refactor: update authentication handling and model configuration

- Enhanced authentication method validation in `auth.ts` and `auth.test.ts`.
- Introduced new model provider configuration logic
- Updated environment variable handling for various auth types.
- Removed deprecated utility functions and tests related to fallback mechanisms.

packages/cli/src/config/auth.test.ts

@@ -1,41 +1,112 @@
 /**
  * @license
- * Copyright 2025 Google LLC
+ * Copyright 2025 Qwen Team
  * SPDX-License-Identifier: Apache-2.0
  */
 
 import { AuthType } from '@qwen-code/qwen-code-core';
 import { vi } from 'vitest';
 import { validateAuthMethod } from './auth.js';
+import * as settings from './settings.js';
 
 vi.mock('./settings.js', () => ({
   loadEnvironment: vi.fn(),
   loadSettings: vi.fn().mockReturnValue({
-    merged: vi.fn().mockReturnValue({}),
+    merged: {},
   }),
 }));
 
 describe('validateAuthMethod', () => {
   beforeEach(() => {
     vi.resetModules();
+    // Reset mock to default
+    vi.mocked(settings.loadSettings).mockReturnValue({
+      merged: {},
+    } as ReturnType<typeof settings.loadSettings>);
   });
 
   afterEach(() => {
     vi.unstubAllEnvs();
+    delete process.env['OPENAI_API_KEY'];
+    delete process.env['CUSTOM_API_KEY'];
+    delete process.env['GEMINI_API_KEY'];
+    delete process.env['GEMINI_API_KEY_ALTERED'];
+    delete process.env['ANTHROPIC_API_KEY'];
+    delete process.env['ANTHROPIC_BASE_URL'];
+    delete process.env['GOOGLE_API_KEY'];
   });
 
-  it('should return null for USE_OPENAI', () => {
+  it('should return null for USE_OPENAI with default env key', () => {
     process.env['OPENAI_API_KEY'] = 'fake-key';
     expect(validateAuthMethod(AuthType.USE_OPENAI)).toBeNull();
   });
 
-  it('should return an error message for USE_OPENAI if OPENAI_API_KEY is not set', () => {
+  it('should return an error message for USE_OPENAI if no API key is available', () => {
-    delete process.env['OPENAI_API_KEY'];
     expect(validateAuthMethod(AuthType.USE_OPENAI)).toBe(
-      "Missing API key for OpenAI-compatible auth. Set settings.security.auth.apiKey, or set the 'OPENAI_API_KEY' environment variable. If you configured a model in settings.modelProviders with an envKey, set that env var as well.",
+      "Missing API key for OpenAI-compatible auth. Set settings.security.auth.apiKey, or set the 'OPENAI_API_KEY' environment variable.",
     );
   });
 
+  it('should return null for USE_OPENAI with custom envKey from modelProviders', () => {
+    vi.mocked(settings.loadSettings).mockReturnValue({
+      merged: {
+        model: { name: 'custom-model' },
+        modelProviders: {
+          openai: [{ id: 'custom-model', envKey: 'CUSTOM_API_KEY' }],
+        },
+      },
+    } as unknown as ReturnType<typeof settings.loadSettings>);
+    process.env['CUSTOM_API_KEY'] = 'custom-key';
+
+    expect(validateAuthMethod(AuthType.USE_OPENAI)).toBeNull();
+  });
+
+  it('should return error with custom envKey hint when modelProviders envKey is set but env var is missing', () => {
+    vi.mocked(settings.loadSettings).mockReturnValue({
+      merged: {
+        model: { name: 'custom-model' },
+        modelProviders: {
+          openai: [{ id: 'custom-model', envKey: 'CUSTOM_API_KEY' }],
+        },
+      },
+    } as unknown as ReturnType<typeof settings.loadSettings>);
+
+    const result = validateAuthMethod(AuthType.USE_OPENAI);
+    expect(result).toContain('CUSTOM_API_KEY');
+  });
+
+  it('should return null for USE_GEMINI with custom envKey', () => {
+    vi.mocked(settings.loadSettings).mockReturnValue({
+      merged: {
+        model: { name: 'gemini-1.5-flash' },
+        modelProviders: {
+          gemini: [
+            { id: 'gemini-1.5-flash', envKey: 'GEMINI_API_KEY_ALTERED' },
+          ],
+        },
+      },
+    } as unknown as ReturnType<typeof settings.loadSettings>);
+    process.env['GEMINI_API_KEY_ALTERED'] = 'altered-key';
+
+    expect(validateAuthMethod(AuthType.USE_GEMINI)).toBeNull();
+  });
+
+  it('should return error with custom envKey for USE_GEMINI when env var is missing', () => {
+    vi.mocked(settings.loadSettings).mockReturnValue({
+      merged: {
+        model: { name: 'gemini-1.5-flash' },
+        modelProviders: {
+          gemini: [
+            { id: 'gemini-1.5-flash', envKey: 'GEMINI_API_KEY_ALTERED' },
+          ],
+        },
+      },
+    } as unknown as ReturnType<typeof settings.loadSettings>);
+
+    const result = validateAuthMethod(AuthType.USE_GEMINI);
+    expect(result).toContain('GEMINI_API_KEY_ALTERED');
+  });
+
   it('should return null for QWEN_OAUTH', () => {
     expect(validateAuthMethod(AuthType.QWEN_OAUTH)).toBeNull();
   });
@@ -45,4 +116,55 @@ describe('validateAuthMethod', () => {
       'Invalid auth method selected.',
     );
   });
+
+  it('should return null for USE_ANTHROPIC with custom envKey and baseUrl', () => {
+    vi.mocked(settings.loadSettings).mockReturnValue({
+      merged: {
+        model: { name: 'claude-3' },
+        modelProviders: {
+          anthropic: [
+            {
+              id: 'claude-3',
+              envKey: 'CUSTOM_ANTHROPIC_KEY',
+              baseUrl: 'https://api.anthropic.com',
+            },
+          ],
+        },
+      },
+    } as unknown as ReturnType<typeof settings.loadSettings>);
+    process.env['CUSTOM_ANTHROPIC_KEY'] = 'custom-anthropic-key';
+
+    expect(validateAuthMethod(AuthType.USE_ANTHROPIC)).toBeNull();
+  });
+
+  it('should return error for USE_ANTHROPIC when baseUrl is missing', () => {
+    vi.mocked(settings.loadSettings).mockReturnValue({
+      merged: {
+        model: { name: 'claude-3' },
+        modelProviders: {
+          anthropic: [{ id: 'claude-3', envKey: 'CUSTOM_ANTHROPIC_KEY' }],
+        },
+      },
+    } as unknown as ReturnType<typeof settings.loadSettings>);
+    process.env['CUSTOM_ANTHROPIC_KEY'] = 'custom-key';
+
+    const result = validateAuthMethod(AuthType.USE_ANTHROPIC);
+    expect(result).toContain('ANTHROPIC_BASE_URL');
+  });
+
+  it('should return null for USE_VERTEX_AI with custom envKey', () => {
+    vi.mocked(settings.loadSettings).mockReturnValue({
+      merged: {
+        model: { name: 'vertex-model' },
+        modelProviders: {
+          'vertex-ai': [
+            { id: 'vertex-model', envKey: 'GOOGLE_API_KEY_VERTEX' },
+          ],
+        },
+      },
+    } as unknown as ReturnType<typeof settings.loadSettings>);
+    process.env['GOOGLE_API_KEY_VERTEX'] = 'vertex-key';
+
+    expect(validateAuthMethod(AuthType.USE_VERTEX_AI)).toBeNull();
+  });
 });

packages/cli/src/config/auth.ts

@@ -1,24 +1,97 @@
 /**
  * @license
- * Copyright 2025 Google LLC
+ * Copyright 2025 Qwen Team
  * SPDX-License-Identifier: Apache-2.0
  */
 
 import { AuthType } from '@qwen-code/qwen-code-core';
-import { loadEnvironment, loadSettings } from './settings.js';
+import type {
+  ModelProvidersConfig,
+  ProviderModelConfig,
+} from '@qwen-code/qwen-code-core';
+import { loadEnvironment, loadSettings, type Settings } from './settings.js';
+
+/**
+ * Default environment variable names for each auth type
+ */
+const DEFAULT_ENV_KEYS: Record<string, string> = {
+  [AuthType.USE_OPENAI]: 'OPENAI_API_KEY',
+  [AuthType.USE_ANTHROPIC]: 'ANTHROPIC_API_KEY',
+  [AuthType.USE_GEMINI]: 'GEMINI_API_KEY',
+  [AuthType.USE_VERTEX_AI]: 'GOOGLE_API_KEY',
+};
+
+/**
+ * Find model configuration from modelProviders by authType and modelId
+ */
+function findModelConfig(
+  modelProviders: ModelProvidersConfig | undefined,
+  authType: string,
+  modelId: string | undefined,
+): ProviderModelConfig | undefined {
+  if (!modelProviders || !modelId) {
+    return undefined;
+  }
+
+  const models = modelProviders[authType];
+  if (!Array.isArray(models)) {
+    return undefined;
+  }
+
+  return models.find((m) => m.id === modelId);
+}
+
+/**
+ * Check if API key is available for the given auth type and model configuration.
+ * Prioritizes custom envKey from modelProviders over default environment variables.
+ */
+function hasApiKeyForAuth(
+  authType: string,
+  settings: Settings,
+): { hasKey: boolean; checkedEnvKey: string | undefined } {
+  const modelProviders = settings.modelProviders as
+    | ModelProvidersConfig
+    | undefined;
+  const modelId = settings.model?.name;
+
+  // Try to find model-specific envKey from modelProviders
+  const modelConfig = findModelConfig(modelProviders, authType, modelId);
+  if (modelConfig?.envKey) {
+    const hasKey = !!process.env[modelConfig.envKey];
+    return { hasKey, checkedEnvKey: modelConfig.envKey };
+  }
+
+  // Fallback to default environment variable
+  const defaultEnvKey = DEFAULT_ENV_KEYS[authType];
+  if (defaultEnvKey) {
+    const hasKey = !!process.env[defaultEnvKey];
+    return { hasKey, checkedEnvKey: defaultEnvKey };
+  }
+
+  // Also check settings.security.auth.apiKey as fallback
+  if (settings.security?.auth?.apiKey) {
+    return { hasKey: true, checkedEnvKey: undefined };
+  }
+
+  return { hasKey: false, checkedEnvKey: undefined };
+}
 
