OpenAI has officially launched GPT-5.1, the latest version of its large language model, introducing significant advancements in intelligence, adaptability, and conversational quality. The update emphasizes a more natural, warm, and flexible dialogue experience, alongside improved reasoning capabilities and customization options for users.
The new model is divided into two primary submodels — GPT-5.1 Instant and GPT-5.1 Thinking — each optimized for different use cases. GPT-5.1 Instant focuses on delivering faster, more conversational, and engaging responses. It is designed to feel more approachable and playful while maintaining clarity and reliability. The model also follows formatting instructions more precisely and uses adaptive reasoning, deciding when to “think” more deeply before answering complex questions. This approach helps it generate more accurate and detailed responses, especially in fields such as mathematics and programming.
The second submodel, GPT-5.1 Thinking, builds on its predecessor with a focus on deep reasoning and contextual understanding. It has been refined to offer clearer explanations, better day-to-day usability, and a warmer tone similar to the Instant model. GPT-5.1 Thinking dynamically adjusts its reasoning time according to the complexity of a task — spending more time on difficult problems and less on simpler ones. Compared to GPT-5 Thinking, it performs twice as fast on simpler tasks and twice as slow on complex ones, improving balance between speed and depth.
OpenAI also introduced enhanced customization options in ChatGPT. Users can now select from predefined tone presets such as Default, Professional, Friendly, Candid, Quirky, Efficient, Nerdy, and Cynical, or manually fine-tune the assistant’s personality and response style. This level of control allows for a more personalized interaction experience tailored to individual preferences or professional needs.
GPT-5.1 represents a major step forward in OpenAI’s pursuit of a more human-like conversational AI. It combines faster performance, smarter adaptive reasoning, and a richer emotional tone, resulting in smoother and more intuitive exchanges. The update is currently available for ChatGPT’s paid tiers — including Go, Plus, Pro, and Business plans — with broader access planned for free users in the near future
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