Cloudflare open sourced their OAuth provider library for Cloudflare Workers, which was largely written with Claude. Kenton Varda writes in the README.md for the project:

I was an AI skeptic. I thought LLMs were glorified Markov chain generators that didn't actually understand code and couldn't produce anything novel. I started this project on a lark, fully expecting the AI to produce terrible code for me to laugh at. And then, uh... the code actually looked pretty good. Not perfect, but I just told the AI to fix things, and it did. I was shocked.

Kenton documented the process by including the prompts he used and these show a partnership between the AI and developer. Almost every feature required iteration and refinement, but in much the same way as a senior developer talking to a junior. Kenton says as much in a post on Twitter, er, I mean X:

A lot of people seem to be looking at my Claude Code prompts to try to learn some sort of techniques. Folks, just to be clear, I didn't know what I was doing, I just talked to it like I'd talk to a human.

This matches my own experience. Pairing with LLMs is the whole ballgame right now.