 export function validateAuthMethod(authMethod: string): string | null {
   const settings = loadSettings();
   loadEnvironment(settings.merged);
 
   if (authMethod === AuthType.USE_OPENAI) {
-    const hasApiKey =
+    const { hasKey, checkedEnvKey } = hasApiKeyForAuth(
-      process.env['OPENAI_API_KEY'] || settings.merged.security?.auth?.apiKey;
+      authMethod,
-    if (!hasApiKey) {
+      settings.merged,
+    );
+    if (!hasKey) {
+      const envKeyHint = checkedEnvKey
+        ? `'${checkedEnvKey}'`
+        : "'OPENAI_API_KEY' (or configure modelProviders[].envKey)";
       return (
         'Missing API key for OpenAI-compatible auth. ' +
-        "Set settings.security.auth.apiKey, or set the 'OPENAI_API_KEY' environment variable. " +
+        `Set settings.security.auth.apiKey, or set the ${envKeyHint} environment variable.`
-        'If you configured a model in settings.modelProviders with an envKey, set that env var as well.'
       );
     }
     return null;
@@ -31,31 +104,50 @@ export function validateAuthMethod(authMethod: string): string | null {
   }
 
   if (authMethod === AuthType.USE_ANTHROPIC) {
-    const hasApiKey = process.env['ANTHROPIC_API_KEY'];
+    const { hasKey, checkedEnvKey } = hasApiKeyForAuth(
-    if (!hasApiKey) {
+      authMethod,
-      return 'ANTHROPIC_API_KEY environment variable not found.';
+      settings.merged,
+    );
+    if (!hasKey) {
+      const envKeyHint = checkedEnvKey || 'ANTHROPIC_API_KEY';
+      return `${envKeyHint} environment variable not found.`;
     }
 
-    const hasBaseUrl = process.env['ANTHROPIC_BASE_URL'];
+    // Check baseUrl - can come from modelProviders or environment
+    const modelProviders = settings.merged.modelProviders as
+      | ModelProvidersConfig
+      | undefined;
+    const modelId = settings.merged.model?.name;
+    const modelConfig = findModelConfig(modelProviders, authMethod, modelId);
+    const hasBaseUrl =
+      modelConfig?.baseUrl || process.env['ANTHROPIC_BASE_URL'];
     if (!hasBaseUrl) {
-      return 'ANTHROPIC_BASE_URL environment variable not found.';
+      return 'ANTHROPIC_BASE_URL environment variable not found (or configure modelProviders[].baseUrl).';
     }
 
     return null;
   }
 
   if (authMethod === AuthType.USE_GEMINI) {
-    const hasApiKey = process.env['GEMINI_API_KEY'];
+    const { hasKey, checkedEnvKey } = hasApiKeyForAuth(
-    if (!hasApiKey) {
+      authMethod,
-      return 'GEMINI_API_KEY environment variable not found. Please set it in your .env file or environment variables.';
+      settings.merged,
+    );
+    if (!hasKey) {
+      const envKeyHint = checkedEnvKey || 'GEMINI_API_KEY';
+      return `${envKeyHint} environment variable not found. Please set it in your .env file or environment variables.`;
     }
     return null;
   }
 
   if (authMethod === AuthType.USE_VERTEX_AI) {
-    const hasApiKey = process.env['GOOGLE_API_KEY'];
+    const { hasKey, checkedEnvKey } = hasApiKeyForAuth(
-    if (!hasApiKey) {
+      authMethod,
-      return 'GOOGLE_API_KEY environment variable not found. Please set it in your .env file or environment variables.';
+      settings.merged,
+    );
+    if (!hasKey) {
+      const envKeyHint = checkedEnvKey || 'GOOGLE_API_KEY';
+      return `${envKeyHint} environment variable not found. Please set it in your .env file or environment variables.`;
     }
 
     process.env['GOOGLE_GENAI_USE_VERTEXAI'] = 'true';

packages/cli/src/config/config.test.ts

@@ -77,10 +77,8 @@ vi.mock('read-package-up', () => ({
   ),
 }));
 
-vi.mock('@qwen-code/qwen-code-core', async () => {
+vi.mock('@qwen-code/qwen-code-core', async (importOriginal) => {
-  const actualServer = await vi.importActual<typeof ServerConfig>(
+  const actualServer = await importOriginal<typeof ServerConfig>();
-    '@qwen-code/qwen-code-core',
-  );
   return {
     ...actualServer,
     IdeClient: {

packages/cli/src/config/config.ts

@@ -31,10 +31,7 @@ import {
 } from '@qwen-code/qwen-code-core';
 import { extensionsCommand } from '../commands/extensions.js';
 import type { Settings } from './settings.js';
-import {
+import { resolveCliGenerationConfig } from '../utils/modelConfigUtils.js';
-  buildGenerationConfigSources,
-  getModelProvidersConfigFromSettings,
-} from '../utils/modelProviderUtils.js';
 import yargs, { type Argv } from 'yargs';
 import { hideBin } from 'yargs/helpers';
 import * as fs from 'node:fs';
@@ -930,26 +927,21 @@ export async function loadCliConfig(
     (argv.authType as AuthType | undefined) ||
     settings.security?.auth?.selectedType;
 
-  const apiKey =
+  // Unified resolution of generation config with source attribution
-    (selectedAuthType === AuthType.USE_OPENAI
+  const resolvedCliConfig = resolveCliGenerationConfig({
-      ? argv.openaiApiKey ||
+    argv: {
-        process.env['OPENAI_API_KEY'] ||
+      model: argv.model,
-        settings.security?.auth?.apiKey
+      openaiApiKey: argv.openaiApiKey,
-      : '') || '';
+      openaiBaseUrl: argv.openaiBaseUrl,
-  const baseUrl =
+      openaiLogging: argv.openaiLogging,
-    (selectedAuthType === AuthType.USE_OPENAI
+      openaiLoggingDir: argv.openaiLoggingDir,
-      ? argv.openaiBaseUrl ||
+    },
-        process.env['OPENAI_BASE_URL'] ||
+    settings,
-        settings.security?.auth?.baseUrl
+    selectedAuthType,
-      : '') || '';
+    env: process.env as Record<string, string | undefined>,
-  const resolvedModel =
+  });
-    argv.model ||
+
-    (selectedAuthType === AuthType.USE_OPENAI
+  const { model: resolvedModel } = resolvedCliConfig;
-      ? process.env['OPENAI_MODEL'] ||
-        process.env['QWEN_MODEL'] ||
-        settings.model?.name
-      : '') ||
-    '';
 
   const sandboxConfig = await loadSandboxConfig(settings, argv);
   const screenReader =
@@ -983,17 +975,7 @@ export async function loadCliConfig(
     }
   }
 
-  const modelProvidersConfig = getModelProvidersConfigFromSettings(settings);
+  const modelProvidersConfig = settings.modelProviders;
-  const generationConfigSources = buildGenerationConfigSources({
-    argv: {
-      model: argv.model,
-      openaiApiKey: argv.openaiApiKey,
-      openaiBaseUrl: argv.openaiBaseUrl,
-    },
-    settings,
-    selectedAuthType,
-    env: process.env as Record<string, string | undefined>,
-  });
 
   return new Config({
     sessionId,
@@ -1053,25 +1035,10 @@ export async function loadCliConfig(
     outputFormat,
     includePartialMessages,
     modelProvidersConfig,
-    generationConfigSources,
+    generationConfigSources: resolvedCliConfig.sources,
-    generationConfig: {
+    generationConfig: resolvedCliConfig.generationConfig,
-      ...(settings.model?.generationConfig || {}),
-      model: resolvedModel,
-      apiKey,
-      baseUrl,
-      enableOpenAILogging:
-        (typeof argv.openaiLogging === 'undefined'
-          ? settings.model?.enableOpenAILogging
-          : argv.openaiLogging) ?? false,
-      openAILoggingDir:
-        argv.openaiLoggingDir || settings.model?.openAILoggingDir,
-    },
     cliVersion: await getCliVersion(),
-    webSearch: buildWebSearchConfig(
+    webSearch: buildWebSearchConfig(argv, settings, selectedAuthType),
-      argv,
-      settings,
-      settings.security?.auth?.selectedType,
-    ),
     summarizeToolOutput: settings.model?.summarizeToolOutput,
     ideMode,
     chatCompression: settings.model?.chatCompression,

