Models
What Is GPT-6.1 Terra? OpenAI’s Leaked Model, Explained
GPT-6.1 Terra is an unreleased OpenAI model found in Microsoft code. What the leak shows, how it compares to GPT-6.1 Sol, price rumors and when it may launch.
GPT-6.1 Terra is a new OpenAI model name that started showing up in code and on X this month. People are asking the same few things: is it out, is it better than GPT-6.1 Sol, and will it be cheaper?
OpenAI has not said a word about it yet. But one piece of evidence is public and easy to check, and it tells us more than the rumors do. Here is what is confirmed and what is still guesswork, as of October 26, 2026.
What is GPT-6.1 Terra?
GPT-6.1 Terra looks like the next mid-tier model in OpenAI’s GPT-6.1 generation. OpenAI started naming models this way with GPT-5.6 in July: the number is the generation, and the word is the tier. From small to large, the tiers are Luna, Terra, Sol and, at the very top, Astra.
So "GPT-6.1 Terra" would be the Terra tier of the 6.1 generation. Today that generation has only one public model, GPT-6.1 Sol, which OpenAI introduced at DevDay on September 29, 2026. The last Terra you can actually use is GPT-5.6 Terra, from July.
Where did GPT-6.1 Terra show up?
The clearest evidence is in Microsoft’s public code. In pull request #39217 of the open-source dotnet/efcore project, titled "Make the evals more realistic and improve the skills accordingly," the team updated the tests it uses to grade AI coding agents. We checked the change ourselves. It was opened on October 10 and merged on October 16, 2026.
In 18 of those test files, the default model being tested is gpt-6.1-sol, and the default "judge" model that grades the answers is gpt-6.1-terra. Before the change, those files used GPT-5.6 Sol and GPT-5.6 Terra. A tester on X named Lumina pointed it out, and TestingCatalog and Android Headlines covered it on October 20.
Two more claims are going around, and both are weaker:
- GitHub Copilot. An X user said a commit by a GitHub Copilot engineer shows Terra being tested for code reviews in place of GPT-6.1 Sol. 36Kr repeated this on October 26. We could not find the commit, so treat it as unconfirmed.
- "Something this week." Some posts read an OpenAI staff hint about "exciting" news as a Terra launch. That is a guess, not a statement.
| Claim | Status | Source |
|---|---|---|
| The name "gpt-6.1-terra" exists in Microsoft code | Confirmed | dotnet/efcore PR #39217, merged Oct 16 |
| Used as the default judge model in 18 test configs | Confirmed | Same pull request |
| Meant to beat GPT-6.1 Sol at a lower price | Reported, not confirmed | The Information, via TestingCatalog and Android Headlines |
| Tested for GitHub Copilot code review | Unverified social post | X post, repeated by 36Kr |
| Price, benchmarks, context window | Unknown | Nothing from OpenAI |
| Release date | Unknown | Some launches may slip into November, per The Information |
GPT-6.1 Sol vs Terra
This is the top search right now, and here is the honest answer: nobody outside OpenAI and its partners has used Terra, so there is no real comparison yet. What we can compare is how OpenAI has positioned the tiers so far, and what has been reported.
| Model | Status | API price (per 1M tokens, in / out) |
|---|---|---|
| GPT-5.6 Terra | Released July 9, 2026 | $2.50 / $15 |
| GPT-6.1 Sol | Released September 29, 2026 | $2 / $10 |
| GPT-6.1 Terra | Unreleased (leak) | Not announced. Reported to be below Sol |
| GPT-6 Astra | Released September 3, 2026 | $10 / $50 |
One detail stands out. GPT-6.1 Sol already costs less than GPT-5.6 Terra did. If the new Terra lands below Sol, it would be the cheapest strong OpenAI model so far. That fits the report from The Information that OpenAI wants to compete with Anthropic on price.
The judge role in the Microsoft tests is also a hint, though only a hint. A judge model reads another model’s work and scores it, so teams usually pick one they trust. Using Terra to grade Sol suggests Microsoft expects it to be good at checking code. It does not prove that Terra is "smarter" than Sol.
When will GPT-6.1 Terra be released?
There is no date. The Information’s Stephanie Palazzolo said October would be busy for new models and named a possible new Terra, then added that some launches might slip into November. Test-config changes like the Microsoft one often come shortly before a release, but that is a pattern, not a promise.
The same report also mentioned new models from Anthropic and Google. We track the Anthropic one in Claude Fable 5.5 release date. We will update this page as soon as OpenAI announces Terra.
Is GPT-6.1 Terra free?
You cannot use it yet, free or paid. When it ships, past Terra models suggest it will reach the OpenAI API first, with ChatGPT access depending on your plan. Be careful with sites that already sell "GPT-6.1 Terra API access." Until OpenAI lists the model, nothing real is behind those offers.
What this means for you
For most people, a new mid-tier model matters in one way: the same quality of work gets cheaper. Cheaper models are what let apps run more steps, more checks and more agents on one task without raising prices.
It also shows how fast the names move. In under four months, OpenAI has gone from GPT-5.6 to GPT-6 Astra to GPT-6.1 Sol, and Terra is next in line. Keeping up with every tier is not a good use of your evening.
That is the idea behind an agentic AI app. Agentic AI gives you ready-made expert agents on iPhone and iPad, and up to 4 of them can work on one job together. You describe the task, the agents plan it and finish it, and you skip the model shopping. There is no account, and your first 3 tasks are free.
Quick answers
Is GPT-6.1 Terra out? No. As of October 26, 2026, OpenAI has not announced or released it. It is known only from Microsoft code and media reports.
What is GPT 6 Terra? It is the same thing people mean by GPT-6.1 Terra: the Terra tier of OpenAI’s GPT-6.1 generation. OpenAI has not announced any model called "GPT-6 Terra," so the leaked name to watch is GPT-6.1 Terra.
Is GPT-6.1 Terra better than GPT-6.1 Sol? The Information reported that it is designed to beat Sol at a lower price. No benchmarks exist yet, so that is a goal, not a result.
How much will GPT-6.1 Terra cost? Unknown. For reference, GPT-6.1 Sol costs $2 per million input tokens and $10 per million output tokens, and GPT-5.6 Terra cost $2.50 and $15.
Where was GPT-6.1 Terra leaked? In Microsoft’s public dotnet/efcore code, pull request #39217, merged October 16, 2026, where it is the default judge model in 18 test configs.
What is the order of OpenAI’s model tiers? From smallest to largest: Luna, Terra, Sol, then Astra at the top. See our glossary for more model names.
Sources: Microsoft dotnet/efcore PR #39217 · TestingCatalog · Android Headlines · 36Kr · OpenAI: GPT-5.6
