The new release introduces two model variants — GPT-5.1 Instant and GPT-5.1 Thinking, News.Az reports, citing The Verge.
According to OpenAI, the Instant version is “warmer, more intelligent, and better at following your instructions” than its predecessor, while the Thinking model is “easier to understand and faster on simple tasks, and more persistent on complex ones.”
ChatGPT will automatically match user queries to the most suitable model, with the rollout beginning this week. The previous GPT-5 models will remain available for three months under the “legacy models” menu before being phased out.
Alongside the technical improvements, OpenAI announced an expansion of its personality presets, allowing users to choose from conversational tones including Default, Professional, Friendly, Candid, Quirky, Efficient, Nerdy, and Cynical.
The company is also testing a new fine-tuning experiment that lets users directly adjust ChatGPT’s conversational style through settings — a feature being gradually introduced to select users this week.
“With more than 800 million people using ChatGPT, we’re well past the point of one-size-fits-all,” Fidji Simo, the company’s CEO of Applications, wrote in a Wednesday Substack post.
While OpenAI CEO Sam Altman hyped up the announce of GPT-5 in August, the release failed the hype test. Many ChatGPT users were left unimpressed, particularly at the incremental improvements, and expressed frustration over OpenAI’s choice to make it the default model for ChatGPT. There was so much pressure that OpenAI decided it would bring back GPT-4o as an option, a day after the launch of GPT-5.
Microsoft, OpenAI’s strategic AI partner, has also increasingly been looking at rival models from Anthropic after GPT-5 failed to raise the bar enough. Anthropic’s models are now helping power Copilot Researcher, GitHub Copilot, Copilot Studio, and a new Office Agent that is able to produce Word and PowerPoint documents from Microsoft’s own Copilot chat interface.
The announcement of GPT-5.1 comes just weeks after OpenAI launched its AI-powered web browser, ChatGPT Atlas. It has an “agent mode” that’s currently only available to ChatGPT Plus and Pro users, and it works much like the company’s Operator tool to take actions in the browser on behalf of users.