packages/cli/src/config/modelProvidersScope.test.ts

@@ -0,0 +1,89 @@
+/**
+ * @license
+ * Copyright 2025 Qwen Team
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, expect, it } from 'vitest';
+import { SettingScope } from './settings.js';
+import { getPersistScopeForModelSelection } from './modelProvidersScope.js';
+
+function makeSettings({
+  isTrusted,
+  userModelProviders,
+  workspaceModelProviders,
+}: {
+  isTrusted: boolean;
+  userModelProviders?: unknown;
+  workspaceModelProviders?: unknown;
+}) {
+  const userSettings: Record<string, unknown> = {};
+  const workspaceSettings: Record<string, unknown> = {};
+
+  // When undefined, treat as "not present in this scope" (the key is omitted),
+  // matching how LoadedSettings is shaped when a settings file doesn't define it.
+  if (userModelProviders !== undefined) {
+    userSettings['modelProviders'] = userModelProviders;
+  }
+  if (workspaceModelProviders !== undefined) {
+    workspaceSettings['modelProviders'] = workspaceModelProviders;
+  }
+
+  return {
+    isTrusted,
+    user: { settings: userSettings },
+    workspace: { settings: workspaceSettings },
+  } as unknown as import('./settings.js').LoadedSettings;
+}
+
+describe('getPersistScopeForModelSelection', () => {
+  it('prefers workspace when trusted and workspace defines modelProviders', () => {
+    const settings = makeSettings({
+      isTrusted: true,
+      workspaceModelProviders: {},
+      userModelProviders: { anything: true },
+    });
+
+    expect(getPersistScopeForModelSelection(settings)).toBe(
+      SettingScope.Workspace,
+    );
+  });
+
+  it('falls back to user when workspace does not define modelProviders', () => {
+    const settings = makeSettings({
+      isTrusted: true,
+      workspaceModelProviders: undefined,
+      userModelProviders: {},
+    });
+
+    expect(getPersistScopeForModelSelection(settings)).toBe(SettingScope.User);
+  });
+
+  it('ignores workspace modelProviders when workspace is untrusted', () => {
+    const settings = makeSettings({
+      isTrusted: false,
+      workspaceModelProviders: {},
+      userModelProviders: undefined,
+    });
+
+    expect(getPersistScopeForModelSelection(settings)).toBe(SettingScope.User);
+  });
+
+  it('falls back to legacy trust heuristic when neither scope defines modelProviders', () => {
+    const trusted = makeSettings({
+      isTrusted: true,
+      userModelProviders: undefined,
+      workspaceModelProviders: undefined,
+    });
+    expect(getPersistScopeForModelSelection(trusted)).toBe(
+      SettingScope.Workspace,
+    );
+
+    const untrusted = makeSettings({
+      isTrusted: false,
+      userModelProviders: undefined,
+      workspaceModelProviders: undefined,
+    });
+    expect(getPersistScopeForModelSelection(untrusted)).toBe(SettingScope.User);
+  });
+});

packages/cli/src/config/modelProvidersScope.ts

@@ -0,0 +1,48 @@
+/**
+ * @license
+ * Copyright 2025 Qwen Team
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { SettingScope, type LoadedSettings } from './settings.js';
+
+function hasOwnModelProviders(settingsObj: unknown): boolean {
+  if (!settingsObj || typeof settingsObj !== 'object') {
+    return false;
+  }
+  const obj = settingsObj as Record<string, unknown>;
+  // Treat an explicitly configured empty object (modelProviders: {}) as "owned"
+  // by this scope, which is important when mergeStrategy is REPLACE.
+  return Object.prototype.hasOwnProperty.call(obj, 'modelProviders');
+}
+
+/**
+ * Returns which writable scope (Workspace/User) owns the effective modelProviders
+ * configuration.
+ *
+ * Note: Workspace scope is only considered when the workspace is trusted.
+ */
+export function getModelProvidersOwnerScope(
+  settings: LoadedSettings,
+): SettingScope | undefined {
+  if (settings.isTrusted && hasOwnModelProviders(settings.workspace.settings)) {
+    return SettingScope.Workspace;
+  }
+
+  if (hasOwnModelProviders(settings.user.settings)) {
+    return SettingScope.User;
+  }
+
+  return undefined;
+}
+
+/**
+ * Choose the settings scope to persist a model selection.
+ * Prefer persisting back to the scope that contains the effective modelProviders
+ * config, otherwise fall back to the legacy trust-based heuristic.
+ */
+export function getPersistScopeForModelSelection(
+  settings: LoadedSettings,
+): SettingScope {
+  return getModelProvidersOwnerScope(settings) ?? SettingScope.User;
+}

packages/cli/src/config/settingsSchema.ts

@@ -113,7 +113,7 @@ const SETTINGS_SCHEMA = {
     description:
       'Model providers configuration grouped by authType. Each authType contains an array of model configurations.',
     showInDialog: false,
-    mergeStrategy: MergeStrategy.SHALLOW_MERGE,
+    mergeStrategy: MergeStrategy.REPLACE,
   },
 
   general: {

packages/cli/src/core/initializer.ts

@@ -45,7 +45,9 @@ export async function initializeApp(
   // Auto-detect and set LLM output language on first use
   initializeLlmOutputLanguage();
 
-  const authType = settings.merged.security?.auth?.selectedType;
+  // Use authType from modelsConfig which respects CLI --auth-type argument
+  // over settings.security.auth.selectedType
+  const authType = config.modelsConfig.getCurrentAuthType();
   const authError = await performInitialAuth(config, authType);
 
   // Fallback to user select when initial authentication fails
@@ -58,8 +60,13 @@ export async function initializeApp(
   }
   const themeError = validateTheme(settings);
 
+  // Open auth dialog if:
+  // 1. No authType was explicitly selected (neither from CLI --auth-type nor settings), OR
+  // 2. Authentication failed
+  // wasAuthTypeExplicitlyProvided() returns true if CLI or settings specified authType,
+  // false if using the default QWEN_OAUTH
   const shouldOpenAuthDialog =
-    settings.merged.security?.auth?.selectedType === undefined || !!authError;
+    !config.modelsConfig.wasAuthTypeExplicitlyProvided() || !!authError;
 
   if (config.getIdeMode()) {
     const ideClient = await IdeClient.getInstance();

packages/cli/src/ui/AppContainer.tsx

@@ -32,7 +32,6 @@ import {
   type Config,
   type IdeInfo,
   type IdeContext,
-  DEFAULT_GEMINI_FLASH_MODEL,
   IdeClient,
   ideContextStore,
   getErrorMessage,
@@ -180,15 +179,10 @@ export const AppContainer = (props: AppContainerProps) => {
     [],
   );
 
-  // Helper to determine the effective model, considering the fallback state.
+  // Helper to determine the current model (polled, since Config has no model-change event).
-  const getEffectiveModel = useCallback(() => {
+  const getCurrentModel = useCallback(() => config.getModel(), [config]);
-    if (config.isInFallbackMode()) {
-      return DEFAULT_GEMINI_FLASH_MODEL;
-    }
-    return config.getModel();
-  }, [config]);
 
-  const [currentModel, setCurrentModel] = useState(getEffectiveModel());
+  const [currentModel, setCurrentModel] = useState(getCurrentModel());
 
   const [isConfigInitialized, setConfigInitialized] = useState(false);
 
@@ -241,12 +235,12 @@ export const AppContainer = (props: AppContainerProps) => {
     [historyManager.addItem],
   );
 
-  // Watch for model changes (e.g., from Flash fallback)
+  // Watch for model changes (e.g., user switches model via /model)
   useEffect(() => {
     const checkModelChange = () => {
-      const effectiveModel = getEffectiveModel();
+      const model = getCurrentModel();
-      if (effectiveModel !== currentModel) {
+      if (model !== currentModel) {
-        setCurrentModel(effectiveModel);
+        setCurrentModel(model);
       }
     };
 
@@ -254,7 +248,7 @@ export const AppContainer = (props: AppContainerProps) => {
     const interval = setInterval(checkModelChange, 1000); // Check every second
 
     return () => clearInterval(interval);
-  }, [config, currentModel, getEffectiveModel]);
+  }, [config, currentModel, getCurrentModel]);
 
   const {
     consoleMessages,

packages/cli/src/ui/auth/useAuth.ts

@@ -8,7 +8,6 @@ import type { Config } from '@qwen-code/qwen-code-core';
 import {
   AuthEvent,
   AuthType,
-  clearCachedCredentialFile,
   getErrorMessage,
   logAuth,
 } from '@qwen-code/qwen-code-core';
@@ -109,7 +108,6 @@ export const useAuthCommand = (
           if (credentials?.model != null) {
             settings.setValue(scope, 'model.name', credentials.model);
           }
-          await clearCachedCredentialFile();
         }
       } catch (error) {
         handleAuthFailure(error);

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

@@ -13,12 +13,6 @@ import {
   type ContentGeneratorConfig,
   type Config,
 } from '@qwen-code/qwen-code-core';
-import * as availableModelsModule from '../models/availableModels.js';
-
-// Mock the availableModels module
-vi.mock('../models/availableModels.js', () => ({
-  getAvailableModelsForAuthType: vi.fn(),
-}));
 
 // Helper function to create a mock config
 function createMockConfig(
@@ -31,9 +25,6 @@ function createMockConfig(
 
 describe('modelCommand', () => {
   let mockContext: CommandContext;
-  const mockGetAvailableModelsForAuthType = vi.mocked(
-    availableModelsModule.getAvailableModelsForAuthType,
-  );
 
   beforeEach(() => {
     mockContext = createMockCommandContext();
@@ -87,10 +78,6 @@ describe('modelCommand', () => {
   });
 
   it('should return dialog action for QWEN_OAUTH auth type', async () => {
-    mockGetAvailableModelsForAuthType.mockReturnValue([
-      { id: 'qwen3-coder-plus', label: 'qwen3-coder-plus' },
-    ]);
-
     const mockConfig = createMockConfig({
       model: 'test-model',
       authType: AuthType.QWEN_OAUTH,
@@ -105,11 +92,7 @@ describe('modelCommand', () => {
     });
   });
 
-  it('should return dialog action for USE_OPENAI auth type when model is available', async () => {
+  it('should return dialog action for USE_OPENAI auth type', async () => {
-    mockGetAvailableModelsForAuthType.mockReturnValue([
-      { id: 'gpt-4', label: 'gpt-4' },
-    ]);
-
     const mockConfig = createMockConfig({
       model: 'test-model',
       authType: AuthType.USE_OPENAI,
@@ -124,28 +107,7 @@ describe('modelCommand', () => {
     });
   });
 
