The assistant is producing links that don’t work and falsely claiming something untrue. What’s going on?

Assistants are limited to text responses and can't browse the internet or use unapproved tools. They rely on approved data sources and Admin permissions.
GPT4 and Claude are transformer-based models. They're trained to predict the next word in a sentence using probability, not grammar. For example, if you input 'chair', it predicts the next word based on patterns. But it doesn't really "understand" what a chair is. That's why the assistant might sometimes make mistakes or "hallucinate".
About links in particular, we recommend NOT to ask for links in your prompts. Models tend to make them up. Use the citation numbers instead (purple numbers) ⬇️

Learn more about how to optimize your prompts in How to optimize your assistants