クラウド障害の免責と継続する対応義務

A valid upstream-risk allocation can defeat damages for interruption of a promised cloud function while leaving entrusted incident-response work enforceable. Under Japanese law, this turns on construction of the undertaking and its risk and remedy provisions. This Article connects system-development decisions on project management and customer cooperation, mandate doctrine, and engineering evidence about correlated failures. The proposed extension concerns professional care in operations: what an operator must investigate, explain or execute when the customer retains business and change authority. For result performance, the content of the promise, Article 415’s excuse inquiry and a contractual restriction on recovery are distinct questions. For an obligation of reasonable care, breach and conduct-based attribution substantially overlap. Approval power restricts implementation but does not alone remove an entrusted duty to enable an informed choice. Operational scope, actual authority, reporting arrangements and agreed resources can support that duty even without an enumerated fallback clause; expertise alone cannot. Judicial decisions on negotiated caps and gross negligence show why a continuing duty does not ensure unrestricted recovery. A completed business-contract illustration expressly allocates the specified upstream confirmation outage to the customer. Two evidentiary variants resolve response claims under that same agreement. They show why forty elapsed minutes alone do not establish breach and why proved reconciliation expense does not establish lost sales. The engineering account specifies unknown recovery time, a preexisting receipt path independent of the failed control, bounded local authorization and staged recommitment. A separate analysis of an IPA-based operational schedule tests the disputed construction of a response duty that is not enumerated. Model provisions and an incident record connect prior authorization, readiness ownership, additional spending and claim proof. The contribution is an incident-specific application of established doctrines with explicit evidentiary limits.