build-mermaid-spec
by MagicPlug
Use when a user wants to generate a Mermaid diagram, visualize a system flow, or says "create a diagram", "mermaid", "visualize the flow", "diagram this". Also use when a design doc or implementation plan exists in docs/plans/ and user asks to diagram it. Use when requirements are vague and need clarification before building — "I want to build", "plan", "design", "let's architect".