Remove previewFeatures and default to Gemini 3 (#18414)

packages/core/src/routing/strategies/classifierStrategy.test.ts

@@ -51,7 +51,6 @@ describe('ClassifierStrategy', () => {
         getResolvedConfig: vi.fn().mockReturnValue(mockResolvedConfig),
       },
       getModel: () => DEFAULT_GEMINI_MODEL_AUTO,
-      getPreviewFeatures: () => false,
       getNumericalRoutingEnabled: vi.fn().mockResolvedValue(false),
     } as unknown as Config;
     mockBaseLlmClient = {

packages/core/src/routing/strategies/classifierStrategy.ts

@@ -166,7 +166,6 @@ export class ClassifierStrategy implements RoutingStrategy {
       const selectedModel = resolveClassifierModel(
         context.requestedModel ?? config.getModel(),
         routerResponse.model_choice,
-        config.getPreviewFeatures(),
       );
 
       return {

packages/core/src/routing/strategies/defaultStrategy.test.ts

@@ -24,7 +24,6 @@ describe('DefaultStrategy', () => {
     const mockContext = {} as RoutingContext;
     const mockConfig = {
       getModel: vi.fn().mockReturnValue(DEFAULT_GEMINI_MODEL_AUTO),
-      getPreviewFeatures: vi.fn().mockReturnValue(false),
     } as unknown as Config;
     const mockClient = {} as BaseLlmClient;
 
@@ -45,7 +44,6 @@ describe('DefaultStrategy', () => {
     const mockContext = {} as RoutingContext;
     const mockConfig = {
       getModel: vi.fn().mockReturnValue(PREVIEW_GEMINI_MODEL_AUTO),
-      getPreviewFeatures: vi.fn().mockReturnValue(false),
     } as unknown as Config;
     const mockClient = {} as BaseLlmClient;
 
@@ -61,12 +59,11 @@ describe('DefaultStrategy', () => {
     });
   });
 
-  it('should route to the preview model when requested model is auto and previewfeature is on', async () => {
+  it('should route to the default model when requested model is auto', async () => {
     const strategy = new DefaultStrategy();
     const mockContext = {} as RoutingContext;
     const mockConfig = {
       getModel: vi.fn().mockReturnValue(GEMINI_MODEL_ALIAS_AUTO),
-      getPreviewFeatures: vi.fn().mockReturnValue(true),
     } as unknown as Config;
     const mockClient = {} as BaseLlmClient;
 
@@ -82,34 +79,12 @@ describe('DefaultStrategy', () => {
     });
   });
 
-  it('should route to the default model when requested model is auto and previewfeature is off', async () => {
-    const strategy = new DefaultStrategy();
-    const mockContext = {} as RoutingContext;
-    const mockConfig = {
-      getModel: vi.fn().mockReturnValue(GEMINI_MODEL_ALIAS_AUTO),
-      getPreviewFeatures: vi.fn().mockReturnValue(false),
-    } as unknown as Config;
-    const mockClient = {} as BaseLlmClient;
-
-    const decision = await strategy.route(mockContext, mockConfig, mockClient);
-
-    expect(decision).toEqual({
-      model: DEFAULT_GEMINI_MODEL,
-      metadata: {
-        source: 'default',
-        latencyMs: 0,
-        reasoning: `Routing to default model: ${DEFAULT_GEMINI_MODEL}`,
-      },
-    });
-  });
-
   // this should not happen, adding the test just in case it happens.
   it('should route to the same model if it is not an auto mode', async () => {
     const strategy = new DefaultStrategy();
     const mockContext = {} as RoutingContext;
     const mockConfig = {
       getModel: vi.fn().mockReturnValue(PREVIEW_GEMINI_FLASH_MODEL),
-      getPreviewFeatures: vi.fn().mockReturnValue(false),
     } as unknown as Config;
     const mockClient = {} as BaseLlmClient;
 

packages/core/src/routing/strategies/defaultStrategy.ts

@@ -21,10 +21,7 @@ export class DefaultStrategy implements TerminalStrategy {
     config: Config,
     _baseLlmClient: BaseLlmClient,
   ): Promise<RoutingDecision> {
-    const defaultModel = resolveModel(
-      config.getModel(),
-      config.getPreviewFeatures(),
-    );
+    const defaultModel = resolveModel(config.getModel());
     return {
       model: defaultModel,
       metadata: {

