feat(core,ui): support Gemini 3.1 Pro Preview and active model filtering (#125)

* feat(core,ui): support Gemini 3.1 Pro Preview and active model filtering

* fix(core,ui): use optional chaining for config methods to support mocks

* fix(core): clear stale authType in refreshAuth to avoid incorrect model resolution

* do not show gemini 3.1 model when users do not have access to gemini 3.1 in stats

packages/core/src/availability/policyHelpers.ts

@@ -43,7 +43,10 @@ export function resolvePolicyChain(
   const configuredModel = config.getModel();
 
   let chain;
-  const resolvedModel = resolveModel(modelFromConfig);
+  const resolvedModel = resolveModel(
+    modelFromConfig,
+    config.getGemini31LaunchedSync?.() ?? false,
+  );
   const isAutoPreferred = preferredModel ? isAutoModel(preferredModel) : false;
   const isAutoConfigured = isAutoModel(configuredModel);
 

packages/core/src/code_assist/experiments/flagNames.ts

@@ -16,6 +16,7 @@ export const ExperimentFlags = {
   MASKING_PROTECTION_THRESHOLD: 45758817,
   MASKING_PRUNABLE_THRESHOLD: 45758818,
   MASKING_PROTECT_LATEST_TURN: 45758819,
+  GEMINI_3_1_PRO_LAUNCHED: 45760185,
 } as const;
 
 export type ExperimentFlagName =

packages/core/src/config/config.ts

@@ -1023,6 +1023,12 @@ export class Config {
     // Reset availability status when switching auth (e.g. from limited key to OAuth)
     this.modelAvailabilityService.reset();
 
+    // Clear stale authType to ensure getGemini31LaunchedSync doesn't return stale results
+    // during the transition.
+    if (this.contentGeneratorConfig) {
+      this.contentGeneratorConfig.authType = undefined;
+    }
+
     const newContentGeneratorConfig = await createContentGeneratorConfig(
       this,
       authMethod,
@@ -1298,7 +1304,10 @@ export class Config {
     if (pooled.remaining !== undefined) {
       return pooled.remaining;
     }
-    const primaryModel = resolveModel(this.getModel());
+    const primaryModel = resolveModel(
+      this.getModel(),
+      this.getGemini31LaunchedSync(),
+    );
     return this.modelQuotas.get(primaryModel)?.remaining;
   }
 
@@ -1307,7 +1316,10 @@ export class Config {
     if (pooled.limit !== undefined) {
       return pooled.limit;
     }
-    const primaryModel = resolveModel(this.getModel());
+    const primaryModel = resolveModel(
+      this.getModel(),
+      this.getGemini31LaunchedSync(),
+    );
     return this.modelQuotas.get(primaryModel)?.limit;
   }
 
@@ -1316,7 +1328,10 @@ export class Config {
     if (pooled.resetTime !== undefined) {
       return pooled.resetTime;
     }
-    const primaryModel = resolveModel(this.getModel());
+    const primaryModel = resolveModel(
+      this.getModel(),
+      this.getGemini31LaunchedSync(),
+    );
     return this.modelQuotas.get(primaryModel)?.resetTime;
   }
 
@@ -2145,6 +2160,36 @@ export class Config {
     );
   }
 
+  /**
+   * Returns whether Gemini 3.1 has been launched.
+   * This method is async and ensures that experiments are loaded before returning the result.
+   */
+  async getGemini31Launched(): Promise<boolean> {
+    await this.ensureExperimentsLoaded();
+    return this.getGemini31LaunchedSync();
+  }
+
+  /**
+   * Returns whether Gemini 3.1 has been launched.
+   *
+   * Note: This method should only be called after startup, once experiments have been loaded.
+   * If you need to call this during startup or from an async context, use
+   * getGemini31Launched instead.
+   */
+  getGemini31LaunchedSync(): boolean {
+    const authType = this.contentGeneratorConfig?.authType;
+    if (
+      authType === AuthType.USE_GEMINI ||
+      authType === AuthType.USE_VERTEX_AI
+    ) {
+      return true;
+    }
+    return (
+      this.experiments?.flags[ExperimentFlags.GEMINI_3_1_PRO_LAUNCHED]
+        ?.boolValue ?? false
+    );
+  }
+
   private async ensureExperimentsLoaded(): Promise<void> {
     if (!this.experimentsPromise) {
       return;

