I used to think UIs would be better for agents, but I changed my mind: UIs suit traditional software very well because there are only X actions that can be performed - it makes sense that if you have an image converter that can take X, Y and Z formats and convert them to A, B and C then you should have a UI that limits what the user can do, preventing them from making mistakes and making it obvious what's possible.

But for something like Claude Code there are unlimited things you can do with it, so it's better for them to accept a free-form input.