Model: GPT-6 Sol / Luna
On 7 October 2026, OpenAI began rolling GPT-6 out as the default model inside ChatGPT — GPT-6 Sol for Plus, Pro, Business and Enterprise, and GPT-6 Luna for Free and Go. Here’s what it means when the engine answering questions about your category quietly changes for the entire ChatGPT base.
Source: ChatGPT release notes — GPT-6 and Intelligent UI in ChatGPT (7 October 2026)
- On 7 October 2026, ChatGPT made GPT-6 its default model, starting with paid plans and expanding to Free and Go.
- Paid plans run GPT-6 Sol; Free and Go run GPT-6 Luna — so most people now meet a different engine than last week.
- The default model is the one that answers the overwhelming majority of questions, including the ones about your category.
- When the default changes, the brands a model reaches for and the way it frames them can shift without warning.
- reconnAI monitors ChatGPT alongside Claude, Gemini, Perplexity, Copilot and Google AI Overview, and re-baselines whenever a default model changes.
What OpenAI actually changed
On 7 October 2026, OpenAI began rolling GPT-6 out as the default model in ChatGPT. The rollout started globally that day for Plus, Pro, Business and Enterprise in the Chat tab, and expanded to Free and Go from the following day, with Enterprise availability depending on each workspace’s admin settings.
This is not a new tab or an opt-in beta. It is a change to the engine that answers by default — the model most people get without choosing anything. The same release introduced ChatGPT’s Intelligent UI, which lets answers add diagrams, comparisons and interactive tools, and the ability to start replying while the model is still thinking. Underneath the new presentation sits a new default brain.
Sol and Luna: the new default split
The headline detail for visibility is which model each user now meets. Plus, Pro, Business and Enterprise use GPT-6 Sol; Free and Go use GPT-6 Luna. Intelligent UI is available from Instant through Extra High reasoning, while the separate Pro reasoning option keeps using GPT-6 Astra and does not support the interactive format. The models powering Work and Codex are unchanged by this release.
Sol is also the sharper agentic line we looked at with GPT-6.1 Sol; here it becomes the everyday default for paying users. Luna is the lighter default for the free tier. That split matters because free and paid users can now receive answers from two genuinely different engines — a point we return to below.
Why a new default model matters
Most people never change the model picker. They open ChatGPT, ask a question and trust the answer they get. That makes the default model the single most important surface in AI search: it shapes the first impression millions of buyers form about a category, and about who is worth considering in it.
When that default changes generation, the way it weighs sources, resolves competing claims and decides who to name can change with it. A brand that was reliably mentioned under the old default is not guaranteed the same treatment under the new one — which is why a default swap is exactly the kind of moment worth measuring rather than assuming.
What a model swap changes for answers
A newer default model tends to be more discerning. It is harder to nudge with keyword tricks, steadier about which sources it carries forward, and more willing to caveat a claim it cannot support — the theme behind our look at how stronger models sharpen recommendations. For brands, a more careful default raises the bar for being included at all.
It also changes the texture of the answer itself. With Intelligent UI layered on top, GPT-6 may present a category as a side-by-side comparison or a short interactive tool rather than a paragraph — and how your brand is represented inside those formats depends on what the model already treats as trustworthy about you.
How GPT-6 chooses which brands to name
When a model answers a question about a category, it leans on the sources and signals it treats as authoritative. A more capable default rewards organisations that state plainly who they help, on what terms and on what basis, and it is less easily swayed by thin or contradictory material.
This is the logic behind how LLMs decide which brands to cite and the readiness checklist in is your brand ready for AI search? As GPT-6 becomes the default everywhere, those fundamentals matter more, not less, because a careful model will not carry forward a brand it cannot corroborate.
Free vs paid: two engines, two answers
Because paid plans run Sol and the free tier runs Luna, the same question can now return different answers depending on which plan the person is on. For most categories your customers are split across both, so checking only one tier gives you half the picture.
That is why tier and region both belong in any serious measurement. Answers already differ by country, as we have tracked with Perplexity going multi-model; adding a free-versus-paid model split on the biggest assistant makes a one-off spot check even less reliable as a guide to how you are really being represented.
