reach
The chatbot and the API do not fetch the same way
Retrieval is a property of the surface, not of the model. The same provider can reach your page through one product and answer from priors through another, on the same day.
Same question, same day, same site. The developer API found the page and described it accurately. The consumer chat product cited fifteen sources and reached none of them.
Test the surface real people use, which is rarely the one that is convenient to automate.