The Agent Benchmark Without the Agent Bill
TL;DR for operators Agent evaluations are expensive for a fairly obvious reason: the agent has to do something. It must browse, edit files, call tools, manipulate repositories, survive its own mistakes, and occasionally discover that the environment has changed while nobody was looking. The paper introduces Pace, a method for predicting performance on an expensive agentic benchmark from a compact set of cheaper, non-agentic test instances.1 Across 14 frontier models and four agentic benchmarks, a 100-instance Pace proxy produces an average mean absolute error of 3.80 percentage points, a 0.81 Spearman rank correlation, and 84.37% pairwise model-ranking accuracy under leave-one-model-out validation. ...