I'll second this. I'm making a fairly basic iOS/Swift app with an accompanying React-based site. I was able to vibe-code the React site (it isn't pretty, but it works and the code is fairly decent). But I've struggled to get the Swift code to be reliable.

Which makes sense. I'm sure there's lots of training data for React/HTML/CSS/etc. but much less with Swift, especially the newer versions.

I had surprising success vibe coding a swift iOS app a while back. Just for fun, since I have a bluetooth OBD2 dongle and an electric truck, I told Claude to make me an app that could connect to the truck using the dongle, read me the VIN, odometer, and state of charge. This was middle of 2025, so before Opus 4.5. It took Claude a few attempts and some feedback on what was failing, but it did eventually make a working app after a couple hours.

Now, was the code quality any good? Beats me, I am not a swift developer. I did it partly as an experiment to see what Claude was currently capable of and partly because I wanted to test the feasibility of setting up a simple passive data logger for my truck.

I'm tempted to take another swing with Opus 4.5 for the science.

I hate "vibe code" as a verb. May I suggest "prompt" instead? "I was able to prompt the React site…."