-  it('should return error for USE_OPENAI auth type when no model is available', async () => {
+  it('should return dialog action for unsupported auth types', async () => {
-    mockGetAvailableModelsForAuthType.mockReturnValue([]);
-
-    const mockConfig = createMockConfig({
-      model: 'test-model',
-      authType: AuthType.USE_OPENAI,
-    });
-    mockContext.services.config = mockConfig as Config;
-
-    const result = await modelCommand.action!(mockContext, '');
-
-    expect(result).toEqual({
-      type: 'message',
-      messageType: 'error',
-      content:
-        'No models available for the current authentication type (openai).',
-    });
-  });
-
-  it('should return error for unsupported auth types', async () => {
-    mockGetAvailableModelsForAuthType.mockReturnValue([]);
-
     const mockConfig = createMockConfig({
       model: 'test-model',
       authType: 'UNSUPPORTED_AUTH_TYPE' as AuthType,
@@ -155,10 +117,8 @@ describe('modelCommand', () => {
     const result = await modelCommand.action!(mockContext, '');
 
     expect(result).toEqual({
-      type: 'message',
+      type: 'dialog',
-      messageType: 'error',
+      dialog: 'model',
-      content:
-        'No models available for the current authentication type (UNSUPPORTED_AUTH_TYPE).',
     });
   });
 

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

@@ -11,7 +11,6 @@ import type {
   MessageActionReturn,
 } from './types.js';
 import { CommandKind } from './types.js';
-import { getAvailableModelsForAuthType } from '../models/availableModels.js';
 import { t } from '../../i18n/index.js';
 
 export const modelCommand: SlashCommand = {
@@ -52,22 +51,6 @@ export const modelCommand: SlashCommand = {
       };
     }
 
-    const availableModels = getAvailableModelsForAuthType(authType);
-
-    if (availableModels.length === 0) {
-      return {
-        type: 'message',
-        messageType: 'error',
-        content: t(
-          'No models available for the current authentication type ({{authType}}).',
-          {
-            authType,
-          },
-        ),
-      };
-    }
-
-    // Trigger model selection dialog
     return {
       type: 'dialog',
       dialog: 'model',

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

@@ -10,7 +10,11 @@ import { ModelDialog } from './ModelDialog.js';
 import { useKeypress } from '../hooks/useKeypress.js';
 import { DescriptiveRadioButtonSelect } from './shared/DescriptiveRadioButtonSelect.js';
 import { ConfigContext } from '../contexts/ConfigContext.js';
+import { SettingsContext } from '../contexts/SettingsContext.js';
 import type { Config } from '@qwen-code/qwen-code-core';
+import { AuthType } from '@qwen-code/qwen-code-core';
+import type { LoadedSettings } from '../../config/settings.js';
+import { SettingScope } from '../../config/settings.js';
 import {
   AVAILABLE_MODELS_QWEN,
   MAINLINE_CODER,
@@ -36,18 +40,29 @@ const renderComponent = (
   };
   const combinedProps = { ...defaultProps, ...props };
 
+  const mockSettings = {
+    isTrusted: true,
+    user: { settings: {} },
+    workspace: { settings: {} },
+    setValue: vi.fn(),
+  } as unknown as LoadedSettings;
+
   const mockConfig = contextValue
     ? ({
         // --- Functions used by ModelDialog ---
         getModel: vi.fn(() => MAINLINE_CODER),
-        setModel: vi.fn(),
+        setModel: vi.fn().mockResolvedValue(undefined),
+        switchModel: vi.fn().mockResolvedValue(undefined),
         getAuthType: vi.fn(() => 'qwen-oauth'),
 
         // --- Functions used by ClearcutLogger ---
         getUsageStatisticsEnabled: vi.fn(() => true),
         getSessionId: vi.fn(() => 'mock-session-id'),
         getDebugMode: vi.fn(() => false),
-        getContentGeneratorConfig: vi.fn(() => ({ authType: 'mock' })),
+        getContentGeneratorConfig: vi.fn(() => ({
+          authType: AuthType.QWEN_OAUTH,
+          model: MAINLINE_CODER,
+        })),
         getUseSmartEdit: vi.fn(() => false),
         getUseModelRouter: vi.fn(() => false),
         getProxy: vi.fn(() => undefined),
@@ -58,21 +73,27 @@ const renderComponent = (
     : undefined;
 
   const renderResult = render(
+    <SettingsContext.Provider value={mockSettings}>
       <ConfigContext.Provider value={mockConfig}>
         <ModelDialog {...combinedProps} />
-    </ConfigContext.Provider>,
+      </ConfigContext.Provider>
+    </SettingsContext.Provider>,
   );
 
   return {
     ...renderResult,
     props: combinedProps,
     mockConfig,
+    mockSettings,
   };
 };
 
 describe('<ModelDialog />', () => {
   beforeEach(() => {
     vi.clearAllMocks();
+    // Ensure env-based fallback models don't leak into this suite from the developer environment.
+    delete process.env['OPENAI_MODEL'];
+    delete process.env['ANTHROPIC_MODEL'];
   });
 
   afterEach(() => {
@@ -91,8 +112,12 @@ describe('<ModelDialog />', () => {
 
     const props = mockedSelect.mock.calls[0][0];
     expect(props.items).toHaveLength(AVAILABLE_MODELS_QWEN.length);
-    expect(props.items[0].value).toBe(MAINLINE_CODER);
+    expect(props.items[0].value).toBe(
-    expect(props.items[1].value).toBe(MAINLINE_VLM);
+      `${AuthType.QWEN_OAUTH}::${MAINLINE_CODER}`,
+    );
+    expect(props.items[1].value).toBe(
+      `${AuthType.QWEN_OAUTH}::${MAINLINE_VLM}`,
+    );
     expect(props.showNumbers).toBe(true);
   });
 
@@ -139,16 +164,93 @@ describe('<ModelDialog />', () => {
     expect(mockedSelect).toHaveBeenCalledTimes(1);
   });
 
-  it('calls config.setModel and onClose when DescriptiveRadioButtonSelect.onSelect is triggered', () => {
+  it('calls config.switchModel and onClose when DescriptiveRadioButtonSelect.onSelect is triggered', async () => {
-    const { props, mockConfig } = renderComponent({}, {}); // Pass empty object for contextValue
+    const { props, mockConfig, mockSettings } = renderComponent({}, {}); // Pass empty object for contextValue
 
     const childOnSelect = mockedSelect.mock.calls[0][0].onSelect;
     expect(childOnSelect).toBeDefined();
 
-    childOnSelect(MAINLINE_CODER);
+    await childOnSelect(`${AuthType.QWEN_OAUTH}::${MAINLINE_CODER}`);
 
-    // Assert against the default mock provided by renderComponent
+    expect(mockConfig?.switchModel).toHaveBeenCalledWith(
-    expect(mockConfig?.setModel).toHaveBeenCalledWith(MAINLINE_CODER);
+      AuthType.QWEN_OAUTH,
+      MAINLINE_CODER,
+      undefined,
+      {
+        reason: 'user_manual',
+        context: 'Model switched via /model dialog',
+      },
+    );
+    expect(mockSettings.setValue).toHaveBeenCalledWith(
+      SettingScope.Workspace,
+      'model.name',
+      MAINLINE_CODER,
+    );
+    expect(mockSettings.setValue).toHaveBeenCalledWith(
+      SettingScope.Workspace,
+      'security.auth.selectedType',
+      AuthType.QWEN_OAUTH,
+    );
+    expect(props.onClose).toHaveBeenCalledTimes(1);
+  });
+
+  it('calls config.switchModel and persists authType+model when selecting a different authType', async () => {
+    const switchModel = vi.fn().mockResolvedValue(undefined);
+    const getAuthType = vi.fn(() => AuthType.USE_OPENAI);
+    const getAvailableModelsForAuthType = vi.fn((t: AuthType) => {
+      if (t === AuthType.USE_OPENAI) {
+        return [{ id: 'gpt-4', label: 'GPT-4', authType: t }];
+      }
+      if (t === AuthType.QWEN_OAUTH) {
+        return AVAILABLE_MODELS_QWEN.map((m) => ({
+          id: m.id,
+          label: m.label,
+          authType: AuthType.QWEN_OAUTH,
+        }));
+      }
+      return [];
+    });
+
+    const mockConfigWithSwitchAuthType = {
+      getAuthType,
+      getModel: vi.fn(() => 'gpt-4'),
+      getContentGeneratorConfig: vi.fn(() => ({
+        authType: AuthType.QWEN_OAUTH,
+        model: MAINLINE_CODER,
+      })),
+      // Add switchModel to the mock object (not the type)
+      switchModel,
+      getAvailableModelsForAuthType,
+    };
+
+    const { props, mockSettings } = renderComponent(
+      {},
+      // Cast to Config to bypass type checking, matching the runtime behavior
+      mockConfigWithSwitchAuthType as unknown as Partial<Config>,
+    );
+
+    const childOnSelect = mockedSelect.mock.calls[0][0].onSelect;
+    await childOnSelect(`${AuthType.QWEN_OAUTH}::${MAINLINE_CODER}`);
+
+    expect(switchModel).toHaveBeenCalledWith(
+      AuthType.QWEN_OAUTH,
+      MAINLINE_CODER,
+      { requireCachedCredentials: true },
+      {
+        reason: 'user_manual',
+        context: 'AuthType+model switched via /model dialog',
+      },
+    );
+    expect(mockSettings.setValue).toHaveBeenCalledWith(
+      SettingScope.Workspace,
+      'model.name',
+      MAINLINE_CODER,
+    );
+    expect(mockSettings.setValue).toHaveBeenCalledWith(
+      SettingScope.Workspace,
+      'security.auth.selectedType',
+      AuthType.QWEN_OAUTH,
+    );
     expect(props.onClose).toHaveBeenCalledTimes(1);
   });
 
