Respect backend definitions for 3.5 flash and Update auto mode to use 3.5 flash when the flag is enabled.

docs/reference/configuration.md

@@ -602,10 +602,10 @@
           "model": "gemini-3.1-flash-lite"
         }
       },
       "gemini-3.5-flash": {
         "extends": "chat-base-3",
         "modelConfig": {
           "model": "gemini-3.5-flash"
         }
       },
       "gemma-4-31b-it": {
@@ -632,10 +632,10 @@
           "model": "gemini-3-flash-preview"
         }
       },
       "gemini-3.5-flash-base": {
         "extends": "base",
         "modelConfig": {
           "model": "gemini-3.5-flash"
         }
       },
       "classifier": {
@@ -880,7 +880,7 @@
           "multimodalToolUse": true
         }
       },
       "gemini-3.5-flash": {
         "tier": "flash",
         "family": "gemini-3",
         "isPreview": false,
@@ -1042,20 +1042,22 @@
         "contexts": [
           {
             "condition": {
+              "hasAccessToPreview": false,
               "useGemini3_5Flash": true
             },
             "target": "gemini-3.5-flash"
           },
           {
             "condition": {
-              "hasAccessToPreview": false
+              "hasAccessToPreview": false,
+              "useGemini3_5Flash": false
             },
             "target": "gemini-2.5-flash"
           }
         ]
       },
       "gemini-3.5-flash": {
         "default": "gemini-3.5-flash",
         "contexts": [
           {
             "condition": {
@@ -1079,7 +1081,7 @@
             "condition": {
               "useGemini3_5Flash": true
             },
             "target": "gemini-3.5-flash"
           }
         ]
       },
@@ -1165,7 +1167,7 @@
             "condition": {
               "useGemini3_5Flash": true
             },
             "target": "gemini-3.5-flash"
           },
           {
             "condition": {

packages/cli/src/acp/acpUtils.ts

@@ -265,6 +265,7 @@ export function buildAvailableModels(
   const preferredModel = config.getModel() || GEMINI_MODEL_ALIAS_AUTO;
   const shouldShowPreviewModels = config.getHasAccessToPreviewModel();
   const useGemini31 = config.getGemini31LaunchedSync?.() ?? false;
+  const useGemini3_5Flash = config.hasGemini35FlashGAAccess?.() ?? false;
   const selectedAuthType = settings.merged.security.auth.selectedType;
   const useCustomToolModel =
     useGemini31 && selectedAuthType === AuthType.USE_GEMINI;
@@ -276,6 +277,7 @@ export function buildAvailableModels(
   ) {
     const options = config.getModelConfigService().getAvailableModelOptions({
       useGemini3_1: useGemini31,
+      useGemini3_5Flash,
       useCustomTools: useCustomToolModel,
       hasAccessToPreview: shouldShowPreviewModels,
     });
@@ -294,6 +296,7 @@ export function buildAvailableModels(
       description: getAutoModelDescription(
         shouldShowPreviewModels,
         useGemini31,
+        useGemini3_5Flash,
       ),
     },
   ];

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

@@ -67,6 +67,7 @@ export function ModelDialog({ onClose }: ModelDialogProps): React.JSX.Element {
 
