LexAgentHallu - Plan-and-Execute - L2 Hallucination Frequency: leaderboard

LexAgentHallu evaluates hallucinations in multi-step legal agents. L1 covers substantive legal knowledge and L2 procedural reasoning. Hallucination frequency is the fraction of rollouts with at least one flagged error; density is the mean fraction of applicable error subclasses triggered. Frameworks are separate protocols; the LRAS fine-tuned models retain their own identities. This series reports LexAgentHallu - Plan-and-Execute - L2 Hallucination Frequency from 2609.09754v1, S4.T2: Hallucination Frequency (%). Lower is better.

Metric: Hallucination Frequency (%). Source: arxiv.org. Saturation forecast: Around August 2027. 5 models tracked.

Top models

#ModelScoreOverall rank
1Gemini 3.1 Pro (Preview)64.3#66
2GPT-5.466.6#85
3Qwen 3.6 27B82.9#183
4Qwen 3.5 27B84.4#194
5Qwen 3.5 9B85.5#395

No result here: #3 Claude Opus 5.5, #5 GPT-6 Astra, #6 GPT-6.1 Sol.

Interactive version: theaggregate.ai/benchmark?slug=lexagenthallu-plan-and-execute-l2-hallucination-frequency · How It Works · Data refreshed daily, snapshot 2026-11-07.