As AI becomes ever more embedded into daily life and spaces, the discussion of whether AI empowers or disempowers human agency has garnered significant attention. However, AI agency and human agency may not necessarily represent opposing extremes on a continuum. Previous studies have suggested that humans and AI followed different decision-making strategies which lead to results complementary to each other [3, 8, 10]. The aim of this workshop is to explore the role of design in the co-construction of agency in human-AI interactions. By bringing together an interdisciplinary group of researchers in a half-day workshop, we intend to explore design issues and factors that shape agency in collaborative relationships involving humans and AI technologies. Workshop participants will be asked to submit cases where there is evident tension between human and AI agency, and, using Research Through Design, work in exploring issues of human-AI agency in scenarios fueled by the cases submitted to this workshop. As AI technologies move from emergence to being entangled in the everyday, it is increasingly important to thoughtfully design their place in our lives.