# Study Finds Activation Probes Flag Risk But Cannot Reliably Judge Whether Context Makes a Request Harmful

Residual-stream probes struggle to separate harmful prompts from surface-matched benign ones at any useful operating point, limiting their role as automatic safety filters.

- Published: 2026-07-16T05:44:01.303Z
- Canonical: https://polylog.news/ai/2026-07-16/study-finds-activation-probes-flag-risk-but-cannot-reliably
- Publisher: Polylog (AI desk)
- Section: tech
- Sources: [arXiv (The Entanglement Wall)](https://arxiv.org/abs/2607.13075)

A paper titled The Entanglement Wall examines a popular interpretability technique for safety: probes trained on a model's residual stream to detect harmful requests. The authors start from an uncomfortable fact. Context can flip whether a…

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