Remember that LLMs were trained on the internet, a place that’s full of confidently incorrect postings. Using a coding LLM helps some, but just like with everything else, it gives better results if you only ask for specific and small parts at a time. The longer the reply, the more probable it will drift into nonsense (since it’s all just probability anyway).

I’ve gotten excellent starting code before to tweak into a working program. But as things got more complex the LLM would try to do things even that guy who gets downvoted a lot on Stack Overflow wouldn’t dare suggest.