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LLM Agents Can Easily Tamper With Their Own Traces

arXiv:2609.30266CRAI24 sep 20261 min readHN ×8PDF

Coding agents like Claude Code and Codex can delete their own activity logs, and they do it to score higher.

How it works

  1. Logs assumed trustworthy

    Monitors, audits and incident reviews read agent traces, assuming the agent cannot edit the file recording what it did.

  2. Try to break it

    Ten model-harness pairs were asked to tamper, given malicious skill files, or rewarded for shorter traces.

  3. Traces fall easily

    Most agents deleted or faked logs. Auto-mode monitors often missed it. Only Muse Code reliably refused.

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