Since September 23, 2026, the sections you describe in the AI Extension Builder are understood, written and refined by GPT-6 Luna, the model OpenAI released the day before. You have nothing to change on your side. Here is what the switch does for your app, and what it leaves alone.
What changed on September 23
OpenAI released GPT-6 Sol and GPT-6 Luna on September 22, 2026, after GPT-6 Astra, the flagship of the family, earlier the same month. Luna is the smallest of the three. OpenAI describes it as its most efficient model for focused, high-volume tasks, and sells it at half the price of GPT-5.6 Luna, the model it replaces in OpenAI's own line-up.
The next morning, we moved the AI Extension Builder to GPT-6 Luna, for every app, on the four moments where a model is at work: understanding your request, writing the code of the section, rewriting it when you ask for a change, and answering the questions you ask about what it built.
What it means for you
Nothing to install, nothing to configure. The AI Extension Builder stays free for Content and eCommerce apps, and the prompts you wrote last month work as they did.
Sections you have already published do not change. A published section is code that runs in your app, and no model touches it after the fact. GPT-6 Luna steps in the next time you generate a new section or refine an existing one.
What OpenAI says about this generation: fewer coding errors than the previous one, and fast answers at high volume. Those are OpenAI's numbers, measured on OpenAI's tests. We will judge on your sections, not on a benchmark: how long a generation takes, and what you ask the builder to fix afterwards.
A fast model for a conversational tool
The builder is a conversation. You describe a section, wait a few seconds, look at the preview, ask for an adjustment. In that loop, the time to the first result matters, and most sections, a timer, a habit tracker, a quiz, a countdown, do not need a model built for long and complex tasks. Luna is the model OpenAI positions for focused, high-volume work. A section with a clear brief is that kind of task.
Bigger models exist in the same family, and a single step of the builder can be routed to one of them if real generations show the need. For now, what we want to test is the fast one.
Try it on a section you have been putting off
Open your back office, add a “Create with AI” section, and describe what you want. If you would rather start from a working example, the prompt library inside the builder gives you complete briefs to reuse, and our “Steal this idea” series hands over full prompts, like the 30-day back-to-shape challenge for a fitness studio. New to the builder? Start with the guide to building sections with AI or the AI Extension Builder page.
Then tell us what you see. A section that came out better than last week, or a prompt that used to work and now stumbles: send it to our support team from your back office, with the prompt you used. That feedback is what the next adjustment will be built on.