OpenAI has begun a limited preview of GPT-5.6, the new family of language models consisting of Sol, Terra, and Luna. Initial access is restricted to trusted partners via API, with a broader rollout planned later on ChatGPT. The staggered release was not voluntary: the U.S. government requested a 30-day early access window for new models, as established by an executive order from President Donald Trump. OpenAI expressed dissatisfaction with this procedure, emphasizing that advanced tools should be available to users, developers, and cyber defenders without bureaucratic delays.
The three models offer different balances of intelligence, speed, and cost. Sol is the flagship model, designed for complex tasks such as advanced coding, multi-step reasoning, and agentic work. Terra is the mid-range option, with competitive performance to GPT-5.5 but at half the cost, ideal for everyday use. Luna is the fastest and cheapest model, suitable for simple queries, summaries, and quick interactions. OpenAI has not yet clarified whether ChatGPT will automatically route requests to the appropriate model based on complexity.
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The U.S. Government Imposes a Limited Preview for GPT-5.6
Trump's executive order established a voluntary framework under which AI developers grant the government early access to new models for up to 30 days before public release. OpenAI stated that it previewed its plans and the models' capabilities with the government ahead of launch, and at their request, started with a limited preview for a small group of trusted partners. The company stressed that this process should not become the long-term default, as it slows the distribution of useful tools. As reported in a previous article, OpenAI obtained government approval for the launch but with these temporary restrictions.
GPT-5.6 Sol is the Most Powerful Model Ever Created by OpenAI
Sol is the flagship model of GPT-5.6, with improved capabilities in coding, biology, and cybersecurity. OpenAI introduced two new modes: max and ultra. Max mode grants more processing time, while ultra mode uses additional sub-agents to handle complex tasks. Sol is likened to the big brain of the family, to be used when the difficulty of the problem justifies a longer wait. Its performance has been tested in multi-step reasoning scenarios, demonstrating an ability to maintain context and follow detailed instructions without constant guidance.
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GPT-5.6 Terra is the Balanced Model for Daily Use
Terra is positioned as the mid-range option, with performance comparable to GPT-5.5 but at half the cost. It is designed for writing, planning, research, coding assistance, and general ChatGPT use. For most users, Terra will be the default model, capable of handling the majority of daily tasks without requiring Sol's power. OpenAI estimates that Terra will become the most widely used model in practice, offering a good compromise between quality and speed.
GPT-5.6 Luna is the Fast and Affordable Model
Luna is the smallest and most cost-effective model in the GPT-5.6 family. It is optimized for quick responses and light tasks such as summaries, rewrites, and rapid brainstorming. Although not the flagship, Luna may be the model users interact with most often, thanks to its speed and low operational cost. For OpenAI, Luna represents an opportunity to make ChatGPT more responsive and economical, especially for simple requests that do not require Sol's intelligence.
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The GPT-5.6 preview is currently available only via API and Codex for a limited group of partners and organizations. Full integration into ChatGPT is expected in the coming weeks, but no specific date has been announced. Ordinary users will not notice immediate changes, but OpenAI suggests the main difference will be a greater ability to understand complex requests and produce more complete results on the first attempt. For further details, refer to the TechRadar article that first reported the news.
