SDD Phase-Gate Review

Enforcing the SDD pipeline's gated structure: every artifact is reviewed before the next phase proceeds. This skill owns the Review gates between every pair of SDD phases.

SDD Pipeline Position

[SPECIFY] → REVIEW → [PLAN] → REVIEW → [TASKS] → REVIEW → [IMPLEMENT] → REVIEW → [VERIFY]
     ↑         ↑        ↑        ↑         ↑         ↑           ↑          ↑
     └─────────┘        └────────┘         └─────────┘           └──────────┘
   Gate 1: Spec      Gate 2: Plan      Gate 3: Tasks          Gate 4: Implementation

Every gate asks the same question: "Is the artifact for this phase complete, correct, and unambiguous enough for the next phase to proceed safely?"

Core Principle: The Gate Is the Quality Mechanism

In SDD, quality is not enforced by code review — that's too late. Quality is enforced by the phase gate. A defect caught at Gate 1 (spec review) costs minutes to fix. The same defect caught at Gate 4 (implementation review) costs hours — the implementation may need to be discarded and rewritten against a corrected spec.