TO THE JAPANESE FINANCIAL AUTHORITIES : On the Directive to Prepare for Shutdown, the Known Action Library, and the Containment That Makes the Shutdown Unnecessary

In November 2026, Japan's Financial Services Agency and the Bank of Japan issued a jointdirective to financial institutions. The directive tells banks and insurers to prepare for thepossibility that, even with thorough defenses, AI-powered cyberattacks may succeed. The measure: top management should proactively consider suspending critical systems — online banking, payment infrastructure — rather than let them be compromised. The trigger is named. Anthropic's Claude Mythos, a model with enhancedvulnerability-discovery capabilities, and the expectation that a flood of patches will bereleased that banks cannot apply fast enough. A working group of over 30 companies, led bythe financial services minister, drafted the measures in eight days. The directive is a real institutional response to a real capability. It is also the unboundedarchitecture's answer to an unbounded exposure: if the system can do anything, the only safe state is off. This paper presents a different answer. It presents the system, then the specification, then the containment. The action library is known. The blast radius is finite. The system can be switched on, because it cannot do the thing you are afraid of.