OpenAI rolls out GPT-5.1 with new variants and custom chat options

OpenAI has announced a major upgrade to its GPT-5 series with the release of GPT-5.1, describing it as “smarter, more reliable, and a lot more conversational”.

CEO Sam Altman, sharing the news on X, said, “I particularly like the improvements in instruction following, and the adaptive thinking. The intelligence and style improvements are good too.”

He added, “Also, we've made it easier to customise ChatGPT. You can pick from presets (Default, Friendly, Efficient, Professional, Candid, or Quirky) or tune it yourself.”



In a company blog, OpenAI said it is upgrading the GPT-5 series with two new variants:

• GPT-5.1 Instant, described as “warmer, more intelligent, and better at following your instructions”.
• GPT-5.1 Thinking, an advanced reasoning model that is “easier to understand and faster on simple tasks, more persistent on complex ones”.

GPT-5.1 release

The rollout will begin with paid users on Pro, Plus, Go, and Business plans, followed by free and logged-out users. Enterprise and Edu plans will get a seven-day early access option which will be off by default. After that period, GPT-5.1 will become the default model for everyone.

Both GPT-5.1 Instant and GPT-5.1 Thinking will be added to the API later this week. GPT-5.1 Instant will appear as gpt-5.1-chat-latest, while GPT-5.1 Thinking will be listed as GPT-5.1, both featuring adaptive reasoning. OpenAI also plans to update GPT-5 Pro to GPT-5.1 Pro soon.

Personality upgrades

OpenAI has refined ChatGPT’s preset personality options, allowing users to adjust how the AI responds. The existing modes: Default, Friendly (formerly Listener), and Efficient (formerly Robot) will remain with updates. Three new tones are being added: Professional, Candid, and Quirky.

These settings will apply across all models. The earlier Cynical (formerly Cynic) and Nerdy (formerly Nerd) presets will also stay available in the personalisation menu.

Users who want more fine-tuned control can directly adjust ChatGPT’s behaviour in settings, choosing how concise, warm, or scannable its replies are, and even how often it uses emojis. This feature will begin rolling out later this week.

ChatGPT will also be able to suggest preference changes automatically during conversations when it notices a user asking for a specific tone or style. These settings can be changed or removed at any time.

In addition, according to OpenAI, GPT-5.1 delivers noticeable gains in math and coding, performing better on AIME 2025 and Codeforces benchmarks. The GPT-5.1 Thinking model focuses on clarity, removing unnecessary technical language and explaining concepts in simple, plain terms.

The company highlighted that users increasingly want AI that is both capable and enjoyable to talk to.

Beyond one-size-fits-all

Fidji Simo, CEO of Applications at OpenAI, said in a blog post that ChatGPT’s evolution reflects its huge and diverse user base. With millions of users worldwide, she said that OpenAI has now moved beyond a “one-size-fits-all” approach, focusing instead on more personalised and adaptive experiences.