Key Points
- OpenAI releases GPT-5.1 Instant (fast default) and GPT-5.1 Thinking (complex reasoning).
- Eight personality presets added: Professional, Friendly, Candid, Quirky, Efficient, Cynical, Nerdy, Default.
- Models incorporate adaptive reasoning to allocate extra compute time when needed.
- Performance gains reported on benchmarks such as AIME and Codeforces.
- Initial rollout to paid ChatGPT subscribers; broader release and API integration planned.
- Legacy GPT-5 models stay available for three months for paid users.
- Launch follows user complaints about tone and occurs amid heightened regulatory scrutiny.
An illustration showing GPT-5.1’s eight personality styles in ChatGPT.
New Model Variants and Availability
OpenAI announced the release of GPT-5.1 Instant and GPT-5.1 Thinking, two variants of its latest language model now integrated into the ChatGPT interface. GPT-5.1 Instant is positioned as the faster default option for most tasks, while GPT-5.1 Thinking is designed for more complex problem‑solving, employing simulated reasoning capabilities.
Personality Presets and Adaptive Reasoning
Responding to user feedback that called for more varied communication styles, OpenAI introduced eight preset personality options: Professional, Friendly, Candid, Quirky, Efficient, Cynical, Nerdy, and the standard Default. These presets adjust the system instructions that guide the model’s tone without altering the underlying capabilities. In addition, the models feature adaptive reasoning, allowing the system to decide when to spend additional computational resources on a prompt before generating a response.
Performance Improvements
OpenAI claims that both GPT-5.1 variants achieve higher scores on technical benchmarks compared with the earlier GPT-5 release. Specific improvements are noted on mathematics and coding evaluations, including the AIME competition and Codeforces challenges.
Rollout Strategy
The company is deploying the new models to paid ChatGPT subscribers first, with plans to extend access to free users in the coming days. An API version of GPT-5.1 Instant (identified as gpt-5.1-chat-latest) and GPT-5.1 Thinking will be made available later in the week. Existing GPT-5 models will remain accessible in the legacy dropdown for paid users for a limited period of three months.
Context and Regulatory Environment
The launch arrives after earlier complaints that prior models sounded overly cheerful and sycophantic, as well as controversy surrounding changes to the default output style following several lawsuits related to suicide content. OpenAI now faces intensified scrutiny from lawyers and regulators, adding pressure to demonstrate responsible deployment of its AI technology.
Source: arstechnica.com