The "natural language tokenizer" itself is often an LLM (they do a pretty good job of this).
A further extension this article doesn't talk about is to have a LLM with a different prompt analyze the answer before returning to the user, and do more queries if it doesn't believe the question has been well answered (imagine clicking "next page" of google search results under the hood).
The potential complexity of this scales all the way up to a full "research assistant" LLM "agent" that calls itself recursively.