Open models by OpenAI

OpenAI presents its open-weight reasoning models as customizable for any use case and runnable anywhere, released under the Apache 2.0 license. The models support agentic tasks, including instruction following and tool use such as web search and Python code execution, within the chain-of-thought. Users can set reasoning effort to low, medium, or high and apply full-parameter fine-tuning, and the full chain-of-thought is accessible for debugging. The page also says safety testing is part of the release and that OpenAI is working with deployment and hardware partners, though it names none of them and gives no figures.