OpenAI publishes a model guide for its GPT-6 family

OpenAI has spent the past month shipping GPT-6 models at a steady clip. Now it has published the instruction manual. On October 2, 2026, the company released “A model guide for the GPT-6 family.” The document targets developers and startups who need to decide which model to use, how much thinking to ask of it, and how to move a workflow from prototype to production. Four models, three tiers, one menu The guide sorts the GPT-6 lineup by workload and reasoning capability. At the top sits Astra, which OpenAI positions as its flagship for complex reasoning, with state-of-the-art performance in fields such as coding and science. Astra launched on September 3, 2026. It posted a 98% score on FrontierMath Tier 4 and 99.9% on ARC-AGI-3. Next come Sol and Luna, which launched on September 22, 2026. Their selling point is price. API rates for both come in 50% lower than their GPT-5.6 counterparts. Sol costs $2 per million input tokens and $10 per million output tokens. Luna goes much lower, at $0.10 per million input tokens and $0.50 per million output tokens. Then there is 6.1 Sol, released on September 29, 2026. OpenAI says it delivers near-Astra performance at one-fifth of Astra’s cost. Al...