Over two decades, the checklist has risen to prominence in healthcare improvement. This paper contributes to the debate between its proponents and critics, making the case for an STS-informed understanding of the checklist that demonstrates the limitations of both the ‘checklist-as-panacea’ and ‘checklist-as-socially-determined’ positions. Attending to the checklist as a socio-material object endowed with affordances that call upon clinicians to act (Hutchby 2001, Allen 2012), the study revisits the efforts of a recent improvement initiative, the Enhanced Peri-Operative Care for High-risk patients (EPOCH) trial. Rather than a singularised simple tool, this study discusses four different and relationally enacted logics of the checklist as a stop and check tool, a clinical prompt, an audit tool, and a clinical record. Each logic is associated with specific temporality, beneficiaries, relationship to material forms, and interpellates (Law 2002) clinicians to initiate specific actions which can conflict. The paper seeks to make the case for intervention to improve such tools and consciously account for the consequences of their design and materiality and calls for supporting such settings and arrangements in which incoherences collected in tools can be locally negotiated.