Current interactive virtual agent (IVA) architectures are so complex that it takes enormous amounts of effort to craft even short experiences, with lengthier, polished experiences (e.g., Facade, Ada and Grace) often requiring person-years of effort by expert authors. We present our analysis of the System-Specific Step (SSS) in the authoring process, encapsulated in the case studies of three different architectures tackling a simple scenario. The case studies revealed distinctly different behaviors by each team in their SSS, resulting in the need for different authoring solutions. We iteratively proposed and discussed each team’s SSS Components and potential authoring support strategies to identify actionable software improvements. Further, our case-study approach provides a methodology for detailed comparison of the authoring affordances of different IVA architectures, providing a lens for understanding the similarities, differences and tradeoffs between architectures.