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MODEL SIGNAL · ANTHROPIC

Claude Mythos 5

Anthropic's frontier Claude Mythos 5 model was launched and subsequently disabled worldwide following a US government security directive.

CATEGORYReasoning
RELEASEDJune 9, 2026
Key Features
  • Frontier-class reasoning and capability profile
  • Public access globally disabled due to US export control directive
  • Flagged for advanced software vulnerability identification capabilities

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Claude Mythos 5

Identity

Claude Mythos 5 is a frontier-class reasoning model developed by Anthropic [Source 1]. Released on June 9, 2026, it transitioned "Mythos-class" capabilities from restricted internal cybersecurity programs into a commercial release tier [Source 11, Source 12, Source 13]. On Friday, June 12, 2026, at 5:21 PM, Anthropic received an "unprecedented" US export control directive citing "unspecified national security authorities" to suspend access for foreign nationals [Source 8, Source 10]. Due to cloud infrastructure limitations in enforcing nationality-based restrictions, the model was disabled globally on June 13, 2026 [Source 1, Source 9, Source 10]. On June 26, 2026, the US government partially lifted the block, allowing release to over 100 approved US institutions involved in national security and critical infrastructure [Source 5, Source 6].

What it is

Claude Mythos