OpenAI had already launched its “Trusted Access for Cyber” pilot program in February after releasing GPT-5.3-Codex, its most capable cybersecurity-focused model to date. Participants in the program receive access to especially powerful models for defensive security work, backed by $10 million in API credits.

It remains unclear whether OpenAI plans to make the new model more widely available later on. Anthropic, for its part, has ruled out a public release of Mythos Preview. The company says models in the Mythos class will only be released once adequate safety guardrails are in place