diff --git a/docs/reference/configuration.md b/docs/reference/configuration.md
index 04034c1973..b82afe62fb 100644
--- a/docs/reference/configuration.md
+++ b/docs/reference/configuration.md
@@ -563,6 +563,12 @@ their corresponding top-level category object in your `settings.json` file.
           "model": "gemini-2.5-flash-lite"
         }
       },
+      "gemini-3.1-flash-lite": {
+        "extends": "chat-base-2.5",
+        "modelConfig": {
+          "model": "gemini-3.1-flash-lite"
+        }
+      },
       "gemma-4-31b-it": {
         "extends": "chat-base-3",
         "modelConfig": {
@@ -590,7 +596,7 @@ their corresponding top-level category object in your `settings.json` file.
       "classifier": {
         "extends": "base",
         "modelConfig": {
-          "model": "gemini-2.5-flash-lite",
+          "model": "flash-lite",
           "generateContentConfig": {
             "maxOutputTokens": 1024,
             "thinkingConfig": {
@@ -602,7 +608,7 @@ their corresponding top-level category object in your `settings.json` file.
       "prompt-completion": {
         "extends": "base",
         "modelConfig": {
-          "model": "gemini-2.5-flash-lite",
+          "model": "flash-lite",
           "generateContentConfig": {
             "temperature": 0.3,
             "maxOutputTokens": 16000,
@@ -615,7 +621,7 @@ their corresponding top-level category object in your `settings.json` file.
       "fast-ack-helper": {
         "extends": "base",
         "modelConfig": {
-          "model": "gemini-2.5-flash-lite",
+          "model": "flash-lite",
           "generateContentConfig": {
             "temperature": 0.2,
             "maxOutputTokens": 120,
@@ -628,7 +634,7 @@ their corresponding top-level category object in your `settings.json` file.
       "edit-corrector": {
         "extends": "base",
         "modelConfig": {
-          "model": "gemini-2.5-flash-lite",
+          "model": "flash-lite",
           "generateContentConfig": {
             "thinkingConfig": {
               "thinkingBudget": 0
@@ -639,7 +645,7 @@ their corresponding top-level category object in your `settings.json` file.
       "summarizer-default": {
         "extends": "base",
         "modelConfig": {
-          "model": "gemini-2.5-flash-lite",
+          "model": "flash-lite",
           "generateContentConfig": {
             "maxOutputTokens": 2000
           }
@@ -648,7 +654,7 @@ their corresponding top-level category object in your `settings.json` file.
       "summarizer-shell": {
         "extends": "base",
         "modelConfig": {
-          "model": "gemini-2.5-flash-lite",
+          "model": "flash-lite",
           "generateContentConfig": {
             "maxOutputTokens": 2000
           }
@@ -725,7 +731,7 @@ their corresponding top-level category object in your `settings.json` file.
       },
       "chat-compression-3.1-flash-lite": {
         "modelConfig": {
-          "model": "gemini-3.1-flash-lite-preview"
+          "model": "gemini-3.1-flash-lite"
         }
       },
       "chat-compression-2.5-pro": {
@@ -779,6 +785,16 @@ their corresponding top-level category object in your `settings.json` file.
 
