diff --git a/apps/mobile-shell/scripts/check-config.mjs b/apps/mobile-shell/scripts/check-config.mjs
index 302338f2a..4bca38ea6 100644
--- a/apps/mobile-shell/scripts/check-config.mjs
+++ b/apps/mobile-shell/scripts/check-config.mjs
@@ -1497,6 +1497,8 @@ for (const snippet of [
   'source: window',
   'MOBILE_WEBVIEW_BEFORE_CONTENT_SCRIPT',
   'shouldBlockMobileWebViewNavigationRequest',
+  'logMobileShellDownloadBlocked',
+  "console.warn('mobile shell blocked WebView file download', event)",
   'SafeAreaProvider',
   'SafeAreaView',
   'MOBILE_SHELL_SAFE_AREA_EDGES',
@@ -1515,6 +1517,7 @@ for (const snippet of [
   'webviewDebuggingEnabled={false}',
   'injectedJavaScriptBeforeContentLoaded={MOBILE_WEBVIEW_BEFORE_CONTENT_SCRIPT}',
   'handleBlockedFileDownload',
+  'logMobileShellDownloadBlocked(event)',
   'onFileDownload={handleBlockedFileDownload}',
   'setSupportMultipleWindows={false}',
   'logMobileShellNavigationFailure',
@@ -1530,6 +1533,10 @@ if (shellAppSource.includes('catch(() => undefined)')) {
   throw new Error('mobile shell ShellApp must not hide async navigation failures');
 }
 
+if (!shellAppTestSource.includes('blocked WebView file downloads are logged for host diagnostics')) {
+  throw new Error('mobile shell tests must cover blocked WebView file download diagnostics');
+}
+
 for (const snippet of [
   "describe('mobile shell safe area'",
   "test('protects the WebView from every device edge'",
diff --git a/apps/mobile-shell/src/shell/ShellApp.test.tsx b/apps/mobile-shell/src/shell/ShellApp.test.tsx
index 0b88f00a1..5596908d4 100644
--- a/apps/mobile-shell/src/shell/ShellApp.test.tsx
+++ b/apps/mobile-shell/src/shell/ShellApp.test.tsx
@@ -630,6 +630,30 @@ describe('ShellApp HostBridge event injection', () => {
     warnSpy.mockRestore();
   });
 
+  test('blocked WebView file downloads are logged for host diagnostics', async () => {
+    const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => undefined);
+    const ShellApp = await importShellApp();
+    render(<ShellApp />);
+
+    const webViewProps = shellHarness.webViewProps.current as {
+      onFileDownload?: (event: unknown) => void;
+    };
+    const downloadEvent = {
+      nativeEvent: {
+        downloadUrl: 'blob:https://app.genarrative.world/download-id',
+      },
+    };
+
+    webViewProps.onFileDownload?.(downloadEvent);
+
+    expect(warnSpy).toHaveBeenCalledWith(
+      'mobile shell blocked WebView file download',
+      downloadEvent,
+    );
+
+    warnSpy.mockRestore();
+  });
+
   test('initial deep link read failures are logged without replacing the current WebView URL', async () => {
     const { Linking } = await import('react-native');
     const initialUrlError = new Error('initial URL unavailable');
diff --git a/apps/mobile-shell/src/shell/ShellApp.tsx b/apps/mobile-shell/src/shell/ShellApp.tsx
index 563cf0cc3..5e0c9fb09 100644
--- a/apps/mobile-shell/src/shell/ShellApp.tsx
+++ b/apps/mobile-shell/src/shell/ShellApp.tsx
@@ -71,6 +71,10 @@ function logMobileShellNavigationFailure(label: string, error: unknown) {
   console.warn(`mobile shell navigation failed for ${label}`, error);
 }
 
+function logMobileShellDownloadBlocked(event: unknown) {
+  console.warn('mobile shell blocked WebView file download', event);
+}
+
 function logMobileShellDeepLinkFailure(label: string, error: unknown) {
   console.warn(`mobile shell deep link failed for ${label}`, error);
 }
@@ -445,7 +449,9 @@ export default function ShellApp() {
       ),
     );
   };
-  const handleBlockedFileDownload = () => undefined;
+  const handleBlockedFileDownload = (event: unknown) => {
+    logMobileShellDownloadBlocked(event);
+  };
 
   return (
     <SafeAreaProvider>