@@ -193,7 +295,14 @@ describe('<ModelDialog />', () => {
   it('updates initialIndex when config context changes', () => {
     const mockGetModel = vi.fn(() => MAINLINE_CODER);
     const mockGetAuthType = vi.fn(() => 'qwen-oauth');
+    const mockSettings = {
+      isTrusted: true,
+      user: { settings: {} },
+      workspace: { settings: {} },
+      setValue: vi.fn(),
+    } as unknown as LoadedSettings;
     const { rerender } = render(
+      <SettingsContext.Provider value={mockSettings}>
         <ConfigContext.Provider
           value={
             {
@@ -203,7 +312,8 @@ describe('<ModelDialog />', () => {
           }
         >
           <ModelDialog onClose={vi.fn()} />
-      </ConfigContext.Provider>,
+        </ConfigContext.Provider>
+      </SettingsContext.Provider>,
     );
 
     expect(mockedSelect.mock.calls[0][0].initialIndex).toBe(0);
@@ -215,9 +325,11 @@ describe('<ModelDialog />', () => {
     } as unknown as Config;
 
     rerender(
+      <SettingsContext.Provider value={mockSettings}>
         <ConfigContext.Provider value={newMockConfig}>
           <ModelDialog onClose={vi.fn()} />
-      </ConfigContext.Provider>,
+        </ConfigContext.Provider>
+      </SettingsContext.Provider>,
     );
 
     // Should be called at least twice: initial render + re-render after context change

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

@@ -5,52 +5,210 @@
  */
 
 import type React from 'react';
-import { useCallback, useContext, useMemo } from 'react';
+import { useCallback, useContext, useMemo, useState } from 'react';
 import { Box, Text } from 'ink';
 import {
   AuthType,
   ModelSlashCommandEvent,
   logModelSlashCommand,
+  type ContentGeneratorConfig,
+  type ContentGeneratorConfigSource,
+  type ContentGeneratorConfigSources,
 } from '@qwen-code/qwen-code-core';
 import { useKeypress } from '../hooks/useKeypress.js';
 import { theme } from '../semantic-colors.js';
 import { DescriptiveRadioButtonSelect } from './shared/DescriptiveRadioButtonSelect.js';
 import { ConfigContext } from '../contexts/ConfigContext.js';
+import { UIStateContext } from '../contexts/UIStateContext.js';
+import { useSettings } from '../contexts/SettingsContext.js';
 import {
   getAvailableModelsForAuthType,
   MAINLINE_CODER,
 } from '../models/availableModels.js';
+import { getPersistScopeForModelSelection } from '../../config/modelProvidersScope.js';
 import { t } from '../../i18n/index.js';
 
 interface ModelDialogProps {
   onClose: () => void;
 }
 
+function formatSourceBadge(
+  source: ContentGeneratorConfigSource | undefined,
+): string | undefined {
+  if (!source) return undefined;
+
+  switch (source.kind) {
+    case 'cli':
+      return source.detail ? `CLI ${source.detail}` : 'CLI';
+    case 'env':
+      return source.envKey ? `ENV ${source.envKey}` : 'ENV';
+    case 'settings':
+      return source.settingsPath
+        ? `Settings ${source.settingsPath}`
+        : 'Settings';
+    case 'modelProviders': {
+      const suffix =
+        source.authType && source.modelId
+          ? `${source.authType}:${source.modelId}`
+          : source.authType
+            ? `${source.authType}`
+            : source.modelId
+              ? `${source.modelId}`
+              : '';
+      return suffix ? `ModelProviders ${suffix}` : 'ModelProviders';
+    }
+    case 'default':
+      return source.detail ? `Default ${source.detail}` : 'Default';
+    case 'computed':
+      return source.detail ? `Computed ${source.detail}` : 'Computed';
+    case 'programmatic':
+      return source.detail ? `Programmatic ${source.detail}` : 'Programmatic';
+    case 'unknown':
+    default:
+      return undefined;
+  }
+}
+
+function readSourcesFromConfig(config: unknown): ContentGeneratorConfigSources {
+  if (!config) {
+    return {};
+  }
+  const maybe = config as {
+    getContentGeneratorConfigSources?: () => ContentGeneratorConfigSources;
+  };
+  return maybe.getContentGeneratorConfigSources?.() ?? {};
+}
+
+function maskApiKey(apiKey: string | undefined): string {
+  if (!apiKey) return '(not set)';
+  const trimmed = apiKey.trim();
+  if (trimmed.length === 0) return '(not set)';
+  if (trimmed.length <= 6) return '***';
+  const head = trimmed.slice(0, 3);
+  const tail = trimmed.slice(-4);
+  return `${head}…${tail}`;
+}
+
+function persistModelSelection(
+  settings: ReturnType<typeof useSettings>,
+  modelId: string,
+): void {
+  const scope = getPersistScopeForModelSelection(settings);
+  settings.setValue(scope, 'model.name', modelId);
+}
+
+function persistAuthTypeSelection(
+  settings: ReturnType<typeof useSettings>,
+  authType: AuthType,
+): void {
+  const scope = getPersistScopeForModelSelection(settings);
+  settings.setValue(scope, 'security.auth.selectedType', authType);
+}
+
+function ConfigRow({
+  label,
+  value,
+  badge,
+}: {
+  label: string;
+  value: React.ReactNode;
+  badge?: string;
+}): React.JSX.Element {
+  return (
+    <Box flexDirection="column">
+      <Box>
+        <Box minWidth={12} flexShrink={0}>
+          <Text color={theme.text.secondary}>{label}:</Text>
+        </Box>
+        <Box flexGrow={1} flexDirection="row" flexWrap="wrap">
+          <Text>{value}</Text>
+        </Box>
+      </Box>
+      {badge ? (
+        <Box>
+          <Box minWidth={12} flexShrink={0}>
+            <Text> </Text>
+          </Box>
+          <Box flexGrow={1}>
+            <Text color={theme.text.secondary}>{badge}</Text>
+          </Box>
+        </Box>
+      ) : null}
+    </Box>
+  );
+}
+
 export function ModelDialog({ onClose }: ModelDialogProps): React.JSX.Element {
   const config = useContext(ConfigContext);
+  const uiState = useContext(UIStateContext);
+  const settings = useSettings();
+
+  // Local error state for displaying errors within the dialog
+  const [errorMessage, setErrorMessage] = useState<string | null>(null);
 
-  // Get auth type from config, default to QWEN_OAUTH if not available
   const authType = config?.getAuthType() ?? AuthType.QWEN_OAUTH;
+  const effectiveConfig =
+    (config?.getContentGeneratorConfig?.() as
+      | ContentGeneratorConfig
+      | undefined) ?? undefined;
+  const sources = readSourcesFromConfig(config);
 
-  // Get available models based on auth type
+  const availableModelEntries = useMemo(() => {
-  const availableModels = useMemo(
+    const allAuthTypes = Object.values(AuthType) as AuthType[];
-    () => getAvailableModelsForAuthType(authType),
+    const modelsByAuthType = allAuthTypes
-    [authType],
+      .map((t) => ({
+        authType: t,
+        models: getAvailableModelsForAuthType(t, config ?? undefined),
+      }))
+      .filter((x) => x.models.length > 0);
+
+    // Fixed order: qwen-oauth first, then others in a stable order
+    const authTypeOrder: AuthType[] = [
+      AuthType.QWEN_OAUTH,
+      AuthType.USE_OPENAI,
+      AuthType.USE_ANTHROPIC,
+      AuthType.USE_GEMINI,
+      AuthType.USE_VERTEX_AI,
+    ];
+
+    // Filter to only include authTypes that have models
+    const availableAuthTypes = new Set(modelsByAuthType.map((x) => x.authType));
+    const orderedAuthTypes = authTypeOrder.filter((t) =>
+      availableAuthTypes.has(t),
     );
 
+    return orderedAuthTypes.flatMap((t) => {
+      const models =
+        modelsByAuthType.find((x) => x.authType === t)?.models ?? [];
+      return models.map((m) => ({ authType: t, model: m }));
+    });
+  }, [config]);
+
   const MODEL_OPTIONS = useMemo(
     () =>
-      availableModels.map((model) => ({
+      availableModelEntries.map(({ authType: t2, model }) => {
-        value: model.id,
+        const value = `${t2}::${model.id}`;
-        title: model.label,
+        const title = (
-        description: model.description || '',
+          <Text>
-        key: model.id,
+            <Text bold color={theme.text.accent}>
-      })),
+              [{t2}]
-    [availableModels],
+            </Text>
+            <Text>{` ${model.label}`}</Text>
+          </Text>
+        );
+        const description = model.description || '';
+        return {
+          value,
+          title,
+          description,
+          key: value,
+        };
+      }),
+    [availableModelEntries],
   );
 
-  // Determine the Preferred Model (read once when the dialog opens).
+  const preferredModelId = config?.getModel() || MAINLINE_CODER;
-  const preferredModel = config?.getModel() || MAINLINE_CODER;
+  const preferredKey = `${authType}::${preferredModelId}`;
 
   useKeypress(
     (key) => {
@@ -61,25 +219,97 @@ export function ModelDialog({ onClose }: ModelDialogProps): React.JSX.Element {
     { isActive: true },
   );
 
-  // Calculate the initial index based on the preferred model.
   const initialIndex = useMemo(
-    () => MODEL_OPTIONS.findIndex((option) => option.value === preferredModel),
+    () => MODEL_OPTIONS.findIndex((option) => option.value === preferredKey),
-    [MODEL_OPTIONS, preferredModel],
+    [MODEL_OPTIONS, preferredKey],
   );
 
