What AI model does Notion AI use?
Short answer
Notion AI uses several companies' models, and by default Auto chooses one for each task. On Business and Enterprise you can pick instead: Notion's help center lists Claude Fable 5.1, Claude Sonnet 5, "the newest GPT models", Gemini and Grok, and its September 15, 2026 release adds Opus 5, GPT-5.6 Sol and Kimi K3.
Notion's AI used to be described as "GPT under the hood". That's been out of date for a while. Its help center, read on September 25, 2026, shows a model picker with five companies' models in it and an Auto setting that picks for you.
Auto is the default
Most people never touch the picker, and Notion encourages that. "Leave it on Auto and Notion will choose a model for each task," its Notion Agent page says, and the Custom Agents page calls Auto "the recommended default." Notion doesn't say which model Auto lands on for a given job.
What's in the picker
The help center lists the choices in one sentence: "Available models include Claude Fable 5.1 (Business and Enterprise plans only), Claude Sonnet 5, the newest GPT models, Gemini, and Grok." Notion's September 15, 2026 release notes are more specific about the top end, promising "all the latest frontier models in Notion, including Opus 5, GPT-5.6 Sol, and Kimi K3."
Kimi K3 is the one I didn't expect. It's a model from Moonshot AI, a Chinese lab, sitting next to the US labs' flagships (it turns up in Cursor's, Devin's and Perplexity's lists too, so Notion isn't alone).
There's a practical catch in the picker as well. Depending on which model you choose, Notion says the agent "may look only at info from the web" and "may not be able to look at info from your workspace or connected apps." Picking a model can cost you the thing that makes Notion AI useful.
Who can choose, and what it costs
The full picker is for Business and Enterprise. "Premium models spend Notion credits, and a workspace admin has to turn each one on" before members see it. Since September 9, 2026, workspace owners can set which models Notion Agent and Custom Agents can use, separately. Notion's AI FAQ adds that Business trials "may not have access to the model picker", and that tokens are charged "at each provider's published rates, with no markup."
Free and Plus plans get a limited number of complimentary AI responses, and Notion doesn't say which model answers them.
Notion's own models
The security page has one line that's easy to skim past: "Notion currently utilizes various large language models (LLMs) hosted by Notion as well as by organizations such as Anthropic and OpenAI." So some models run on Notion's own servers, and which ones is left unsaid.
What Notion doesn't say
Which model Auto picks per task, which models it hosts itself, and version numbers for the GPT, Gemini and Grok entries in its help pages.
Quick answers
Does Notion AI use ChatGPT?
It uses OpenAI's GPT models, among others. Notion's help center lists "the newest GPT models" in the picker, and its security page names OpenAI as one of its model providers.
Does Notion AI use Claude?
Yes. Claude Sonnet 5 is in the picker, and Claude Fable 5.1 is available on Business and Enterprise plans.
Which model does Notion AI use on the free plan?
Notion doesn't name one. Free and Plus get a limited number of complimentary AI responses, and the model picker is a Business and Enterprise feature.
Sources
Every source below was read on September 25, 2026. The date beside a link is the date the page itself carries, where it has one.