OpenAI has introduced a new "Think Longer" tool in the ChatGPT interface, allowing users to access the o3 reasoning model without selecting it from the model dropdown menu. This feature aims to simplify user experience, particularly for those unfamiliar with specific model names and capabilities. Tests comparing the "Think Longer" option with the regular o3 model indicate that responses generated using "Think Longer" tend to be more detailed, wordier, and less compressed. The feature appeared in the ChatGPT tool menu without an official announcement from OpenAI. Discussions suggest that "Think Longer" may be part of the upcoming GPT-5 capabilities and could potentially be offered as a Pro or Plus tier feature, differentiating compute levels across subscription plans. Previously, a similar reasoning function was available to free users under the "Think" button, which automatically selected the reasoning model in the background.