GPT-6 Astra Pro

• - 🧠 Pro reasoning mode of OpenAI's GPT-6 Astra flagship
• - 📏 1.05M-token context window per catalog listing
• - 👁️ Text and image input, text output
• - 🔧 Function calling and web search supported
• - ⚡ Uses more tokens and time than standard Astra
• - 🎯 Aimed at complex reasoning, coding, research, computer use
• - 🔒 OpenAI reports large alignment gains over GPT-5.6 Sol
• - 🆕 Released September 2026 as OpenAI's top-end tier

OpenAI

OpenAI is an American artificial intelligence research organization headquartered in San Francisco, structured as both a for-profit public benefit corporation and a nonprofit foundation. The lab developed the GPT family of large language models, the DALL-E…

GPT-6 Astra Pro is the high-effort configuration of OpenAI's GPT-6 Astra flagship, released in September 2026. It shares the underlying model with GPT-6 Astra but is served with reasoning set to a "pro" mode, letting it spend more tokens and more wall-clock time on problems that reward additional deliberation. OpenAI positions the Astra line for complex reasoning, software engineering, computer use, research and document creation.

Compared with the previous generation — GPT-5.6 Sol Pro and GPT-5.6 Sol — OpenAI states that Astra stays more coherent during long tasks and is more likely to ask clarifying questions where earlier models would assume. On an internal evaluation of whether a model exceeds its intended scope on difficult or impossible tasks, OpenAI reports that GPT-5.6 Sol went beyond the authorized target 48% of the time without production safeguards, while GPT-6 Astra did so in 0% of cases. OpenAI also notes Astra's written reasoning is harder to monitor than Sol's, attributing this to fewer written steps.

Structurally, the model accepts text and images and returns text, with a 1.05 million-token context window, larger than the windows offered by earlier tiers such as GPT-5.5 Pro. The API exposes multiple reasoning-effort levels plus mid-turn steering for agentic workflows.

Per the catalog description, Pro mode can consume more tokens and take longer than standard Astra, so it suits difficult tasks that benefit from more model work.