This design-based study occurred within a writing methods course in an urban teacher education program. We designed an intervention to develop student teachers’ meta-composing strategies, critical thinking, and justice-oriented reflexivity by revising a teacher-as-writer course assignment to achieve two pedagogical goals: (1) synthesizing antiracist and pedagogical content from curated source texts, and (2) explicating racial literacy as future writing teachers of K-6 students. Using discourse synthesis as both an instructional and research method, we analyzed the synthesis outputs of student teachers during a writing assignment designed to communicate their learnings to an intended audience. Outputs included graphic organizers, planning documents, and a range of final products. We employed discourse synthesis to analyze source and synthesis texts through propositionalization, template formation, and thematic categorization, identifying idea unit origins, progression, or omission. Additionally, content and thematic analyses evaluated instructional strategies and materials to assess whether pedagogical objectives were met. Results indicated discourse synthesis instruction facilitated student engagement with antiracism content, such as historical events, systemic trends, and awareness of racist practices in schools. Findings also highlighted areas for improvement, including modifying source texts, revising the teacher-as-writer assignment, and reevaluating assessment practices in antiracist writing pedagogy.