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

@@ -23,6 +23,7 @@ import {
   PREVIEW_GEMINI_FLASH_MODEL,
   PREVIEW_GEMINI_MODEL_AUTO,
   DEFAULT_GEMINI_MODEL_AUTO,
+  isActiveModel,
 } from './models.js';
 
 describe('isGemini3Model', () => {
@@ -194,3 +195,24 @@ describe('resolveClassifierModel', () => {
     ).toBe(PREVIEW_GEMINI_MODEL);
   });
 });
+
+describe('isActiveModel', () => {
+  it('should return true for valid models when useGemini3_1 is false', () => {
+    expect(isActiveModel(DEFAULT_GEMINI_MODEL)).toBe(true);
+    expect(isActiveModel(PREVIEW_GEMINI_MODEL)).toBe(true);
+    expect(isActiveModel(DEFAULT_GEMINI_FLASH_MODEL)).toBe(true);
+  });
+
+  it('should return false for invalid models', () => {
+    expect(isActiveModel('invalid-model')).toBe(false);
+    expect(isActiveModel(GEMINI_MODEL_ALIAS_AUTO)).toBe(false);
+  });
+
+  it('should return false for PREVIEW_GEMINI_MODEL when useGemini3_1 is true', () => {
+    expect(isActiveModel(PREVIEW_GEMINI_MODEL, true)).toBe(false);
+  });
+
+  it('should return true for other valid models when useGemini3_1 is true', () => {
+    expect(isActiveModel(DEFAULT_GEMINI_MODEL, true)).toBe(true);
+  });
+});

packages/core/src/config/models.ts

@@ -5,6 +5,7 @@
  */
 
 export const PREVIEW_GEMINI_MODEL = 'gemini-3-pro-preview';
+export const PREVIEW_GEMINI_3_1_MODEL = 'gemini-3.1-pro-preview';
 export const PREVIEW_GEMINI_FLASH_MODEL = 'gemini-3-flash-preview';
 export const DEFAULT_GEMINI_MODEL = 'gemini-2.5-pro';
 export const DEFAULT_GEMINI_FLASH_MODEL = 'gemini-2.5-flash';
@@ -12,6 +13,7 @@ export const DEFAULT_GEMINI_FLASH_LITE_MODEL = 'gemini-2.5-flash-lite';
 
 export const VALID_GEMINI_MODELS = new Set([
   PREVIEW_GEMINI_MODEL,
+  PREVIEW_GEMINI_3_1_MODEL,
   PREVIEW_GEMINI_FLASH_MODEL,
   DEFAULT_GEMINI_MODEL,
   DEFAULT_GEMINI_FLASH_MODEL,
@@ -37,19 +39,24 @@ export const DEFAULT_THINKING_MODE = 8192;
  * to a concrete model name.
  *
  * @param requestedModel The model alias or concrete model name requested by the user.
+ * @param useGemini3_1 Whether to use Gemini 3.1 Pro Preview for auto/pro aliases.
  * @returns The resolved concrete model name.
  */
-export function resolveModel(requestedModel: string): string {
+export function resolveModel(
+  requestedModel: string,
+  useGemini3_1: boolean = false,
+): string {
   switch (requestedModel) {
+    case PREVIEW_GEMINI_MODEL:
     case PREVIEW_GEMINI_MODEL_AUTO: {
-      return PREVIEW_GEMINI_MODEL;
+      return useGemini3_1 ? PREVIEW_GEMINI_3_1_MODEL : PREVIEW_GEMINI_MODEL;
     }
     case DEFAULT_GEMINI_MODEL_AUTO: {
       return DEFAULT_GEMINI_MODEL;
     }
     case GEMINI_MODEL_ALIAS_AUTO:
     case GEMINI_MODEL_ALIAS_PRO: {
-      return PREVIEW_GEMINI_MODEL;
+      return useGemini3_1 ? PREVIEW_GEMINI_3_1_MODEL : PREVIEW_GEMINI_MODEL;
     }
     case GEMINI_MODEL_ALIAS_FLASH: {
       return PREVIEW_GEMINI_FLASH_MODEL;
@@ -115,11 +122,26 @@ export function getDisplayString(model: string) {
 export function isPreviewModel(model: string): boolean {
   return (
     model === PREVIEW_GEMINI_MODEL ||
+    model === PREVIEW_GEMINI_3_1_MODEL ||
     model === PREVIEW_GEMINI_FLASH_MODEL ||
     model === PREVIEW_GEMINI_MODEL_AUTO
   );
 }
 
