# Z.ai confirms development of Ox Alpha AI model > Live situation record from CLSTR: https://clstr.news/situations/ox-alpha-stealth-ai-model-release > Updated: 2026-08-25T17:14:41.000Z. Sources: 64. Developments: 3. The mystery surrounding the Ox Alpha stealth AI model has been resolved. The Chinese AI laboratory Z.ai, also known as Zhipu, confirmed that it developed the model as a stealth preview for its new GLM-5.3-Flash series. Initially appearing anonymously on the OpenRouter and OpenCode platforms, Ox Alpha gained rapid attention for its high performance in coding, reasoning, and long-horizon agentic tasks. The model features a 1,048,576-token context window and supports multimodal inputs including text, images, and video, though it rejects audio requests. During its limited free preview, the model saw massive usage, with reports indicating it processed 11.6 trillion tokens in just three days, supported by a claimed daily processing capacity of up to 100 trillion tokens. Following the confirmation of its origins, Z.ai released the model weights for GLM-5.3-Flash on Hugging Face. This move allows developers to build upon the architecture and highlights the increasing competition in the global AI landscape, as Chinese firms deploy highly capable, open-weight models at competitive price points. The model’s performance, which early testing suggested could rival or exceed established frontier models, was previously described by Stripe CEO Patrick Collison as “very impressive.” Recent reports indicate that the GLM-5.3-Flash model is specifically optimized to run on Chinese AI chips. ## Claims - Ox Alpha supports multimodal inputs including text, images, and video, but rejects audio. (disputed by 8 sources) - Ox Alpha is a reasoning model designed for coding, sustained agentic work, and production workloads. (corroborated by 20 sources) - Ox Alpha features a context window of 1,048,576 tokens. (corroborated by 14 sources) - Speculation suggests the model may be a variant of Zhipu AI's GLM series. (corroborated by 13 sources) - Ox Alpha is offered for free for one week with a claimed daily capacity of 100 trillion tokens. (corroborated by 11 sources) - Z.ai is the developer behind the Ox Alpha AI model. (corroborated by 9 sources) - Ox Alpha is a preview of the GLM-5.3-Flash model. (corroborated by 9 sources) - Stripe CEO Patrick Collison described the model as ‘very impressive’ on X. (corroborated by 7 sources) - The model weights for GLM-5.3-Flash have been released on Hugging Face. (corroborated by 7 sources) - Ox Alpha was initially released on OpenRouter without disclosing its developer. (corroborated by 7 sources) - Developer Ben Davis reported Ox Alpha scored above 80% on the DeepSWE software engineering benchmark. (corroborated by 5 sources) - Google DeepMind launched a double-blind AI evaluation pilot using cryptographic safeguards. (corroborated by 5 sources) ## Timeline ### 2026-08-25: Z.ai reveals Ox Alpha is its new GLM-5.3-Flash AI model Z.ai revealed that the popular anonymous “Ox Alpha” model is its new GLM-5.3-Flash. Meanwhile, Google DeepMind launched a double-blind AI evaluation pilot to prevent benchmark contamination. 20 sources. https://clstr.news/cluster/ox-alpha-ai-model-emerges-as-anonymous-stealth-system ### 2026-08-23: Ox Alpha: Mysterious stealth AI model debuts on OpenRouter The mysterious Ox Alpha AI model has debuted on OpenRouter, offering free, high-capacity reasoning for coding. Its anonymous origins have sparked speculation of a link to China's Zhipu AI. 37 sources. https://clstr.news/cluster/ox-alpha-ai-model-sparks-mystery-over-developer-identity ### 2026-08-21: Ox Alpha AI model emerges anonymously with high coding performance An anonymous AI model called Ox Alpha has surfaced on OpenRouter, impressing developers with its million-token context window and high-level coding abilities while sparking speculation about its origin. 16 sources. https://clstr.news/cluster/ox-alpha-ai-model-debuts-on-openrouter-with-1m-context-window --- Cite as: Z.ai confirms development of Ox Alpha AI model. CLSTR, https://clstr.news/situations/ox-alpha-stealth-ai-model-release