Logo via Wikimedia Commons; license to verify on approval
The 27-year-old researcher walked away from Anthropic after four months, warning that the industry's race toward self-improving AI could become uncontrollable by the end of 2027
Jacob Coxon lasted four months at Anthropic. Before that, he spent three years at OpenAI. Now he’s at neither, and his reason for leaving has racked up over 100 million views on X.
The 27-year-old British AI researcher, who worked on pretraining at Anthropic, resigned on September 8 after concluding that the trajectory of AI development at both companies he’s worked for amounts to what he called a “race to self-improving superintelligence.” His core argument: none of this matters if China isn’t at the table when it comes to enforcing safety limits.
The case for alarm #
Coxon joined Anthropic in May 2026 after contributing to GPT-4o during his stint at OpenAI. His public posts painted a picture of an industry culture that has adopted the language of urgency without the corresponding caution. He pointed to terms like “crunchtime” and “endgame” circulating inside AI labs.
The specific warning is stark: Coxon believes advanced AI systems could become uncontrollable by the end of 2027. Evan Hubinger, Anthropic’s own alignment lead, essentially backed him up. Hubinger has publicly estimated a greater than 10% probability that AI leads to human extinction this decade.
Why China matters #
Coxon’s resignation letter wasn’t just a warning. It was a policy argument. His central thesis is that unilateral restrictions on AI development would simply disadvantage the side playing it safe. Coxon urged global cooperation, specifically with China, to enforce limits on recursive self-improvement in AI systems.
The timing of this argument is particularly charged. US and Chinese AI developers are locked in an escalating competition, with both Anthropic and OpenAI reportedly preparing for potential IPOs.
What it costs to speak up #
One detail worth noting: Coxon left before his equity fully vested. At a company valued in the tens of billions and potentially heading toward an IPO, that’s not a trivial financial decision for a 27-year-old researcher.
Over 100 million views suggests Coxon’s concerns resonated well beyond the usual AI safety circles. Major media outlets picked up the story. This creates a specific problem for Anthropic, which was founded by former OpenAI researchers who left precisely because they felt safety wasn’t being prioritized, and now faces an employee leaving for the same reason.
Market and regulatory ripple effects #
Both Anthropic and OpenAI are navigating a delicate moment. They need to demonstrate commercial viability to investors while simultaneously arguing that their safety practices are robust enough to justify continued rapid development. A high-profile resignation undermines the second half of that pitch.
Disclosure: This article was edited by Editorial Team. For more information on how we create and review content, see our