OpenAI’s advanced GPT-5.6 models to be publicly released

OpenAI announced Tuesday evening that its advanced GPT-5.6 series artificial intelligence models will be publicly available later this week.

GPT-5.6 Sol, Terra and Luna models will launch publicly on Thursday, the company said via a post on X. This update follows OpenAI’s announcement in late June that it was working with government partners to assess the safety of these models prior to their release, an approach the company does not believe “should become the long-term default,” per its statement in June.

“We’re expanding preview access globally now,” OpenAI’s post reads. 

Delays to the public rollout of OpenAI’s GPT-5.6 series were due to the powerful capabilities of the models. GPT-5.6 Sol is the strongest model of the series, and is tuned for work in biology, chemistry and cybersecurity. It is also accompanied by its stronger variation, Sol Ultra. 

Whether any changes were made to the GPT-5.6 models — such as updates to parameters, model weights or other architecture — prior to their release remains unclear. OpenAI did not respond to a request for more information by the time of publication. The GPT-5.6 models are said to feature strong safeguards that can withstand “real-world adversarial pressure,” according to OpenAI. 

The GPT-5.6 model’s availability after undergoing government evaluation follows objectives outlined in a recent June AI executive order signed by President Donald Trump that asked for major AI developers to voluntarily submit their leading AI models to government regulators for safety evaluations, largely stemming from Anthropic’s development and release of Mythos, a powerful cybersecurity-focused model that sparked widespread concern over its potential to be used offensively against digital networks if it falls into adversarial hands.