OpenAI is upgrading its main model, announcing that ChatGPT will soon be faster and more interactive with the launch of GPT-5.1. The company has released two updates to the GPT-5 series: GPT-5.1 Instant and GPT-5.1 Thinking. Both are now available on ChatGPT.
ChatGPT 5.1 is the default model designed for warmth, intelligence, and instruction following. GPT 5.1 Thinking is an advanced reasoning model that answers quickly to simple tasks but takes longer for complex ones.
We heard clearly from users that great AI should not only be smart but also entertaining to talk to, the company said in a blog post. GPT-5.1 improves meaningfully on both intelligence and communication manner.
OpenAI says this update lets users have no control over ChatGPT’s tone, so they can adjust how it communicates based on the situation.
The new models are now available to ChatGPT Pro, Plus, Go, and Business users, as well as to users of the free version. Enterprise and Edu customers will get 7 days of early access before GPT-5.1 becomes the default. Both models can also be used via the API, with updated resume features.
OpenAI confirmed that GPD 5 Pro will soon be updated to 5.1. This update delivers improvements to the base model, which is still part of the GPT-5 family and uses the same data and infrastructure as the resmi versions. The biggest change from GPT-5 to GPT-5.1 is a more natural tone, according to OpenAI’s CEO for applications, FidjiSimo, in a Substack post. GPT 5.1 Instant now uses adaptive reasoning, so it can hand-decide when a prompt needs deeper thought, notably for complex questions. OpenAI also says the model is better at following instructions, responding quickly, and providing more direct responses to user queries.
Under pressure
This update comes as computing models like Baidu’s Ernie-4.5-VL-28B-A3B thinking have started to outperform GPT-5 on benchmarks for instruction-following.
GPT 5.1 Thinking can independently decide how much reasoning to dedicate to a prompt, allocating more when needed. GPT 5.1 Thinking can decide on its own how much reasoning to use for each prompt, spending more time on complex questions and less on simple ones like summaries. OpenAI says their tests show GPT‑5.1 Thinking uses fewer tokens and responds faster on simple tasks than GPT‑5. Undefined terms make it easier to explain technical concepts. Another major update is deeper personalization. ChatGPT users can now toggle between friendly and strong tones to modify their conversational experience.
ChatGPT’s new version adds more ways to customize how it speaks, better matching common user preferences. Chat styles now include default, friendly, formal listener, fast, previously robot, professional, honest, and fun, with options like cynical and nerdy still there. Each chat style has its own instructions. Users can set how often emojis appear, and OpenAI is testing ways to make answers shorter and easier to read.
Rocky Rollout
The launch of GPT-5 sparked user frustration when OpenAI initially retired older models, prompting reports of issues with math, science, and writing. Altman reversed the decision, citing routing problems, and now GPT-5.1 Auto manages prompt routing. GPT-5 Instant, Thinking, and Pro are still available in ChatGPT’s model selector. However, paid subscribers will have only 3 months to compare older versions with the 5.1 update. Retiring GPT-5 will not affect models like GPT-4o.
Safety Concerns
Concerns about too much personalization are real. Over the past year, there have been reports of AI chatbots allegedly adding to suicides and encouraging obsessive, fantasy-driven behaviors. In response, OpenAI has published safety research explaining how it handles users who form unhealthy attachments to its AI systems. The company says such cases are rare, but it is working with an expert counsel and mental health professionals to define healthy interactions with AI.
Still, the core issue remains that chat equity continues to present itself as a person, a consistent, steady, familiar presence that seems to know users and adjusts to their preferences. Copying human emotions and seeming to understand and empathize can lead users into the same problems seen before. This puts OpenAI in a tough spot. Some users complain that ChatGPT sounds too robotic; if they feel too friendly or warm, can worry experts about their effect on vulnerable people.
The new personality options are open-eyed ways of addressing these means, serving everyone from technical users to those looking for a virtual companion, enough for broad adoption while avoiding user behavior that could become awkward. Simo addressed some of those concerns in her blog post. We also have to be vigilant concerning the potential for some people to develop attachment to our models at the expense of their real-world relationships, well-being, or obligations. She wrote that there will be many new challenges as this technology progresses and people use new ways. Building at this scale means never assuming we have all the answers.
Source: ChatGPT set for speed and conversational upgrades as OpenAI rolls out GPT-5.1