What this means for your content
The response is not to chase a single model but to make your expertise unmistakable to any careful one. Spell out who you serve, the problems you solve, your credentials and the evidence behind your claims, in clean, structured content a model can read and trust across your site, your profiles and third-party sources.
Consistency does the heavy lifting: when your key facts line up everywhere a model looks, even a new default summarising at speed can carry you forward without hedging. That discipline sits at the heart of building a GEO strategy and Google’s own llms.txt guidance, and it pays off across ChatGPT, Claude and Gemini alike.
What the GPT-6 default change means
OpenAI began the GPT-6 default rollout on 7 October 2026.
Does ChatGPT cite the brands it names?
ChatGPT does not return a ranked list of brands the way a search engine does. It answers in prose, and when it names a provider, product or study, it is drawing on the knowledge and sources it treats as trustworthy. When it browses, it can reference public pages directly; even when it does not, the brands it has learned to associate with a topic shape the framing a user receives.
So the influence brands have is indirect but genuine, which is exactly why the logic of citation matters. Under a new default you are competing to be the source a careful model reaches for — and GPT-6 doing the retrieval and summarising makes that competition more about substance than tactics.
How to check your visibility in GPT-6
Because a new default spreads to everyone fast, it is worth taking a baseline now. Here is a short, practical way to see how GPT-6 handles the questions around your brand — today is 13 October 2026:
- List your real questions. Write down the questions your customers actually ask before choosing you.
- Ask ChatGPT directly. Run those questions in ChatGPT and record which brands, providers and sources it names.
- Check both tiers. Repeat on a paid plan (Sol) and a free one (Luna), since the default engine differs.
- Note the framing. Watch how it describes you, who it mentions alongside you, and what it caveats.
- Compare across models and regions. Repeat in Claude, Gemini and Perplexity, and in your key markets, since answers differ.
- Track the trend. One run is a snapshot; the value is in watching movement as GPT-6 settles in as the default.
How reconnAI tracks ChatGPT answers
reconnAI monitors how the leading AI models — ChatGPT, Claude, Gemini, Perplexity, Copilot and Google AI Overview — answer questions across regions, and re-baselines that tracking whenever a platform ships something that changes behaviour. A new default model on the biggest assistant is exactly that kind of moment, because it changes the engine behind most of the answers people actually see.
It joins a busy run of shifts we have followed lately, from the Claude Haiku 5.5 launch and Gemini Skills to the wider picture in this week in AI. If you want to see how ChatGPT represents your brand when people ask about your category, get in touch with our team, explore how AI visibility tracking works, or read our overview of ChatGPT advertising for where paid placement is heading.
GPT-6 Sol and Luna: your questions answered
What changed on 7 October 2026? OpenAI began rolling GPT-6 out as the default model in ChatGPT, starting with Plus, Pro, Business and Enterprise and expanding to Free and Go from the next day.
What is the difference between GPT-6 Sol and Luna? Paid plans (Plus, Pro, Business, Enterprise) use GPT-6 Sol; Free and Go use the lighter GPT-6 Luna. The Pro reasoning option continues to use GPT-6 Astra.
Why does a default model change matter for AI visibility? Because the default answers most questions. When it changes generation, the brands it names and the way it frames them can shift for the whole user base without anyone opting in.
Does my brand appear inside ChatGPT? Not as a ranked list. ChatGPT answers in prose and names the providers and sources it trusts, so being the evidence a careful model reaches for is what earns a mention.
How do I track my visibility across models? Baseline the questions your customers ask, run them across ChatGPT (both tiers), Claude, Gemini and Perplexity, and watch how the answers change over time — which is what reconnAI automates.
About reconnAI
reconnAI tracks how the major AI models represent topics and sources across ChatGPT, Claude, Gemini, Perplexity, Copilot and Google AI Overview — across multiple regions. We monitor how those models answer and how they change over time, so you can stay ahead of shifts in the AI landscape.
Last updated: 13 October 2026.