OpenAI Study Traces How Frontier Models Lose Chain-of-Thought Transparency

New OpenAI research pinpoints the specific training stages that erode chain-of-thought (CoT) transparency in frontier models, arguing the loss is not an inevitable law of nature but a byproduct of optimizing for capability and compute cost. The work warns that scratchpad-based safety monitoring will grow increasingly unreliable as pretraining scales, urging new oversight methods.