Do Thinking Tokens Help with Safety?
On the map: LLM reasoning → Reasoning for agents, planning and code
Abstract (arXiv)
Today's reasoning models use thinking tokens to attain stronger performance on benchmarks than their instruction-tuned counterparts. It is also generally believed that this more "deliberative" mode should improve alignment and safety, by providing the model a safe space to consider whether its planned answer to a request violates its safety principles. We present evidence that this intuition is not always correct. Across frontier open-weight reasoning models spanning GPT-OSS, Qwen, Olmo, and Phi families, we find that the eventual refusal/compliance outcome is already strongly predictable via a trained head on the first token's hidden representation (0.84-0.95 AUROC and ~88% balanced accuracy for predicting refusal/compliance) before any visible thinking. The thinking process turns out to be more akin to prefix completion than to deliberative revision, with the final outcome rarely changing after the first ~20% of thinking, despite giving the appearance of deliberation at the text level (~74% of text-level deliberations occur when the response distribution is already locked to one refusal/compliance side). We also find that existing inference-time and training-based safety interventions, despite being motivated by the goal of inducing deliberation, largely shift model behavior toward over-refusal while suppressing already-scarce deliberation signals. Our results suggest that safety behavior in current reasoning models is much less deliberative than commonly assumed, and highlight the need for methods that induce real safety deliberation.
Key facts. Cited by 3 papers in the map (data through 14 Oct 2026). Placed in Reasoning for agents, planning and code, one of 17 directions in LLM reasoning. Builds on 53 of its 67 references that are in the map. First posted on arXiv 23 Jun 2026.
Builds on
53 of 67 references.
Closest ancestors · 13
Same direction, newest first
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- 2026THINKSAFE: Self-Generated Safety Alignment for Reasoning Models30 Jan
- 2026How Does the Thinking Step Influence Model Safety? An Entropy-based Safety Reminder for LRMs7 Jan
- 2025Refusal Falls off a Cliff: How Safety Alignment Fails in Reasoning?7 Oct
- 2025R1-ACT: Efficient Reasoning Model Safety Alignment by Activating Safety Knowledge1 Aug
- 2025SafeKey: Amplifying Aha-Moment Insights for Safety Reasoning22 May
- 2025SAFEPATH: Preventing Harmful Reasoning in Chain-of-Thought via Early Alignment20 May
- 2025FalseReject: A Resource for Improving Contextual Safety and Mitigating Over-Refusals in LLMs via Structured Reasoning12 May
- 2025Safety in Large Reasoning Models: A Survey24 Apr
- 2025STAR-1: Safer Alignment of Reasoning LLMs with 1K Data2 Apr
- 2025The Hidden Risks of Large Reasoning Models: A Safety Assessment of R118 Feb
- 2025SafeChain: Safety of Language Models with Long Chain-of-Thought Reasoning Capabilities17 Feb
1 more
Other references · 40
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- 2024WildTeaming at Scale: From In-the-Wild Jailbreaks to (Adversarially) Safer Language Modelscited by 223
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- 2025ORFuzz: Fuzzing the "Other Side" of LLM Safety -- Testing Over-Refusalcited by 6
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Citing papers per year: 2026: 3.
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