   const shouldShowPreviewModels = config?.getHasAccessToPreviewModel() ?? false;
   const useGemini31 = config?.getGemini31LaunchedSync?.() ?? false;
+  const useGemini3_5Flash = config?.hasGemini35FlashGAAccess?.() ?? false;
   const selectedAuthType = settings.merged.security.auth.selectedType;
   const useCustomToolModel =
     useGemini31 && selectedAuthType === AuthType.USE_GEMINI;
@@ -129,6 +130,7 @@ export function ModelDialog({ onClose }: ModelDialogProps): React.JSX.Element {
         .getModelConfigService()
         .getAvailableModelOptions({
           useGemini3_1: useGemini31,
+          useGemini3_5Flash,
           useCustomTools: useCustomToolModel,
           hasAccessToPreview: shouldShowPreviewModels,
           hasAccessToProModel,
@@ -162,6 +164,7 @@ export function ModelDialog({ onClose }: ModelDialogProps): React.JSX.Element {
         description: getAutoModelDescription(
           shouldShowPreviewModels,
           useGemini31,
+          useGemini3_5Flash,
         ),
         key: GEMINI_MODEL_ALIAS_AUTO,
       },
@@ -181,6 +184,7 @@ export function ModelDialog({ onClose }: ModelDialogProps): React.JSX.Element {
     shouldShowPreviewModels,
     manualModelSelected,
     useGemini31,
+    useGemini3_5Flash,
     useCustomToolModel,
     hasAccessToProModel,
   ]);
@@ -195,6 +199,7 @@ export function ModelDialog({ onClose }: ModelDialogProps): React.JSX.Element {
         .getModelConfigService()
         .getAvailableModelOptions({
           useGemini3_1: useGemini31,
+          useGemini3_5Flash,
           useCustomTools: useCustomToolModel,
           hasAccessToPreview: shouldShowPreviewModels,
           hasAccessToProModel,
@@ -287,6 +292,7 @@ export function ModelDialog({ onClose }: ModelDialogProps): React.JSX.Element {
   }, [
     shouldShowPreviewModels,
     useGemini31,
+    useGemini3_5Flash,
     useCustomToolModel,
     hasAccessToProModel,
     config,

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

@@ -353,6 +353,49 @@ describe('<ModelStatsDisplay />', () => {
     unmount();
   });
 
+  it('should resolve gemini-3-flash to gemini-3.5-flash via getDisplayString', async () => {
+    const { lastFrame, unmount } = await renderWithMockedStats({
+      models: {
+        'gemini-3-flash': {
+          api: { totalRequests: 1, totalErrors: 0, totalLatencyMs: 100 },
+          tokens: {
+            input: 5,
+            prompt: 10,
+            candidates: 20,
+            total: 30,
+            cached: 5,
+            thoughts: 2,
+            tool: 1,
+          },
+          roles: {},
+        },
+      },
+      tools: {
+        totalCalls: 0,
+        totalSuccess: 0,
+        totalFail: 0,
+        totalDurationMs: 0,
+        totalDecisions: {
+          accept: 0,
+          reject: 0,
+          modify: 0,
+          [ToolCallDecision.AUTO_ACCEPT]: 0,
+        },
+        byName: {},
+      },
+      files: {
+        totalLinesAdded: 0,
+        totalLinesRemoved: 0,
+      },
+    });
+
+    const output = lastFrame();
+    expect(output).toContain('gemini-3.5-flash');
+    expect(output).not.toContain('gemini-3-flash');
+    expect(output).toMatchSnapshot();
+    unmount();
+  });
+
   it('should handle models with long names (gemini-3-*-preview) without layout breaking', async () => {
     const { lastFrame, unmount } = await renderWithMockedStats(
       {

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

@@ -299,7 +299,7 @@ export const ModelStatsDisplay: React.FC<ModelStatsDisplayProps> = ({
     },
     ...modelNames.map((name) => ({
       key: name,
-      header: name,
+      header: getDisplayString(name),
       flexGrow: 1,
       renderCell: (row: StatRowData) => {
         // Don't render anything for section headers in model columns

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

@@ -131,6 +131,33 @@ describe('<StatsDisplay />', () => {
     expect(output).toMatchSnapshot();
   });
 
+  it('resolves gemini-3-flash to gemini-3.5-flash in the model usage table', async () => {
+    const metrics = createTestMetrics({
+      models: {
+        'gemini-3-flash': {
+          api: { totalRequests: 5, totalErrors: 0, totalLatencyMs: 3000 },
+          tokens: {
+            input: 1000,
+            prompt: 2000,
+            candidates: 3000,
+            total: 5000,
+            cached: 500,
+            thoughts: 100,
+            tool: 50,
+          },
+          roles: {},
+        },
+      },
+    });
+
+    const { lastFrame } = await renderWithMockedStats(metrics);
+    const output = lastFrame();
+
+    expect(output).toContain('gemini-3.5-flash');
+    expect(output).not.toContain('gemini-3-flash\u0020'); // Avoid matching parts of substrings if not intended
+    expect(output).toMatchSnapshot();
+  });
+
   it('renders role breakdown correctly under models', async () => {
     const metrics = createTestMetrics({
       models: {

