Invoke for product and UX/UI design: user research and problem framing, information architecture and navigation, user flows and interaction design, wireframing, visual design and hierarchy, design systems and components, usability heuristics and evaluation, accessibility and inclusive design, prototyping and usability testing, content/UX writing direction, and design handoff to engineering. Use when the question is what the experience should be and why — the user's goals, the flow, the structure, and the interface decisions upstream of (and feeding) front-end implementation.