What problem does it solve? It turns an approved change proposal and specs into a concrete technical design document, capturing architecture decisions, data flow, file changes, and testing strategy so implementation work starts from a documented plan rather than guesswork. ## Core Features & Use Cases - Design Document Generation: Produces a design.md with architecture decisions, alternatives considered, data flow diagrams, file change tables, and interface contracts. - Multi-Mode Persistence: Supports engram, openspec, hybrid, and none artifact store modes, reading proposals and specs from the appropriate source. - Threat Matrix Integration: Applies an applicability-driven threat matrix for designs touching routing, shell commands, subprocesses, or VCS/PR automation, propagating cases to RED tests. - Use Case: After a change proposal is approved, the orchestrator delegates to this sub-agent, which reads the actual codebase and returns a design under 800 words ready for task breakdown. ## Quick Start Delegate the design phase for my approved change to the sdd-design sub-agent so it produces the technical design document.
