On June 26, 2026, OpenAI announced a limited preview of GPT-5.6 Sol, its next-generation frontier model, along with GPT-5.6 Terra for balanced everyday tasks and GPT-5.6 Luna for high-volume affordable work, according to OpenAI's official Twitter post. This release targets businesses seeking advanced AI capabilities for specialized, routine, and scalable applications. GPT-5.6 Sol delivers frontier-level performance for complex reasoning while GPT-5.6 Terra and Luna optimize cost and speed for different workloads. The GPT-5.6 family introduces differentiated performance tiers that address varying business needs, with Sol focusing on cutting-edge capabilities for research, advanced coding, and strategic decision support, Terra balancing quality with efficiency for daily operations, and Luna prioritizing speed and low cost for high-throughput scenarios. Each model variant optimizes distinct trade-offs between accuracy, latency, and compute requirements. The preview highlights OpenAI's strategy to segment the market and compete directly with other frontier AI providers on performance and efficiency.