     ```json
     {
+      "gemini-3.1-flash-lite": {
+        "tier": "flash-lite",
+        "family": "gemini-3",
+        "isPreview": false,
+        "isVisible": true,
+        "features": {
+          "thinking": false,
+          "multimodalToolUse": true
+        }
+      },
       "gemini-3.1-flash-lite-preview": {
         "tier": "flash-lite",
         "family": "gemini-3",
@@ -1106,6 +1122,17 @@ their corresponding top-level category object in your `settings.json` file.
           }
         ]
       },
+      "gemini-3.1-flash-lite": {
+        "default": "gemini-3.1-flash-lite",
+        "contexts": [
+          {
+            "condition": {
+              "useGemini3_1FlashLite": false
+            },
+            "target": "gemini-2.5-flash-lite"
+          }
+        ]
+      },
       "flash": {
         "default": "gemini-3-flash-preview",
         "contexts": [
@@ -1118,13 +1145,13 @@ their corresponding top-level category object in your `settings.json` file.
         ]
       },
       "flash-lite": {
-        "default": "gemini-2.5-flash-lite",
+        "default": "gemini-3.1-flash-lite",
         "contexts": [
           {
             "condition": {
-              "useGemini3_1FlashLite": true
+              "useGemini3_1FlashLite": false
             },
-            "target": "gemini-3.1-flash-lite-preview"
+            "target": "gemini-2.5-flash-lite"
           }
         ]
       }
@@ -1333,7 +1360,7 @@ their corresponding top-level category object in your `settings.json` file.
       ],
       "lite": [
         {
-          "model": "gemini-2.5-flash-lite",
+          "model": "flash-lite",
           "actions": {
             "terminal": "silent",
             "transient": "silent",
diff --git a/packages/cli/src/acp/acpSessionManager.test.ts b/packages/cli/src/acp/acpSessionManager.test.ts
index 81a556a952..c37cde7820 100644
--- a/packages/cli/src/acp/acpSessionManager.test.ts
+++ b/packages/cli/src/acp/acpSessionManager.test.ts
@@ -234,8 +234,8 @@ describe('AcpSessionManager', () => {
     expect(response.models?.availableModels).toEqual(
       expect.arrayContaining([
         expect.objectContaining({
-          modelId: 'gemini-3.1-flash-lite-preview',
-          name: 'gemini-3.1-flash-lite-preview',
+          modelId: 'gemini-3.1-flash-lite',
+          name: 'gemini-3.1-flash-lite',
         }),
       ]),
     );
diff --git a/packages/cli/src/acp/acpUtils.ts b/packages/cli/src/acp/acpUtils.ts
index 403227628e..8f898e3ffe 100644
--- a/packages/cli/src/acp/acpUtils.ts
+++ b/packages/cli/src/acp/acpUtils.ts
@@ -19,7 +19,7 @@ import {
   PREVIEW_GEMINI_MODEL,
   PREVIEW_GEMINI_3_1_CUSTOM_TOOLS_MODEL,
   PREVIEW_GEMINI_FLASH_MODEL,
-  PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL,
+  GEMINI_3_1_FLASH_LITE_MODEL,
   getDisplayString,
   AuthType,
   ToolConfirmationOutcome,
@@ -346,8 +346,8 @@ export function buildAvailableModels(
 
     if (useGemini31FlashLite) {
       previewOptions.push({
-        value: PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL,
-        title: getDisplayString(PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL),
+        value: GEMINI_3_1_FLASH_LITE_MODEL,
+        title: getDisplayString(GEMINI_3_1_FLASH_LITE_MODEL),
       });
     }
 
diff --git a/packages/cli/src/ui/components/ModelDialog.test.tsx b/packages/cli/src/ui/components/ModelDialog.test.tsx
index c313e53a98..8696cdc8ba 100644
--- a/packages/cli/src/ui/components/ModelDialog.test.tsx
+++ b/packages/cli/src/ui/components/ModelDialog.test.tsx
@@ -19,7 +19,7 @@ import {
   PREVIEW_GEMINI_3_1_MODEL,
   PREVIEW_GEMINI_3_1_CUSTOM_TOOLS_MODEL,
   PREVIEW_GEMINI_FLASH_MODEL,
-  PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL,
+  GEMINI_3_1_FLASH_LITE_MODEL,
   AuthType,
 } from '@google/gemini-cli-core';
 import type { Config, ModelSlashCommandEvent } from '@google/gemini-cli-core';
@@ -43,6 +43,7 @@ vi.mock('@google/gemini-cli-core', async (importOriginal) => {
       }
     },
     PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL: 'gemini-3.1-flash-lite-preview',
+    GEMINI_3_1_FLASH_LITE_MODEL: 'gemini-3.1-flash-lite',
   };
 });
 
@@ -155,9 +156,7 @@ describe('<ModelDialog />', () => {
 
     // Verify order: Flash Preview -> Flash Lite Preview -> Flash -> Flash Lite
     const flashPreviewIdx = output.indexOf(PREVIEW_GEMINI_FLASH_MODEL);
-    const flashLitePreviewIdx = output.indexOf(
-      PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL,
-    );
+    const flashLitePreviewIdx = output.indexOf(GEMINI_3_1_FLASH_LITE_MODEL);
     const flashIdx = output.indexOf(DEFAULT_GEMINI_FLASH_MODEL);
     const flashLiteIdx = output.indexOf(DEFAULT_GEMINI_FLASH_LITE_MODEL);
 
