Use when exploring how a feature or screen could work before committing to a direction — "prototype this", "let's prototype", "show me options", "what could this look like", "mock it up". Builds the brief from the conversation so far (or interviews the user when there isn't one), then generates several low-fidelity, interactive HTML wireframes in a throwaway folder, recommends one, and iterates on the user's pick. Fast, cheap, disposable — a thinking tool, not finished work.