+/**
+ * Checks if the model is a Pro model.
+ *
+ * @param model The model name to check.
+ * @returns True if the model is a Pro model.
+ */
+export function isProModel(model: string): boolean {
+  return (
+    model === PREVIEW_GEMINI_MODEL ||
+    model === PREVIEW_GEMINI_3_1_MODEL ||
+    model === DEFAULT_GEMINI_MODEL
+  );
+}
+
 /**
  * Checks if the model is a Gemini 3 model.
  *
@@ -165,3 +187,24 @@ export function isAutoModel(model: string): boolean {
 export function supportsMultimodalFunctionResponse(model: string): boolean {
   return model.startsWith('gemini-3-');
 }
+
+/**
+ * Checks if the given model is considered active based on the current configuration.
+ *
+ * @param model The model name to check.
+ * @param useGemini3_1 Whether Gemini 3.1 Pro Preview is enabled.
+ * @returns True if the model is active.
+ */
+export function isActiveModel(
+  model: string,
+  useGemini3_1: boolean = false,
+): boolean {
+  if (!VALID_GEMINI_MODELS.has(model)) {
+    return false;
+  }
+  if (useGemini3_1) {
+    return model !== PREVIEW_GEMINI_MODEL;
+  } else {
+    return model !== PREVIEW_GEMINI_3_1_MODEL;
+  }
+}

packages/core/src/core/client.ts

@@ -541,7 +541,10 @@ export class GeminiClient {
 
     // Availability logic: The configured model is the source of truth,
     // including any permanent fallbacks (config.setModel) or manual overrides.
-    return resolveModel(this.config.getActiveModel());
+    return resolveModel(
+      this.config.getActiveModel(),
+      this.config.getGemini31LaunchedSync?.() ?? false,
+    );
   }
 
   private async *processTurn(

packages/core/src/core/contentGenerator.ts

@@ -122,7 +122,12 @@ export async function createContentGenerator(
       return new LoggingContentGenerator(fakeGenerator, gcConfig);
     }
     const version = await getVersion();
-    const model = resolveModel(gcConfig.getModel());
+    const model = resolveModel(
+      gcConfig.getModel(),
+      config.authType === AuthType.USE_GEMINI ||
+        config.authType === AuthType.USE_VERTEX_AI ||
+        ((await gcConfig.getGemini31Launched?.()) ?? false),
+    );
     const customHeadersEnv =
       process.env['GEMINI_CLI_CUSTOM_HEADERS'] || undefined;
     const userAgent = `GeminiCLI/${version}/${model} (${process.platform}; ${process.arch})`;

packages/core/src/core/geminiChat.ts

@@ -492,13 +492,14 @@ export class GeminiChat {
     const initialActiveModel = this.config.getActiveModel();
 
     const apiCall = async () => {
+      const useGemini3_1 = (await this.config.getGemini31Launched?.()) ?? false;
       // Default to the last used model (which respects arguments/availability selection)
-      let modelToUse = resolveModel(lastModelToUse);
+      let modelToUse = resolveModel(lastModelToUse, useGemini3_1);
 
