Commerce Lifts Mythos 5 Export Block for 100+ US Entities

The letter from Secretary Lutnick to Anthropic chief compute officer Tom Brown ended a two-week block imposed after external warnings on jailbreak risks to Mythos 5 and Fable 5. It explicitly covers in-country transfers and foreign national employees at listed entities while remaining silent on Fable 5. The decision follows daily negotiations and parallels OpenAI's simultaneous limited release of GPT-5.6 to approved partners.

Primary evidence consists of the Commerce letter text citing "significant progress" on safeguards and Anthropic's commitment to joint protocol development. This marks the first documented instance of a tiered domestic access regime replacing blanket export controls on a frontier model. Prior controls referenced Amazon reports on misuse vectors but provided no public benchmark data.

The policy establishes trusted-access lists as an operational alternative to full export restrictions, shifting enforcement from model capability thresholds to recipient vetting. It creates precedent for future models where domestic entities receive earlier access than foreign ones under identical technical constraints. Operational impact includes reduced licensing overhead for the 100+ listed organizations while preserving government oversight on subsequent releases.

Next steps center on Fable 5 resolution and formalization of ongoing standards working groups. Similar arrangements are expected for subsequent Anthropic releases once verification protocols stabilize.