According to Beating, over 40 cybersecurity experts led by former Facebook Chief Security Officer Alex Stamos signed an open letter on June 15, protesting the Trump administration's export ban on Anthropic's AI models Mythos and Fable 5. The experts warned that restricting these defense tools will undermine the U.S. position in AI competition against China.
The ban stemmed from a vulnerability report submitted by Amazon security researchers, citing concerns that Fable 5 could auto-generate proof-of-concept code for exploits. However, Stamos clarified that the public version of Fable 5 lacks such autonomous attack capabilities. He noted that other leading AI models, including OpenAI's GPT-5.5 and Chinese model Kimi 2.7, offer equivalent vulnerability analysis capabilities, arguing that halting the U.S.'s most advanced defensive tools amounts to self-sabotage.