GPT-6 Astra
OpenAI's most capable model — 1.05M context, 128K output
Verdict
Announced September 3, 2026, and the top of the GPT-6 family. $10/$50 per million tokens puts it in the same price band as Claude Fable 5.1, so treat it the same way: a model for the hardest reasoning and long-horizon agent work, not a default. Prompts over 272K input tokens bill at a higher long-context rate ($20/$75). Most teams should start on GPT-6.1 Sol and only move up when evals show Sol is the bottleneck.
Other Text Generation & Reasoning
- GPT-6.1 SolProduction
The OpenAI default — near-Astra quality at a fifth of the price
- GPT-6 LunaProduction
OpenAI's efficient tier — $0.10/$0.50 with the full 1.05M context
- GPT-5.6Superseded
Previous OpenAI family — Sol/Terra/Luna tiers, superseded by GPT-6
- GPT-5Superseded
OpenAI's 2025 flagship — two families back now
- GPT-5 miniSuperseded
OpenAI's 2025 cost-efficient model — superseded by GPT-6 Luna
- GPT-4oSuperseded
OpenAI 2024 multimodal model — legacy, with retirement dates on Azure