A machine-implemented method for evaluating a context-based (e.g., XACML) policy having a set of attributes formulates a search against one or more existing external repositories using a query that is dynamically-generated based on the security policy being evaluated. The approach shifts the building of a candidate set of potentially-allowable resources to the authorization engine (e.g., a Policy Decision Point (PDP)). In operation, an application calls the PDP using an entitlement request and, in response, the PDP builds the candidate set of values based on the defined security policy by generating a query to an external data repository and receiving the results of that query. This approach enables a policy-driven entitlement query at runtime.