The Free On-line Dictionary of Computing (30 December 2018):

knowledge level

    A level of description of the
   knowledge of an agent that is independent of the agent's
   internal symbol-level representation.  Knowledge can be
   attributed to agents by observing their actions.  An agent
   "knows" something if it acts as if it had the information and
   is acting rationally to achieve its goals.  The "actions" of
   agents, including knowledge base servers and knowledge-based
   systems, can be seen through a "tell and ask" functional
   interface, where a client interacts with an agent by making
   logical assertions (tell), and posing queries (ask).

   (1994-10-19)