OpenAI Releases GPT-5.1 With Smarter Reasoning and New Customization Features

OpenAI today announced GPT-5.1, a significant upgrade to the artificial intelligence models that power its ChatGPT service. The update, announced just a few months after the launch of GPT-5, is an important one for Apple users, as OpenAI's technology is used to handle complex queries for Siri and other Apple Intelligence features.

The company says the new release improves both the intelligence and communication style of its AI. GPT-5.1 Instant, the model most users interact with, is now warmer and more conversational, with better instruction-following. For the first time, it can also use adaptive reasoning to decide when to spend more time on challenging questions, which OpenAI says is reflected in significant improvements on math and coding evaluations like AIME 2025 and Codeforces.




The more advanced GPT-5.1 Thinking model has also been upgraded for efficiency. It now adapts its thinking time more precisely to the question—spending more time on complex problems while responding more quickly to simpler ones. This means more thorough answers for difficult requests and less waiting for simpler ones, with clearer responses that use less jargon.

The upgrade to OpenAI's models is particularly relevant as Apple works to deliver its own advanced Siri features, which were delayed until 2026. The update also comes as OpenAI deepens its presence on Apple's platforms, having recently launched its ChatGPT Atlas browser for Mac and acquired the Mac app Sky for deeper OS integration.

Alongside the model improvements, OpenAI is making it easier to customize ChatGPT's tone. The company is refining its preset options with new and updated styles, including Professional, Candid, and Quirky. For users who want more granular control, OpenAI is also testing the ability to fine-tune characteristics like warmth and conciseness, with the app proactively offering to update these settings during conversations. Personalization settings now take effect across all chats instantly, including ongoing ones.

The new GPT-5.1 models are starting to roll out today, beginning with paid subscribers and expanding to free users in the coming days. Both GPT-5.1 Instant and Thinking will be available through the API later this week, and the older GPT-5 models will remain accessible for three months to allow for a gradual transition.