sorry from what I understand it goes something like this:

LLM processes prompt, formats output as per the initial few shot demos.

This output is an intermediary step in plain text including keywords that then get picked up by Toolformer

Toolformer goes off does the search things and returns predefined chunks formatted from the search results

The prompt is then stuffed with those chunks and asked the question again with the added retrieved search context

(and I'm sure there is more pixie dust sprinkled in somewhere. )