OpenAI launches GPT-5.1, introducing dual models, improved reasoning, and eight personality styles for more humanlike ChatGPT interaction.
SAN FRANCISCO: OpenAI has rolled out GPT-5.1, the latest version of its flagship AI model powering ChatGPT, bringing with it more personalised experiences, better reasoning, and a choice of eight personality styles, making conversations feel warmer and more intuitive.
The upgrade introduces two key model types: GPT-5.1 Instant and GPT-5.1 Thinking. Instant is designed for fast, casual conversations and quick answers, while Thinking is more reflective and analytical — ideal for complex queries. ChatGPT will automatically choose between the two depending on the prompt, improving clarity and flow for users.
GPT-5.1 in ChatGPT is rolling out to all users this week.
— OpenAI (@OpenAI) November 12, 2025
It’s smarter, more reliable, and a lot more conversational.https://t.co/SA1Q1GPyxV
The model also introduces a fresh personality system, letting users tailor ChatGPT’s tone. Options include Friendly, Efficient, Professional, Candid, Quirky, Cynical, Nerdy, and a Default setting. These preset tones influence how the AI responds, while maintaining its core capabilities. Users can now fine-tune warmth, brevity, and even emoji use, creating more dynamic and adaptable conversations.
“GPT-5.1 feels more like a personal assistant than a tool,” said a company spokesperson. “It moves through tasks intelligently — whether you need a quick fix or thoughtful feedback.”
The new model improves instruction-following, delivering tailored responses to specific requests such as fixed word counts or highly focused advice. Backed by benchmark wins in AIME 2025, Codeforces, and similar platforms, GPT-5.1 shows clear gains in math, logic, and programming.
GPT-5.1 Instant is now warmer and more conversational.
— OpenAI (@OpenAI) November 12, 2025
The model can use adaptive reasoning to decide to think a bit longer before responding to tougher questions.
It also has improved instruction following, so the model more reliably answers the question you actually asked. pic.twitter.com/5zP0ft0ekm
Early access is available to Pro, Plus, Go, Business, Enterprise, and Edu users, with broader rollout planned for free users soon. Developers can access GPT-5.1 through the API as gpt-5.1-chat-latest (Instant) and gpt-5.1 (Thinking).
While GPT-5 remains temporarily available during the transition, GPT-5.1 is expected to become the new standard, enhancing user experience through a more approachable, responsive, and versatile AI assistant.
