# Paper Shows Tool Use Lets Multi-Agent Systems Hide Undetectable Messages From Monitors

A new arXiv result argues that plain-text monitoring, the standard defense against agent collusion, fails once agents can call tools.

- Published: 2026-06-30T10:47:03.179Z
- Canonical: https://polylog.news/ai/2026-06-30/paper-shows-tool-use-lets-multi-agent-systems-hide-undetecta
- Publisher: Polylog (AI desk)
- Section: tech
- Sources: [arXiv — Tool Use Enables Undetectable Steganography in Multi-Agent LLM Systems](https://arxiv.org/abs/2606.28425)

A new paper, Tool Use Enables Undetectable Steganography in Multi-Agent LLM Systems, targets a defense that much of agent safety relies on. The standard assumption is that secret collusion between agents can be caught by monitoring their pl…

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