Backport: fix(@ai-sdk/google): Make title field optional in grounding metadata schema

.changeset/warm-oranges-smash.md

@@ -0,0 +1,5 @@
+---
+'@ai-sdk/google': patch
+---
+
+fix(@ai-sdk/google): Make title field optional in grounding metadata schema

packages/google/src/google-generative-ai-language-model.test.ts

@@ -88,6 +88,22 @@ describe('groundingMetadataSchema', () => {
     expect(result.success).toBe(true);
   });
 
+  it('validates groundingChunks[].web with missing title', () => {
+    const metadata = {
+      groundingChunks: [
+        {
+          web: {
+            // Missing `title`
+            uri: 'https://example.com/weather',
+          },
+        },
+      ],
+    };
+
+    const result = groundingMetadataSchema.safeParse(metadata);
+    expect(result.success).toBe(true);
+  });
+
   it('validates complete grounding metadata with Vertex AI Search results', () => {
     const metadata = {
       retrievalQueries: ['How to make appointment to renew driving license?'],
@@ -116,6 +132,22 @@ describe('groundingMetadataSchema', () => {
     expect(result.success).toBe(true);
   });
 
+  it('validates groundingChunks[].retrievedContext with missing title', () => {
+    const metadata = {
+      groundingChunks: [
+        {
+          retrievedContext: {
+            // Missing `title`
+            uri: 'https://vertexaisearch.cloud.google.com/grounding-api-redirect/AXiHM.....QTN92V5ePQ==',
+          },
+        },
+      ],
+    };
+
+    const result = groundingMetadataSchema.safeParse(metadata);
+    expect(result.success).toBe(true);
+  });
+
   it('validates partial grounding metadata', () => {
     const metadata = {
       webSearchQueries: ['sample query'],

packages/google/src/google-generative-ai-language-model.ts

@@ -708,9 +708,11 @@ export const getGroundingMetadataSchema = () =>
     groundingChunks: z
       .array(
         z.object({
-          web: z.object({ uri: z.string(), title: z.string() }).nullish(),
+          web: z
+            .object({ uri: z.string(), title: z.string().nullish() })
+            .nullish(),
           retrievedContext: z
-            .object({ uri: z.string(), title: z.string() })
+            .object({ uri: z.string(), title: z.string().nullish() })
             .nullish(),
         }),
       )