Ox Alpha, a free model released on OpenRouter on Thursday, is described on the listing as “a reasoning model designed for coding, sustained agentic work, and production workload.” It is also labeled a “stealth model,” developed by a third-party provider that chose to remain anonymous during the preview. On X, Stripe CEO Patrick Collison, whose company is acquiring OpenRouter, called Ox Alpha “very impressive,” adding to the buzz.

No one has confirmed who built the model. Speculation initially centered on the GLM models from Chinese company Z.ai, AI analyst Andrew Curran said in a Friday post, but “this morning people seem less sure of anything.” A Wccftech article first said the evidence pointed to GLM, then updated to suggest Ox Alpha could be an unreleased version of Microsoft’s MAI. Reddit reactions are split, with one post declaring the model “can’t be the Chinese” and another expressing “high confidence” that it is Chinese.

The article records public speculation rather than reporting direct evidence or an official statement. The confirmed details are the OpenRouter listing text, Collison’s comment, and the conflicting guesses circulating online.