packages/core/src/routing/strategies/fallbackStrategy.test.ts

@@ -25,7 +25,6 @@ const createMockConfig = (overrides: Partial<Config> = {}): Config =>
   ({
     getModelAvailabilityService: vi.fn(),
     getModel: vi.fn().mockReturnValue(DEFAULT_GEMINI_MODEL),
-    getPreviewFeatures: vi.fn().mockReturnValue(false),
     ...overrides,
   }) as unknown as Config;
 

packages/core/src/routing/strategies/fallbackStrategy.ts

@@ -23,10 +23,7 @@ export class FallbackStrategy implements RoutingStrategy {
     _baseLlmClient: BaseLlmClient,
   ): Promise<RoutingDecision | null> {
     const requestedModel = context.requestedModel ?? config.getModel();
-    const resolvedModel = resolveModel(
-      requestedModel,
-      config.getPreviewFeatures(),
-    );
+    const resolvedModel = resolveModel(requestedModel);
     const service = config.getModelAvailabilityService();
     const snapshot = service.snapshot(resolvedModel);
 

packages/core/src/routing/strategies/numericalClassifierStrategy.test.ts

@@ -47,7 +47,6 @@ describe('NumericalClassifierStrategy', () => {
         getResolvedConfig: vi.fn().mockReturnValue(mockResolvedConfig),
       },
       getModel: () => DEFAULT_GEMINI_MODEL_AUTO,
-      getPreviewFeatures: () => false,
       getSessionId: vi.fn().mockReturnValue('control-group-id'), // Default to Control Group (Hash 71 >= 50)
       getNumericalRoutingEnabled: vi.fn().mockResolvedValue(true),
       getClassifierThreshold: vi.fn().mockResolvedValue(undefined),

packages/core/src/routing/strategies/numericalClassifierStrategy.ts

@@ -179,7 +179,6 @@ export class NumericalClassifierStrategy implements RoutingStrategy {
       const selectedModel = resolveClassifierModel(
         config.getModel(),
         modelAlias,
-        config.getPreviewFeatures(),
       );
 
       const latencyMs = Date.now() - startTime;

packages/core/src/routing/strategies/overrideStrategy.test.ts

@@ -19,7 +19,6 @@ describe('OverrideStrategy', () => {
   it('should return null when the override model is auto', async () => {
     const mockConfig = {
       getModel: () => DEFAULT_GEMINI_MODEL_AUTO,
-      getPreviewFeatures: () => false,
     } as Config;
 
     const decision = await strategy.route(mockContext, mockConfig, mockClient);
@@ -30,7 +29,6 @@ describe('OverrideStrategy', () => {
     const overrideModel = 'gemini-2.5-pro-custom';
     const mockConfig = {
       getModel: () => overrideModel,
-      getPreviewFeatures: () => false,
     } as Config;
 
     const decision = await strategy.route(mockContext, mockConfig, mockClient);
@@ -48,7 +46,6 @@ describe('OverrideStrategy', () => {
     const overrideModel = 'gemini-2.5-flash-experimental';
     const mockConfig = {
       getModel: () => overrideModel,
-      getPreviewFeatures: () => false,
     } as Config;
 
     const decision = await strategy.route(mockContext, mockConfig, mockClient);
@@ -62,7 +59,6 @@ describe('OverrideStrategy', () => {
     const configModel = 'config-model';
     const mockConfig = {
       getModel: () => configModel,
-      getPreviewFeatures: () => false,
     } as Config;
     const contextWithRequestedModel = {
       requestedModel,

packages/core/src/routing/strategies/overrideStrategy.ts

@@ -33,7 +33,7 @@ export class OverrideStrategy implements RoutingStrategy {
 
     // Return the overridden model name.
     return {
-      model: resolveModel(overrideModel, config.getPreviewFeatures()),
+      model: resolveModel(overrideModel),
       metadata: {
         source: this.name,
         latencyMs: 0,