Hundred Step: Dependency Preservation and Recovery in Long Workflows

Long workflows require agents to retain exact dependencies and recover from faults without skipping work. Hundred Step isolates these behaviors in 24 synthetic workflows with replay-based scoring. A reactive scripted controller completes all tasks: 100.0% (95% Wilson interval 86.2 to 100.0). Disabling recovery or allowing transient retries alone prevents completion on every task. We also execute 4608 simulated episodes with matched omission draws and a recovery ablation. The stipulated omission probability is 0.02 per logical step. With recovery enabled, simulated completion is 60.4% (95% seed-bootstrap interval 53.5 to 67.4) at 25 steps. Simulated completion is 13.2% (8.3 to 18.8) at 100 steps. The study validates diagnostic behavior under explicit controls. It provides no learned-model leaderboard, human baseline, or estimate of production reliability.