AgentHorizon: 1,373-task benchmark exposes unreliable LLM judges for computer-use agents

rohanpaul_ai · x · 2026-10-14

arXiv link post for the AgentHorizon paper (arXiv:2610.11050) by ServiceNow Research and McGill: a benchmark of 1,373 computer-use judging tasks from 166 hours of human-recorded trajectories across three OSes, with negatives built by swapping instructions. Across 11 judges, the best (GPT-5.5) reaches 80.9% balanced accuracy on the frontier split; tool use improves some models but hurts open-weight ones. Released in AH/AH-S/AH-D splits with code on GitHub.

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