feat: implement G1 AI credits overage flow with billing telemetry

Adds end-to-end support for Google One AI credits in quota exhaustion flows:

- New billing module (packages/core/src/billing/) with credit balance
  checking, overage strategy management, and G1 URL construction
- OverageMenuDialog and EmptyWalletDialog UI components for quota
  exhaustion with credit purchase options
- Credits flow handler extracted to creditsFlowHandler.ts with overage
  menu, empty wallet, and auto-use-credits logic
- Server-side credit tracking: enabledCreditTypes on requests,
  consumed/remaining credits from streaming responses
- Billing telemetry events (overage menu shown, option selected, credits
  used, credit purchase click, API key updated)
- OpenTelemetry metrics for overage option and credit purchase counters
- Credit balance display in /stats command with refresh support
- Settings: general.overageStrategy (ask/always/never) for credit usage
- Error handling: INSUFFICIENT_G1_CREDITS_BALANCE as terminal error
  regardless of domain field presence
- Persistent info message after

Author: gsquared94

docs/cli/settings.md

@@ -80,6 +80,12 @@ they appear in the UI.
 | -------- | ------------- | ---------------------------- | ------- |
 | IDE Mode | `ide.enabled` | Enable IDE integration mode. | `false` |
 
+### Billing
+
+| UI Label         | Setting                   | Description                                                                                                                                                | Default |
+| ---------------- | ------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------- | ------- |
+| Overage Strategy | `billing.overageStrategy` | How to handle quota exhaustion when AI credits are available. 'ask' prompts each time, 'always' automatically uses credits, 'never' disables credit usage. | `"ask"` |
+
 ### Model
 
 | UI Label                | Setting                      | Description                                                                            | Default |

docs/reference/configuration.md

@@ -357,6 +357,15 @@ their corresponding top-level category object in your `settings.json` file.
   - **Default:** `true`
   - **Requires restart:** Yes
 
+#### `billing`
+
+- **`billing.overageStrategy`** (enum):
+  - **Description:** How to handle quota exhaustion when AI credits are
+    available. 'ask' prompts each time, 'always' automatically uses credits,
+    'never' disables credit usage.
+  - **Default:** `"ask"`
+  - **Values:** `"ask"`, `"always"`, `"never"`
+
 #### `model`
 
 - **`model.name`** (string):

packages/cli/src/config/settingsSchema.ts

@@ -828,6 +828,36 @@ const SETTINGS_SCHEMA = {
     ref: 'TelemetrySettings',
   },
 
+  billing: {
+    type: 'object',
+    label: 'Billing',
+    category: 'Advanced',
+    requiresRestart: false,
+    default: {},
+    description: 'Billing and AI credits settings.',
+    showInDialog: true,
+    properties: {
+      overageStrategy: {
+        type: 'enum',
+        label: 'Overage Strategy',
+        category: 'Advanced',
+        requiresRestart: false,
+        default: 'ask',
+        description: oneLine`
+          How to handle quota exhaustion when AI credits are available.
+          'ask' prompts each time, 'always' automatically uses credits,
+          'never' disables credit usage.
+        `,
+        showInDialog: true,
+        options: [
+          { value: 'ask', label: 'Ask each time' },
+          { value: 'always', label: 'Always use credits' },
+          { value: 'never', label: 'Never use credits' },
+        ],
+      },
+    },
+  },
+
   model: {
     type: 'object',
     label: 'Model',

packages/cli/src/test-utils/render.tsx

@@ -553,6 +553,8 @@ const mockUIActions: UIActions = {
   handleClearScreen: vi.fn(),
   handleProQuotaChoice: vi.fn(),
   handleValidationChoice: vi.fn(),
+  handleOverageMenuChoice: vi.fn(),
+  handleEmptyWalletChoice: vi.fn(),
   setQueueErrorMessage: vi.fn(),
   popAllMessages: vi.fn(),
   handleApiKeySubmit: vi.fn(),

packages/cli/src/ui/AppContainer.tsx

@@ -47,6 +47,7 @@ import {
   type IdeInfo,
   type IdeContext,
   type UserTierId,
+  type GeminiUserTier,
   type UserFeedbackPayload,
   type AgentDefinition,
   type ApprovalMode,
@@ -82,6 +83,8 @@ import {
   CoreToolCallStatus,
   generateSteeringAckMessage,
   buildUserSteeringHintPrompt,
+  logBillingEvent,
+  ApiKeyUpdatedEvent,
 } from '@google/gemini-cli-core';
 import { validateAuthMethod } from '../config/auth.js';
 import process from 'node:process';
@@ -414,6 +417,9 @@ export const AppContainer = (props: AppContainerProps) => {
       ? { remaining, limit, resetTime }
       : undefined;
   });
+  const [paidTier, setPaidTier] = useState<GeminiUserTier | undefined>(
+    undefined,
+  );
 
   const [isConfigInitialized, setConfigInitialized] = useState(false);
 
