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Do Prompts Guarantee Safety? Mitigating Toxicity from LLM Generations through Subspace Intervention

Authors: Himanshu Singh, Ziwei Xu, A. V. Subramanyam, Mohan Kankanhalli

Published: 2026-02-06

arXiv ID: 2602.06623v1

Added to Library: 2026-02-09 03:04 UTC

Safety

📄 Abstract

Large Language Models (LLMs) are powerful text generators, yet they can produce toxic or harmful content even when given seemingly harmless prompts. This presents a serious safety challenge and can cause real-world harm. Toxicity is often subtle and context-dependent, making it difficult to detect at the token level or through coarse sentence-level signals. Moreover, efforts to mitigate toxicity often face a trade-off between safety and the coherence, or fluency of the generated text. In this work, we present a targeted subspace intervention strategy for identifying and suppressing hidden toxic patterns from underlying model representations, while preserving overall ability to generate safe fluent content. On the RealToxicityPrompts, our method achieves strong mitigation performance compared to existing baselines, with minimal impact on inference complexity. Across multiple LLMs, our approach reduces toxicity of state-of-the-art detoxification systems by 8-20%, while maintaining comparable fluency. Through extensive quantitative and qualitative analyses, we show that our approach achieves effective toxicity reduction without impairing generative performance, consistently outperforming existing baselines.

🔍 Key Points

  • Introduction of a targeted subspace intervention strategy to identify and suppress latent toxic patterns in Large Language Models (LLMs) without sacrificing fluency or coherence.
  • Establishment of a gradient-sensitivity framework for a more accurate identification of toxic directions in model representations, improving upon traditional token-level and sentence-level toxicity detection methods.
  • Demonstrated effectiveness on the RealToxicityPrompts benchmark, achieving toxicity reduction of 8-20% relative to state-of-the-art detoxification techniques while maintaining performance across several LLMs.
  • Conducted extensive quantitative and qualitative analyses showing minimal impact on inference complexity and utility tasks post-intervention, indicating a strong safety-performance balance.
  • Exploration of various intervention strategies, highlighting the superiority of multi-layer and conditional projections for robust toxicity suppression with lower perplexity.

💡 Why This Paper Matters

This work significantly contributes to the safety of AI systems by addressing inherent biases in LLMs that can lead to toxic outputs even in seemingly benign contexts. The proposed intervention strategy not only mitigates harmful content generation but does so with minimal impact on the model's linguistic capabilities or utility, paving the way for safer AI technologies suitable for real-world applications.

🎯 Why It's Interesting for AI Security Researchers

This paper addresses critical safety concerns in AI by presenting a novel method for detoxifying LLMs, a pressing topic for AI security researchers. The focus on representation-level interventions further aligns with the need for robust defense mechanisms against adversarial prompts and potential misuse of AI systems. The implications for deploying safer LLMs directly relate to enhancing public trust in AI technologies and reducing risks associated with toxic or harmful content generation.

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