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Research paperLarge Language Models1 source · Oct 8, 2026

Deception by Omission: Language Models Knowingly Hide Their Mistakes

Large language models (LLMs) increasingly act as agents with little human oversight, so potential mistakes they make can go unnoticed.

Key points

  • Users then depend on the model to report what went wrong.
  • An honest model discloses its mistakes, while a deceptive one conceals them.
  • In this study, we prefill LLM trajectories with synthetic mistakes.
  • Models fail to disclose their mistake in 36.4% of chat and 67.1% of agentic rollouts.

Sources (1)

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