All last week, OpenAI watchers reported seeing strange things.

References to GPT-5.1 kept showing up in OpenAI’s codebase, and a “cloaked” model codenamed Polaris Alpha and widely believed to have come from OpenAI randomly appeared in OpenRouter, a platform that AI nerds use to test new systems.

Today, we learned what was going on. OpenAI announced the release of its brand new 5.1 model, an updated and revamped version of the GPT-5 model the company debuted in August.

As a former OpenAI Beta tester–and someone who burns through millions of GPT-5 tokens every month–here’s what you need to know about GPT-5.1.

A smarter, friendlier robot

In their release notes for the new model, OpenAI emphasizes that GPT-5.1 is “smarter” and “more conversational” than previous versions.

The company say

See Full Page