OpenAI has released the GPT-5.6 model family, comprising three sizes: Luna (smallest), Terra, and Sol (largest). These models feature a one million token context window, 128,000 maximum output tokens, and a knowledge cutoff of February 16th, 2026. Key updates to the API include programmatic tool calling via JavaScript orchestration, native multi-agent support for parallel task execution, explicit prompt cache breakpoints, and an option to receive unresized images in requests.
* Three model tiers: Luna, Terra, and Sol
* Improved performance in long-running agentic professional workflows
* New API features including programmatic tool calling and multi-agent orchestration