OpenAI Releases GPT-5.1 Model With New Personalization Options

OpenAI released two new GPT-5.1 AI models yesterday, which will roll out first to paid ChatGPT users. GPT‑5.1 Instant, an update to ChatGPT’s most used model, should be “warmer” and “more conversational,” while the GPT-5.1 Thinking advanced reasing model should provide clearer responses and spend less time on easy tasks.

“For the first time, GPT‑5.1 Instant can use adaptive reasoning to decide when to think before responding to more challenging questions, resulting in more thorough and accurate answers, while still responding quickly. This is reflected in significant improvements on math and coding evaluations like AIME 2025 and Codeforces,” OpenAI explained yesterday.

With GPT-5.1 Auto, ChatGPT will continue to intelligently choose the model best suited for the task at hand. OpenAI previously acknowledged that many ChatGPT users preferred responses from its older GPT-4o flagship model, and the company said yesterday that “answers across GPT‑5.1 feel both smarter and more natural in tone.”

OpenAI is also introducing more options to customize the tone and style of ChatGPT’s responses. With GPT-5.1, the new Professional, Candid, and Quirky presets join the existing Default, Friendly (formerly Listener), Efficient (formerly Robot), Cynical (formerly Cynic), and Nerdy (formerly Nerd) options. In addition to these new personality settings, users will also find granular controls for fine-tuning the length and tone of the chatbot’s responses.

While GPT-5.1 will soon roll out to free and logged-out users, GPT‑5 models will remain available for paid users in the ChatGPT model picker for three months. “Going forward, when we introduce new ChatGPT models, our approach is to give people ample space to evaluate what’s changed and share feedback, allowing us to continue innovating our frontier models while transitioning smoothly,” the company said yesterday.