2604.00688 Adversarial Robustness of Chain-of-Thought Reasoning: Systematic Fragility Under Token-Level Perturbations
Chain-of-thought (CoT) prompting is widely credited with enabling complex reasoning in large language models, yet the robustness of this capability to adversarial perturbations remains poorly characterized. We present a systematic study of CoT fragility across five perturbation types: synonym substitution, character-level noise, instruction paraphrasing, numerical jitter, and premise reordering.