@@ -468,7 +467,7 @@ describe('<ModelDialog />', () => {
       await waitUntilReady();
 
       const output = lastFrame();
-      expect(output).toContain(PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL);
+      expect(output).toContain(GEMINI_3_1_FLASH_LITE_MODEL);
       unmount();
     });
   });
diff --git a/packages/cli/src/ui/components/ModelDialog.tsx b/packages/cli/src/ui/components/ModelDialog.tsx
index e65811690a..ccf1b01c88 100644
--- a/packages/cli/src/ui/components/ModelDialog.tsx
+++ b/packages/cli/src/ui/components/ModelDialog.tsx
@@ -15,6 +15,7 @@ import {
   PREVIEW_GEMINI_FLASH_MODEL,
   PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL,
   PREVIEW_GEMINI_MODEL_AUTO,
+  GEMINI_3_1_FLASH_LITE_MODEL,
   DEFAULT_GEMINI_MODEL,
   DEFAULT_GEMINI_FLASH_MODEL,
   DEFAULT_GEMINI_FLASH_LITE_MODEL,
@@ -95,6 +96,7 @@ export function ModelDialog({ onClose }: ModelDialogProps): React.JSX.Element {
       PREVIEW_GEMINI_3_1_MODEL,
       PREVIEW_GEMINI_3_1_CUSTOM_TOOLS_MODEL,
       PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL,
+      GEMINI_3_1_FLASH_LITE_MODEL,
       PREVIEW_GEMINI_FLASH_MODEL,
     ];
     if (manualModels.includes(preferredModel)) {
@@ -283,9 +285,9 @@ export function ModelDialog({ onClose }: ModelDialogProps): React.JSX.Element {
 
       if (useGemini31FlashLite) {
         previewOptions.push({
-          value: PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL,
-          title: getDisplayString(PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL),
-          key: PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL,
+          value: GEMINI_3_1_FLASH_LITE_MODEL,
+          title: getDisplayString(GEMINI_3_1_FLASH_LITE_MODEL),
+          key: GEMINI_3_1_FLASH_LITE_MODEL,
         });
       }
 
