Models
What Is GPT-6 Astra? OpenAI’s Top Model, Explained
GPT-6 Astra is OpenAI’s flagship model, released September 3, 2026. What it does, what it costs, who can use it, and how it compares with Claude Fable 5.1.
GPT-6 Astra is OpenAI’s most capable model, and seven weeks after launch people are still typing the same questions into Google: what is it, is it free, how do I get it, and is it better than Claude? The name does not help much. There is also a GPT-6.1 Sol, and an older GPT-5.6 Sol, and they are not the same thing.
This guide sorts it out in plain words. Every number below comes from OpenAI’s launch materials as reported by at least two outlets, and we say clearly where reports disagree.
What is GPT-6 Astra?
GPT-6 Astra is a large AI model from OpenAI, the company behind ChatGPT. OpenAI released it on September 3, 2026 and says it is its strongest model for computer use, browsing, software engineering, science and professional work.
Think of it as the "big engine" of OpenAI’s current lineup. It is slower and pricier than the everyday models, but it is meant for hard, multi-step work, the kind an AI agent does when it clicks through apps, writes and tests code, or reads a huge pile of documents.
| Fact | GPT-6 Astra |
|---|---|
| Made by | OpenAI |
| Released | September 3, 2026 (staged rollout) |
| API name | gpt-6-astra |
| Context window | About 1.05 million tokens, up to 128,000 tokens out |
| API price | $10 in / $50 out per million tokens |
| Fast mode | Up to about 2x faster at about 2x the price |
| Also on | Amazon Bedrock and Microsoft Azure |
| Safety rating | First OpenAI model rated "Critical" for cyber under its Preparedness Framework |
GPT-6 Astra vs GPT-6.1 Sol vs GPT-5.6 Sol
OpenAI now names models with a number for the generation and a word for the tier. We explained that system when it started in What is GPT-5.6? Here is how the three names people mix up fit together:
- GPT-5.6 Sol is last summer’s flagship, released July 9, 2026. It is the model Astra is mostly measured against.
- GPT-6 Astra is the larger, top-tier model of the new generation, out since September 3.
- GPT-6.1 Sol came at DevDay on September 29. It is the cheaper workhorse, at $2 in and $10 out per million tokens, and it powers the COBOL migration results OpenAI shared this week.
So Astra is the one you reach for when the job is long and hard and cost matters less. Sol is the one for everyday volume.
GPT-6 Astra benchmarks
These are OpenAI’s own scores. Independent testing is still limited, so treat them as claims, not final rankings.
| Test | GPT-6 Astra | Compared with |
|---|---|---|
| OSWorld 2.0 (using a computer) | 72.6% | GPT-5.6 Sol 65.7% |
| Terminal-Bench 4.0 (command-line coding) | 57.9% | Claude Fable 5.1 55.8%, GPT-5.6 Sol 37.3% |
| Terminal-Bench Science | 64.6% | Claude Fable 5.1 52.6% |
| FrontierMath Tier 4 | 97.6% | OpenAI’s top math test; a near-perfect score |
| Humanity’s Last Exam (with tools) | 57.2% | Claude Fable 5.1 65.0% |
| ExploitBench (turning known bugs into exploits) | 100% | GPT-5.6 Sol 78.5% |
Two things stand out. First, speed on agent work: OpenAI says Astra finishes an OSWorld task in about 40 minutes where GPT-5.6 Sol needed about 75. Second, it does not win everything. On Humanity’s Last Exam and on a broad intelligence index, Anthropic’s Claude Fable 5.1 scored higher.
Why GPT-6 Astra is "Critical" for cybersecurity
OpenAI grades its models for risk before release. Astra is the first one to hit the top "Critical" level for cyber skills. In plain terms, it is good enough at finding and using software flaws that it could help an attacker.
That is why the launch was staged. Vetted security groups in OpenAI’s Daybreak program got it first. The public version refuses advanced hacking requests, such as writing proof-of-concept exploits, and automatic checks watch what it does. OpenAI also admitted that Astra’s written reasoning is harder to monitor than GPT-5.6 Sol’s, and called that a serious issue.
Google took a similar path a few weeks later, limiting its new model to vetted experts at first. We covered that in What is Gemini 4 Argon?
Is GPT-6 Astra free?
No. OpenAI has not announced Astra for free ChatGPT users. At launch it went to Plus, Pro, Business and Enterprise plans, with usage counted inside your plan’s limits and extra credits for sale. Enterprise admins have to switch it on, since it is off by default.
One caution for Plus users: several reports and user posts say Plus access sits inside ChatGPT Work and Codex rather than the regular chat window. If you do not see it in the model picker, that is the likely reason.
How to access GPT-6 Astra
- ChatGPT: on a paid plan, pick Astra where your plan offers it (ChatGPT Work or Codex for most Plus users).
- Codex: OpenAI’s coding tool can run Astra for long coding jobs.
- API: developers call
gpt-6-astra. Cached input is billed at a lower rate. - Cloud platforms: Amazon Bedrock and Microsoft Azure.
What this means for you
Astra is impressive, but look at what using it actually takes: the right plan, the right tab, an admin switch at work, and a token bill if you build with it. Next month there will be another name. Claude Fable 5.5 is already rumored.
Most people do not want a model. They want the email written, the trip planned, the bug found. That is the point of agentic AI: you give a goal to expert agents and they handle the steps.
That is how our app works. Agentic AI gives you ready-made expert agents on iPhone and iPad, running on frontier models. You can put up to 4 agents on one task, there is no account to create, and your first 3 tasks are free.
Quick answers
What is GPT-6 Astra good at? Long agent tasks: using a computer, command-line coding, hard math and research. OpenAI’s own tests show its biggest gains over GPT-5.6 Sol in those areas.
Is GPT-6 Astra free? No. It needs a paid ChatGPT plan or API credit. Free ChatGPT access has not been announced.
What is the GPT-6 Astra price? In the API, $10 per million input tokens and $50 per million output tokens. Fast mode costs about double.
GPT-6 Astra vs Claude Fable 5.1: which is better? It depends on the task. Astra leads on OpenAI’s coding and computer-use tests; Fable 5.1 leads on Humanity’s Last Exam and a broad intelligence index.
Is GPT-6 Astra AGI? No. OpenAI does not call it AGI. It is a strong model that still misses on many tests, as the scores above show. See our glossary for what AGI means.
When was GPT-6 Astra released? September 3, 2026, first to a limited group, then to paid ChatGPT plans and the API over the following days.
Sources: OpenAI: GPT-6 Astra · Constellation Research · ForkLog · DataNorth · Free Press Journal
