OpenAI replaces the Model Spec’s style checklist with five values

On October 29, 2026, OpenAI reorganized its Model Spec around five values — faithfulness to human intent, harm minimization, honesty, agency, and care — and made them the foundation of an explicit chain of command. For teams that relied on the models’ default tone, the consequence is direct: style now has to be specified, because most of the detailed style rules have been retired.