ものとするShall, To assume, To suppose, To consider

Like many grammar expressions that use もの, this noun will imply that the word or phrase that comes before it is a strong determination. Due to this, when とする ‘as (A)’, or ‘in the capacity of (A)’ is added, it presents a situation in which the speaker is determining that (A) is true for the sake of discussion. In English, this may be interpreted as ‘supposing that (A)’, or ‘on the assumption that (A)’.

ものとする, like ものとして, will primarily be seen after verbs. However, unlike ものとして, ものとする will almost always appear at the end of a sentence, and highlights things that are being taken as facts in legalese, and other forms of contractual writing.