OpenAI Announces GPT-5.1 Instant & GPT-5.1 Thinking

OpenAI has announced GPT-5.1, a major upgrade to its flagship model that debuted in August. The company describes this as an “upgrade” to GPT-5 that makes ChatGPT smarter, faster, and more fun to talk to.

The release introduces two versions: GPT-5.1 Instant and GPT-5.1 Thinking. According to OpenAI, the Instant model feels warmer, more responsive, and better at following instructions, while the Thinking model is designed to handle complex reasoning with more consistency. ChatGPT will automatically route user queries to the model best suited for the task.

Both versions will begin rolling out this week, replacing the current GPT-5 lineup, though older models will remain available for three months under ChatGPT’s “legacy” dropdown.

Alongside the model update, OpenAI is expanding its personality presets, offering users more control over ChatGPT’s conversational tone. You can now pick from eight distinct styles: Default, Professional, Friendly, Candid, Quirky, Efficient, Nerdy, and Cynical.

The company also teased an experimental tool that will allow users to change ChatGPT’s tone directly from settings.

All that said, the latest release follows the lukewarm reception of GPT-5, which many users criticized for underwhelming improvements. OpenAI hopes GPT-5.1, alongside its recently announced ChatGPT Atlas AI browser, will restore some of that lost faith in users as competition from Anthropic and others intensifies.