Epistemic agency has been named as key to supporting sense-making and equity in mathematics education. This study investigates how instructional practices that align with supporting students’ mathematical agency may both disrupt and simultaneously reinscribe boundaries that have historically governed who is valued and vice versa. Coordinating extant studies of institutional exclusion with observational data from a fourth-grade classroom, our analysis shows that sense-making activities that invite students to generate and share their own strategies for solving mathematics problems may function to elevate certain students while marginalizing others. This study calls into question prevailing discourses framing epistemic agency as a self-evident good and raises concerns about the danger of reinscribing values that have long operated to privilege some and exclude others.