@@ -709,10 +715,17 @@ export const AppContainer = (props: AppContainerProps) => {
     handleProQuotaChoice,
     validationRequest,
     handleValidationChoice,
+    // G1 AI Credits
+    overageMenuRequest,
+    handleOverageMenuChoice,
+    emptyWalletRequest,
+    handleEmptyWalletChoice,
   } = useQuotaAndFallback({
     config,
     historyManager,
     userTier,
+    paidTier,
+    settings,
     setModelSwitchedFromQuotaError,
     onShowAuthSelection: () => setAuthState(AuthState.Updating),
   });
@@ -752,6 +765,8 @@ export const AppContainer = (props: AppContainerProps) => {
   const handleAuthSelect = useCallback(
     async (authType: AuthType | undefined, scope: LoadableSettingScope) => {
       if (authType) {
+        const previousAuthType =
+          config.getContentGeneratorConfig()?.authType ?? 'unknown';
         if (authType === AuthType.LOGIN_WITH_GOOGLE) {
           setAuthContext({ requiresRestart: true });
         } else {
@@ -764,6 +779,10 @@ export const AppContainer = (props: AppContainerProps) => {
           config.setRemoteAdminSettings(undefined);
           await config.refreshAuth(authType);
           setAuthState(AuthState.Authenticated);
+          logBillingEvent(
+            config,
+            new ApiKeyUpdatedEvent(previousAuthType, authType),
+          );
         } catch (e) {
           if (e instanceof ChangeAuthRequestedError) {
             return;
@@ -826,6 +845,7 @@ Logging in with Google... Restarting Gemini CLI to continue.
     // Only sync when not currently authenticating
     if (authState === AuthState.Authenticated) {
       setUserTier(config.getUserTier());
+      setPaidTier(config.getUserPaidTier());
     }
   }, [config, authState]);
 
@@ -2056,6 +2076,8 @@ Logging in with Google... Restarting Gemini CLI to continue.
     showIdeRestartPrompt ||
     !!proQuotaRequest ||
     !!validationRequest ||
+    !!overageMenuRequest ||
+    !!emptyWalletRequest ||
     isSessionBrowserOpen ||
     authState === AuthState.AwaitingApiKeyInput ||
     !!newAgents;
@@ -2083,6 +2105,8 @@ Logging in with Google... Restarting Gemini CLI to continue.
     hasLoopDetectionConfirmationRequest ||
     !!proQuotaRequest ||
     !!validationRequest ||
+    !!overageMenuRequest ||
+    !!emptyWalletRequest ||
     !!customDialog;
 
   const allowPlanMode =
@@ -2293,6 +2317,9 @@ Logging in with Google... Restarting Gemini CLI to continue.
         stats: quotaStats,
         proQuotaRequest,
         validationRequest,
+        // G1 AI Credits dialog state
+        overageMenuRequest,
+        emptyWalletRequest,
       },
       contextFileNames,
       errorCount,
@@ -2417,6 +2444,8 @@ Logging in with Google... Restarting Gemini CLI to continue.
       quotaStats,
       proQuotaRequest,
       validationRequest,
+      overageMenuRequest,
+      emptyWalletRequest,
       contextFileNames,
       errorCount,
       availableTerminalHeight,
@@ -2498,6 +2527,9 @@ Logging in with Google... Restarting Gemini CLI to continue.
       handleClearScreen,
       handleProQuotaChoice,
       handleValidationChoice,
+      // G1 AI Credits handlers
+      handleOverageMenuChoice,
+      handleEmptyWalletChoice,
       openSessionBrowser,
       closeSessionBrowser,
       handleResumeSession,
@@ -2583,6 +2615,8 @@ Logging in with Google... Restarting Gemini CLI to continue.
       handleClearScreen,
       handleProQuotaChoice,
       handleValidationChoice,
+      handleOverageMenuChoice,
+      handleEmptyWalletChoice,
       openSessionBrowser,
       closeSessionBrowser,
       handleResumeSession,

packages/cli/src/ui/commands/statsCommand.test.ts

@@ -39,11 +39,19 @@ describe('statsCommand', () => {
     mockContext.session.stats.sessionStartTime = startTime;
   });
 
-  it('should display general session stats when run with no subcommand', () => {
+  it('should display general session stats when run with no subcommand', async () => {
     if (!statsCommand.action) throw new Error('Command has no action');
 
-    // eslint-disable-next-line @typescript-eslint/no-floating-promises
-    statsCommand.action(mockContext, '');
+    mockContext.services.config = {
+      refreshUserQuota: vi.fn(),
+      refreshAvailableCredits: vi.fn(),
+      getUserTierName: vi.fn(),
+      getUserPaidTier: vi.fn(),
+      getModel: vi.fn(),
+    } as unknown as Config;
+
+     
+    await statsCommand.action(mockContext, '');
 
     const expectedDuration = formatDuration(
       endTime.getTime() - startTime.getTime(),
@@ -55,6 +63,7 @@ describe('statsCommand', () => {
       tier: undefined,
       userEmail: 'mock@example.com',
       currentModel: undefined,
+      creditBalance: null,
     });
   });
 
