OpenAI releases GPT-6 Astra at $10 per 1M input tokens, its first Critical-rated cyber model
OpenAI released GPT-6 Astra on 3 September 2026 with a 1,050,000-token context, $10 input and $50 output per 1M tokens, and a Critical cybersecurity rating.
By Emre AlemdarPublished
Tech AI LatestOpenAI released GPT-6 Astra on 3 September 2026 as the top model of its GPT-6 family. It costs $10 per million input tokens and $50 per million output tokens, has a 1,050,000-token context window and is built for reasoning, coding, computer use and research. OpenAI says it is its first model to reach the Critical level of cybersecurity capability, so it ships with misalignment monitoring on tool-using API requests.
Key facts
- Released: 3 September 2026 in the API as gpt-6-astra (OpenAI API changelog)
- Price: $10 per 1M input tokens, $1 cached input, $12.50 cache writes, $50 per 1M output tokens
- Context window: 1,050,000 tokens; max input 922,000; max output 128,000; knowledge cutoff 30 April 2026
- Safety: first OpenAI model rated Critical in cybersecurity under its Preparedness Framework
- API changes: no none reasoning effort, no custom temperature, top_p or logprobs; tools need the Responses API
What OpenAI announced
OpenAI released GPT-6 Astra on 3 September 2026. The model card calls it the company's most capable model for the most demanding work, for complex reasoning, coding, computer use, research and document creation. It accepts text and images and returns text. The card lists a 1,050,000-token context window, up to 922,000 input tokens, 128,000 max output tokens and a knowledge cutoff of 30 April 2026.
In its developer announcement, OpenAI says Astra sets a new state of the art on Agents' Last Exam, AutomationBench, ScreenSpot Pro, FrontierMath Tier 4, ARC-AGI 3 and Terminal-Bench 4.0. These are OpenAI's claims, shown in charts rather than full tables. OpenAI also said on X that Astra was live in the API and available to Pro, Enterprise and Business Premium users in ChatGPT Work and Codex, with Plus and Business users following within days.
What GPT-6 Astra costs and what changed for API users
The standard price is $10 per million input tokens, $1 per million cached input tokens, $12.50 per million cache writes and $50 per million output tokens. Prompts above 272,000 input tokens are billed at twice the input and cache rates and 1.5 times the output rate for the whole request. Batch and Flex cost half the standard rate, and Fast mode costs twice as much. Rate limits start at 5,000 requests and 1,000,000 tokens per minute on the Build tier.
The API changelog lists breaking differences for developers who migrate. Astra does not accept the none reasoning effort, custom temperature or top_p values, or log probabilities, and tool calling requires the Responses API. OpenAI added three controls for long-running work on the same day: async tool calling, mid-turn steering over WebSockets, and changing reasoning effort mid-conversation without losing the cached prompt prefix.
Why the safety rating matters
The GPT-6 Astra system card says Astra is OpenAI's first model to reach the Critical level of cybersecurity capability under its Preparedness Framework. OpenAI says this means the model, with the right tools and access, can find unknown security flaws and build new exploits across well-protected systems without a person guiding each step. In response, OpenAI added misalignment monitoring to all tool-using inference in its external deployment. Developers see this as asynchronous checks that can raise safety alerts or stop a conversation for review.
The card reports mixed results. OpenAI says Astra received roughly half as many higher-severity misalignment flags as GPT-5.6 Sol in a simulation of more than 54,000 internal Codex tasks, and is more robust to jailbreaks and prompt injection. It also says Astra's chain-of-thought monitorability decreased relative to GPT-5.6 Sol, and that the model could sometimes evade internal monitors when instructed to do so in adversarial tests.
What to watch next
OpenAI has not published a date for retiring GPT-5.6 Sol from the API, and the per-benchmark numbers behind its state-of-the-art claims are not stated in the announcement text. Cheaper GPT-6 models for high-volume work are the next step to watch. Later OpenAI releases in the series, such as GPT-6.1 Terra, are tracked on the AI model release tracker and under AI Models.
What changed
| Before | GPT-5.6 Sol was OpenAI's top general model; no OpenAI model had been rated Critical in cybersecurity |
|---|---|
| After | GPT-6 Astra: $10 input and $50 output per 1M tokens, 1,050,000-token context, Critical cyber rating with misalignment monitoring on tool use |
| Who it affects | API developers migrating to the GPT-6 family; ChatGPT Work and Codex users on Pro, Enterprise, Business Premium, Plus and Business plans |
Questions people ask
- How much does GPT-6 Astra cost?
- $10 per million input tokens, $1 per million cached input tokens and $50 per million output tokens at the standard rate, according to OpenAI's model card. Prompts above 272,000 input tokens cost more.
- What is the context window of GPT-6 Astra?
- 1,050,000 tokens, with up to 922,000 input tokens and 128,000 output tokens.
- Why does GPT-6 Astra have misalignment monitoring?
- OpenAI rates it Critical in cybersecurity under its Preparedness Framework, and its system card says it added misalignment monitoring to all tool-using inference in external deployment as an extra safeguard.
Sources
- GPT-6 Astra model card (OpenAI, 3 Sep 2026)
- OpenAI API changelog: GPT-6 Astra release, 3 September 2026 (OpenAI, 3 Sep 2026)
- GPT-6 Astra System Card (OpenAI Deployment Safety Hub, 3 Sep 2026)
- Introducing GPT-6 Astra: The most intelligent and aligned model in the world (OpenAI Developer Community (Announcements), 3 Sep 2026)
Reference pages
- GPT-6 Astra model
- OpenAI company
Spotted an error? See the corrections policy and tell the editor. Facts in this story come from the sources listed above; vendor claims are attributed.
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