  This report describes Athena, a dialogue system for spoken conversation on
popular topics and current events. We develop a flexible topic-agnostic
approach to dialogue management that dynamically configures dialogue based on
general principles of entity and topic coherence. Athena's dialogue manager
uses a contract-based method where discourse constraints are dispatched to
clusters of response generators. This allows Athena to procure responses from
dynamic sources, such as knowledge graph traversals and feature-based
on-the-fly response retrieval methods. After describing the dialogue system
architecture, we perform an analysis of conversations that Athena participated
in during the 2019 Alexa Prize Competition. We conclude with a report on
several user studies we carried out to better understand how individual user
characteristics affect system ratings.
