After only rolling out the GPT 5.6 Sol, Terra, and Luna models to a small group of partners (like what Anthropic did with Project Glasswing), OpenAI is releasing its models to the masses. This comes after Anthropic was given the green light to release Claude Fable 5 and Mythos 5. Sol is the OpenAI flagship model and strongest model yet, which is more capable across coding, biology, and cybersecurity, while the others, Terra and Luna, are focused on lowering performance cost.