GPT-5.6 Preview: Introducing Sol, Terra & Luna
OpenAI has announced a preview of the GPT-5.6 family, introducing three models designed for different levels of capability, speed, and cost. The New Models GPT-5.6 Sol - Flagship model with the strongest reasoning capabilities - Introduces a new Ultra Mode that leverages sub-agents for complex tasks - State-of-the-art performance in coding, biology, and cybersecurity benchmarks GPT-5.6 Terra - Balanced model for everyday work - Delivers performance comparable to GPT-5.5 - Costs 2x less than GPT-5.5 GPT-5.6 Luna - Fast and affordable model - Designed for speed and cost efficiency while maintaining strong capabilities Key Updates - Improved long-horizon reasoning and agentic workflows - Stronger performance in coding and cybersecurity tasks - Enhanced safety systems with extensive automated and human red-teaming - New pricing and prompt caching improvements for developers - New naming system: generation number (5.6) + capability tier (Sol, Terra, Luna) Availability Current Status: Limited preview for a small group of trusted partners through the API and Codex. General Release: OpenAI plans to make GPT-5.6 Sol, Terra, and Luna available in ChatGPT, Codex, and the API in the coming weeks. The GPT-5.6 launch is not just about introducing more powerful models-it is about giving users and developers clearer choices across intelligence, speed, and cost. Which model would best fit your use case: Sol, Terra, or Luna?