All terms
Models & Products
GPT-5.6
OpenAI's July 2026 model family, offered in three tiers — Luna, Terra, and Sol — from most affordable to most capable.
Definition
GPT-5.6 is a family of models released by OpenAI in July 2026, sold in three tiers so users can trade cost against capability: Luna, the cheapest and fastest; Terra, a balanced option for everyday work; and Sol, the flagship aimed at hard reasoning, coding, and agentic tasks where the model works through multi-step jobs on its own. OpenAI positioned the release around enterprise work, software engineering, scientific research, and cybersecurity. Its rollout was unusual: a limited preview went to a small set of partners first, ahead of the general launch.