diff --git a/.sampo/changesets/ait-host-capability-support.md b/.sampo/changesets/ait-host-capability-support.md
new file mode 100644
index 00000000..af8a2cc7
--- /dev/null
+++ b/.sampo/changesets/ait-host-capability-support.md
@@ -0,0 +1,7 @@
+---
+npm/@mpgd/adapter-ait: patch (Fixed)
+---
+
+Treat missing Apps in Toss Ads 2.0 support constants as an unsupported capability instead of
+failing the game wrapper during startup. Preload and display requests remain fail-closed until
+both native full-screen ad APIs report support.
diff --git a/adapters/ait/src/host.test.ts b/adapters/ait/src/host.test.ts
index 265a4d1d..4e119989 100644
--- a/adapters/ait/src/host.test.ts
+++ b/adapters/ait/src/host.test.ts
@@ -138,6 +138,60 @@ describe('AIT production host bridge', () => {
     }
   });
 
+  it('treats missing Ads 2.0 support constants as unsupported without blocking startup', async () => {
+    const warning = vi.spyOn(console, 'warn').mockImplementation(() => {});
+    const diagnostic = vi.spyOn(console, 'debug').mockImplementation(() => {});
+    const missingSupportConstant = Object.assign(
+      () => () => {},
+      {
+        isSupported: () => {
+          throw new Error('native support constant is unavailable');
+        },
+      },
+    );
+
+    try {
+      const bridge = createAitHostBridge({
+        adGroupIds: {
+          SUDOKU_HINT_REWARDED: 'ait-ad-group-1',
+          SUDOKU_BREAK_INTERSTITIAL: 'ait-ad-group-2',
+        },
+        adPlacementTypes: {
+          SUDOKU_HINT_REWARDED: 'rewarded',
+          SUDOKU_BREAK_INTERSTITIAL: 'interstitial',
+        },
+        dependencies: createDependencies({
+          loadFullScreenAd: missingSupportConstant,
+          showFullScreenAd: missingSupportConstant,
+        }),
+      });
+
+      await expect(request(bridge, 'runtime.getCapabilities', {})).resolves.toMatchObject({
+        nativeAds: false,
+        rewardedAds: false,
+        interstitialAds: false,
+      });
+      await expect(request(bridge, 'ads.preload', {
+        placementId: 'SUDOKU_HINT_REWARDED',
+      })).resolves.toEqual({});
+      await expect(request(bridge, 'ads.showRewarded', {
+        placementId: 'SUDOKU_HINT_REWARDED',
+        idempotencyKey: 'reward-1',
+      })).resolves.toEqual({ status: 'unavailable', rewardGranted: false });
+      await expect(request(bridge, 'ads.showInterstitial', {
+        placementId: 'SUDOKU_BREAK_INTERSTITIAL',
+      })).resolves.toEqual({ status: 'unavailable' });
+      expect(warning).toHaveBeenCalledOnce();
+      expect(diagnostic).toHaveBeenCalledWith(
+        'AIT capability support check failed; disabling the feature.',
+        expect.objectContaining({ message: 'native support constant is unavailable' }),
+      );
+    } finally {
+      diagnostic.mockRestore();
+      warning.mockRestore();
+    }
+  });
+
   it('grants a configured rewarded ad only after userEarnedReward and dismissal', async () => {
     let loadCallbacks: LoadAdCallbacks | undefined;
     let showCallbacks: ShowAdCallbacks | undefined;
diff --git a/adapters/ait/src/host.ts b/adapters/ait/src/host.ts
index af84a583..64d1f8e8 100644
--- a/adapters/ait/src/host.ts
+++ b/adapters/ait/src/host.ts
@@ -123,8 +123,7 @@ export function createAitHostBridge(
   async function handleRequest(request: BridgeRequest): Promise<BridgeResponse> {
     switch (request.method) {
       case 'runtime.getCapabilities': {
-        const adsSupported = dependencies.loadFullScreenAd.isSupported()
-          && dependencies.showFullScreenAd.isSupported();
+        const adsSupported = areFullScreenAdsSupported(dependencies);
         const rewardedAds = adsSupported
           && hasConfiguredAdType(adGroupIds, adPlacementTypes, 'rewarded');
         const interstitialAds = adsSupported
@@ -220,7 +219,7 @@ export function createAitHostBridge(
           );
         }
 
-        if (!dependencies.loadFullScreenAd.isSupported()) {
+        if (!isCapabilitySupported(() => dependencies.loadFullScreenAd.isSupported())) {
           if (!warnedUnsupportedAdPreload) {
             warnedUnsupportedAdPreload = true;
             console.warn(
@@ -250,8 +249,7 @@ export function createAitHostBridge(
         if (
           adGroupId === undefined
           || adPlacementTypes.get(placementId) !== 'rewarded'
-          || !dependencies.loadFullScreenAd.isSupported()
-          || !dependencies.showFullScreenAd.isSupported()
+          || !areFullScreenAdsSupported(dependencies)
         ) {
           return ok(request, { status: 'unavailable', rewardGranted: false });
         }
@@ -306,8 +304,7 @@ export function createAitHostBridge(
         if (
           adGroupId === undefined
           || adPlacementTypes.get(placementId) !== 'interstitial'
-          || !dependencies.loadFullScreenAd.isSupported()
-          || !dependencies.showFullScreenAd.isSupported()
+          || !areFullScreenAdsSupported(dependencies)
         ) {
           return ok(request, { status: 'unavailable' });
         }
@@ -928,6 +925,22 @@ function isGameCenterSupported(dependencies: AitHostDependencies): boolean {
   return dependencies.isMinVersionSupported({ android: '5.221.0', ios: '5.221.0' });
 }
 
+function areFullScreenAdsSupported(dependencies: AitHostDependencies): boolean {
+  return isCapabilitySupported(() => dependencies.loadFullScreenAd.isSupported())
+    && isCapabilitySupported(() => dependencies.showFullScreenAd.isSupported());
+}
+
+function isCapabilitySupported(check: () => boolean): boolean {
+  try {
+    return check() === true;
+  } catch (error) {
+    // Older hosts and local wrappers may not expose a native support constant yet.
+    // Missing capability metadata must disable the feature instead of blocking startup.
+    console.debug('AIT capability support check failed; disabling the feature.', error);
+    return false;
+  }
+}
+
 function normalizeAdGroupIds(
   input: Readonly<Record<string, string>> | undefined,
 ): ReadonlyMap<string, string> {