What problem does it solve? Writing a technical design that stays consistent with an existing codebase and a change proposal is slow and error-prone. This Skill acts as a design sub-agent that reads the actual code, then produces a structured design.md capturing architecture decisions, data flow, file changes, interfaces, and testing strategy. ## Core Features & Use Cases - Codebase-grounded design: Reads entry points, patterns, dependencies, and test infrastructure before designing, so decisions follow the project's real conventions. - Structured design document: Generates a design.md with architecture decisions (choice, alternatives, rationale), ASCII data-flow diagrams, file change tables, interface contracts, and a testing strategy. - Multi-mode persistence: Supports engram, openspec, hybrid, and none artifact store modes, persisting to Engram topics, openspec/changes directories, both, or returning inline only. - Use Case: During a spec-driven development workflow, the orchestrator launches this agent after the proposal phase to produce the technical design for a change, which the tasks phase then consumes. ## Quick Start Ask the orchestrator to run the sdd-design phase for your change name so it reads the proposal and codebase and writes the technical design document.
