We describe a student activity visualization tool that we constructed to provide a context for ethnomethodological inquiry – a design-based breach experiment (Crabtree et al, 2004) – into how teachers might think and communicate about student thinking when they have tools that give them better access to student activity. We use the Learning to Notice framework (van Es & Sherin, 2008) to characterize the kinds of activity that occurred when teachers used the tools in a team meeting. Then, we show how theses uses suggest ways that research on and uses of student activity representations may need to be sensitive to how contexts of implementation shape the consumption and use of those representations.