I'm sorry but I don't quite believe you because I've done exactly this for learning much more complicated topics. For fun I've been learning about video game programming in the Odin programming language using a Claude project where I have Opus 4.5 write tutorials, including working code examples that are designed to be integrated with each other into a larger project. We've covered maze generation, Delaunay triangulation, MSTs, state machines, rendering via Raylib and RayGUI, and tweening for animations. All of those worked quite well with only very minor corrections which Opus was also very helpful for diagnosing and fixing. I also had it produce a full tutorial on implementing a relational database in Odin but I haven't had time to work my way through all of it yet. This is all with a somewhat niche language like Odin that I wouldn't expect there to be a lot of training data for so you'll excuse my incredulity that you couldn't get usable introductory code for much more commonly used languages like Java and Python.

I'm wondering if your test includes allowing the models to run their code in order to validate it and then fix it using the error output? Would you be willing to share the prompts and maybe some examples of the errors?

I haven't had many problems working in Claude Code even with full on "vibe coding". One notable recent exception was in writing integration tests for a p2p app that uses WebRTC, XTerm.js, and Yjs where it ran into some difficulty creating a testing framework that involved a headless client and a local MQTT broker where we had to fork a few child processes to test communication between them. Opus got bogged down working on its own so I stepped in and got things set up correctly (while chatting with Opus through the web interface instead of CC). The problem seemed to be due to overfilling the context since the test suite files were too long so I could have probably avoided the manual work by just having Opus break those up first.