OpenAI has introduced GPT-5.1, a major update to its flagship model that refines performance, broadens customization options, and attempts to address user frustration that followed the underwhelming launch of GPT-5 earlier this year. The upgrade, rolling out this week, introduces two new variants - GPT-5.1 Instant and GPT-5.1 Thinking - designed to better match tasks automatically and offer more natural interactions.

GPT-5.1 Instant is built to be faster, sharper, and more responsive to instructions, while GPT-5.1 Thinking focuses on complex reasoning, longer attention, and improved breakdown of multi-step tasks. OpenAI says users will see models selected automatically based on the nature of their query, balancing speed and depth without manual switching. Existing GPT-5 models will remain available for three months before being moved into legacy status.

One of the standout updates is a major expansion in tone and personality controls. ChatGPT now offers a broader list of presets — including Professional, Friendly, Candid, Nerdy, Efficient, Quirky and Cynical — in addition to the default voice. OpenAI says some users will also begin seeing experimental controls that allow them to fine-tune the assistant’s style directly from settings. The decision reflects growing demand for customizable conversational agents, especially as ChatGPT’s user base surpasses 800 million people.

The upgrade arrives as OpenAI faces renewed competition and internal questions about direction. GPT-5 struggled to meet expectations, prompting the company to restore GPT-4o after sustained user pushback. Meanwhile, Microsoft, one of OpenAI’s closest partners, has been quietly leaning more heavily on Anthropic models across its Copilot tools, signaling a more pluralistic approach to AI integration.

GPT-5.1 also follows the recent release of ChatGPT Atlas, OpenAI’s browser-based assistant featuring agent mode for automated tasks. While currently limited to Plus and Pro users, Atlas is part of a broader strategy to extend ChatGPT from a conversational engine into a general-purpose digital executor that can operate across apps and websites.

The question now is whether GPT-5.1 is enough to reassert OpenAI’s momentum. While not a leap in raw capability, the update represents a shift toward personalization, speed, and task-specific adaptability — features that may matter more to everyday users than benchmark performance alone.

With pressure mounting from rivals and enterprise customers demanding more flexibility, GPT-5.1 marks OpenAI’s attempt to reset expectations; an incremental evolution that aims to feel more human, more intuitive, and more aligned with how people actually use AI.