diff --git a/packages/ai/src/providers/google-shared.ts b/packages/ai/src/providers/google-shared.ts
index e86815c1f..b24c68d4e 100644
--- a/packages/ai/src/providers/google-shared.ts
+++ b/packages/ai/src/providers/google-shared.ts
@@ -166,7 +166,7 @@ ${params}
 					const part: Part = {
 						functionCall: {
 							name: block.name,
-							args: block.arguments,
+							args: block.arguments ?? {},
 							...(requiresToolCallId(model.id) ? { id: block.id } : {}),
 						},
 					};