diff --git a/ui/src/components/SidebarAccountMenu.test.tsx b/ui/src/components/SidebarAccountMenu.test.tsx
index 5935f1a6ef..f596c625d1 100644
--- a/ui/src/components/SidebarAccountMenu.test.tsx
+++ b/ui/src/components/SidebarAccountMenu.test.tsx
@@ -100,7 +100,7 @@ describe("SidebarAccountMenu", () => {
     vi.clearAllMocks();
   });
 
-  it("renders the signed-in user and opens the account card menu", async () => {
+  it("keeps authenticated self-hosted sign-out on the local auth flow", async () => {
     const root = createRoot(container);
     const queryClient = new QueryClient({
       defaultOptions: { queries: { retry: false } },
@@ -167,19 +167,29 @@ describe("SidebarAccountMenu", () => {
     await flushReact();
 
     expect(mockAuthApi.signOut).toHaveBeenCalledOnce();
-    expect(mockNavigateTopLevel).toHaveBeenCalledWith("/cloud/logout");
+    expect(mockNavigateTopLevel).not.toHaveBeenCalled();
+    expect(queryClient.getQueryState(queryKeys.health)?.isInvalidated).toBe(true);
 
     await act(async () => {
       root.unmount();
     });
   });
 
-  it("falls back to the managed logout route when sign-out omits a redirect", async () => {
-    mockAuthApi.signOut.mockResolvedValue({ success: true });
+  it("navigates cloud-managed sign-out through the harness without calling local auth", async () => {
     const root = createRoot(container);
     const queryClient = new QueryClient({
       defaultOptions: { queries: { retry: false } },
     });
+    queryClient.setQueryData(queryKeys.health, {
+      status: "ok",
+      deploymentMode: "authenticated",
+      cloud: {
+        managed: true,
+        managedBy: "paperclip-cloud",
+        stackSlug: "acme-labs",
+        cloudBaseUrl: "https://cloud.example.test",
+      },
+    });
 
     await act(async () => {
       root.render(
@@ -198,6 +208,7 @@ describe("SidebarAccountMenu", () => {
     });
     await flushReact();
 
+    expect(mockAuthApi.signOut).not.toHaveBeenCalled();
     expect(mockNavigateTopLevel).toHaveBeenCalledWith("/cloud/logout");
 
     await act(async () => {
diff --git a/ui/src/components/SidebarAccountMenu.tsx b/ui/src/components/SidebarAccountMenu.tsx
index 368888bf1e..8713b12de1 100644
--- a/ui/src/components/SidebarAccountMenu.tsx
+++ b/ui/src/components/SidebarAccountMenu.tsx
@@ -13,6 +13,7 @@ import { Link } from "@/lib/router";
 import { authApi } from "@/api/auth";
 import { queryKeys } from "@/lib/queryKeys";
 import { navigateTopLevel } from "@/lib/browserNavigation";
+import { useCloudInstance } from "@/hooks/useCloudInstance";
 import { useSidebar } from "../context/SidebarContext";
 import { Popover, PopoverContent, PopoverTrigger } from "@/components/ui/popover";
 import { Avatar, AvatarFallback, AvatarImage } from "@/components/ui/avatar";
@@ -120,6 +121,7 @@ export function SidebarAccountMenu({
 }: SidebarAccountMenuProps) {
   const [internalOpen, setInternalOpen] = useState(false);
   const queryClient = useQueryClient();
+  const isCloud = Boolean(useCloudInstance());
   const { isMobile, setSidebarOpen, collapsed, peeking } = useSidebar();
   const rail = collapsed && !peeking;
   const open = controlledOpen ?? internalOpen;
@@ -132,12 +134,8 @@ export function SidebarAccountMenu({
 
   const signOutMutation = useMutation({
     mutationFn: () => authApi.signOut(),
-    onSuccess: async (result) => {
+    onSuccess: async () => {
       setOpen(false);
-      if (deploymentMode === "authenticated") {
-        navigateTopLevel(result?.redirectTo?.trim() || MANAGED_SIGN_OUT_PATH);
-        return;
-      }
       await queryClient.invalidateQueries({ queryKey: queryKeys.auth.session });
       await queryClient.invalidateQueries({ queryKey: queryKeys.health });
     },
@@ -161,6 +159,15 @@ export function SidebarAccountMenu({
     if (isMobile) setSidebarOpen(false);
   }
 
+  function handleSignOut() {
+    if (isCloud) {
+      closeNavigationChrome();
+      navigateTopLevel(MANAGED_SIGN_OUT_PATH);
+      return;
+    }
+    signOutMutation.mutate();
+  }
+
   return (
     <div className="border-t border-r border-border bg-background px-3 py-2">
       <Popover open={open} onOpenChange={setOpen}>
@@ -269,7 +276,7 @@ export function SidebarAccountMenu({
                     "flex w-full items-start gap-3 rounded-xl px-3 py-3 text-left transition-colors hover:bg-destructive/10",
                     signOutMutation.isPending && "cursor-not-allowed opacity-60",
                   )}
-                  onClick={() => signOutMutation.mutate()}
+                  onClick={handleSignOut}
                   disabled={signOutMutation.isPending}
                 >
                   <span className="mt-0.5 rounded-lg border border-border bg-background/70 p-2 text-muted-foreground">