OpenAI Begins Public Rollout of GPT-5.6 in Three Tiers

On July 9, 2026, OpenAI began rolling out its new-generation model "GPT-5.6" across ChatGPT, Codex and the API as three distinct tiers — Sol, Terra and Luna — differing in performance, speed and cost. The public rollout follows a limited preview, and its defining feature is a structure that lets users pick the model best suited to each task. According to the official announcement, the flagship Sol handles long-horizon coding and agentic work that demands planning, tool use and follow-through; Terra balances performance and cost for everyday work; and Luna brings speed to well-defined, high-volume tasks.