A senior artificial intelligence researcher who spent the past three years building foundational models at tech giants OpenAI and Anthropic has resigned, issuing a stark warning that leading industry labs are rushing recklessly toward uncontrollable superintelligent systems.

Jacob Coxon, 27, announced his departure from Anthropic on Tuesday, stating that neither the firm nor its rival OpenAI is acting responsibly in their push to develop advanced AI.

“Neither company is acting responsibly. They are racing straight to self-improving superintelligence and gambling with our lives,” Coxon wrote in a series of posts on the US social media platform X on Tuesday.

Coxon specialized in pretraining — the core, computationally intensive phase of training large language models that underpin products like OpenAI’s ChatGPT and Anthropic’s Claude. His high-profile exit marks the latest in a series of resignations by safety-focused researchers leaving top AI developers over ethical and existential concerns.

In his statement, Coxon warned against underestimating the speed and capability of upcoming AI systems, predicting they could soon gain the ability to hack software, disrupt entire industries and autonomously acquire real-world resources.

“The people building AI earnestly believe that it could kill us all by the end of the decade. This is not a marketing stunt. If anything, many executives and senior researchers will couch their phrasing in the press to sound sensible – but I hear the same people express fear privately,” he said.

Addressing fellow researchers across commercial labs, Coxon urged workers to “call for different conditions” and noted that slowing the competitive race may require drastic measures, including pacing agreements between labs or a temporary ban on capability advancements.​​​​​​​