One problem would be that you can't just check the URL, you'd have to check the content. Not only are there many URLs that could point to the same content, but

One problem would be that you can't just check the URL, you'd have to check the content. Not only are there many URLs that could point to the same content, but content on a page can obviously change. I suppose you could compare against wayback, and not sure I'd try to compare with an LLM or RAG.