What problem does it solve? Design decisions about state models, business logic, or UI layouts are hard to judge on paper, and building the real thing just to evaluate it wastes effort. This Skill produces throwaway prototypes that let you drive a state machine or flip between radically different UI variants before committing to a design. ## Core Features & Use Cases - Logic prototypes: Generates a single self-contained HTML file with free-play action buttons and tabbed guided walkthroughs so non-developers can push a state model through awkward edge cases. - UI prototypes: Renders 3-5 structurally different variants of a page on one route, switchable via a ?variant= URL param and a floating bottom bar with arrow-key navigation. - Answer capture: Records the question, what was tried, and the user's verdicts as rules with reasons in an ANSWER.md, then archives the prototype under agent/prototypes/ as a primary source. - Use Case: A team is unsure whether a multi-step checkout state machine handles cancellations correctly. The Skill builds a clickable HTML demo with scenarios for the happy path, an illegal transition, and an edge case, letting a product manager feel the model and report what feels wrong. ## Quick Start Ask the agent to prototype the design question you are facing, for example: build a clickable prototype comparing three layouts for the settings page, or a state-machine demo for the checkout flow.