       // If the active model has changed (e.g. due to a fallback updating the config),
       // we switch to the new active model.
       if (this.config.getActiveModel() !== initialActiveModel) {
-        modelToUse = resolveModel(this.config.getActiveModel());
+        modelToUse = resolveModel(this.config.getActiveModel(), useGemini3_1);
       }
 
       if (modelToUse !== lastModelToUse) {

packages/core/src/prompts/promptProvider.ts

@@ -58,7 +58,10 @@ export class PromptProvider {
     const enabledToolNames = new Set(toolNames);
     const approvedPlanPath = config.getApprovedPlanPath();
 
-    const desiredModel = resolveModel(config.getActiveModel());
+    const desiredModel = resolveModel(
+      config.getActiveModel(),
+      config.getGemini31LaunchedSync?.() ?? false,
+    );
     const isGemini3 = isPreviewModel(desiredModel);
     const activeSnippets = isGemini3 ? snippets : legacySnippets;
     const contextFilenames = getAllGeminiMdFilenames();
@@ -233,7 +236,10 @@ export class PromptProvider {
   }
 
   getCompressionPrompt(config: Config): string {
-    const desiredModel = resolveModel(config.getActiveModel());
+    const desiredModel = resolveModel(
+      config.getActiveModel(),
+      config.getGemini31LaunchedSync?.() ?? false,
+    );
     const isGemini3 = isPreviewModel(desiredModel);
     const activeSnippets = isGemini3 ? snippets : legacySnippets;
     return activeSnippets.getCompressionPrompt();

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

@@ -21,7 +21,10 @@ export class DefaultStrategy implements TerminalStrategy {
     config: Config,
     _baseLlmClient: BaseLlmClient,
   ): Promise<RoutingDecision> {
-    const defaultModel = resolveModel(config.getModel());
+    const defaultModel = resolveModel(
+      config.getModel(),
+      config.getGemini31LaunchedSync?.() ?? false,
+    );
     return {
       model: defaultModel,
       metadata: {

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

@@ -23,7 +23,10 @@ export class FallbackStrategy implements RoutingStrategy {
     _baseLlmClient: BaseLlmClient,
   ): Promise<RoutingDecision | null> {
     const requestedModel = context.requestedModel ?? config.getModel();
-    const resolvedModel = resolveModel(requestedModel);
+    const resolvedModel = resolveModel(
+      requestedModel,
+      config.getGemini31LaunchedSync?.() ?? false,
+    );
     const service = config.getModelAvailabilityService();
     const snapshot = service.snapshot(resolvedModel);
 

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

@@ -33,7 +33,10 @@ export class OverrideStrategy implements RoutingStrategy {
 
     // Return the overridden model name.
     return {
-      model: resolveModel(overrideModel),
+      model: resolveModel(
+        overrideModel,
+        config.getGemini31LaunchedSync?.() ?? false,
+      ),
       metadata: {
         source: this.name,
         latencyMs: 0,

packages/core/src/services/chatCompressionService.ts

@@ -29,6 +29,7 @@ import {
   DEFAULT_GEMINI_MODEL,
   PREVIEW_GEMINI_MODEL,
   PREVIEW_GEMINI_FLASH_MODEL,
+  PREVIEW_GEMINI_3_1_MODEL,
 } from '../config/models.js';
 import { PreCompressTrigger } from '../hooks/types.js';
 
@@ -100,6 +101,7 @@ export function findCompressSplitPoint(
 export function modelStringToModelConfigAlias(model: string): string {
   switch (model) {
     case PREVIEW_GEMINI_MODEL:
+    case PREVIEW_GEMINI_3_1_MODEL:
       return 'chat-compression-3-pro';
     case PREVIEW_GEMINI_FLASH_MODEL:
       return 'chat-compression-3-flash';