PURPOSE: Competency-based medical education (CBME) promises to improve medical education through curricular reforms to support learner development. This intention may be at risk in the case of a Canadian approach to CBME called Competence by Design (CBD), since there have been negative impacts on residents. According to Joseph Schwab, teachers, learners and milieu must be included in the process of curriculum-making to prevent misalignments between intended values and practice. This study considered what can be learned from the process of designing, enacting and adapting CBD to better support learners. METHODS: This qualitative study explored the making of CBD through the perspectives of implementation leads (N = 18) at national, institutional and programme levels. A sociomaterial orientation to agency in curriculum-making guided the inductive approach to interviewing and analysis in phase one. A deductive analysis in phase two applied Schwab's theory to further understand sources of misalignments and the purpose of adaptive responses. RESULTS: Misalignments occurred when the needs of teachers, learners and milieu were initially underestimated in the process of curriculum-making, disconnecting assessment practices from experiences of teaching, learning and entrustment. While technical and structural issues posed significant constraints on agency, some implementation leads were able to make changes to the curriculum or context to fix the disconnects. We identified six purposes for principled adaptations to align with CBME values of responsive teaching, individualised learning and meaningful entrustment. CONCLUSION: Collectively, the adaptations we characterise demonstrate constructive alignment, a foundational principle of CBME in which assessment and teaching work together to support learning. This study proposes a model for making context-shaped, values-based adaptations to CBME to achieve its promise.