Theo hides running agent threads in T3 Code
A beta option surfaces an agent thread only when it wants attention, and Theo says the cost is the spatial stability he spent effort building.
Theo shipped a beta T3 Code feature called "Hide threads while working" that takes running work off the screen until it needs something from you. His stated motivation is simple. He does not like running work taking space in his brain.
Don't like "running work" taking space in my brain.
A day of using it, and he says he is obsessed. He reports having 18 threads working at once and says it no longer feels claustrophobic. That is one person's experience in his own product, not a benchmark, but it is the kind of number that makes the design argument concrete. Eighteen simultaneous agent threads is an unreadable list if every one of them is always visible and most of them are mid-task and fine.
Things appear when they need your attention, and disappear when they don't.
The tradeoff he names himself
Theo is explicit about what this costs. He says he put a lot of effort into minimizing how often things shift around and move in T3 Code, because he wanted to build a sense of spatial awareness into the product. Hiding and unhiding threads breaks that. Items appear and vanish, so the position of a thread no longer means anything stable, and you cannot build muscle memory for where a given task lives.
He has not decided the question. His words are "Not sure how I feel just yet but good vibes so far" and "Not sure if this will stick", and he asked users to try it and tell him how it feels. So this is a beta flag and an open question, not a settled design.
For working engineers, the useful part is the framing rather than the feature. Once you are running many agents in parallel, the scarce resource is your attention, not tokens or CPU. A list that shows every thread treats all of them as equally urgent, when in practice the only ones that matter at any moment are the ones blocked on a decision. Filtering to those is a pattern you can copy in a tmux layout, a dashboard or a notification rule without waiting for your tool to ship it. The counter-argument is Theo's own, that a UI which constantly rearranges itself has its own tax.