The study investigated tool development by three middle school mathematics teachers. The tools they designed were intended to support the use of model-eliciting activities (a form of instruction related to problem-based learning) and particularly the students' presentations of their solutions for the whole class. The study examined the design and purposes for the presentation tools and resulted in a framework for categorizing teachers' purposes for tools. The framework addressed the unit of analysis for the tools (individual students or groups of students) and the nature of teachers' purposes for the tools. Design research was used as a theoretical perspective for conducting the investigation.