Fix tool output fragmentation by encapsulating content in functionResponse (#13082)

packages/core/src/config/models.test.ts

@@ -14,8 +14,25 @@ import {
   GEMINI_MODEL_ALIAS_PRO,
   GEMINI_MODEL_ALIAS_FLASH,
   GEMINI_MODEL_ALIAS_FLASH_LITE,
+  supportsMultimodalFunctionResponse,
 } from './models.js';
 
+describe('supportsMultimodalFunctionResponse', () => {
+  it('should return true for gemini-3 model', () => {
+    expect(supportsMultimodalFunctionResponse('gemini-3-pro')).toBe(true);
+  });
+
+  it('should return false for gemini-2 models', () => {
+    expect(supportsMultimodalFunctionResponse('gemini-2.5-pro')).toBe(false);
+    expect(supportsMultimodalFunctionResponse('gemini-2.5-flash')).toBe(false);
+  });
+
+  it('should return false for other models', () => {
+    expect(supportsMultimodalFunctionResponse('some-other-model')).toBe(false);
+    expect(supportsMultimodalFunctionResponse('')).toBe(false);
+  });
+});
+
 describe('getEffectiveModel', () => {
   describe('When NOT in fallback mode', () => {
     const isInFallbackMode = false;

packages/core/src/config/models.ts

@@ -99,8 +99,19 @@ export function getEffectiveModel(
  * Checks if the model is a Gemini 2.x model.
  *
  * @param model The model name to check.
- * @returns True if the model is a Gemini 2.x model.
+ * @returns True if the model is a Gemini-2.x model.
  */
 export function isGemini2Model(model: string): boolean {
   return /^gemini-2(\.|$)/.test(model);
 }
+
+/**
+ * Checks if the model supports multimodal function responses (multimodal data nested within function response).
+ * This is supported in Gemini 3.
+ *
+ * @param model The model name to check.
+ * @returns True if the model supports multimodal function responses.
+ */
+export function supportsMultimodalFunctionResponse(model: string): boolean {
+  return model.startsWith('gemini-3-');
+}