The CEO of an Ant-backed humanoid robotics startup has published a letter to OpenAI in Chinese that raises questions about technical and design similarities between the two companies’ recent models.

“People often say major tech companies have intelligence networks monitoring the whole internet, this time I believe it, this is a direct distillation of us without any modifications,” Guo Renjie, CEO of Suzhou-based JoyIn, said in a public statement Thursday, according to a CNBC translation.

He said the startup had publicly presented its “extraterrestrial visitor” AI model framework in Silicon Valley a few weeks ago, before OpenAI’s Chief Scientist published “An Alien Mind” on Sept. 6. Guo questioned similarities in core technological approaches such as “recursive self-improvement” and the use of AI to optimize computing power.

Guo also highlighted similarities in the outer space-inspired design of OpenAI’s GPT-6 Astra web page and the website for JoyIn’s Aether model that he claimed was released two months ago. He added the startup has started the process of filing a lawsuit.

CNBC was unable to independently verify the claims. Some concepts are existing parts of AI research more broadly, although companies connect and implement them differently. OpenAI did not immediately respond to a request for comment.

U.S.-based Anthropic has repeatedly flagged unauthorized “distillation” of its models by Chinese companies to improve their own AI capabilities. On Tuesday, a U.S. cybersecurity agency said six Chinese companies, including DeepSeek and Alibaba, distilled models from Anthropic, Google and OpenAI.

JoyIn’s Aether model, which Guo said he decided to publicly announce Thursday, claims its perceptive, rather than text-based, approach to robotic control enables humanoids to complete tasks with a 90% success rate on first attempt.

Zhu Mingxuan, who led the model’s development, said she left U.S. humanoid company Figure last year, where she had also worked on models for helping humanoid robots mimic human actions. She told CNBC earlier this week that Aether reduced training time by two-thirds, and that she planned to open-source parts of the model, such as those relating to touch, but not portions related to energy use.

Getting humanoids and AI models to perform as intelligently as humans across a variety of tasks has remained a challenge, amid a broader tech race between U.S. and Chinese companies.

Garry Tan, chief executive of famed startup accelerator Y Combinator, told CNBC this month that he would “do nothing” about distillation and joined others in pointing out that the U.S. companies have trained their AI models on data covered under copyright law.

—CNBC’s Kate Rooney and Isabel O’Brien contributed to this report.