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

@@ -24,7 +24,7 @@ import {
 import { computeSessionStats } from '../utils/computeStats.js';
 import { useSettings } from '../contexts/SettingsContext.js';
 import type { QuotaStats } from '../types.js';
-import { LlmRole } from '@google/gemini-cli-core';
+import { LlmRole, getDisplayString } from '@google/gemini-cli-core';
 
 // A more flexible and powerful StatRow component
 interface StatRowProps {
@@ -101,7 +101,7 @@ const ModelUsageTable: React.FC<ModelUsageTableProps> = ({ models }) => {
   Object.entries(models).forEach(([name, metrics]) => {
     rows.push({
       name,
-      displayName: name,
+      displayName: getDisplayString(name),
       requests: metrics.api.totalRequests,
       cachedTokens: metrics.tokens.cached.toLocaleString(),
       inputTokens: metrics.tokens.prompt.toLocaleString(),

packages/cli/src/ui/components/__snapshots__/ModelStatsDisplay.test.tsx.snap

@@ -215,3 +215,26 @@ exports[`<ModelStatsDisplay /> > should render "no API calls" message when there
 ╰──────────────────────────────────────────────────────────────────────────────────────────────────╯
 "
 `;
+
+exports[`<ModelStatsDisplay /> > should resolve gemini-3-flash to gemini-3.5-flash via getDisplayString 1`] = `
+"╭──────────────────────────────────────────────────────────────────────────────────────────────────╮
+│                                                                                                  │
+│  Model Stats For Nerds                                                                           │
+│                                                                                                  │
+│                                                                                                  │
+│  Metric                      gemini-3.5-flash                                                    │
+│  ──────────────────────────────────────────────────────────────────────────────────────────────  │
+│  API                                                                                             │
+│  Requests                    1                                                                   │
+│  Errors                      0 (0.0%)                                                            │
+│  Avg Latency                 100ms                                                               │
+│  Tokens                                                                                          │
+│  Total                       30                                                                  │
+│    ↳ Input                   5                                                                   │
+│    ↳ Cache Reads             5 (50.0%)                                                           │
+│    ↳ Thoughts                2                                                                   │
+│    ↳ Tool                    1                                                                   │
+│    ↳ Output                  20                                                                  │
+╰──────────────────────────────────────────────────────────────────────────────────────────────────╯
+"
+`;

packages/cli/src/ui/components/__snapshots__/StatsDisplay.test.tsx.snap

@@ -292,3 +292,30 @@ exports[`<StatsDisplay /> > renders role breakdown correctly under models 1`] =
 ╰──────────────────────────────────────────────────────────────────────────────────────────────────╯
 "
 `;
+
+exports[`<StatsDisplay /> > resolves gemini-3-flash to gemini-3.5-flash in the model usage table 1`] = `
+"╭──────────────────────────────────────────────────────────────────────────────────────────────────╮
+│                                                                                                  │
+│  Session Stats                                                                                   │
+│                                                                                                  │
+│  Interaction Summary                                                                             │
+│  Session ID:                 test-session-id                                                     │
+│  Tool Calls:                 0 ( ✓ 0 x 0 )                                                       │
+│  Success Rate:               0.0%                                                                │
+│                                                                                                  │
+│  Performance                                                                                     │
+│  Wall Time:                  1s                                                                  │
+│  Agent Active:               3.0s                                                                │
+│    » API Time:               3.0s (100.0%)                                                       │
+│    » Tool Time:              0s (0.0%)                                                           │
+│                                                                                                  │
+│                                                                                                  │
+│  Model Usage                                                                                     │
+│  Use /model to view model quota information                                                      │
+│                                                                                                  │
+│  Model                           Reqs  Input Tokens   Cache Reads Output Tokens                  │
+│  ──────────────────────────────────────────────────────────────────────────────────────────────  │
+│  gemini-3.5-flash                   5         2,000           500         3,000                  │
+╰──────────────────────────────────────────────────────────────────────────────────────────────────╯
+"
+`;

