OpenAI Releases GPT-5.1 With Improved Reasoning and New Customization Controls

The latest update to the GPT-5 family introduces two model variants, Instant and Thinking, and adds new options for tone and response style. The rollout began Nov. 12, 2025, for paid users.

What’s new in GPT-5.1

OpenAI released GPT-5.1 as the next evolution of the GPT-5 line. The update centers on two models:

• GPT-5.1 Instant, the company’s most-used option, which is designed to sound more natural and conversational.
• GPT-5.1 Thinking, which focuses on complex reasoning and produces clearer, more deliberate responses.

The Thinking model can adjust how much computation it uses based on task difficulty. It responds faster to simple requests and spends more time on complex ones, which improves accuracy for coding, math and analytical prompts.

Improved reasoning and responsiveness

GPT-5.1 Thinking adapts its processing time to the user’s request. For straightforward tasks, it performs roughly twice as fast as before. For demanding tasks, it takes additional time in order to deliver more complete and accurate answers. The model also reduces unnecessary technical language and undefined terms, which helps users understand responses more easily.

New controls for tone and style

The update also expands customization options. OpenAI introduced several new style presets that include Professional, Candid and Quirky, along with the existing Default, Friendly and Efficient options.
Users will soon be able to choose how concise or detailed answers should be and select how warm, formal or casual the tone sounds. Settings such as emoji frequency will also be adjustable. Updates to style preferences apply across existing and future chats.

Rollout timeline and availability

The rollout for GPT-5.1 begins Nov. 12, 2025. Paid users on the Pro, Plus, Go and Business plans will receive access first. Free and logged-out users will gain access shortly after.
For developers, GPT-5.1 Instant will appear in the API as “gpt-5.1-chat-latest,” and GPT-5.1 Thinking will appear as “GPT-5.1.” Earlier GPT-5 versions will remain available for three months in a legacy selector so developers can compare performance.

Implications for users and developers

For everyday users, GPT-5.1 offers more natural conversation and tighter control over how the model communicates. For developers and organizations, the improved reasoning and expanded customization tools provide more flexibility when integrating AI into products, workflows or customer-facing applications.

AI for B2B Media Insights

• Tone customization reflects a broader shift toward brand alignment. As AI becomes part of content creation and customer communication, the ability to tune style and voice becomes essential. This change helps media companies, marketers and publishers align AI output with their brand identity.
• Adaptive reasoning suggests stronger internal architecture. The Thinking model’s ability to increase or decrease processing time shows a more mature approach to task difficulty. This is likely to benefit technical and analytical use cases such as modeling, forecasting and automated decision support.
• The rollout strategy shows a move toward enterprise stability. OpenAI’s plan to release GPT-5.1 in stages and keep legacy models accessible signals a focus on reliability. This is especially relevant for businesses that depend on consistent model behavior for production systems.

This article was written with the help of ChatGPT