diff --git a/packages/core/src/config/defaultModelConfigs.ts b/packages/core/src/config/defaultModelConfigs.ts
index 396e3d5094..4ca12d1275 100644
--- a/packages/core/src/config/defaultModelConfigs.ts
+++ b/packages/core/src/config/defaultModelConfigs.ts
@@ -89,6 +89,12 @@ export const DEFAULT_MODEL_CONFIGS: ModelConfigServiceConfig = {
         model: 'gemini-2.5-flash-lite',
       },
     },
+    'gemini-3.1-flash-lite': {
+      extends: 'chat-base-2.5',
+      modelConfig: {
+        model: 'gemini-3.1-flash-lite',
+      },
+    },
     'gemma-4-31b-it': {
       extends: 'chat-base-3',
       modelConfig: {
@@ -118,7 +124,7 @@ export const DEFAULT_MODEL_CONFIGS: ModelConfigServiceConfig = {
     classifier: {
       extends: 'base',
       modelConfig: {
-        model: 'gemini-2.5-flash-lite',
+        model: 'flash-lite',
         generateContentConfig: {
           maxOutputTokens: 1024,
           thinkingConfig: {
@@ -130,7 +136,7 @@ export const DEFAULT_MODEL_CONFIGS: ModelConfigServiceConfig = {
     'prompt-completion': {
       extends: 'base',
       modelConfig: {
-        model: 'gemini-2.5-flash-lite',
+        model: 'flash-lite',
         generateContentConfig: {
           temperature: 0.3,
           maxOutputTokens: 16000,
@@ -143,7 +149,7 @@ export const DEFAULT_MODEL_CONFIGS: ModelConfigServiceConfig = {
     'fast-ack-helper': {
       extends: 'base',
       modelConfig: {
-        model: 'gemini-2.5-flash-lite',
+        model: 'flash-lite',
         generateContentConfig: {
           temperature: 0.2,
           maxOutputTokens: 120,
@@ -156,7 +162,7 @@ export const DEFAULT_MODEL_CONFIGS: ModelConfigServiceConfig = {
     'edit-corrector': {
       extends: 'base',
       modelConfig: {
-        model: 'gemini-2.5-flash-lite',
+        model: 'flash-lite',
         generateContentConfig: {
           thinkingConfig: {
             thinkingBudget: 0,
@@ -167,7 +173,7 @@ export const DEFAULT_MODEL_CONFIGS: ModelConfigServiceConfig = {
     'summarizer-default': {
       extends: 'base',
       modelConfig: {
-        model: 'gemini-2.5-flash-lite',
+        model: 'flash-lite',
         generateContentConfig: {
           maxOutputTokens: 2000,
         },
@@ -176,7 +182,7 @@ export const DEFAULT_MODEL_CONFIGS: ModelConfigServiceConfig = {
     'summarizer-shell': {
       extends: 'base',
       modelConfig: {
-        model: 'gemini-2.5-flash-lite',
+        model: 'flash-lite',
         generateContentConfig: {
           maxOutputTokens: 2000,
         },
@@ -246,7 +252,7 @@ export const DEFAULT_MODEL_CONFIGS: ModelConfigServiceConfig = {
     },
     'chat-compression-3.1-flash-lite': {
       modelConfig: {
-        model: 'gemini-3.1-flash-lite-preview',
+        model: 'gemini-3.1-flash-lite',
       },
     },
     'chat-compression-2.5-pro': {
@@ -287,6 +293,13 @@ export const DEFAULT_MODEL_CONFIGS: ModelConfigServiceConfig = {
   ],
   modelDefinitions: {
     // Concrete Models
+    'gemini-3.1-flash-lite': {
+      tier: 'flash-lite',
+      family: 'gemini-3',
+      isPreview: false,
+      isVisible: true,
+      features: { thinking: false, multimodalToolUse: true },
+    },
     'gemini-3.1-flash-lite-preview': {
       tier: 'flash-lite',
       family: 'gemini-3',
@@ -505,6 +518,15 @@ export const DEFAULT_MODEL_CONFIGS: ModelConfigServiceConfig = {
         },
       ],
     },
+    'gemini-3.1-flash-lite': {
+      default: 'gemini-3.1-flash-lite',
+      contexts: [
+        {
+          condition: { useGemini3_1FlashLite: false },
+          target: 'gemini-2.5-flash-lite',
+        },
+      ],
+    },
     flash: {
       default: 'gemini-3-flash-preview',
       contexts: [
@@ -515,11 +537,11 @@ export const DEFAULT_MODEL_CONFIGS: ModelConfigServiceConfig = {
       ],
     },
     'flash-lite': {
-      default: 'gemini-2.5-flash-lite',
+      default: 'gemini-3.1-flash-lite',
       contexts: [
         {
-          condition: { useGemini3_1FlashLite: true },
-          target: 'gemini-3.1-flash-lite-preview',
+          condition: { useGemini3_1FlashLite: false },
+          target: 'gemini-2.5-flash-lite',
         },
       ],
     },
@@ -699,7 +721,7 @@ export const DEFAULT_MODEL_CONFIGS: ModelConfigServiceConfig = {
     ],
     lite: [
       {
-        model: 'gemini-2.5-flash-lite',
+        model: 'flash-lite',
         actions: {
           terminal: 'silent',
           transient: 'silent',
diff --git a/packages/core/src/config/models.test.ts b/packages/core/src/config/models.test.ts
index d49f3305c2..b791b3dbfc 100644
--- a/packages/core/src/config/models.test.ts
+++ b/packages/core/src/config/models.test.ts
@@ -29,6 +29,7 @@ import {
   isActiveModel,
   PREVIEW_GEMINI_3_1_MODEL,
   PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL,
+  GEMINI_3_1_FLASH_LITE_MODEL,
   PREVIEW_GEMINI_3_1_CUSTOM_TOOLS_MODEL,
   isPreviewModel,
   isProModel,
@@ -363,6 +364,12 @@ describe('getDisplayString', () => {
     );
   });
 
