Both, but it’s mostly the models. The programs like Claude Code are actually simpler than the ones from before because of this.

Both.

Yeah, definitely both.

New models come out all the time. One of the most interesting signals to look out for is when they tip over the quality boundary from "not useful at task X" to "useful at task X". It happened for coding about a year ago. It happened for search-based research assistants just two months ago, in my opinion - I wrote about that here: https://simonwillison.net/2025/Apr/21/ai-assisted-search/