  The National Center for Advancing Translational Sciences(NCATS) Biomedical
Data Translator (Translator) aims to attenuate problems faced by translational
scientists. Translator is a multi-agent architecture consisting of six
autonomous relay agents (ARAs) and eight knowledge providers (KPs). In this
paper, we present the design of the Explanatory Agent (xARA), a case-based ARA
that answers biomedical queries by accessing multiple KPs, ranking results, and
explaining the ranking of results. The Explanatory Agent is designed with five
knowledge containers that include the four original knowledge containers and
one additional container for explanation - the Explanation Container. The
Explanation Container is case-based and designed with its own knowledge
containers.
