Following a period of limited preview and regulatory scrutiny, OpenAI has announced that its latest generation of large language models, the GPT-5.6 series, will be officially released to the public this Thursday. The series includes three models: the flagship Sol, the balanced Terra, and the cost-effective Luna.

Timeline of the Launch Process

The release was previously delayed due to a US national security review. In late June, OpenAI provided a limited preview to a small, pre-approved group of partners at the request of US authorities, with all trial permissions requiring individual approval. The AI Standards and Innovation Center under the US Department of Commerce, after completing multiple rounds of supplementary testing, granted approval for the full public launch of GPT-5.6 on Tuesday.

Official Announcement and Commentary

OpenAI CEO Sam Altman confirmed the news on social media. Responding to the restricted initial release, he stated that extensive safety testing is not a bad thing, but expressed his dislike for the government's practice of selecting which customers could access the technology.

Model Capabilities and Performance

Among the three models, the flagship Sol is particularly notable for its performance in areas like coding and cybersecurity. In the Terminal-Bench 2.1 programming test, Sol's Ultra mode achieved a score of 91.9%, surpassing the 88.0% score of Anthropic's Claude Mythos 5. In cybersecurity evaluations, Sol required only about one-third the number of output tokens to reach performance levels comparable to competing products. Terra's performance is benchmarked against GPT-5.5 but at half the price, while Luna is positioned with the lowest pricing for high-frequency usage scenarios.

Pricing and New Features

The pricing is set at $5 per million input tokens and $30 per million output tokens for Sol; $2.5 and $15 for Terra; and $1 and $6 for Luna. OpenAI has also introduced new reasoning control modes, including a Max mode for deep reasoning and an Ultra mode that employs a sub-agent mechanism to handle complex tasks.

Regulatory Context

This clearance comes amid a broader loosening of restrictions on other AI models. The export controls previously imposed by the US government on Anthropic's Mythos 5 and Fable 5 models began to be lifted last week.