Introducing our new alignment strategy for o-series models, which are directly taught safety specifications and how to reason over them.

We introduce deliberative alignment, a training paradigm that directly teaches reasoning LLMs the text of human-written and interpretable safety specifications, and trains them to reason explicitly about these specifications before answering. We used deliberative alignment to align OpenAI’s o-series models, enabling them to use chain-of-thought (CoT) reasoning to reflect on user prompts, identify relevant text from OpenAI’s internal policies, and draft safer responses. Our approach achieves highly precise adherence to OpenAI’s safety policies, and without requiring human-labeled CoTs or answers. We find that o1 dramatically outperforms GPT‑4o and other state-of-the art LLMs across a range of internal and external safety benchmarks, and saturates performance on many challenging datasets. We believe this presents an exciting new path to improve safety, and we find this to be an encouraging example of how improvements in capabilities can be leveraged to improve safety as well.