diff --git a/tauri/src/runtime/app-management/app-registry.test.ts b/tauri/src/runtime/app-management/app-registry.test.ts
new file mode 100644
index 0000000..2ab58e0
--- /dev/null
+++ b/tauri/src/runtime/app-management/app-registry.test.ts
@@ -0,0 +1,13 @@
+import { describe, expect, it } from "vitest";
+import { CoreAppRegistry } from "@/runtime/app-management/app-registry";
+
+describe("CoreAppRegistry SDK v1 kind policy", () => {
+  it("keeps Interact as the only system MiniApp", () => {
+    const registry = new CoreAppRegistry();
+    expect(registry.get("chat")?.kind).toBe("system");
+    expect(() => registry.install({
+      app_scope: "other-system", kind: "system", enabled: true, default_eligible: false, recovery: false,
+      manifest: { app_scope: "other-system", version: "1.0.0", permissions: [], tools: [] },
+    })).toThrow("Only the Interact system MiniApp");
+  });
+});
diff --git a/tauri/src/runtime/app-management/app-registry.ts b/tauri/src/runtime/app-management/app-registry.ts
index 12a4985..bd55550 100644
--- a/tauri/src/runtime/app-management/app-registry.ts
+++ b/tauri/src/runtime/app-management/app-registry.ts
@@ -16,6 +16,7 @@ import type { JsonObject } from "@/runtime/protocol/lineup-v1";
 
 export type AppScope = "chat" | "app-registry" | "settings" | "runtime" | (string & {});
 export type MiniAppKind = "system" | "bundled";
+const SYSTEM_APP_SCOPE: AppScope = "chat";
 
 export type AppToolDefinition = {
   name: string;
@@ -134,6 +135,7 @@ export class CoreAppRegistry {
 
   private register(record: CoreAppRecordInput): void {
     if (!isAppScope(record.app_scope) || record.manifest.app_scope !== record.app_scope) throw new Error("Core App Registry received an invalid app_scope.");
+    if (record.kind === "system" && record.app_scope !== SYSTEM_APP_SCOPE) throw new Error("Only the Interact system MiniApp may use kind=system in SDK v1.");
     if (this.apps.has(record.app_scope)) throw new Error(`Core App Registry has duplicate app_scope: ${record.app_scope}`);
     if (!isManifest(record.manifest)) throw new Error(`Core App Registry has an invalid manifest: ${record.app_scope}`);
     this.apps.set(record.app_scope, copyRecord(record));