It's wild how much these agent interfaces have aligned UI-wise. There's almost zero difference between all of them.
It's kind of bizarre in that it's not like this is an optimal interface, either. I mean, it's fine, but why not try something different? I also don't really get why TUI's have become such a big deal, other than maybe nerd bait. The only time I want a TUI is when I'm SSH'd into a machine, which isn't very often? TUI's have so many downsides. Selecting text is inconsistent, copy paste is inconsistent, mouse behaviors..…
First up - I completely agree that parts of the terminal experience are decidedly lackluster, you can make them "fine" but the general experience doesn't align with consistent OS principles users are familiar with, and I agree that good mouse support, expected copy and paste, selection behaviors, adding files/attachments to prompts, etc... all could be better (and actually are mostly better on decent modern terminals, as an aside)
But... And this is the big but... LLMs are basically text IO systems. And terminals are designed from the ground up to allow text IO to control the entire system, including the TUI (ex - multiplayer agent tmux is a fun demo).
It's a genuinely powerful pairing, and basically ALL of the non-TUI systems basically end up just embedding a terminal [cough* xterm *cough] and becoming a non-standard TUI themselves, anyways.
So TUIs have become a big deal because it's the obvious and easy way to give an LLM "computer use" skills, without spending a fortune on tokens doing graphical processing for GUIs, which are geared towards humans and not agents, and are generally less powerful anyways.