Aim Guided by the World Federation of Occupational Therapists (WFOT) 2025 call to strengthen social health and participation, this study aims to evaluate the feasibility, usability, and contextual appropriateness of the Assessment Tool for Occupation and Social Engagement (ATOSE) in Australian residential aged care homes. The study responds to a critical gap in aged care evaluation, where wellbeing is often inferred from activity attendance rather than from residents’ actual social inclusion and engagement. Methods A mixed methods feasibility study, informed by action research principles and guided by the Consolidated Framework for Implementation Research (CFIR), was conducted. Trained occupational therapists and allied health professionals used ATOSE to complete brief standardised observations in communal areas during routine daily periods. Feasibility and usability data were collected through questionnaires and research artefacts generated by the research team (e.g. reflections and process notes). Results Preliminary findings suggest that ATOSE can be integrated into everyday aged care workflows. Participants reported the tool was clear, acceptable, and useful for identifying differences between presence, participation, and meaningful engagement. Contextual factors influencing implementation were identified, indicating areas for adaptation across diverse residential aged care settings. Conclusions / Implications ATOSE shows strong promise as a practical, engagement focused assessment aligned with contemporary social health priorities. By shifting attention from who is present to who is meaningfully engaged, ATOSE offers aged care organisations a tool to better understand, evaluate, and design environments that genuinely support wellbeing, inclusion, and quality of life.