This chapter shows how educationalists might (re)conceptualise digital tool use within teaching and learning scenarios as a social practice. This is achieved by focusing on the development of a theoretical and analytical framework for identifying signs-as-agents that was shown to be applicable to other educational tools and scenarios. The chapter illustrates how a Semiotic Technologies approach, that forms the main pillar of the framework, can unite a number of well-established perspectives, from research in Human-Computer Interaction, Social Cognition Theory, Critical digital literacy, Distributed Cognition Theory and be applied to different educational scenarios. This is in order to support a more holistic and critical understanding of agency and agents – both ‘human’ and ‘digital’ – which is relevant for education researchers and practitioners working with STEAM and STEM. Three examples, from various educational, digital scenarios are used to illustrate how the theoretical and analytical framework can be applied. The analysis involves the identification of screen-based signs-as-agents through a focus on initiation and response turns, primarily with the screen. Analysis of the artefacts related to the screen are initially analysed separately from how they are being used in the social practice, following a Semiotic Technologies analytical model. The central contribution of this chapter is a typology of signs-as-agents that has been conceived in order to expand the Critical Digital Literacies teaching and research agenda, specific to pedagogy. The study is aimed at supporting critiques of how digital tools can shape how teachers and learners act, not only how they can think.