spec-driven-development

# Spec-Driven Development ## Overview Write a structured specification before writing any code. The spec is the shared source of truth between you and the human engineer — it defines what we're building, why, and how we'll know it's done. Code without a spec is guessing. ## When to Use - Starting a new project or feature - Requirements are ambiguous or incomplete - The change touches multiple files or modules - You're about to make an architectural decision - The task would take more than 30 minutes to implement **When NOT to use:** Single-line fixes, typo corrections, or changes where requirements are unambiguous and self-contained. ## The Gated Workflow Spec-driven development has four phases, preceded by a scope check (Phase 0) that activates only when one request bundles several independently testable capabilities. Do not advance to the next phase until the current one is validated. ``` SPECIFY ──→ PLAN ──→ TASKS ──→ IMPLEMENT │ │ │ │ ▼ ▼ ▼ ▼ Human Human Human Human reviews reviews reviews reviews ``` ### Phase 0: Scope Check Most requests describe one capability. If this one does, skip this phase and go straight to Specify — Phase 0 exists for the exception, not the rule, and it puts no hierarchy on single-capability features. **Detection.** Decompose before specifying when a single requirement bundles several independently testable capabilities: - The requirement names distinct cap...