AI Safety & Alignment

Building Production-Ready Probes For Gemini

JJános KramárJJoshua EngelsZZheng WangBBilal ChughtaiRRohin ShahNNeel NandaAArthur Conmy
Published
January 16, 2026
Authors
7
Word Count
17,412
Code
Includes code

Enhancing LLM safety with cost-effective activation probes.

Abstract

Frontier language model capabilities are improving rapidly. We thus need stronger mitigations against bad actors misusing increasingly powerful systems. Prior work has shown that activation probes may be a promising misuse mitigation technique, but we identify a key remaining challenge: probes fail to generalize under important production distribution shifts. In particular, we find that the shift from short-context to long-context inputs is difficult for existing probe architectures. We propose several new probe architecture that handle this long-context distribution shift. We evaluate these probes in the cyber-offensive domain, testing their robustness against various production-relevant shifts, including multi-turn conversations, static jailbreaks, and adaptive red teaming. Our results demonstrate that while multimax addresses context length, a combination of architecture choice and training on diverse distributions is required for broad generalization. Additionally, we show that pairing probes with prompted classifiers achieves optimal accuracy at a low cost due to the computational efficiency of probes. These findings have informed the successful deployment of misuse mitigation probes in user-facing instances of Gemini, Google's frontier language model. Finally, we find early positive results using AlphaEvolve to automate improvements in both probe architecture search and adaptive red teaming, showing that automating some AI safety research is already possible.

Key Takeaways

  • 1

    New probe architectures handle long-context inputs effectively.

  • 2

    Automated methods like AlphaEvolve improve probe designs.

  • 3

    Cascading classifiers balance cost and accuracy for misuse detection.

Limitations

  • Evaluations are based on simulated misuse scenarios.

  • Real-world performance may vary under different conditions.

Keywords

activation probeslanguage modelmisuse mitigationcontext lengthprobe architecturecyber-offensive domainmulti-turn conversationsjailbreaksred teamingAlphaEvolveautomated AI safety research

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