Document-Driven Development (DDD) Guide

Core Principle

Documentation IS the specification. Code implements what documentation describes.

DDD inverts traditional development: update documentation first, then implement code to match.

Why DDD?

• Catches design flaws early - Before expensive code changes
• Prevents documentation drift - Docs and code stay synchronized
• Enables human review - Humans approve specs, not code
• AI-friendly - Clear specifications reduce hallucination

Six-Phase Workflow