fix(ui-kit): edge-trigger StateBoundary failure notifications

apps/loopover-ui/src/components/site/state-views.test.tsx

@@ -138,3 +138,42 @@ describe("StateBoundary retry/refresh actions (#793 regression guard)", () => {
     expect(screen.getByText("content")).toBeTruthy();
   });
 });
+
+describe("StateBoundary onFailureNotify edge-trigger (#7436)", () => {
+  it("notifies exactly once while staying in error across unstable callback identities, then again on re-entry", () => {
+    notifyApiFailure.mockClear();
+    const { rerender } = render(
+      <StateBoundary isError errorLabel="Widgets" onRetry={() => {}}>
+        <div>content</div>
+      </StateBoundary>,
+    );
+    expect(notifyApiFailure).toHaveBeenCalledTimes(1);
+
+    // Simulate the app wrapper's fresh onFailureNotify arrow + a fresh onRetry each parent render
+    // while isError stays true — must NOT re-fire.
+    for (let i = 0; i < 4; i += 1) {
+      rerender(
+        <StateBoundary isError errorLabel="Widgets" onRetry={() => {}}>
+          <div>content</div>
+        </StateBoundary>,
+      );
+    }
+    expect(notifyApiFailure).toHaveBeenCalledTimes(1);
+
+    // Leave the error state…
+    rerender(
+      <StateBoundary isError={false} errorLabel="Widgets" onRetry={() => {}}>
+        <div>content</div>
+      </StateBoundary>,
+    );
+    expect(notifyApiFailure).toHaveBeenCalledTimes(1);
+
+    // …then re-enter: exactly one more notification for the second false→true edge.
+    rerender(
+      <StateBoundary isError errorLabel="Widgets" onRetry={() => {}}>
+        <div>content</div>
+      </StateBoundary>,
+    );
+    expect(notifyApiFailure).toHaveBeenCalledTimes(2);
+  });
+});

packages/loopover-ui-kit/src/components/state-views.tsx

@@ -1,5 +1,5 @@
 import { Loader2, Inbox, AlertTriangle, RefreshCw, WifiOff } from "lucide-react";
-import { useEffect, type ReactNode } from "react";
+import { useEffect, useRef, type ReactNode } from "react";
 import { toast } from "sonner";
 
 import { cn } from "../utils";
@@ -265,8 +265,14 @@ export function StateBoundary({
       : "The data source did not respond. Retry the request, or check back once the service has recovered.");
 
   // When this boundary flips into the error state, surface a toast with Retry.
+  // Edge-triggered (#7436): only fire on false→true of (isError && errorLabel). Level-triggering here
+  // re-notified on every re-render while already errored because app wrappers pass a fresh
+  // `onFailureNotify` arrow each render (see apps/loopover-ui site/state-views.tsx). Mirrors the
+  // wasError-ref pattern used by mcp-version-badge for transition detection.
+  const wasFailureNotifyActive = useRef(false);
   useEffect(() => {
-    if (isError && errorLabel) {
+    const failureNotifyActive = Boolean(isError && errorLabel);
+    if (isError && errorLabel && !wasFailureNotifyActive.current) {
       onFailureNotify?.({
         label: errorLabel,
         kind: errorKind ?? "network",
@@ -277,6 +283,7 @@ export function StateBoundary({
         retry: onRetry,
       });
     }
+    wasFailureNotifyActive.current = failureNotifyActive;
   }, [isError, errorLabel, errorKind, resolvedErrorDescription, onRetry, onFailureNotify]);
 
   if (isLoading) {