Tier 0 Proprietary service
What the publisher claims:
The one-liner: The famous game-playing agent that was never released.
The six questions
No code or weights have ever been released for OpenAI Five.
Nothing published to license or reuse.
It ran only on OpenAI infrastructure.
The 66-page paper documents method, hyperparameters and training procedure in unusual detail.
A skilled group could build a comparable system from the paper, but not the original.
No artifacts, no repo, no channel — OpenAI published only a paper and blog post.
License
No released code or weights; paper and blog post only — license source ↗
- Nothing published to license or reuse; it ran as an internal research artifact
What is actually released
- paper
- blog post
- arena demonstrations
Why it matters
The negative control, a landmark result whose openness stops at the paper, which is where open usually stops.
Sources
Derived from the openness dataset behind But Is It Open? — snapshot 2026-11-07 ↗. Scores are qualitative readings of the cited evidence, not verdicts; tier measures openness, not intelligence.