+  it('should return GEMINI_3_1_FLASH_LITE_MODEL for GEMINI_3_1_FLASH_LITE_MODEL', () => {
+    expect(getDisplayString(GEMINI_3_1_FLASH_LITE_MODEL)).toBe(
+      GEMINI_3_1_FLASH_LITE_MODEL,
+    );
+  });
+
   it('should return the model name as is for other models', () => {
     expect(getDisplayString('custom-model')).toBe('custom-model');
     expect(getDisplayString(GEMMA_4_31B_IT_MODEL)).toBe(GEMMA_4_31B_IT_MODEL);
@@ -420,7 +427,7 @@ describe('resolveModel', () => {
 
     it('should return the Preview Flash-Lite model when flash-lite is requested and useGemini3_1FlashLite is true', () => {
       const model = resolveModel(GEMINI_MODEL_ALIAS_FLASH_LITE, false, true);
-      expect(model).toBe(PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL);
+      expect(model).toBe(GEMINI_3_1_FLASH_LITE_MODEL);
     });
 
     it('should return the requested model as-is for explicit specific models', () => {
@@ -624,16 +631,19 @@ describe('isActiveModel', () => {
     expect(isActiveModel(DEFAULT_GEMINI_MODEL, true)).toBe(true);
   });
 
-  it('should return true for PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL only when useGemini3_1FlashLite is true', () => {
+  it('should return true for PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL and GEMINI_3_1_FLASH_LITE_MODEL only when useGemini3_1FlashLite is true', () => {
     expect(
       isActiveModel(PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL, false, true),
     ).toBe(true);
+    expect(isActiveModel(GEMINI_3_1_FLASH_LITE_MODEL, false, true)).toBe(true);
     expect(isActiveModel(PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL, true, true)).toBe(
       true,
     );
+    expect(isActiveModel(GEMINI_3_1_FLASH_LITE_MODEL, true, true)).toBe(true);
     expect(
       isActiveModel(PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL, true, false),
     ).toBe(false);
+    expect(isActiveModel(GEMINI_3_1_FLASH_LITE_MODEL, true, false)).toBe(false);
   });
 
