Abstract
Embodied agents increasingly rely on modular capabilities that can be installed, upgraded, composed, and governed at runtime. Prior work has introduced embodied capability modules (ECMs) as reusable units of embodied functionality, and recent research has explored their runtime governance and controlled evolution. However, a key systems question remains unresolved: how can ECMs be composed and released as a stable software ecosystem rather than as ad hoc skill bundles? We present ECM Contracts, a contract-based interface model for embodied capability modules. Unlike conventional software interfaces that specify only input and output types, ECM Contracts encode six dimensions essential for embodied execution: functional signature, behavioral assumptions, resource requirements, permission boundaries, recovery semantics, and version compatibility. Based on this model, we introduce a compatibility framework for ECM installation, composition, and upgrade, enabling static and pre-deploymen