A building system of a building including one or more memory devices having instructions thereon, that, when executed by one or more processors, cause the one or more processors to receive a request to access a portion of a building graph of the building from a system, the building graph including a plurality of nodes and a plurality of edges, the plurality of nodes representing entities of the building and the plurality of edges representing relationships between the entities of the building. The instructions cause one or more processors to determine whether the system has access to the portion of the building graph based on a policy indicated by the plurality of nodes and edges of the building graph and provide the portion of the building graph to the system in response to a determination that the system has access to the portion of the building graph.