OpenAI announced the limited preview of GPT-5.6 Sol along with GPT-5.6 Terra and GPT-5.6 Luna on June 26 2026 according to OpenAI. The frontier model GPT-5.6 Sol targets advanced reasoning tasks while Terra offers balanced performance for daily workflows and Luna focuses on speed and cost efficiency for large scale operations. GPT-5.6 Sol delivers frontier level capabilities that can accelerate complex problem solving across research and enterprise sectors. The new suite improves multimodal understanding and long context retention enabling more reliable outputs in professional environments. Developers benefit from reduced hallucination rates in specialized domains like legal review and financial modeling. Businesses gain flexible model choices allowing cost optimized deployments for different workload volumes and accuracy needs. Competitive pressure increases on rivals as OpenAI expands its model portfolio with tiered performance options. Access occurs through OpenAI.