When should an AI app in a chat take over your whole screen, versus just showing up as a small card in the conversation?

This explores how developers building apps inside a chat assistant should decide when a task deserves the whole screen and when a compact card in the conversation will do. The corpus has only one direct source here, OpenAI's Apps SDK guidelines. Those guidelines define three display modes: inline cards, fullscreen and picture-in-picture. The detail that matters most is that the chat input box stays visible in all three, even fullscreen How should UI widgets coexist with conversational interfaces?. So choosing fullscreen doesn't mean leaving the conversation. It means the interface and the conversation run side by side, and the real question is how much room the interface needs next to the chat.

The corpus has no explicit decision rules, but other research points to a useful test: how dense and structured is the task? Studies of AI-generated interfaces found that users preferred interactive dashboards and tools over text in more than 70% of cases. The preference was strongest for information-dense, structured work, where seeing everything at once reduces mental effort Do generated interfaces outperform text-based chat for most tasks?. That suggests a simple rule of thumb. If people need to compare, explore or edit many things at once, the task has outgrown a card. If it's a quick confirmation, a single result or one choice, an inline card keeps people moving.

There's a cost to going bigger, though. The TaskArtisan study found that generated analysis interfaces made results clearer but harder to change partway through: the more polished the interface, the harder it was to adjust Do generated analysis UIs really work better than chat?. That may be why OpenAI keeps the chat box visible in fullscreen. Typing stays available as a way to change course when the interface can't. Friedman's design levers make a similar case from the other direction. Direct manipulation, such as canvases, style lenses and node views, removes the slow work of typing out what you want, but works best alongside conversation rather than replacing it Can task-oriented UI patterns reduce the friction of AI chat interfaces?.

A second test is whether the user is already partway through a workflow. Friedman's 'AI-second' argument holds that AI features work best when they fit into habits people already have, not when they open a separate destination Should AI features integrate into existing workflows or stand alone?. Applied to display modes, a card that slots into the flow of a conversation is the default. Fullscreen should be saved for moments where the task itself becomes the destination, such as a map, an editor or a long form. Anthropic gives similar advice about agents: start with the simplest option and add complexity only when the task requires it When should teams choose workflows over agents?.

The surprising part is that for many users, the hardest part is knowing what interface they need at all. Moran argues that the value of generated interfaces is that the AI makes that design decision on the user's behalf Can generative UI serve users who cannot specify interfaces?. If the system chooses between card and fullscreen, though, it needs to be reliable. A benchmark of AI interface-generation tools found they skipped about a quarter of the design reasoning they stated, and a third of functional requirements Do generative UI tools actually implement their stated design rationales?. For now, developers are better off making that choice themselves than leaving it to the model.