HalluHard: Sonnet 5 and Fable 5 Show No Major Drop in Hallucinations

maksym_andr · x · 2026-07-06

Latest data from the HalluHard hallucination benchmark shows Sonnet 5 at a 50.9% hallucination rate and Fable 5 at 59.7%, with both performing better without web search than with it. Compared to GLM-5.2's 74.8%, the Claude series leads overall, though researchers note no significant breakthrough.

The author criticizes the AI community for hyper-focusing on Agent capabilities while neglecting hallucination issues that impact almost all real users, urging the industry to reprioritize.

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