OpenAI released GPT-5.6 on July 9, 2026, ending a two-week limited preview period. The model family includes three variants: Sol (flagship), Terra (balanced), and Luna (cost-efficient). All three are now available in ChatGPT, Codex, and the API.

GPT-5.6 Sol represents a major leap forward in AI capability. The model sets a new standard for both intelligence and efficiency, achieving state-of-the-art results across coding, knowledge work, cybersecurity, and science. It outperforms previous and competing frontier models while using fewer tokens and costing less to run.

Three Models for Different Needs

Sol is the flagship model, built for developers and researchers pushing the boundaries of what’s possible. Terra sits in the middle, designed for everyday work, handling complex tasks without the overhead of Sol. Luna is the most cost-efficient, perfect for applications where speed and affordability matter more than raw intelligence.

All three models include a 1 million token context window, giving them the ability to process entire books or codebases in a single request. The knowledge cutoff is February 2026.

Pricing Structure

OpenAI priced the models from $1 to $5 per million input tokens, making advanced AI more accessible across different budgets and use cases. The tiered pricing reflects each model’s capabilities and computational requirements.

Government Safety Review Process

GPT-5.6 entered limited preview on June 26, 2026, after the U.S. government requested OpenAI prioritize safety testing. The model was available only through the API and Codex to a small group of government-approved partners. Sam Altman, OpenAI’s CEO, warned of “hiccups” with Sol, noting the model’s “insane” growth trajectory.

New Voice Capabilities

OpenAI also announced GPT-Live, a new generation of voice models that can listen and speak simultaneously. The technology makes conversations feel much more natural, closer to having a real human conversation with an AI.

GPT-5.6 marks a turning point in AI accessibility. Three tiers mean developers can choose the model that fits their budget, not just their ambitions.

FYI (keeping you in the loop)

What is the difference between GPT-5.6 Sol, Terra, and Luna?

Sol is the flagship model for advanced tasks. Terra is balanced for everyday work. Luna is cost-efficient for high-volume applications. All use the same 1 million token context window.

References

OpenAI. GPT-5.6: Frontier intelligence that scales with your ambition. Published July 2026.
Engadget. OpenAI releases GPT-5.6 to the public. Published July 9, 2026.