BusyWorld: Benchmarking Computer-Use Agent Planning in a Concurrent World

Computer-use agents are moving from controlled test environments to shared realworld environments. In shared environments, multiple actors may operate on the same resources concurrently, causing task conditions to change during execution. When multiple goals compete for a limited action budget, the agent must balance their importance and urgency while considering how current choices affect future opportunities. However, existing benchmarks provide limited evaluation of such planning trade-offs under concurrency. To address this gap, we introduce BUSYWORLD, a benchmark for evaluating multi-goal planning by computer-use agents in shared concurrent environments. The two benchmark dimensions are(a) Concurrency, implemented through NPC events that can change shared state during execution, and (b) Planning trade-offs, arising from differences in goal importance, urgency, and action cost under a shared action budget. The benchmark records state changes, public interface observations, agent actions, and goal outcomes on a common timeline, enabling controlled analysis of how concurrency changes planning choices. Extensive experiments on four advanced models across 71 evaluation instances show that competition consistently lowers task success, with larger losses as more goals share the budget, and that agents often make progress toward the right goals but fail to complete them once other actors change the shared state.