Students are taught about the foundations of inquiry--questions, tasks, and sources--and how to build inquiry-based curriculum and instructional strategies for social studies. They begin their student teaching experiences knowing the difference between a compelling and supporting question, the role of a formative and summative performance task, and how disciplinary sources should be curated and adapted for classroom use. But student teaching placements can also be noisy places with competing and contradictory signals around inquiry. One of the most powerful of these signals is actually from within, consisting of the experiences of student teachers as learners. This article introduces the Questions-Tasks-Sources (QTS) Observation Protocol that the authors have just deployed in spring 2020. The article begins with a short overview of the authors' teacher education program and the curricular goals and outcomes of their core methods class. In doing so, they set the context for the QTS Observation Protocol and how the foundations of questions, tasks, and sources are operationalized in the instrument. The article then describes the four parts of the instrument, highlighting important criteria and the big ideas of each part. The authors conclude with a discussion of how they are using the instrument, early lessons they are learning, and suggestions for how the instrument might be used in schools.