Complex organisations require coherence to achieve adaptive goals through agency. This paper introduces Mindset Agency Theory (MAT), a metatheoretical framework designed for modelling and diagnosing agency within culturally diverse populations. MAT, a cybernetic multi-ontology framework, delineates five formative traits defining agency character. Its cognitive style trait (with bipolar values of Patterning–Dramatising) elucidates how agencies acquire information. Examining diverse agencies requires an appreciation of the social relationships that exist there, but MAT is currently devoid of this capability. Using the configuration approach to enable the integration of Tönnies’ social organisation theory into MAT, social relationships can be suitably explored, thus enhancing its capacity to investigate agency coherence. Tönnies’ theory of social organisation (with bipolar values of Gemeinschaft-Gesellschaft) that frames inter-agent interactions is configured within MAT. This integration births a new formative trait, pairing cognitive style with social organisation, and is thus capable of indicating the likelihood of operative coherence. Configuration is applied by relating propositional attributes of a holding metatheory framework such as MAT, with an entry theory such as Tönnies’ social organisation theory as determined from the literature. The elaborated MAT serves as a diagnostic tool, linking trait instabilities with agency pathologies that deliver dysfunction. A subsequent paper will apply this framework to ASEAN, a regional intergovernmental organisation addressing cultural diversity issues. The study aims to evaluate ASEAN’s mindset and diagnose its pathologies, such as narcissism and paradoxical behaviour.