-  // Handle selection internally (Autonomous Dialog).
   const handleSelect = useCallback(
-    (model: string) => {
+    async (selected: string) => {
+      // Clear any previous error
+      setErrorMessage(null);
+
+      const sep = '::';
+      const idx = selected.indexOf(sep);
+      const selectedAuthType = (
+        idx >= 0 ? selected.slice(0, idx) : authType
+      ) as AuthType;
+      const modelId = idx >= 0 ? selected.slice(idx + sep.length) : selected;
+
       if (config) {
-        config.setModel(model);
+        try {
-        const event = new ModelSlashCommandEvent(model);
+          await config.switchModel(
+            selectedAuthType,
+            modelId,
+            selectedAuthType !== authType &&
+              selectedAuthType === AuthType.QWEN_OAUTH
+              ? { requireCachedCredentials: true }
+              : undefined,
+            {
+              reason: 'user_manual',
+              context:
+                selectedAuthType === authType
+                  ? 'Model switched via /model dialog'
+                  : 'AuthType+model switched via /model dialog',
+            },
+          );
+        } catch (e) {
+          const baseErrorMessage = e instanceof Error ? e.message : String(e);
+
+          // Some auth types (notably openai without modelProviders configured) can present
+          // env-based "raw" model IDs in the list. These are not registry-backed and will
+          // fail switchModel(). Fall back to setModel() to keep UX functional.
+          const isNotFound =
+            baseErrorMessage.includes('not found for authType') ||
+            (baseErrorMessage.includes('Model') &&
+              baseErrorMessage.includes('not found'));
+          if (!isNotFound) {
+            setErrorMessage(
+              `Failed to switch model to '${modelId}'.\n\n${baseErrorMessage}`,
+            );
+
+            // Keep the dialog open so the user can choose another model.
+            return;
+          }
+          await config.setModel(modelId, {
+            reason: 'user_manual',
+            context: 'Model set via /model dialog (raw)',
+          });
+        }
+        const event = new ModelSlashCommandEvent(modelId);
         logModelSlashCommand(config, event);
+
+        const after = config.getContentGeneratorConfig?.() as
+          | ContentGeneratorConfig
+          | undefined;
+        const effectiveAuthType =
+          after?.authType ?? selectedAuthType ?? authType;
+        const effectiveModelId = after?.model ?? modelId;
+
+        persistModelSelection(settings, effectiveModelId);
+        persistAuthTypeSelection(settings, effectiveAuthType);
+
+        const baseUrl = after?.baseUrl ?? '(default)';
+        const maskedKey = maskApiKey(after?.apiKey);
+        uiState?.historyManager.addItem(
+          {
+            type: 'info',
+            text:
+              `authType: ${effectiveAuthType}\n` +
+              `Using model: ${effectiveModelId}\n` +
+              `Base URL: ${baseUrl}\n` +
+              `API key: ${maskedKey}`,
+          },
+          Date.now(),
+        );
       }
       onClose();
     },
-    [config, onClose],
+    [authType, config, onClose, settings, uiState, setErrorMessage],
   );
 
+  const hasModels = MODEL_OPTIONS.length > 0;
+
   return (
     <Box
       borderStyle="round"
@@ -89,6 +319,75 @@ export function ModelDialog({ onClose }: ModelDialogProps): React.JSX.Element {
       width="100%"
     >
       <Text bold>{t('Select Model')}</Text>
+
+      <Box marginTop={1} flexDirection="column">
+        <Text color={theme.text.secondary}>
+          {t('Current (effective) configuration')}
+        </Text>
+        <Box flexDirection="column" marginTop={1}>
+          <ConfigRow label="AuthType" value={authType} />
+          <ConfigRow
+            label="Model"
+            value={effectiveConfig?.model ?? config?.getModel?.() ?? ''}
+            badge={formatSourceBadge(sources['model'])}
+          />
+
+          {authType !== AuthType.QWEN_OAUTH && (
+            <>
+              <ConfigRow
+                label="Base URL"
+                value={effectiveConfig?.baseUrl ?? ''}
+                badge={formatSourceBadge(sources['baseUrl'])}
+              />
+              <ConfigRow
+                label="API Key"
+                value={effectiveConfig?.apiKey ? t('(set)') : t('(not set)')}
+                badge={formatSourceBadge(sources['apiKey'])}
+              />
+            </>
+          )}
+
+          {effectiveConfig?.samplingParams ? (
+            <ConfigRow
+              label="Sampling"
+              value={
+                `temperature=${effectiveConfig.samplingParams.temperature ?? t('unset')} ` +
+                `top_p=${effectiveConfig.samplingParams.top_p ?? t('unset')} ` +
+                `max_tokens=${effectiveConfig.samplingParams.max_tokens ?? t('unset')}`
+              }
+              badge={formatSourceBadge(sources['samplingParams'])}
+            />
+          ) : null}
+
+          {effectiveConfig?.timeout !== undefined ? (
+            <ConfigRow
+              label="Timeout"
+              value={String(effectiveConfig.timeout)}
+              badge={formatSourceBadge(sources['timeout'])}
+            />
+          ) : null}
+        </Box>
+      </Box>
+
+      {!hasModels ? (
+        <Box marginTop={1} flexDirection="column">
+          <Text color={theme.status.warning}>
+            {t(
+              'No models available for the current authentication type ({{authType}}).',
+              {
+                authType,
+              },
+            )}
+          </Text>
+          <Box marginTop={1}>
+            <Text color={theme.text.secondary}>
+              {t(
+                'Please configure models in settings.modelProviders or use environment variables.',
+              )}
+            </Text>
+          </Box>
+        </Box>
+      ) : (
         <Box marginTop={1}>
           <DescriptiveRadioButtonSelect
             items={MODEL_OPTIONS}
@@ -97,6 +396,16 @@ export function ModelDialog({ onClose }: ModelDialogProps): React.JSX.Element {
             showNumbers={true}
           />
         </Box>
+      )}
+
+      {errorMessage && (
+        <Box marginTop={1} flexDirection="column" paddingX={1}>
+          <Text color={theme.status.error} wrap="wrap">
+            ✕ {errorMessage}
+          </Text>
+        </Box>
+      )}
+
       <Box marginTop={1} flexDirection="column">
         <Text color={theme.text.secondary}>{t('(Press Esc to close)')}</Text>
       </Box>

packages/cli/src/ui/components/shared/DescriptiveRadioButtonSelect.tsx

@@ -11,7 +11,7 @@ import { BaseSelectionList } from './BaseSelectionList.js';
 import type { SelectionListItem } from '../../hooks/useSelectionList.js';
 
 export interface DescriptiveRadioSelectItem<T> extends SelectionListItem<T> {
-  title: string;
+  title: React.ReactNode;
   description: string;
 }
 

packages/cli/src/ui/hooks/useGeminiStream.ts

@@ -912,7 +912,7 @@ export const useGeminiStream = (
       // Reset quota error flag when starting a new query (not a continuation)
       if (!options?.isContinuation) {
         setModelSwitchedFromQuotaError(false);
-        config.setQuotaErrorOccurred(false);
+        // No quota-error / fallback routing mechanism currently; keep state minimal.
       }
 
       abortControllerRef.current = new AbortController();

packages/cli/src/ui/hooks/useToolScheduler.test.ts

@@ -62,7 +62,7 @@ const mockConfig = {
   getAllowedTools: vi.fn(() => []),
   getContentGeneratorConfig: () => ({
     model: 'test-model',
-    authType: 'gemini-api-key',
+    authType: 'gemini',
   }),
   getUseSmartEdit: () => false,
   getUseModelRouter: () => false,

