feat(core,ui): Add experiment-gated support for gemini flash 3.1 lite (#23794)

packages/cli/src/config/settingsSchema.ts

@@ -3024,6 +3024,7 @@ export const SETTINGS_SCHEMA_DEFINITIONS: Record<
               type: 'object',
               properties: {
                 useGemini3_1: { type: 'boolean' },
+                useGemini3_1FlashLite: { type: 'boolean' },
                 useCustomTools: { type: 'boolean' },
                 hasAccessToPreview: { type: 'boolean' },
                 requestedModels: {

packages/cli/src/ui/components/ModelDialog.test.tsx

@@ -53,6 +53,7 @@ describe('<ModelDialog />', () => {
   const mockOnClose = vi.fn();
   const mockGetHasAccessToPreviewModel = vi.fn();
   const mockGetGemini31LaunchedSync = vi.fn();
+  const mockGetGemini31FlashLiteLaunchedSync = vi.fn();
   const mockGetProModelNoAccess = vi.fn();
   const mockGetProModelNoAccessSync = vi.fn();
   const mockGetUserTier = vi.fn();
@@ -63,6 +64,7 @@ describe('<ModelDialog />', () => {
     getHasAccessToPreviewModel: () => boolean;
     getIdeMode: () => boolean;
     getGemini31LaunchedSync: () => boolean;
+    getGemini31FlashLiteLaunchedSync: () => boolean;
     getProModelNoAccess: () => Promise<boolean>;
     getProModelNoAccessSync: () => boolean;
     getUserTier: () => UserTierId | undefined;
@@ -74,6 +76,7 @@ describe('<ModelDialog />', () => {
     getHasAccessToPreviewModel: mockGetHasAccessToPreviewModel,
     getIdeMode: () => false,
     getGemini31LaunchedSync: mockGetGemini31LaunchedSync,
+    getGemini31FlashLiteLaunchedSync: mockGetGemini31FlashLiteLaunchedSync,
     getProModelNoAccess: mockGetProModelNoAccess,
     getProModelNoAccessSync: mockGetProModelNoAccessSync,
     getUserTier: mockGetUserTier,
@@ -84,6 +87,7 @@ describe('<ModelDialog />', () => {
     mockGetModel.mockReturnValue(DEFAULT_GEMINI_MODEL_AUTO);
     mockGetHasAccessToPreviewModel.mockReturnValue(false);
     mockGetGemini31LaunchedSync.mockReturnValue(false);
+    mockGetGemini31FlashLiteLaunchedSync.mockReturnValue(false);
     mockGetProModelNoAccess.mockResolvedValue(false);
     mockGetProModelNoAccessSync.mockReturnValue(false);
     mockGetUserTier.mockReturnValue(UserTierId.STANDARD);
@@ -131,6 +135,7 @@ describe('<ModelDialog />', () => {
     mockGetProModelNoAccessSync.mockReturnValue(true);
     mockGetProModelNoAccess.mockResolvedValue(true);
     mockGetHasAccessToPreviewModel.mockReturnValue(true);
+    mockGetGemini31FlashLiteLaunchedSync.mockReturnValue(true);
     mockGetUserTier.mockReturnValue(UserTierId.FREE);
     mockGetDisplayString.mockImplementation((val: string) => val);
 
@@ -463,6 +468,7 @@ describe('<ModelDialog />', () => {
       mockGetProModelNoAccessSync.mockReturnValue(false);
       mockGetProModelNoAccess.mockResolvedValue(false);
       mockGetHasAccessToPreviewModel.mockReturnValue(true);
+      mockGetGemini31FlashLiteLaunchedSync.mockReturnValue(true);
       mockGetUserTier.mockReturnValue(UserTierId.FREE);
       const { lastFrame, stdin, waitUntilReady, unmount } =
         await renderComponent();

packages/cli/src/ui/components/ModelDialog.tsx

@@ -63,6 +63,8 @@ export function ModelDialog({ onClose }: ModelDialogProps): React.JSX.Element {
 
   const shouldShowPreviewModels = config?.getHasAccessToPreviewModel();
   const useGemini31 = config?.getGemini31LaunchedSync?.() ?? false;
+  const useGemini31FlashLite =
+    config?.getGemini31FlashLiteLaunchedSync?.() ?? false;
   const selectedAuthType = settings.merged.security.auth.selectedType;
   const useCustomToolModel =
     useGemini31 && selectedAuthType === AuthType.USE_GEMINI;
@@ -86,6 +88,7 @@ export function ModelDialog({ onClose }: ModelDialogProps): React.JSX.Element {
       PREVIEW_GEMINI_MODEL,
       PREVIEW_GEMINI_3_1_MODEL,
       PREVIEW_GEMINI_3_1_CUSTOM_TOOLS_MODEL,
+      PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL,
       PREVIEW_GEMINI_FLASH_MODEL,
     ];
     if (manualModels.includes(preferredModel)) {
@@ -210,7 +213,10 @@ export function ModelDialog({ onClose }: ModelDialogProps): React.JSX.Element {
 
