SI Model · OpenAI
GPT-6 Astra
On this page
| Developer | OpenAI |
|---|---|
| Released | September 3, 2026 |
| Status | Current |
| Inputs | Text, Images |
| Context window | 1.1M tokens |
| API price (input) | $10 / 1M tokens |
| API price (output) | $50 / 1M tokens |
| Open weights | No |
| Access | ChatGPT (Plus, Pro, Business, Enterprise), OpenAI API, AWS |
Specs and list prices last verified October 7, 2026. Prices change often; check the provider before you buy.
Strengths
- Long-horizon agentic work and computer use
- Software engineering
- About 1.05M-token context with 128K output
- First model rated "Critical" for cyber capability under OpenAI's framework
Best for
- The hardest multi-step agent tasks
- Large codebases and complex engineering
- Research and analysis where quality matters more than cost
GPT-6 Astra is the top model in OpenAI’s GPT-6 family. OpenAI launched it on September 3, 2026, calling it its most intelligent model, built for computer use, software engineering, science and long-running agent work.
Rollout and safety
Astra was the first model reported to reach the “Critical” cybersecurity level under OpenAI’s Preparedness Framework, meaning it was judged capable of finding and exploiting previously unknown software vulnerabilities. OpenAI rolled it out in stages: first to vetted enterprises and cyber-defence partners, then over the following days to paid ChatGPT plans, the API and AWS. OpenAI later cancelled a planned October release of GPT-6.1 Astra after safety testing.
The GPT-6 family
| Model | Role | Price (in / out per 1M) |
|---|---|---|
| GPT-6 Astra | Flagship | $10 / $50 |
| GPT-6.1 Sol | Near-flagship value | $2 / $10 |
| GPT-6 Luna | Fast, lowest cost | $0.10 / $0.50 |
All three offer about a 1.05-million-token context window and up to 128,000 output tokens.
How it compares
Astra’s closest rival is Anthropic’s Claude Fable 5.1, at the same list price. See GPT-6 Astra vs Claude Fable 5.1. Google’s Gemini 4 Argon, announced September 30, claims benchmark leads but isn’t generally available yet.
Frequently asked questions
How much does GPT-6 Astra cost?
$10 per million input tokens and $50 per million output tokens on the OpenAI API, with discounted cached input. It is also included in ChatGPT's paid plans.
What is the difference between GPT-6 Astra and GPT-6.1 Sol?
Astra is OpenAI's most capable model. GPT-6.1 Sol, released September 29, 2026, costs a fifth as much ($2/$10) and OpenAI says it nearly matches Astra on agentic coding, computer use and professional work.
Sources
- OpenAI API models — OpenAI
- OpenAI launches GPT-6 Astra — Constellation Research
Written by
Luka Kušec · Editor
Editor of SI.info. Writes about Super Intelligence, technology policy and the people building frontier models.