feat(core): Preliminary changes for subagent model routing. (#16035)

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

@@ -9,6 +9,7 @@ import {
   resolveModel,
   resolveClassifierModel,
   isGemini2Model,
+  isAutoModel,
   getDisplayString,
   DEFAULT_GEMINI_MODEL,
   PREVIEW_GEMINI_MODEL,
@@ -18,6 +19,7 @@ import {
   GEMINI_MODEL_ALIAS_PRO,
   GEMINI_MODEL_ALIAS_FLASH,
   GEMINI_MODEL_ALIAS_FLASH_LITE,
+  GEMINI_MODEL_ALIAS_AUTO,
   PREVIEW_GEMINI_FLASH_MODEL,
   PREVIEW_GEMINI_MODEL_AUTO,
   DEFAULT_GEMINI_MODEL_AUTO,
@@ -171,6 +173,26 @@ describe('isGemini2Model', () => {
   });
 });
 
+describe('isAutoModel', () => {
+  it('should return true for "auto"', () => {
+    expect(isAutoModel(GEMINI_MODEL_ALIAS_AUTO)).toBe(true);
+  });
+
+  it('should return true for "auto-gemini-3"', () => {
+    expect(isAutoModel(PREVIEW_GEMINI_MODEL_AUTO)).toBe(true);
+  });
+
+  it('should return true for "auto-gemini-2.5"', () => {
+    expect(isAutoModel(DEFAULT_GEMINI_MODEL_AUTO)).toBe(true);
+  });
+
+  it('should return false for concrete models', () => {
+    expect(isAutoModel(DEFAULT_GEMINI_MODEL)).toBe(false);
+    expect(isAutoModel(PREVIEW_GEMINI_MODEL)).toBe(false);
+    expect(isAutoModel('some-random-model')).toBe(false);
+  });
+});
+
 describe('resolveClassifierModel', () => {
   it('should return flash model when alias is flash', () => {
     expect(

packages/core/src/config/models.ts

@@ -146,6 +146,20 @@ export function isGemini2Model(model: string): boolean {
   return /^gemini-2(\.|$)/.test(model);
 }
 
+/**
+ * Checks if the model is an auto model.
+ *
+ * @param model The model name to check.
+ * @returns True if the model is an auto model.
+ */
+export function isAutoModel(model: string): boolean {
+  return (
+    model === GEMINI_MODEL_ALIAS_AUTO ||
+    model === PREVIEW_GEMINI_MODEL_AUTO ||
+    model === DEFAULT_GEMINI_MODEL_AUTO
+  );
+}
+
 /**
  * Checks if the model supports multimodal function responses (multimodal data nested within function response).
  * This is supported in Gemini 3.