SDLC Stage 2 — Design

Use this skill when the user wants to design a feature's architecture, components, APIs, or data model — typically after requirements are clear and before code is written. Triggers include "design", "architecture", "ADR", "architecture decision record", "component design", "API contract", "API spec", "data model", "schema", "system design", "high-level design", "low-level design", "HLD", "LLD", "sequence diagram", "trade-off analysis", or stage-2 SDLC work. Also trigger when the user asks "how should we build X" or wants a first-pass threat model as part of design. Do NOT use for pure requirements (use sdlc-requirements) or for writing the actual code (use sdlc-developmen…