Spec Kit, Manual (file-based) |