OpenAI has announced the release of GPT-5.1, its newest flagship artificial intelligence model, which introduces two distinct operating modes, GPT-5.1 Instant and GPT-5.1 Thinking, aimed at improving both speed and reasoning capabilities, according to The Indian Express.
The company explained that the GPT-5.1 Thinking mode is designed for deeper reasoning and handling complex queries, while GPT-5.1 Instant focuses on delivering quicker, more conversational responses. The models can automatically gauge the complexity of a question and allocate more computational power to challenging problems while replying instantly to simpler ones, Indian Express reported.
OpenAI also added eight personality styles — Default, Professional, Friendly, Candid, Quirky, Efficient, Nerdy, and Cynical — giving users control over tone and expressiveness. Adjustments such as emoji usage or warmth of language can now be applied instantly across all chats.
According to the company, early access will begin this week for Pro, Plus, Go, and Business subscribers, with free users to follow soon. Enterprise and Education users will get a week-long preview, while older GPT-5 versions will stay available for three months through a dropdown option.
OpenAI said GPT-5.1 demonstrates marked improvements in coding and mathematical performance, outperforming previous models in AIME 2025 and Codeforces benchmarks. The Thinking model has also been refined to explain complex topics in simpler terms. Applications CEO Fidji Simo said users had sought a model that felt both intelligent and engaging, describing GPT-5.1 as a “balance between depth and personality.”
The company noted that both modes will be gradually added to the API later in the week to maintain platform stability. The launch comes roughly three months after GPT-5’s debut in August, which faced criticism for being less personable and consistent. With GPT-5.1, OpenAI hopes to rebuild trust and make interactions feel more natural and connected.