This document discusses the relationship between self-quantifying technologies and the self through the lens of agential realism. It explores how these technologies can be seen as forms of discourse that enable and constrain what can be said about the self, and how they help produce both the object and subject of measurement. The document also examines how self-tracking tools can act as "apparatuses" that give meaning to self-improvement while materializing parts of the self. Finally, it considers how these technologies may reflect and shape the "agential cuts" people make in defining and understanding their self.