Model family
gpt-oss
Family overview — summarizes releases; licenses and availability belong to each release.
gpt-oss is OpenAI's series of open-weight, text-only reasoning models, released in August 2025 in two sizes: gpt-oss-120b and gpt-oss-20b. Both are mixture-of-experts transformers trained for OpenAI's harmony response format. OpenAI later published gpt-oss-safeguard models fine-tuned from them for safety classification.125
- Repository: gpt-oss repository (external site: github.com)
- Model hub: gpt-oss-120b on Hugging Face (external site: huggingface.co)
- Model hub: gpt-oss-20b on Hugging Face (external site: huggingface.co)
- Paper: gpt-oss-120b & gpt-oss-20b Model Card (arXiv) (external site: arxiv.org)
Last reviewedEntry updated Documented release
Releases assessed
Each release is assessed on its own. This family has no family-wide openness label.
| Release | Weights | Tier (USASI rubric v0.1) | License | Released |
|---|---|---|---|---|
| gpt-oss-120b | Weights: Public | Model-disclosure tier (USASI rubric v0.1): Open-weight | Apache-2.0, Apache-2.0 | Aug 2025 |
| gpt-oss-20b | Weights: Public | Model-disclosure tier (USASI rubric v0.1): Open-weight | Apache-2.0, Apache-2.0 | Aug 2025 |
What it is useful for
The model card describes use in agentic workflows with instruction following, tool use such as web search and Python execution, adjustable reasoning effort, and structured outputs.1
Organization context
U.S. eligibility
Project eligibility rests on documented governing or maintaining entities, not on contributors.
Sources
This listing is not an endorsement, a safety assessment, or a federal approval.