           // Flag Guard: Versioned models only show if their flag is active.
           if (id === PREVIEW_GEMINI_3_1_MODEL && !useGemini31) return false;
-          if (id === PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL && !useGemini31)
+          if (
+            id === PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL &&
+            !useGemini31FlashLite
+          )
             return false;
 
           return true;
@@ -218,11 +224,13 @@ export function ModelDialog({ onClose }: ModelDialogProps): React.JSX.Element {
         .map(([id, m]) => {
           const resolvedId = config.modelConfigService.resolveModelId(id, {
             useGemini3_1: useGemini31,
+            useGemini3_1FlashLite: useGemini31FlashLite,
             useCustomTools: useCustomToolModel,
           });
           // Title ID is the resolved ID without custom tools flag
           const titleId = config.modelConfigService.resolveModelId(id, {
             useGemini3_1: useGemini31,
+            useGemini3_1FlashLite: useGemini31FlashLite,
           });
           return {
             value: resolvedId,
@@ -284,7 +292,7 @@ export function ModelDialog({ onClose }: ModelDialogProps): React.JSX.Element {
         },
       ];
 
-      if (isFreeTier) {
+      if (isFreeTier && useGemini31FlashLite) {
         previewOptions.push({
           value: PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL,
           title: getDisplayString(PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL),
@@ -304,6 +312,7 @@ export function ModelDialog({ onClose }: ModelDialogProps): React.JSX.Element {
   }, [
     shouldShowPreviewModels,
     useGemini31,
+    useGemini31FlashLite,
     useCustomToolModel,
     hasAccessToProModel,
     config,

packages/cli/src/ui/components/StatsDisplay.tsx

@@ -92,6 +92,7 @@ const buildModelRows = (
   config: Config,
   quotas?: RetrieveUserQuotaResponse,
   useGemini3_1 = false,
+  useGemini3_1FlashLite = false,
   useCustomToolModel = false,
 ) => {
   const getBaseModelName = (name: string) => name.replace('-001', '');
@@ -124,7 +125,12 @@ const buildModelRows = (
       ?.filter(
         (b) =>
           b.modelId &&
-          isActiveModel(b.modelId, useGemini3_1, useCustomToolModel) &&
+          isActiveModel(
+            b.modelId,
+            useGemini3_1,
+            useGemini3_1FlashLite,
+            useCustomToolModel,
+          ) &&
           !usedModelNames.has(getDisplayString(b.modelId, config)),
       )
       .map((bucket) => ({
@@ -152,6 +158,7 @@ const ModelUsageTable: React.FC<{
   pooledLimit?: number;
   pooledResetTime?: string;
   useGemini3_1?: boolean;
+  useGemini3_1FlashLite?: boolean;
   useCustomToolModel?: boolean;
 }> = ({
   models,
@@ -164,6 +171,7 @@ const ModelUsageTable: React.FC<{
   pooledLimit,
   pooledResetTime,
   useGemini3_1,
+  useGemini3_1FlashLite,
   useCustomToolModel,
 }) => {
   const { stdout } = useStdout();
@@ -173,6 +181,7 @@ const ModelUsageTable: React.FC<{
     config,
     quotas,
     useGemini3_1,
+    useGemini3_1FlashLite,
     useCustomToolModel,
   );
 
@@ -541,6 +550,8 @@ export const StatsDisplay: React.FC<StatsDisplayProps> = ({
   const settings = useSettings();
   const config = useConfig();
   const useGemini3_1 = config.getGemini31LaunchedSync?.() ?? false;
+  const useGemini3_1FlashLite =
+    config.getGemini31FlashLiteLaunchedSync?.() ?? false;
   const useCustomToolModel =
     useGemini3_1 &&
     config.getContentGeneratorConfig().authType === AuthType.USE_GEMINI;
@@ -697,6 +708,7 @@ export const StatsDisplay: React.FC<StatsDisplayProps> = ({
         pooledLimit={pooledLimit}
         pooledResetTime={pooledResetTime}
         useGemini3_1={useGemini3_1}
+        useGemini3_1FlashLite={useGemini3_1FlashLite}
         useCustomToolModel={useCustomToolModel}
       />
       {renderFooter()}