Prospective Trial Planning for Average Hazard Estimands R package AHTauDesign version 1.0 Provides a simulation-based prospective planning workflow for average hazard estimands in two-arm time-to-event trials. Supports calibration and freezing of design-specific information-support rules, assessment of clinically preferred truncation horizons, conditional selection of clinically acceptable alternative horizons, and reverse design over sample size and additional follow-up. Separates information support from statistical power and supports auditable planning reports. Software Depends: R (>= 4.1.0) Imports: stats, survAH (>= 1.2.0) Suggests: knitr, rmarkdown, testthat (>= 3.0.0), roxygen2 Xinyue Zhao <xinyuezhao27@gwu.edu> Comprehensive R Archive Network (CRAN) Xinyue Zhao [aut, cre], Haitao Pan [aut] GPL-3 2026-10-18 application/tgz https://CRAN.R-project.org/package=AHTauDesign doi:10.32614/CRAN.package.AHTauDesign