Domain-specific languages (DSLs) are small languages tailored to narrow domains. Their purpose is to cope with the needs of domain experts, who might not have a software engineering background. In previous work, we proposed the novel notion of Active DSLs, which are graphical DSLs extended to benefit from mobility using geolocation and interactions with external services and devices. Active DSLs are the central component of a mobile collaborative appl called DSL-comet. Modelling using DSLs can be done collaboratively by a group of stakeholders, and the levels of required confidentiality and integrity may vary across modelling artefacts. While preventing the access to protected data has been tackled for DSLs used on static environments like laptops and desktop computers, it has not been envisioned for modelling on mobile devices. The latter poses further challenges as access permissions may depend not just on user profiles but also on conditions that only make sense in mobility, such as geolocation or information retrieved from nearby sensors. Embracing the approach of Active DSLs, we propose an annotation meta-model to provide fine-grained role-based access control to any domain meta-model, hence enabling model element protection when collaborating in mobility. The paper describes our current implementation and our envisioned low-code solution, which includes a cloud-based textual editor to define role hierarchies and permissions for the domain meta-models. CCS CONCEPTS • Software and its engineering → Domain specific languages.