I've tried using Codex and ChatGPT while working on a small SwiftUI app. It's not very good when it comes to newer APIs and features - I imagine due to lack of data about these things. Very often it would rather push something AppKit-based instead of SwiftUI.

It works, but feels really janky and messy.

I had one very annoying bug with file export API where extra view on export window would appear with a delay. No matter what I tried it didn't manage to fix it. Instead it would go on to try and completely rewrite whole file export class in various ways... which still didn't work as it claimed it would. Ended up fixing it manually by caching instance view locally.