The 'rfacts' package is an R interface to the Fixed and Adaptive Clinical Trial Simulator ('FACTS') on Unix-like systems. It programmatically invokes 'FACTS' to run clinical trial simulations, and it aggregates simulation output data into tidy data frames. These capabilities provide end-to-end automation for large-scale simulation workflows, and they enhance computational reproducibility. For more information on 'FACTS' itself, please visit < https://www.berryconsultants.com/software/>.