packages/cli/src/ui/models/availableModels.test.ts

@@ -0,0 +1,205 @@
+/**
+ * @license
+ * Copyright 2025 Qwen Team
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
+import {
+  getAvailableModelsForAuthType,
+  getFilteredQwenModels,
+  getOpenAIAvailableModelFromEnv,
+  isVisionModel,
+  getDefaultVisionModel,
+  AVAILABLE_MODELS_QWEN,
+  MAINLINE_VLM,
+  MAINLINE_CODER,
+} from './availableModels.js';
+import { AuthType, type Config } from '@qwen-code/qwen-code-core';
+
+describe('availableModels', () => {
+  describe('AVAILABLE_MODELS_QWEN', () => {
+    it('should include coder model', () => {
+      const coderModel = AVAILABLE_MODELS_QWEN.find(
+        (m) => m.id === MAINLINE_CODER,
+      );
+      expect(coderModel).toBeDefined();
+      expect(coderModel?.isVision).toBeFalsy();
+    });
+
+    it('should include vision model', () => {
+      const visionModel = AVAILABLE_MODELS_QWEN.find(
+        (m) => m.id === MAINLINE_VLM,
+      );
+      expect(visionModel).toBeDefined();
+      expect(visionModel?.isVision).toBe(true);
+    });
+  });
+
+  describe('getFilteredQwenModels', () => {
+    it('should return all models when vision preview is enabled', () => {
+      const models = getFilteredQwenModels(true);
+      expect(models.length).toBe(AVAILABLE_MODELS_QWEN.length);
+    });
+
+    it('should filter out vision models when preview is disabled', () => {
+      const models = getFilteredQwenModels(false);
+      expect(models.every((m) => !m.isVision)).toBe(true);
+    });
+  });
+
+  describe('getOpenAIAvailableModelFromEnv', () => {
+    const originalEnv = process.env;
+
+    beforeEach(() => {
+      process.env = { ...originalEnv };
+    });
+
+    afterEach(() => {
+      process.env = originalEnv;
+    });
+
+    it('should return null when OPENAI_MODEL is not set', () => {
+      delete process.env['OPENAI_MODEL'];
+      expect(getOpenAIAvailableModelFromEnv()).toBeNull();
+    });
+
+    it('should return model from OPENAI_MODEL env var', () => {
+      process.env['OPENAI_MODEL'] = 'gpt-4-turbo';
+      const model = getOpenAIAvailableModelFromEnv();
+      expect(model?.id).toBe('gpt-4-turbo');
+      expect(model?.label).toBe('gpt-4-turbo');
+    });
+
+    it('should trim whitespace from env var', () => {
+      process.env['OPENAI_MODEL'] = '  gpt-4  ';
+      const model = getOpenAIAvailableModelFromEnv();
+      expect(model?.id).toBe('gpt-4');
+    });
+  });
+
+  describe('getAvailableModelsForAuthType', () => {
+    const originalEnv = process.env;
+
+    beforeEach(() => {
+      process.env = { ...originalEnv };
+    });
+
+    afterEach(() => {
+      process.env = originalEnv;
+    });
+
+    it('should return hard-coded qwen models for qwen-oauth', () => {
+      const models = getAvailableModelsForAuthType(AuthType.QWEN_OAUTH);
+      expect(models).toEqual(AVAILABLE_MODELS_QWEN);
+    });
+
+    it('should return hard-coded qwen models even when config is provided', () => {
+      const mockConfig = {
+        getAvailableModels: vi
+          .fn()
+          .mockReturnValue([
+            { id: 'custom', label: 'Custom', authType: AuthType.QWEN_OAUTH },
+          ]),
+      } as unknown as Config;
+
+      const models = getAvailableModelsForAuthType(
+        AuthType.QWEN_OAUTH,
+        mockConfig,
+      );
+      expect(models).toEqual(AVAILABLE_MODELS_QWEN);
+    });
+
+    it('should use config.getAvailableModels for openai authType when available', () => {
+      const mockModels = [
+        {
+          id: 'gpt-4',
+          label: 'GPT-4',
+          description: 'Test',
+          authType: AuthType.USE_OPENAI,
+          isVision: false,
+        },
+      ];
+      const getAvailableModelsForAuthType = vi.fn().mockReturnValue(mockModels);
+      const mockConfigWithMethod = {
+        // Prefer the newer API when available.
+        getAvailableModelsForAuthType,
+      };
+
+      const models = getAvailableModelsForAuthType(
+        AuthType.USE_OPENAI,
+        mockConfigWithMethod as unknown as Config,
+      );
+
+      expect(getAvailableModelsForAuthType).toHaveBeenCalled();
+      expect(models[0].id).toBe('gpt-4');
+    });
+
+    it('should fallback to env var for openai when config returns empty', () => {
+      process.env['OPENAI_MODEL'] = 'fallback-model';
+      const mockConfig = {
+        getAvailableModelsForAuthType: vi.fn().mockReturnValue([]),
+      } as unknown as Config;
+
+      const models = getAvailableModelsForAuthType(
+        AuthType.USE_OPENAI,
+        mockConfig,
+      );
+
+      expect(models).toEqual([]);
+    });
+
+    it('should fallback to env var for openai when config throws', () => {
+      process.env['OPENAI_MODEL'] = 'fallback-model';
+      const mockConfig = {
+        getAvailableModelsForAuthType: vi.fn().mockImplementation(() => {
+          throw new Error('Registry not initialized');
+        }),
+      } as unknown as Config;
+
+      const models = getAvailableModelsForAuthType(
+        AuthType.USE_OPENAI,
+        mockConfig,
+      );
+
+      expect(models).toEqual([]);
+    });
+
+    it('should return env model for openai without config', () => {
+      process.env['OPENAI_MODEL'] = 'gpt-4-turbo';
+      const models = getAvailableModelsForAuthType(AuthType.USE_OPENAI);
+      expect(models[0].id).toBe('gpt-4-turbo');
+    });
+
+    it('should return empty array for openai without config or env', () => {
+      delete process.env['OPENAI_MODEL'];
+      const models = getAvailableModelsForAuthType(AuthType.USE_OPENAI);
+      expect(models).toEqual([]);
+    });
+
+    it('should return empty array for other auth types', () => {
+      const models = getAvailableModelsForAuthType(AuthType.USE_GEMINI);
+      expect(models).toEqual([]);
+    });
+  });
+
+  describe('isVisionModel', () => {
+    it('should return true for vision model', () => {
+      expect(isVisionModel(MAINLINE_VLM)).toBe(true);
+    });
+
+    it('should return false for non-vision model', () => {
+      expect(isVisionModel(MAINLINE_CODER)).toBe(false);
+    });
+
+    it('should return false for unknown model', () => {
+      expect(isVisionModel('unknown-model')).toBe(false);
+    });
+  });
+
+  describe('getDefaultVisionModel', () => {
+    it('should return the vision model ID', () => {
+      expect(getDefaultVisionModel()).toBe(MAINLINE_VLM);
+    });
+  });
+});

packages/cli/src/ui/models/availableModels.ts

@@ -4,7 +4,12 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-import { AuthType, DEFAULT_QWEN_MODEL } from '@qwen-code/qwen-code-core';
+import {
+  AuthType,
+  DEFAULT_QWEN_MODEL,
+  type Config,
+  type AvailableModel as CoreAvailableModel,
+} from '@qwen-code/qwen-code-core';
 import { t } from '../../i18n/index.js';
 
 export type AvailableModel = {
@@ -57,20 +62,78 @@ export function getFilteredQwenModels(
  */
 export function getOpenAIAvailableModelFromEnv(): AvailableModel | null {
   const id = process.env['OPENAI_MODEL']?.trim();
-  return id ? { id, label: id } : null;
+  return id
+    ? {
+        id,
+        label: id,
+        get description() {
+          return t('Configured via OPENAI_MODEL environment variable');
+        },
+      }
+    : null;
 }
 
 export function getAnthropicAvailableModelFromEnv(): AvailableModel | null {
   const id = process.env['ANTHROPIC_MODEL']?.trim();
-  return id ? { id, label: id } : null;
+  return id
+    ? {
+        id,
+        label: id,
+        get description() {
+          return t('Configured via ANTHROPIC_MODEL environment variable');
+        },
+      }
+    : null;
 }
 
+/**
+ * Convert core AvailableModel to CLI AvailableModel format
+ */
+function convertCoreModelToCliModel(
+  coreModel: CoreAvailableModel,
+): AvailableModel {
+  return {
+    id: coreModel.id,
+    label: coreModel.label,
+    description: coreModel.description,
+    isVision: coreModel.isVision ?? coreModel.capabilities?.vision ?? false,
+  };
+}
+
+/**
+ * Get available models for the given authType.
+ *
+ * If a Config object is provided, uses config.getAvailableModelsForAuthType().
+ * For qwen-oauth, always returns the hard-coded models.
+ * Falls back to environment variables only when no config is provided.
+ */
 export function getAvailableModelsForAuthType(
   authType: AuthType,
+  config?: Config,
 ): AvailableModel[] {
-  switch (authType) {
+  // For qwen-oauth, always use hard-coded models, this aligns with the API gateway.
-    case AuthType.QWEN_OAUTH:
+  if (authType === AuthType.QWEN_OAUTH) {
     return AVAILABLE_MODELS_QWEN;
+  }
+
+  // Use config's model registry when available
+  if (config) {
+    try {
+      const models = config.getAvailableModelsForAuthType(authType);
+      if (models.length > 0) {
+        return models.map(convertCoreModelToCliModel);
+      }
+    } catch {
+      // If config throws (e.g., not initialized), return empty array
+    }
+    // When a Config object is provided, we intentionally do NOT fall back to env-based
+    // "raw" models. These may reflect the currently effective config but should not be
+    // presented as selectable options in /model.
+    return [];
+  }
+
+  // Fall back to environment variables for specific auth types (no config provided)
+  switch (authType) {
     case AuthType.USE_OPENAI: {
       const openAIModel = getOpenAIAvailableModelFromEnv();
       return openAIModel ? [openAIModel] : [];
@@ -80,13 +143,10 @@ export function getAvailableModelsForAuthType(
       return anthropicModel ? [anthropicModel] : [];
     }
     default:
-      // For other auth types, return empty array for now
-      // This can be expanded later according to the design doc
       return [];
   }
 }
 
-/**
 /**
  * Hard code the default vision model as a string literal,
  * until our coding model supports multimodal.

packages/cli/src/utils/modelConfigUtils.ts

@@ -0,0 +1,112 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import {
+  AuthType,
+  type ContentGeneratorConfig,
+  type ContentGeneratorConfigSources,
+  resolveModelConfig,
+  type ModelConfigSourcesInput,
+} from '@qwen-code/qwen-code-core';
+import type { Settings } from '../config/settings.js';
+
+export interface CliGenerationConfigInputs {
+  argv: {
+    model?: string | undefined;
+    openaiApiKey?: string | undefined;
+    openaiBaseUrl?: string | undefined;
+    openaiLogging?: boolean | undefined;
+    openaiLoggingDir?: string | undefined;
+  };
+  settings: Settings;
+  selectedAuthType: AuthType | undefined;
+  /**
+   * Injectable env for testability. Defaults to process.env at callsites.
+   */
+  env?: Record<string, string | undefined>;
+}
+
+export interface ResolvedCliGenerationConfig {
+  /** The resolved model id (may be empty string if not resolvable at CLI layer) */
+  model: string;
+  /** API key for OpenAI-compatible auth */
+  apiKey: string;
+  /** Base URL for OpenAI-compatible auth */
+  baseUrl: string;
+  /** The full generation config to pass to core Config */
+  generationConfig: Partial<ContentGeneratorConfig>;
+  /** Source attribution for each resolved field */
+  sources: ContentGeneratorConfigSources;
+}
+
+/**
+ * Unified resolver for CLI generation config.
+ *
+ * Precedence (for OpenAI auth):
+ * - model: argv.model > OPENAI_MODEL > QWEN_MODEL > settings.model.name
+ * - apiKey: argv.openaiApiKey > OPENAI_API_KEY > settings.security.auth.apiKey
+ * - baseUrl: argv.openaiBaseUrl > OPENAI_BASE_URL > settings.security.auth.baseUrl
+ *
+ * For non-OpenAI auth, only argv.model override is respected at CLI layer.
+ */
+export function resolveCliGenerationConfig(
+  inputs: CliGenerationConfigInputs,
+): ResolvedCliGenerationConfig {
+  const { argv, settings, selectedAuthType } = inputs;
+  const env = inputs.env ?? (process.env as Record<string, string | undefined>);
+
+  const authType = selectedAuthType ?? AuthType.QWEN_OAUTH;
+
+  const configSources: ModelConfigSourcesInput = {
+    authType,
+    cli: {
+      model: argv.model,
+      apiKey: argv.openaiApiKey,
+      baseUrl: argv.openaiBaseUrl,
+    },
+    settings: {
+      model: settings.model?.name,
+      apiKey: settings.security?.auth?.apiKey,
+      baseUrl: settings.security?.auth?.baseUrl,
+      generationConfig: settings.model?.generationConfig as
+        | Partial<ContentGeneratorConfig>
+        | undefined,
+    },
+    env,
+  };
+
+  const resolved = resolveModelConfig(configSources);
+
+  // Log warnings if any
+  for (const warning of resolved.warnings) {
+    console.warn(`[modelProviderUtils] ${warning}`);
+  }
+
+  // Resolve OpenAI logging config (CLI-specific, not part of core resolver)
+  const enableOpenAILogging =
+    (typeof argv.openaiLogging === 'undefined'
+      ? settings.model?.enableOpenAILogging
+      : argv.openaiLogging) ?? false;
+
+  const openAILoggingDir =
+    argv.openaiLoggingDir || settings.model?.openAILoggingDir;
+
+  // Build the full generation config
+  // Note: we merge the resolved config with logging settings
+  const generationConfig: Partial<ContentGeneratorConfig> = {
+    ...resolved.config,
+    enableOpenAILogging,
+    openAILoggingDir,
+  };
+
+  return {
+    model: resolved.config.model || '',
+    apiKey: resolved.config.apiKey || '',
+    baseUrl: resolved.config.baseUrl || '',
+    generationConfig,
+    sources: resolved.sources,
+  };
+}

