Situated in the literature on threshold concepts and transfer of prior knowledge in WAC/WID and composition studies, with particular emphasis on the scholarship of writing across difference, our article explores the possibility of re-envisioning the role of the composition classroom within the broader literacy ecology of colleges and universities largely comprised of students from socioeconomically and ethno- linguistically underrepresented communities. We recount the pilot of a composi- tion course prompting students to examine their own prior and other literacy values and practices, then transfer that growing meta-awareness to the critical acquisition of academic discourse. Our analysis of students’ self-assessment memos reveals that students apply certain threshold concepts to acquire critical agency as academic writ- ers, and in a manner consistent with Guerra’s concept of transcultural repositioning. We further consider the role collective rubric development plays as a critical incident facilitating transcultural repositioning.