applet_install_plan_mismatch· code· HTTP 409· scope endpoint· applies to service_callak.self.applet.command.install.v1 recomputed the canonical InstallPlan from the submitted Applet Package, caller-signed registration/capability-grant Events, effective_scope, and current Realm/Circle policy, and the recomputed plan_digest did not exactly match the submitted plan_digest. Server MUST fail closed and require a fresh preview/approval before formal Event admission. See zh/extensions/applet-integration.md §4b.