  The deployment of Socially Intelligent Agents (SIAs) in learning environments
has proven to have several advantages in different areas of application. Social
Agent Authoring Tools allow scenario designers to create tailored experiences
with high control over SIAs behaviour, however, on the flip side, this comes at
a cost as the complexity of the scenarios and its authoring can become
overbearing. In this paper we introduce the concept of Explainable Social Agent
Authoring Tools with the goal of analysing if authoring tools for social agents
are understandable and interpretable. To this end we examine whether an
authoring tool, FAtiMA-Toolkit, is understandable and its authoring steps
interpretable, from the point-of-view of the author. We conducted two user
studies to quantitatively assess the Interpretability, Comprehensibility and
Transparency of FAtiMA-Toolkit from the perspective of a scenario designer. One
of the key findings is the fact that FAtiMA-Toolkit's conceptual model is, in
general, understandable, however the emotional-based concepts were not as
easily understood and used by the authors. Although there are some positive
aspects regarding the explainability of FAtiMA-Toolkit, there is still progress
to be made to achieve a fully explainable social agent authoring tool. We
provide a set of key concepts and possible solutions that can guide developers
to build such tools.
