ThinkGuard: Deliberative Slow Thinking Leads to Cautious Guardrails

Fuente: arXiv
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Main Authors: Wen, Xiaofei, Zhou, Wenxuan, Mo, Wenjie Jacky, Chen, Muhao
Format: Preprint
Published: 2025
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author Wen, Xiaofei
Zhou, Wenxuan
Mo, Wenjie Jacky
Chen, Muhao
author_facet Wen, Xiaofei
Zhou, Wenxuan
Mo, Wenjie Jacky
Chen, Muhao
contents Ensuring the safety of large language models (LLMs) is critical as they are deployed in real-world applications. Existing guardrails rely on rule-based filtering or single-pass classification, limiting their ability to handle nuanced safety violations. To address this, we propose ThinkGuard, a critique-augmented guardrail model that distills knowledge from high-capacity LLMs by generating structured critiques alongside safety labels. Fine-tuned on critique-augmented data, the captured deliberative thinking ability drastically enhances the guardrail's cautiousness and interpretability. Evaluated on multiple safety benchmarks, ThinkGuard achieves the highest average F1 and AUPRC, outperforming all baselines. Compared to LLaMA Guard 3, ThinkGuard improves accuracy by 16.1% and macro F1 by 27.0%. Moreover, it surpasses label-only fine-tuned models, confirming that structured critiques enhance both classification precision and nuanced safety reasoning while maintaining computational efficiency.
format Preprint
id arxiv_https___arxiv_org_abs_2502_13458
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle ThinkGuard: Deliberative Slow Thinking Leads to Cautious Guardrails
Wen, Xiaofei
Zhou, Wenxuan
Mo, Wenjie Jacky
Chen, Muhao
Computation and Language
Artificial Intelligence
Cryptography and Security
Machine Learning
Ensuring the safety of large language models (LLMs) is critical as they are deployed in real-world applications. Existing guardrails rely on rule-based filtering or single-pass classification, limiting their ability to handle nuanced safety violations. To address this, we propose ThinkGuard, a critique-augmented guardrail model that distills knowledge from high-capacity LLMs by generating structured critiques alongside safety labels. Fine-tuned on critique-augmented data, the captured deliberative thinking ability drastically enhances the guardrail's cautiousness and interpretability. Evaluated on multiple safety benchmarks, ThinkGuard achieves the highest average F1 and AUPRC, outperforming all baselines. Compared to LLaMA Guard 3, ThinkGuard improves accuracy by 16.1% and macro F1 by 27.0%. Moreover, it surpasses label-only fine-tuned models, confirming that structured critiques enhance both classification precision and nuanced safety reasoning while maintaining computational efficiency.
title ThinkGuard: Deliberative Slow Thinking Leads to Cautious Guardrails
topic Computation and Language
Artificial Intelligence
Cryptography and Security
Machine Learning
url https://arxiv.org/abs/2502.13458