The US export-control directive that suspended access to Claude Fable 5 and Mythos 5 reaches further than "foreign companies." According to Isaacus, a frontier legal-AI lab, it bars any foreign national from using the models, including, in its words, "even Anthropic's own employees."
Isaacus notes the directive covers nationals of the United States' closest allies, the UK, Canada, Australia and New Zealand, regardless of where they live or work, and that access "ceased almost immediately" with no forewarning. The practical sting is small for now only because Fable 5 had been out three days before the ban and Mythos 5 was limited to select partners, so few users had built anything on them yet.
The lasting lesson Isaacus draws is dependency risk: any product built on a closed frontier model can be shut down at any moment by a directive its own builder did not see coming, which is precisely the case open-weight advocates have been pressing all week.