Managing Context in a Conversational Agent

This paper describes a conversational agent, called “ProBot”, that uses a novel structure for handling context. The ProBot is implemented as a rule-based system embedded in a Prolog interpreter. The rules consist of patterns and responses, where each pattern matches a user’s input sentence and the response is an output sentence. Both patterns and responses may have attached Prolog expressions that act as constraints in the patterns and can invoke some action when used in the response. The main contributions of this work are in the use of hierarchies of contexts to handle unexpected inputs. The ProBot is also interesting in its link to an underlying engine capable of implementing deeper reasoning, which is usually not present in conversational agents based on shallow parsing.