React's whole promise was to be declarative and tree-like, but useEffect quietly reintroduced the timeline, and most codebases leaned into it. Moves like banning useEffect aren't just about agents. They're about closing the gap between what React promised and how it's actually used. When your code reads like a tree, it's not just agents that benefit. It's the PM investigating a bug. The support engineer tracing a customer issue. The new hire on week two. Legibility isn't a style preference. It's infrastructure. https://rachel.fyi/posts/why-banning-useeffect-is-really-about-agents