Implementations of the present disclosure include methods, systems, and computer-readable storage mediums for evaluating access control constraints and include actions of receiving an access control request, obtaining a set of attributes based on an abstract evaluation of a policy, the set of attributes including one or more attributes that could be required to evaluate the access control request, requesting respective values of the one or more attributes in a batch request, receiving the respective values, and providing an access control decision based on the respective values and the policy.