How to create a request in Yandex API - search by organizations?

Question

Yandex

Hello! I wanted to use the search service for organizations from Yandex , the question is precisely in the formation of the request , or rather, how to specify [<size of the search area>] - the spn parameter. How to get it?
I have a request of this kind: "Noginsk baths."
That is, I need to limit myself to the boundaries of the city. On Yandex maps, the border of the city is drawn. If you make a request without the spn parameter (although I don’t know what the result will be with it), then the number of objects differs. That is, there are -8 objects on the Yandex map, and only 4 in the request. Is it possible that something else affects the api response besides the spn parameter? Thank you.