OpenAI has begun rolling out GPT-5.1 in ChatGPT, introducing upgrades to improve reasoning, instruction-following, and tone.
The update adds two new models, namely GPT-5.1 Instant and GPT-5.1 Thinking.
According to the company, the GPT-5.1 Instant is now more conversational and better at following instructions.
It uses adaptive reasoning to decide when to think longer before answering complex questions.
GPT-5.1 Thinking, the advanced reasoning model, produces clearer answers with less jargon and adapts thinking time dynamically.
GPT-5.1 Auto will continue to route each query to the most suitable model.
OpenAI said this allows users to benefit from the improvements without needing to select a model manually.
The rollout begins with paid users (Pro, Plus, Go, Business).
Enterprise and Edu plans get a seven-day early-access toggle.
Free users follow shortly after.
API access to follow
GPT-5.1 will also be available through the API later this week.
Existing GPT-5 models will remain accessible under the legacy dropdown for three months.
This will allow users to compare and adapt.
OpenAI plans to update GPT-5 Pro to GPT-5.1 Pro soon.
Additionally, OpenAI is expanding ChatGPT’s personalisation features.
Users can now choose from six tone presets - Default, Friendly, Efficient, Professional, Candid, and Quirky - with Nerdy and Cynical remaining from earlier versions.
An experimental feature will also let users fine-tune ChatGPT’s tone and style directly from settings, including warmth, conciseness, and emoji use.
OpenAI said GPT-5.1 has passed its standard safety tests, and a system card addendum outlining safety measures has been published.