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

@@ -4357,8 +4357,9 @@ describe('hasGemini35FlashGAAccess model setting', () => {
     cwd: '.',
   };
 
-  it('should set DEFAULT_GEMINI_FLASH_MODEL and PREVIEW_GEMINI_FLASH_MODEL to gemini-3.5-flash if hasGemini35FlashGAAccess returns true', () => {
+  it('should set DEFAULT_GEMINI_FLASH_MODEL to gemini-3.5-flash and PREVIEW_GEMINI_FLASH_MODEL to gemini-3-flash-preview if hasGemini35FlashGAAccess returns true and authType is USE_GEMINI', () => {
     const config = new Config(baseParams);
+    config['contentGeneratorConfig'] = { authType: AuthType.USE_GEMINI };
 
     // Set experiment to return true for GEMINI_3_5_FLASH_GA_LAUNCHED
     config.setExperiments({
@@ -4375,6 +4376,28 @@ describe('hasGemini35FlashGAAccess model setting', () => {
     expect(result).toBe(true);
 
     expect(DEFAULT_GEMINI_FLASH_MODEL).toBe('gemini-3.5-flash');
-    expect(PREVIEW_GEMINI_FLASH_MODEL).toBe('gemini-3.5-flash');
+    expect(PREVIEW_GEMINI_FLASH_MODEL).toBe('gemini-3-flash-preview');
+  });
+
+  it('should set DEFAULT_GEMINI_FLASH_MODEL and PREVIEW_GEMINI_FLASH_MODEL to gemini-3-flash if hasGemini35FlashGAAccess returns true and authType is not USE_GEMINI', () => {
+    const config = new Config(baseParams);
+    config['contentGeneratorConfig'] = { authType: AuthType.LOGIN_WITH_GOOGLE };
+
+    // Set experiment to return true for GEMINI_3_5_FLASH_GA_LAUNCHED
+    config.setExperiments({
+      experimentIds: [],
+      flags: {
+        [ExperimentFlags.GEMINI_3_5_FLASH_GA_LAUNCHED]: {
+          boolValue: true,
+        },
+      },
+    });
+
+    // Call the method
+    const result = config.hasGemini35FlashGAAccess();
+    expect(result).toBe(true);
+
+    expect(DEFAULT_GEMINI_FLASH_MODEL).toBe('gemini-3-flash');
+    expect(PREVIEW_GEMINI_FLASH_MODEL).toBe('gemini-3-flash');
   });
 });

packages/core/src/config/config.ts

@@ -3561,7 +3561,13 @@ export class Config implements McpContext, AgentLoopContext {
     // Used to set default flash models based on access
     // TODO: Remove once the experiment for 3_5 flash rollut can be cleaned up.
     if (hasAccess) {
-      setFlashModels('gemini-3.5-flash', 'gemini-3.5-flash');
+      // Gemini API key users should have the ability to manually select the
+      // old preview flash model.
+      if (authType === AuthType.USE_GEMINI) {
+        setFlashModels('gemini-3-flash-preview', 'gemini-3.5-flash');
+      } else {
+        setFlashModels('gemini-3-flash', 'gemini-3-flash');
+      }
     } else {
       setFlashModels('gemini-3-flash-preview', 'gemini-2.5-flash');
     }

packages/core/src/config/defaultModelConfigs.ts

@@ -469,9 +469,12 @@ export const DEFAULT_MODEL_CONFIGS: ModelConfigServiceConfig = {
     'gemini-3-flash-preview': {
       default: 'gemini-3-flash-preview',
       contexts: [
-        { condition: { useGemini3_5Flash: true }, target: 'gemini-3.5-flash' },
         {
-          condition: { hasAccessToPreview: false },
+          condition: { hasAccessToPreview: false, useGemini3_5Flash: true },
+          target: 'gemini-3.5-flash',
+        },
+        {
+          condition: { hasAccessToPreview: false, useGemini3_5Flash: false },
           target: 'gemini-2.5-flash',
         },
       ],