GPT-5.6 Sol vs Terra vs Luna: OpenAI's New 3-Tier AI Model Explained
OpenAI just killed the "one model to rule them all" approach — and quietly admitted that picking an AI model is now as complicated as picking a phone plan. GPT-5.6 went publicly live on July 9, 2026, and for the first time, it didn't ship as a single model. It arrived as three: Sol, Terra, and Luna — each built for a different mix of intelligence, speed, and cost. No more "which GPT number is the good one." Now you pick a tier. Is this actually useful, or just a more confusing way to sell the same thing? Let's break it down.