diff --git a/src/media-understanding/provider-registry.test.ts b/src/media-understanding/provider-registry.test.ts
index 4a920d3660f..167dc32d08f 100644
--- a/src/media-understanding/provider-registry.test.ts
+++ b/src/media-understanding/provider-registry.test.ts
@@ -18,6 +18,18 @@ function createMediaProvider(
   return params;
 }
 
+function requireMediaProvider(
+  registry: Map<string, MediaUnderstandingProvider>,
+  providerId: string,
+): MediaUnderstandingProvider {
+  const provider = getMediaUnderstandingProvider(providerId, registry);
+  expect(provider).toBeDefined();
+  if (!provider) {
+    throw new Error(`expected media-understanding provider ${providerId}`);
+  }
+  return provider;
+}
+
 describe("media-understanding provider registry", () => {
   beforeEach(() => {
     resolvePluginCapabilityProvidersMock.mockReset();
@@ -32,8 +44,8 @@ describe("media-understanding provider registry", () => {
 
     const registry = buildMediaUnderstandingRegistry();
 
-    expect(getMediaUnderstandingProvider("groq", registry)?.id).toBe("groq");
-    expect(getMediaUnderstandingProvider("deepgram", registry)?.id).toBe("deepgram");
+    expect(requireMediaProvider(registry, "groq").id).toBe("groq");
+    expect(requireMediaProvider(registry, "deepgram").id).toBe("deepgram");
     expect(resolvePluginCapabilityProvidersMock).toHaveBeenCalledWith({
       key: "mediaUnderstandingProviders",
       cfg: undefined,
@@ -47,7 +59,7 @@ describe("media-understanding provider registry", () => {
 
     const registry = buildMediaUnderstandingRegistry();
 
-    expect(getMediaUnderstandingProvider("gemini", registry)?.id).toBe("google");
+    expect(requireMediaProvider(registry, "gemini").id).toBe("google");
   });
 
   it("auto-registers media-understanding for config providers with image-capable models (#51392)", () => {
@@ -96,11 +108,19 @@ describe("media-understanding provider registry", () => {
     } as never;
 
     const registry = buildMediaUnderstandingRegistry(undefined, cfg);
-    const provider = getMediaUnderstandingProvider("google", registry);
+    const provider = requireMediaProvider(registry, "google");
 
-    expect(provider?.capabilities).toEqual(["image", "audio", "video"]);
-    expect(await provider?.describeImage?.({} as never)).toEqual({ text: "plugin image" });
-    expect(await provider?.transcribeAudio?.({} as never)).toEqual({ text: "plugin audio" });
+    expect(provider.capabilities).toEqual(["image", "audio", "video"]);
+    expect(provider.describeImage).toBeTypeOf("function");
+    if (!provider.describeImage) {
+      throw new Error("expected google describeImage provider hook");
+    }
+    expect(provider.transcribeAudio).toBeTypeOf("function");
+    if (!provider.transcribeAudio) {
+      throw new Error("expected google transcribeAudio provider hook");
+    }
+    expect(await provider.describeImage({} as never)).toEqual({ text: "plugin image" });
+    expect(await provider.transcribeAudio({} as never)).toEqual({ text: "plugin audio" });
     expect(resolvePluginCapabilityProvidersMock).toHaveBeenCalledWith({
       key: "mediaUnderstandingProviders",
       cfg,