Computer use panel: watch what an agent is doing on the Mac, and pick the engine separately from the model

[PrivateVictories-Main]

The Device panel is one of my favorite parts of T3: I can watch an agent drive a simulator, tap it myself, and float it over the chat. I'd love the same thing for computer use and browser use on the Mac itself.

I'm a longtime Codex user, and one thing it gets right is that computer use feels visible and organized: you can watch the agent work on screen as it goes. In T3 I run Claude and Codex side by side, and a lot of my work is desktop and browser automation. The preview browser already shows pages an agent opens there, but when an agent drives a desktop app or my own browser, I only see tool calls in the timeline, not the screen.

What would help:

1. A Computer panel, like the Device panel: a live view of the app, window, or browser an agent is working in, with the same float-over-chat option.
2. Choosing the computer-use and browser engine separately from the chat model, with setup and permission status in one place. Computer use and the model driving it are different layers, and with several providers in T3 it would be great to mix them, for example Claude orchestrating while a specific computer-use engine does the clicking.

Related: #6726 covers Codex Computer Use approvals in T3, and #15112 covers viewing a connected machine's desktop. This is the local side: seeing what the agent is doing on this machine while it works.

Totally understand if this is further out on the roadmap; just sharing the use case.