The passage comes from the standard primer on Navya Nyāya, Annambhaṭṭa's autocommentary on his Tarkasaṅgraha. The context is that of the inference about the existence of a Lord, namely ''A sprout is made by a doer, because it is a product, like a pot", so that the agency here described might be only the God's one. If this were not the case, one would have the following three requisites of agency in general:
1. direct knowledge of the material causes (i.e., applied and unmediated knowledge)
2. desire to do
3. doing (or undertaking of the action)
The material causes are later in the TS defined as samavāyikārana 'causes inhering in the result' (like clay in case of a pot). Direct knowledge is a typical requisite of God, since He does not need to depend on the complex epistemological system we are bound to, and can just know everything directly. If the definition does not only apply to Him, then it means that agency requires this sort of direct knowledge to the things one needs in order to act. Does it refer only to practical actions, such as doing a pot, where you must have a direct knowledge of the clay? Or can it apply also to general concepts? And what would a ''material cause" be, in such cases?
On action and knowledge, see also this post (and the tag "action").