Auto86%Harbor: pendingAgentic / Tool UseSafety & AlignmentMultimodal

AgentHorizon

AgentHorizon: Evaluating Agentic Judges for Long-Horizon Computer-Use Tasks

A benchmark of 1,373 computer-use tasks with paired instructions to evaluate agentic judges on long-horizon trajectory success verification across three OSs.

How to run

ltb · agenthorizon
$ npm i -g lettokenburn-cli
$ ltb bench info agenthorizon

External harness. No Harbor adapter has been generated for this benchmark yet. `ltb bench info` prints the known links.

Runs happen on your machine with your own subscription; only the score summary is pushed. CLI docs

Scores

10 sourced entries
HarnessSourceConfidenceLink
GPT-5.580.9codexIndependentmediumOct 8, 2026arxiv.org
Gemini 3.1 Pro77.7gemini cliIndependentmediumOct 8, 2026arxiv.org
Claude Opus 4.776.0claude codeIndependentmediumOct 8, 2026arxiv.org
Qwen3.6 27B70.4opencodeIndependentmediumOct 8, 2026arxiv.org
GPT-5.4-mini69.2codexIndependentmediumOct 8, 2026arxiv.org
Qwen3.6 35B A3B64.6opencodeIndependentmediumOct 8, 2026arxiv.org
Claude Haiku 4.552.2claude codeIndependentmediumOct 8, 2026arxiv.org
Gemini 3.1 Flash Lite52.1gemini cliIndependentmediumOct 8, 2026arxiv.org
google/gemma-4-26B-A4B-it49.4opencodeIndependentmediumOct 8, 2026arxiv.org
google/gemma-4-31B-it46.8opencodeIndependentmediumOct 8, 2026arxiv.org

Every number links to where it was published. Low-confidence rows are muted and need per-cell verification.

Reproduced by the community

All runs
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About

AgentHorizon comprises 1,373 instruction-trajectory pairs from 166 hours of human recordings. It uses a paired design where swapping instructions creates negative examples to test if judges distinguish successful trajectories from incompatible ones.

Scoring uses balanced accuracy to measure a judge's ability to accept valid trajectories and reject failed ones. The best agentic judge, GPT-5.5, achieved 80.9% balanced accuracy, highlighting discrepancies between frontier and open-weight models in tool-use scenarios.