   it('should correctly filter Gemini 3.1 models based on useCustomToolModel when useGemini3_1 is true', () => {
@@ -670,5 +680,8 @@ describe('isActiveModel', () => {
     expect(
       isActiveModel(PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL, false, false),
     ).toBe(false);
+    expect(isActiveModel(GEMINI_3_1_FLASH_LITE_MODEL, false, false)).toBe(
+      false,
+    );
   });
 });
diff --git a/packages/core/src/config/models.ts b/packages/core/src/config/models.ts
index 684ded959e..dfc6569dc1 100644
--- a/packages/core/src/config/models.ts
+++ b/packages/core/src/config/models.ts
@@ -57,6 +57,7 @@ export const PREVIEW_GEMINI_3_1_CUSTOM_TOOLS_MODEL =
 export const PREVIEW_GEMINI_FLASH_MODEL = 'gemini-3-flash-preview';
 export const PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL =
   'gemini-3.1-flash-lite-preview';
+export const GEMINI_3_1_FLASH_LITE_MODEL = 'gemini-3.1-flash-lite';
 export const DEFAULT_GEMINI_MODEL = 'gemini-2.5-pro';
 export const DEFAULT_GEMINI_FLASH_MODEL = 'gemini-2.5-flash';
 export const DEFAULT_GEMINI_FLASH_LITE_MODEL = 'gemini-2.5-flash-lite';
@@ -70,6 +71,7 @@ export const VALID_GEMINI_MODELS = new Set([
   PREVIEW_GEMINI_3_1_CUSTOM_TOOLS_MODEL,
   PREVIEW_GEMINI_FLASH_MODEL,
   PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL,
+  GEMINI_3_1_FLASH_LITE_MODEL,
   DEFAULT_GEMINI_MODEL,
   DEFAULT_GEMINI_FLASH_MODEL,
   DEFAULT_GEMINI_FLASH_LITE_MODEL,
@@ -163,7 +165,7 @@ export function resolveModel(
     }
     case GEMINI_MODEL_ALIAS_FLASH_LITE: {
       resolved = useGemini3_1FlashLite
-        ? PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL
+        ? GEMINI_3_1_FLASH_LITE_MODEL
         : DEFAULT_GEMINI_FLASH_LITE_MODEL;
       break;
     }
@@ -282,6 +284,8 @@ export function getDisplayString(
       return PREVIEW_GEMINI_3_1_MODEL;
     case PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL:
       return PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL;
+    case GEMINI_3_1_FLASH_LITE_MODEL:
+      return GEMINI_3_1_FLASH_LITE_MODEL;
     default:
       return model;
   }
@@ -463,7 +467,10 @@ export function isActiveModel(
   if (model === GEMMA_4_31B_IT_MODEL || model === GEMMA_4_26B_A4B_IT_MODEL) {
     return experimentalGemma;
   }
-  if (model === PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL) {
+  if (
+    model === PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL ||
+    model === GEMINI_3_1_FLASH_LITE_MODEL
+  ) {
     return useGemini3_1FlashLite;
   }
   if (useGemini3_1) {
diff --git a/packages/core/src/context/chatCompressionService.ts b/packages/core/src/context/chatCompressionService.ts
index 992ca67cf9..8fcef5b495 100644
--- a/packages/core/src/context/chatCompressionService.ts
+++ b/packages/core/src/context/chatCompressionService.ts
@@ -27,6 +27,7 @@ import {
   DEFAULT_GEMINI_FLASH_LITE_MODEL,
   DEFAULT_GEMINI_FLASH_MODEL,
   DEFAULT_GEMINI_MODEL,
+  GEMINI_3_1_FLASH_LITE_MODEL,
   PREVIEW_GEMINI_MODEL,
   PREVIEW_GEMINI_FLASH_MODEL,
   PREVIEW_GEMINI_3_1_MODEL,
@@ -107,6 +108,7 @@ export function modelStringToModelConfigAlias(model: string): string {
     case PREVIEW_GEMINI_FLASH_MODEL:
       return 'chat-compression-3-flash';
     case PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL:
+    case GEMINI_3_1_FLASH_LITE_MODEL:
       return 'chat-compression-3.1-flash-lite';
     case DEFAULT_GEMINI_MODEL:
       return 'chat-compression-2.5-pro';
diff --git a/packages/core/src/services/modelConfigService.ts b/packages/core/src/services/modelConfigService.ts
index a6d59365d7..86a1ab11a5 100644
--- a/packages/core/src/services/modelConfigService.ts
+++ b/packages/core/src/services/modelConfigService.ts
@@ -10,6 +10,7 @@ import {
   getDisplayString,
   PREVIEW_GEMINI_3_1_MODEL,
   PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL,
+  GEMINI_3_1_FLASH_LITE_MODEL,
   isProModel,
 } from '../config/models.js';
 
