GPT-6 Astra

Astra was announced in August 2026 as OpenAI’s next model family and shipped on 3 September as GPT-6 Astra, four weeks later than planned after the company said it had slowed the release over cyber risk. It takes a context window of roughly 1.1 million tokens, produces up to 128,000 tokens per reply, and costs $10 per million input tokens and $50 per million output. OpenAI reports 72.6 percent on OSWorld 2.0, the benchmark for driving a computer desktop, ahead of GPT-5.6 Sol and Claude Opus 5.

The detail that got the most attention was not a benchmark. OpenAI says Astra is the first model to reach the Critical tier of its own cyber risk scale, meaning it can find unknown software flaws and write working exploits without step-by-step human guidance. It ships with alignment training plus production safeguards including automated code review and misalignment monitoring.