What problem does it solve? It turns approved spec-driven development artifacts (proposal, specs, design, tasks) into actual working code, ensuring implementation strictly follows the design and that task completion is tracked and persisted across batches. ## Core Features & Use Cases - Spec-Driven Implementation: Reads proposal, spec, design, and tasks artifacts before writing code, treating spec scenarios as acceptance criteria and design decisions as constraints. - Strict TDD Mode: When enabled with an available test runner, enforces a RED-GREEN-TRIANGULATE-REFACTOR cycle with a mandatory TDD Cycle Evidence table and banned trivial-assertion rules. - Progress Persistence & Workload Guardrails: Merges apply-progress across batches, marks tasks complete in tasks.md or Engram, and blocks work when PR size forecasts require a chaining or size-exception decision. - Use Case: An orchestrator assigns Phase 1 tasks 1.1-1.3 of a change; the skill reads the specs and design, implements the code following project conventions, marks tasks complete, and returns a structured summary ready for the verify phase. ## Quick Start Delegate the pending tasks for a specific SDD change to the sdd-apply sub-agent so it implements them according to the specs and design.
