OpenAI has officially launched GPT-5.1, an enhancement to its flagship model that debuted in August. The release is being described as an “upgrade” to GPT-5, intended to make interactions with ChatGPT more intelligent and enjoyable.
The new offerings include two specific models: GPT-5.1 Instant and GPT-5.1 Thinking. According to OpenAI’s announcement, GPT-5.1 Instant is characterized as “warmer, more intelligent, and better at following your instructions” compared to its predecessor. On the other hand, GPT-5.1 Thinking is designed to be “easier to understand, faster on simple tasks, and more persistent on complex queries.” With the update, user queries will generally be matched to the models best suited to respond effectively. The rollout of these models will take place this week, while the previous GPT-5 models will remain accessible in a legacy menu for the next three months before being phased out.
Additionally, OpenAI plans to broaden its personality presets for the AI’s conversational tone. The updated list now includes options such as Default, Professional, Friendly, Candid, Quirky, Efficient, Nerdy, and Cynical. OpenAI has also announced an experimental feature that allows users to fine-tune ChatGPT’s style directly from the settings, with some users set to gain access to this by the week’s end.
Fidji Simo, OpenAI’s CEO of Applications, noted in a Substack post that with over 800 million users utilizing ChatGPT, a one-size-fits-all approach is no longer viable.
Despite the excitement surrounding the initial announcement of GPT-5, feedback from users was mixed, with many feeling that the update fell short of expectations due to its incremental improvements. This prompted OpenAI to reintroduce GPT-4o as an available option a day after the launch of GPT-5.
Meanwhile, Microsoft, a key partner of OpenAI, has been looking into alternative models from Anthropic, following the mixed reception of GPT-5. Anthropic’s models are already being utilized in various Microsoft tools, including Copilot Researcher, GitHub Copilot, and the Office Agent responsible for generating Word and PowerPoint documents within Microsoft’s Copilot chat interface.
This announcement comes on the heels of OpenAI’s recent launch of ChatGPT Atlas, an AI-powered web browser featuring an “agent mode.” Currently available only to ChatGPT Plus and Pro users, this mode functions similarly to the company’s Operator tool, allowing the AI to perform tasks on the web for users.