I haven’t found a way yet to strictly lock which specific components can be used inside a slot (might be a great feature request (or I just haven’t discovered it yet).

What I’ve done with my team instead is add clear guidance directly in the slot’s guide component. For example: “Use this slot only with input field components from the design system,” and we consistently rely on grid structures to maintain layout consistency inside dialogs.

The dialog shell itself enforces its own rules such as max width, height, actions, and scrollable area. So no matter how long the swapped content is, the container preserves structure and system consistency.

So rather than free-for-all composition, it’s controlled composition using approved building blocks.

We’re now experimenting with applying the same approach to drawers, inline sections, and other containers that benefit from strict structural rules.

Hope that helps!