Recent scholarship has demonstrated the need for criticality toward writing assessments that privilege standard language ideologies and correctness-based approaches. However, teachers continue to experience discrepancies between their intentions and actions, struggling to address both content and form in facilitative, constructive commentary. This study uses the activity theory framework of pedagogical tools, composed of conceptual and practical tools, to analyze through interviews and commented-on papers how two college composition graduate instructors responded to student writing. This study finds that while one teacher held and enacted consistent and congruent pedagogical tools grounded in sociocultural theories of writing development, the other experienced entrenched conflict between competing beliefs about evaluative and process-oriented purposes for teaching writing. These contrastive experiences illustrate how instructors’ development of pedagogical tools is mediated by interactions between their epistemological orientations and language ideologies, reinforcing the need to surface tacit beliefs about Standardized English and academic writing. This study concludes with recommendations for productive intervention in novice composition teachers’ development of response practices.