Large language model
GPT-6 Astra
GPT-6 Astra is a reasoning model released by OpenAI on 3 September 2026 as the most capable member of the GPT-6 family. It accepts text and images, has a 1,050,000-token context window and is built for complex reasoning, coding, computer use, research and document creation in the API, ChatGPT Work and Codex.
Last reviewed 28 Oct 2026 · by OpenAI
Facts at a glance
| Developer | OpenAI |
|---|---|
| Released | 3 September 2026 source |
| API name | gpt-6-astra source |
| Context window | 1,050,000 tokens (922,000 max input) source |
| Max output | 128,000 tokens source |
| Knowledge cutoff | 30 April 2026 source |
| API price | $10 per 1M input tokens, $1 cached input, $12.50 cache writes, $50 per 1M output tokens source |
| Preparedness Framework | First OpenAI model to reach the Critical level of cybersecurity capability source |
What GPT-6 Astra is used for
OpenAI describes GPT-6 Astra as its most capable model for the most demanding work, able to carry multi-step workflows across code, browsers and professional software. Reasoning effort runs from low to max; the none level, custom temperature and top_p, and log probabilities are not supported. Tool calling requires the Responses API, and the supported tools include web search, file search, code interpreter, hosted shell, computer use and MCP. OpenAI runs asynchronous misalignment monitoring on supported Responses API requests.
Questions people ask
- When was GPT-6 Astra released?
- OpenAI released it in the API on 3 September 2026, according to the API changelog.
- How much does GPT-6 Astra cost?
- $10 per million input tokens and $50 per million output tokens at the standard rate, with cached input at $1 per million, per OpenAI's model card.
- 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.