On Wednesday, OpenAI released GPT-5.1 Instant and GPT-5.1 Thinking, two updated versions of its flagship AI models now available in ChatGPT. The company is wrapping the models in the language of anthropomorphism, claiming they are warmer, more conversational and better at following instructions.
This release follows complaints earlier this year that its previous models were overly cheesy and cheesy, as well as an antitrust controversy among users over how OpenAI modified the default GPT-5 output style following several suicide lawsuits.
The company now faces intense scrutiny from lawyers and regulators that could jeopardize its future operations. In that kind of environment, it’s difficult to just release a new AI model, present some data, and move forward the way a company could have done even a year ago. But here are the basics: The new GPT-5.1 Instant model will serve as ChatGPT’s faster default alternative for most tasks, while GPT-5.1 Thinking is a simulated logic model that attempts to handle more complex problem-solving tasks.
OpenAI claims that both models perform better on technical benchmarks such as math and coding assessments (including AIME 2025 and Codeforces) compared to GPT-5, which was released in August.
The improved benchmarks may win over some users, but the biggest change with GPT-5.1 is in its presentation. OpenAI says it’s heard from users that they want AI models to simulate different communication styles depending on the task, so the company is offering eight preset options, including Professional, Friendly, Candid, Quirky, Efficient, Cynical, and Nerdy, along with the default setting.
These presets change the instructions given in each prompt to simulate different personality styles, but the underlying model capabilities remain the same across all settings.
An illustration showing the eight personality styles of GPT-5.1 in ChatGPT.
Credit: OpenAI
Additionally, the company trained GPT-5.1 Instant to use “adaptive logic,” meaning the model decides when to spend more computational time processing the prompt before generating output.
The company plans to gradually introduce the models over the next few days, starting with paid customers and then expanding to free users. OpenAI plans to bring both GPT-5.1 Instant and GPT-5.1 Thinking to its API later this week. GPT-5.1 Instant will appear as gpt-5.1-chat-latest, and GPT-5.1 Thinking will be released in the API as GPT-5.1, both with adaptive logic enabled. Older GPT-5 models will remain available in ChatGPT under the Legacy Models dropdown for paid customers for three months.