GPT-5.1 debuts with new Instant and Thinking models

OpenAI announced an upgrade to its flagship model today, November 12, 2025, releasing GPT-5.1. The new version, which powers ChatGPT, is split into two models: GPT-5.1 Instant and GPT-5.1 Thinking. According to OpenAI, GPT-5.1 Instant, the most-used model, is now "warmer, more intelligent, and better at following instructions," with a more playful default tone. It can also now use adaptive...

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