Technological advances in artificial intelligence (AI) are promising continuous improvements in problem-solving, perception, and reasoning that are edging closer to human capabilities. AI technologies are raising important questions regarding fundamental issues of organizing, especially regarding the impact of AI on professionals and their work practices. I examine the work practices of professionals facing growing availability of AI tools in their field: medical diagnosis. I draw on ethnographic field data collected across four radiology units within at a major hospital in the United States at the cutting-edge of adopting and evaluating diagnostic AI tools. My data collection and analysis spans processes of developing, evaluating, adopting, and using numerous AI tools over time and in multiple diagnostic contexts. In one chapter, I compare four theoretical approaches to studying technology in organizational processes, answering the question, how does each perspective account for material agency? In the following chapter, I investigate how are professionals using AI tools in their judgment forming processes? I uncover how physicians were experiencing ambiguity throughout their process, and even more so after viewing AI results. I unpack the ways in which they manage this surge in ambiguity and its impact on how AI results are incorporated (or not) into their final diagnosis. These findings contribute to literatures of augmentation, ambiguity, and how professionals experience opaque technologies. In the final chapter, I ask how are managers evaluating which AI tools to adopt in their organizations? I shed light on how organizational leaders are evaluating the potential opportunities and challenges of adopting AI tools and addressing new knowledge issues that emerge. This chapter contributes to literatures on ground truth, technology evaluation practices, and studies of sociomateriality. Overall, the findings of this project illuminate critical challenges to the adoption and evaluation of AI tools that must be understood and addressed if professionals, organizations, and society is to gain the full extent of the transformative promise of AI technologies