While there are many documented approaches to using technological tools to support collaboration in remote environments, studies related to proof-based courses are overwhelmingly situated in the context of geometry. This study uses instrumental genesis theory to study how students in an introduction to proofs course operationalize the technological tools, namely Google Docs and Zoom, available to them to engage in collaborative proof activity during small group work. Results from our analysis found that students coordinate uses of different tools to develop instruments that can be used to (1) engage in collective argumentation by coordinating visual mediators and verbal communication and (2) co-construct a group solution by refining shared text. In particular, Google Docs was found to be a versatile and rich tool that supported the students' collaborative activity and encouraged a more active approach to proof-related writing. We discuss implications of the students' tool use on their collective mathematical proof activity.