GPT-6 Astra Is Live — OpenAI's Flagship At Apex

September 5, 2026

GPT-6 Astra is in the model selector today. It is OpenAI's most capable model for the hardest end-to-end work — complex reasoning, coding, research, and long agent loops — with a 1.05M-token context window and 128K max output. It sits at quality 71, in the Apex 18× band, and Auto and Swarm can both pick it.

Independent boards already put it at the front of the pack. ARC Prize has Astra at 95% on ARC-AGI-2 and 62.7% on ARC-AGI-3 with their standard harness — both state-of-the-art on those boards. Artificial Analysis ranks GPT-6 Astra (max) #2 on the Intelligence Index.

What you can do

• Pick GPT-6 Astra from Closed SOTA in the model selector. It is the highest-rated model in the catalog.
• Leave the picker on Auto. When a turn escalates to SOTA, Astra is eligible — unlike Claude Fable 5.1, which stays a manual pin because it is non-ZDR.
• Use it in Swarm as the planner or the specialist on the hardest sub-task.
• Keep the whole project in one context — 1.05M input and 128K output, with tools and high-effort reasoning on by default.

Where this shows up

You have a multi-day refactor or a research brief that already outgrew GPT-5.6 Sol. Pin GPT-6 Astra and keep going in the same thread.

You leave Auto on for a hard analysis. The router can now land on Astra for SOTA turns instead of stopping at Sol or Opus 5.

You want Anthropic's Mythos-class pass and you know Fable 5.1 does not support zero data retention. Pin Fable yourself. For the same Apex 18× band without that constraint, pick Astra — or let Auto / Swarm choose it.

Try it

• "Use GPT-6 Astra to find the root cause of this rare crash — disassemble if you need to, then write the fix and the tests."
• "Challenge this market-entry plan, research the missing evidence, and produce a board-ready recommendation."
• Leave the picker on Auto, then: "Try again — go deeper on the assumptions that do not hold."

Heads up

• Apex 18× — the same token band as Claude Fable 5.1. Reach for it when the turn deserves the top of the catalog, not as an everyday default.
• Auto and Swarm can select it. Fable 5.1 stays out of both pools because it is non-ZDR. Astra does not have that restriction.
• Community accounts on the Budget 1× ceiling still cannot reach Apex until review approval or a purchase. Paid plans can pin it; Pro Max and Black Auto can route to it.