OpenAI Unveils GPT-5.1: A Smarter, Warmer, and Wittier ChatGPT With Custom Personality Modes

OpenAI has announced the release of GPT-5.1, its latest and most human-like chatbot model yet. The new version takes a significant leap forward in both intelligence and personality, designed to make interactions with ChatGPT more natural, expressive, and adaptable to individual users.

CEO Sam Altman described the update modestly as “a nice upgrade,” but in reality, GPT-5.1 marks one of the most substantial refinements since the GPT-5 rollout. OpenAI says the model is not only “smarter” but also “warmer, wittier, and more human” in tone—a clear response to user feedback that GPT-5 felt too mechanical compared to previous iterations.

The new model arrives in two versions: GPT-5.1 Instant and GPT-5.1 Thinking. The “Instant” variant caters to everyday users who rely on ChatGPT for quick tasks like trip planning, content drafting, or debugging code. OpenAI describes it as “now warmer, more intelligent, and better at following your instructions,” giving the AI a friendlier and more playful voice. Testers reportedly found themselves “taken aback by its newfound playfulness,” which the company says is intentional—ChatGPT is meant to feel like a witty, helpful colleague rather than a stiff assistant.

For users tackling complex or abstract challenges, GPT-5.1 Thinking steps in as the more advanced counterpart. According to OpenAI, it delivers answers that are “easier to understand and faster on simple tasks, more persistent on complex ones.” The model also consumes fewer tokens on basic queries, making it more efficient. Even while tackling intricate topics like explaining quantum computing to a six-year-old, GPT-5.1 Thinking strives to remain “clearer, with less jargon and fewer undefined terms.” Despite its analytical power, OpenAI assures that this version still feels “warmer and more empathetic,” capable of checking in with human-like care.

Another major highlight of GPT-5.1 is its expanded personality system. OpenAI is rolling out new conversation styles—Professional, Candid, and Quirky—joining an already diverse set that includes Default, Friendly (formerly Listener), Efficient (formerly Robot), Cynical (formerly Cynic), and Nerdy (formerly Nerd). These modes allow users to choose how ChatGPT interacts with them, from a polished consultant to a blunt coworker or an eccentric friend who loves lowercase musings.

In an official statement, OpenAI said, “Today’s GPT-5.1 updates and new customisation options are a step toward a ChatGPT that feels like it fits you, smarter, more enjoyable to talk to, and more adaptable to your preferences.” The company also revealed that it is experimenting with even finer personality controls, eventually enabling users to fine-tune traits beyond preset styles.

For now, GPT-5.1 is available exclusively to paid users, but OpenAI plans to make it accessible to everyone within the next three months. The company also confirmed that GPT-5 Pro will soon be upgraded to GPT-5.1, while older models will remain unaffected.

By prioritising warmth, humour, and adaptability, GPT-5.1 reflects OpenAI’s evolving vision of AI: not just powerful and precise, but also distinctly personal.