Claude Opus 5 shows 50% hallucination rate in Artificial Analysis report
July 26, 2026
Artificial Analysis identifies a 50% hallucination rate for Claude Opus 5. Despite high scores in intelligence and coding benchmarks, the model frequently provides answers even when it lacks certainty.
HOW THIS AFFECTS YOU
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builderYou must implement robust verification layers if using this model for high-precision tasks.
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researcherThe gap between intelligence benchmarks and hallucination rates warrants further investigation.