@@ -185,7 +186,11 @@ export class ModelConfigService {
         if (context.hasAccessToProModel === false && isProModel(id))
           return false;
         if (id === PREVIEW_GEMINI_3_1_MODEL && !useGemini31) return false;
-        if (id === PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL && !useGemini31FlashLite)
+        if (
+          (id === PREVIEW_GEMINI_3_1_FLASH_LITE_MODEL ||
+            id === GEMINI_3_1_FLASH_LITE_MODEL) &&
+          !useGemini31FlashLite
+        )
           return false;
         return true;
       })
diff --git a/packages/core/src/services/test-data/resolved-aliases-retry.golden.json b/packages/core/src/services/test-data/resolved-aliases-retry.golden.json
index bab67caedd..3ccd494036 100644
--- a/packages/core/src/services/test-data/resolved-aliases-retry.golden.json
+++ b/packages/core/src/services/test-data/resolved-aliases-retry.golden.json
@@ -97,6 +97,18 @@
       "topK": 64
     }
   },
+  "gemini-3.1-flash-lite": {
+    "model": "gemini-3.1-flash-lite",
+    "generateContentConfig": {
+      "temperature": 1,
+      "topP": 0.95,
+      "thinkingConfig": {
+        "includeThoughts": true,
+        "thinkingBudget": 8192
+      },
+      "topK": 64
+    }
+  },
   "gemma-4-31b-it": {
     "model": "gemma-4-31b-it",
     "generateContentConfig": {
@@ -136,7 +148,7 @@
     }
   },
   "classifier": {
-    "model": "gemini-2.5-flash-lite",
+    "model": "flash-lite",
     "generateContentConfig": {
       "temperature": 0,
       "topP": 1,
@@ -147,7 +159,7 @@
     }
   },
   "prompt-completion": {
-    "model": "gemini-2.5-flash-lite",
+    "model": "flash-lite",
     "generateContentConfig": {
       "temperature": 0.3,
       "topP": 1,
@@ -158,7 +170,7 @@
     }
   },
   "fast-ack-helper": {
-    "model": "gemini-2.5-flash-lite",
+    "model": "flash-lite",
     "generateContentConfig": {
       "temperature": 0.2,
       "topP": 1,
@@ -169,7 +181,7 @@
     }
   },
   "edit-corrector": {
-    "model": "gemini-2.5-flash-lite",
+    "model": "flash-lite",
     "generateContentConfig": {
       "temperature": 0,
       "topP": 1,
@@ -179,7 +191,7 @@
     }
   },
   "summarizer-default": {
-    "model": "gemini-2.5-flash-lite",
+    "model": "flash-lite",
     "generateContentConfig": {
       "temperature": 0,
       "topP": 1,
@@ -187,7 +199,7 @@
     }
   },
   "summarizer-shell": {
-    "model": "gemini-2.5-flash-lite",
+    "model": "flash-lite",
     "generateContentConfig": {
       "temperature": 0,
       "topP": 1,
@@ -273,7 +285,7 @@
     "generateContentConfig": {}
   },
   "chat-compression-3.1-flash-lite": {
-    "model": "gemini-3.1-flash-lite-preview",
+    "model": "gemini-3.1-flash-lite",
     "generateContentConfig": {}
   },
   "chat-compression-2.5-pro": {
diff --git a/packages/core/src/services/test-data/resolved-aliases.golden.json b/packages/core/src/services/test-data/resolved-aliases.golden.json
index bab67caedd..3ccd494036 100644
--- a/packages/core/src/services/test-data/resolved-aliases.golden.json
+++ b/packages/core/src/services/test-data/resolved-aliases.golden.json
@@ -97,6 +97,18 @@
       "topK": 64
     }
   },
+  "gemini-3.1-flash-lite": {
+    "model": "gemini-3.1-flash-lite",
+    "generateContentConfig": {
+      "temperature": 1,
+      "topP": 0.95,
+      "thinkingConfig": {
+        "includeThoughts": true,
+        "thinkingBudget": 8192
+      },
+      "topK": 64
+    }
+  },
   "gemma-4-31b-it": {
     "model": "gemma-4-31b-it",
     "generateContentConfig": {
@@ -136,7 +148,7 @@
     }
   },
   "classifier": {
-    "model": "gemini-2.5-flash-lite",
+    "model": "flash-lite",
     "generateContentConfig": {
       "temperature": 0,
       "topP": 1,
@@ -147,7 +159,7 @@
     }
   },
   "prompt-completion": {
-    "model": "gemini-2.5-flash-lite",
+    "model": "flash-lite",
     "generateContentConfig": {
       "temperature": 0.3,
       "topP": 1,
@@ -158,7 +170,7 @@
     }
   },
   "fast-ack-helper": {
-    "model": "gemini-2.5-flash-lite",
+    "model": "flash-lite",
     "generateContentConfig": {
       "temperature": 0.2,
       "topP": 1,
@@ -169,7 +181,7 @@
     }
   },
   "edit-corrector": {
-    "model": "gemini-2.5-flash-lite",
+    "model": "flash-lite",
     "generateContentConfig": {
       "temperature": 0,
       "topP": 1,
@@ -179,7 +191,7 @@
     }
   },
   "summarizer-default": {
-    "model": "gemini-2.5-flash-lite",
+    "model": "flash-lite",
     "generateContentConfig": {
       "temperature": 0,
       "topP": 1,
@@ -187,7 +199,7 @@
     }
   },
   "summarizer-shell": {
-    "model": "gemini-2.5-flash-lite",
+    "model": "flash-lite",
     "generateContentConfig": {
       "temperature": 0,
       "topP": 1,
@@ -273,7 +285,7 @@
     "generateContentConfig": {}
   },
   "chat-compression-3.1-flash-lite": {
-    "model": "gemini-3.1-flash-lite-preview",
+    "model": "gemini-3.1-flash-lite",
     "generateContentConfig": {}
   },
   "chat-compression-2.5-pro": {