US splits frontier AI access: Mythos 5 cleared, Fable 5 still under review

The Trump administration approved foreign-national access to Anthropic's Mythos 5 model on June 26 but explicitly withheld clearance for Fable 5, signaling capability-based rather than categorical restrictions on frontier models. The divergent treatment suggests each new capability tier may require individual government review, creating structural compliance overhead for AI labs and forcing enterprise customers to plan for model-specific supply-chain disruptions.