@@ -78,6 +87,8 @@ describe('statsCommand', () => {
       getQuotaRemaining: mockGetQuotaRemaining,
       getQuotaLimit: mockGetQuotaLimit,
       getQuotaResetTime: mockGetQuotaResetTime,
+      getUserPaidTier: vi.fn(),
+      refreshAvailableCredits: vi.fn(),
     } as unknown as Config;
 
     await statsCommand.action(mockContext, '');

packages/cli/src/ui/commands/statsCommand.ts

@@ -11,7 +11,10 @@ import type {
 } from '../types.js';
 import { MessageType } from '../types.js';
 import { formatDuration } from '../utils/formatters.js';
-import { UserAccountManager } from '@google/gemini-cli-core';
+import {
+  UserAccountManager,
+  getG1CreditBalance,
+} from '@google/gemini-cli-core';
 import {
   type CommandContext,
   type SlashCommand,
@@ -27,8 +30,10 @@ function getUserIdentity(context: CommandContext) {
   const userEmail = cachedAccount ?? undefined;
 
   const tier = context.services.config?.getUserTierName();
+  const paidTier = context.services.config?.getUserPaidTier();
+  const creditBalance = getG1CreditBalance(paidTier);
 
-  return { selectedAuthType, userEmail, tier };
+  return { selectedAuthType, userEmail, tier, creditBalance };
 }
 
 async function defaultSessionView(context: CommandContext) {
@@ -43,7 +48,8 @@ async function defaultSessionView(context: CommandContext) {
   }
   const wallDuration = now.getTime() - sessionStartTime.getTime();
 
-  const { selectedAuthType, userEmail, tier } = getUserIdentity(context);
+  const { selectedAuthType, userEmail, tier, creditBalance } =
+    getUserIdentity(context);
   const currentModel = context.services.config?.getModel();
 
   const statsItem: HistoryItemStats = {
@@ -53,10 +59,14 @@ async function defaultSessionView(context: CommandContext) {
     userEmail,
     tier,
     currentModel,
+    creditBalance,
   };
 
   if (context.services.config) {
-    const quota = await context.services.config.refreshUserQuota();
+    const [quota] = await Promise.all([
+      context.services.config.refreshUserQuota(),
+      context.services.config.refreshAvailableCredits(),
+    ]);
     if (quota) {
       statsItem.quotas = quota;
       statsItem.pooledRemaining = context.services.config.getQuotaRemaining();

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

@@ -80,6 +80,8 @@ describe('DialogManager', () => {
       stats: undefined,
       proQuotaRequest: null,
       validationRequest: null,
+      overageMenuRequest: null,
+      emptyWalletRequest: null,
     },
     shouldShowIdePrompt: false,
     isFolderTrustDialogOpen: false,
@@ -132,6 +134,8 @@ describe('DialogManager', () => {
             resolve: vi.fn(),
           },
           validationRequest: null,
+          overageMenuRequest: null,
+          emptyWalletRequest: null,
         },
       },
       'ProQuotaDialog',

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

@@ -18,6 +18,8 @@ import { EditorSettingsDialog } from './EditorSettingsDialog.js';
 import { PrivacyNotice } from '../privacy/PrivacyNotice.js';
 import { ProQuotaDialog } from './ProQuotaDialog.js';
 import { ValidationDialog } from './ValidationDialog.js';
+import { OverageMenuDialog } from './OverageMenuDialog.js';
+import { EmptyWalletDialog } from './EmptyWalletDialog.js';
 import { runExitCleanup } from '../../utils/cleanup.js';
 import { RELAUNCH_EXIT_CODE } from '../../utils/processUtils.js';
 import { SessionBrowser } from './SessionBrowser.js';
@@ -151,6 +153,28 @@ export const DialogManager = ({
       />
     );
   }
+  if (uiState.quota.overageMenuRequest) {
+    return (
+      <OverageMenuDialog
+        failedModel={uiState.quota.overageMenuRequest.failedModel}
+        fallbackModel={uiState.quota.overageMenuRequest.fallbackModel}
+        resetTime={uiState.quota.overageMenuRequest.resetTime}
+        creditBalance={uiState.quota.overageMenuRequest.creditBalance}
+        onChoice={uiActions.handleOverageMenuChoice}
+      />
+    );
+  }
+  if (uiState.quota.emptyWalletRequest) {
+    return (
+      <EmptyWalletDialog
+        failedModel={uiState.quota.emptyWalletRequest.failedModel}
+        fallbackModel={uiState.quota.emptyWalletRequest.fallbackModel}
+        resetTime={uiState.quota.emptyWalletRequest.resetTime}
+        onGetCredits={uiState.quota.emptyWalletRequest.onGetCredits}
+        onChoice={uiActions.handleEmptyWalletChoice}
+      />
+    );
+  }
   if (uiState.shouldShowIdePrompt) {
     return (
       <IdeIntegrationNudge