Open vs. closed prompts are two types of prompts used in conversations to elicit responses from users. Open prompts provide the user with an unlimited choice of responses, while closed prompts elicit a limited set of potential answers. The difference between open and closed intents lies in their contextual availability, with top-level or open intents always available and closed intents only available at a specific point in the conversation. To craft effective open or closed prompts, designers must align the prompt's structure with its content, considering whether the conversation is user-led or system-led. System-led conversations are designed to achieve a specific objective, such as determining a pizza order preference, while user-led conversations allow the user to set the conversation's objective. The narrowing principle can be employed to steadily go from open to closed prompts as the conversation progresses, allowing users to define their objectives before the assistant takes over. Effective conversation design uses this principle to create a shared objective and achieve a smooth user experience.