OpenAI officially unveiled GPT-5.1 on November 13, 2025, the next update in the GPT-5 lineup. According to the OpenAI blog, the update focuses on improving user experience and controllability. The key innovation is two modes: "GPT-5.1 Instant" (for quick answers) and "GPT-5.1 Thinking" (for deep reasoning), as well as an "Auto" mode that selects the required depth. Additionally, ChatGPT now features a "persona" system (Default, Professional, Friendly, etc.) and sliders for fine-tuning the tone, length, and structure of the response. OpenAI emphasizes the focus is on communication style, better instruction following, and clarity, not just benchmarks. The update is already rolling out to paid and some free users.
OpenAI Launches GPT-5.1 with "Instant" and "Thinking" Modes and "Persona" Sliders
