To be a 'free' agent one would have to be causa sui (self caused).

Against the Free Will Thesis, Nietzsche argues that a free agent (that is, one sufficiently free to be morally responsible) would have to be causa sui (i.e., self-caused, or the cause of itself); but since we are not causa sui, no one can be a free agent. Nietzsche takes for granted — not implausibly — that our moral and religious traditions are incompatibilist at their core: causally determined wills are not free wills

Incompatibilism is the view that a deterministic universe is completely at odds with the notion that persons have a free will; that there is a dichotomy between determinism and free will where philosophers must choose one or the other. This view is pursued in at least three ways: libertarians deny that the universe is deterministic, the hard determinists deny that any free will exists, and pessimistic incompatibilists (hard indeterminists) deny both that the universe is determined and that free will exists.