packages/cli/src/utils/modelProviderUtils.ts

@@ -1,142 +0,0 @@
-/**
- * @license
- * Copyright 2025 Google LLC
- * SPDX-License-Identifier: Apache-2.0
- */
-
-import {
-  AuthType,
-  type ContentGeneratorConfig,
-  type ContentGeneratorConfigSource,
-  type ContentGeneratorConfigSources,
-  type ModelProvidersConfig,
-  type ProviderModelConfig as ModelConfig,
-} from '@qwen-code/qwen-code-core';
-import type { Settings } from '../config/settings.js';
-
-export interface GenerationConfigSourceInputs {
-  argv: {
-    model?: string | undefined;
-    openaiApiKey?: string | undefined;
-    openaiBaseUrl?: string | undefined;
-  };
-  settings: Settings;
-  selectedAuthType: AuthType | undefined;
-  /**
-   * Injectable env for testability. Defaults to process.env at callsites.
-   */
-  env?: Record<string, string | undefined>;
-}
-
-/**
- * Get models configuration from settings, grouped by authType.
- * Returns the models config from the merged settings without mutating files.
- */
-export function getModelProvidersConfigFromSettings(
-  settings: Settings,
-): ModelProvidersConfig {
-  return (settings.modelProviders as ModelProvidersConfig) || {};
-}
-
-/**
- * Get models for a specific authType from settings.
- */
-export function getModelsForAuthType(
-  settings: Settings,
-  authType: AuthType,
-): ModelConfig[] {
-  const modelProvidersConfig = getModelProvidersConfigFromSettings(settings);
-  return modelProvidersConfig[authType] || [];
-}
-
-/**
- * Best-effort attribution for the seed generationConfig fields.
- *
- * NOTE:
- * - This does not attempt to distinguish user vs workspace settings; it reflects merged settings.
- * - This should stay consistent with the actual precedence used to compute the corresponding values.
- */
-export function buildGenerationConfigSources(
-  inputs: GenerationConfigSourceInputs,
-): ContentGeneratorConfigSources {
-  const { argv, settings, selectedAuthType } = inputs;
-  const env = inputs.env ?? (process.env as Record<string, string | undefined>);
-
-  const sources: ContentGeneratorConfigSources = {};
-
-  const setSource = (path: string, source: ContentGeneratorConfigSource) => {
-    sources[path] = source;
-  };
-
-  // Model/apiKey/baseUrl attribution mirrors current CLI precedence:
-  // - model: argv.model > (OPENAI_MODEL|QWEN_MODEL|settings.model.name) only for OpenAI auth
-  // - apiKey/baseUrl: only meaningful for OpenAI auth in current CLI wiring
-  if (selectedAuthType === AuthType.USE_OPENAI) {
-    if (argv.model) {
-      setSource('model', { kind: 'cli', detail: '--model' });
-    } else if (env['OPENAI_MODEL']) {
-      setSource('model', { kind: 'env', envKey: 'OPENAI_MODEL' });
-    } else if (env['QWEN_MODEL']) {
-      setSource('model', { kind: 'env', envKey: 'QWEN_MODEL' });
-    } else if (settings.model?.name) {
-      setSource('model', { kind: 'settings', settingsPath: 'model.name' });
-    }
-
-    if (argv.openaiApiKey) {
-      setSource('apiKey', { kind: 'cli', detail: '--openaiApiKey' });
-    } else if (env['OPENAI_API_KEY']) {
-      setSource('apiKey', { kind: 'env', envKey: 'OPENAI_API_KEY' });
-    } else if (settings.security?.auth?.apiKey) {
-      setSource('apiKey', {
-        kind: 'settings',
-        settingsPath: 'security.auth.apiKey',
-      });
-    }
-
-    if (argv.openaiBaseUrl) {
-      setSource('baseUrl', { kind: 'cli', detail: '--openaiBaseUrl' });
-    } else if (env['OPENAI_BASE_URL']) {
-      setSource('baseUrl', { kind: 'env', envKey: 'OPENAI_BASE_URL' });
-    } else if (settings.security?.auth?.baseUrl) {
-      setSource('baseUrl', {
-        kind: 'settings',
-        settingsPath: 'security.auth.baseUrl',
-      });
-    }
-  } else if (argv.model) {
-    // For non-openai auth types, the CLI only wires through an explicit raw model override.
-    setSource('model', { kind: 'cli', detail: '--model' });
-  }
-
-  const mergedGenerationConfig = settings.model?.generationConfig as
-    | Partial<ContentGeneratorConfig>
-    | undefined;
-  if (mergedGenerationConfig) {
-    setSource('generationConfig', {
-      kind: 'settings',
-      settingsPath: 'model.generationConfig',
-    });
-    // We also map the known top-level fields used by core.
-    if (mergedGenerationConfig.samplingParams) {
-      setSource('samplingParams', {
-        kind: 'settings',
-        settingsPath: 'model.generationConfig.samplingParams',
-      });
-    }
-    for (const k of [
-      'timeout',
-      'maxRetries',
-      'disableCacheControl',
-      'schemaCompliance',
-    ] as const) {
-      if (mergedGenerationConfig[k] !== undefined) {
-        setSource(k, {
-          kind: 'settings',
-          settingsPath: `model.generationConfig.${k}`,
-        });
-      }
-    }
-  }
-
-  return sources;
-}

packages/core/index.ts

@@ -8,12 +8,8 @@ export * from './src/index.js';
 export { Storage } from './src/config/storage.js';
 export {
   DEFAULT_QWEN_MODEL,
+  DEFAULT_QWEN_FLASH_MODEL,
   DEFAULT_QWEN_EMBEDDING_MODEL,
-  DEFAULT_GEMINI_MODEL,
-  DEFAULT_GEMINI_MODEL_AUTO,
-  DEFAULT_GEMINI_FLASH_MODEL,
-  DEFAULT_GEMINI_FLASH_LITE_MODEL,
-  DEFAULT_GEMINI_EMBEDDING_MODEL,
 } from './src/config/models.js';
 export {
   serializeTerminalToObject,

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

@@ -15,10 +15,16 @@ import {
   DEFAULT_OTLP_ENDPOINT,
   QwenLogger,
 } from '../telemetry/index.js';
-import type { ContentGeneratorConfig } from '../core/contentGenerator.js';
+import type {
+  ContentGenerator,
+  ContentGeneratorConfig,
+} from '../core/contentGenerator.js';
+import { DEFAULT_DASHSCOPE_BASE_URL } from '../core/openaiContentGenerator/constants.js';
 import {
   AuthType,
+  createContentGenerator,
   createContentGeneratorConfig,
+  resolveContentGeneratorConfigWithSources,
 } from '../core/contentGenerator.js';
 import { GeminiClient } from '../core/client.js';
 import { GitService } from '../services/gitService.js';
@@ -208,6 +214,19 @@ describe('Server Config (config.ts)', () => {
     vi.spyOn(QwenLogger.prototype, 'logStartSessionEvent').mockImplementation(
       async () => undefined,
     );
+
+    // Setup default mock for resolveContentGeneratorConfigWithSources
+    vi.mocked(resolveContentGeneratorConfigWithSources).mockImplementation(
+      (_config, authType, generationConfig) => ({
+        config: {
+          ...generationConfig,
+          authType,
+          model: generationConfig?.model || MODEL,
+          apiKey: 'test-key',
+        } as ContentGeneratorConfig,
+        sources: {},
+      }),
+    );
   });
 
   describe('initialize', () => {
@@ -255,31 +274,28 @@ describe('Server Config (config.ts)', () => {
       const mockContentConfig = {
         apiKey: 'test-key',
         model: 'qwen3-coder-plus',
+        authType,
       };
 
-      vi.mocked(createContentGeneratorConfig).mockReturnValue(
+      vi.mocked(resolveContentGeneratorConfigWithSources).mockReturnValue({
-        mockContentConfig,
+        config: mockContentConfig as ContentGeneratorConfig,
-      );
+        sources: {},
-
+      });
-      // Set fallback mode to true to ensure it gets reset
-      config.setFallbackMode(true);
-      expect(config.isInFallbackMode()).toBe(true);
 
       await config.refreshAuth(authType);
 
-      expect(createContentGeneratorConfig).toHaveBeenCalledWith(
+      expect(resolveContentGeneratorConfigWithSources).toHaveBeenCalledWith(
         config,
         authType,
-        {
+        expect.objectContaining({
           model: MODEL,
-          baseUrl: undefined,
+        }),
-        },
+        expect.anything(),
+        expect.anything(),
       );
       // Verify that contentGeneratorConfig is updated
       expect(config.getContentGeneratorConfig()).toEqual(mockContentConfig);
       expect(GeminiClient).toHaveBeenCalledWith(config);
-      // Verify that fallback mode is reset
-      expect(config.isInFallbackMode()).toBe(false);
     });
 
     it('should not strip thoughts when switching from Vertex to GenAI', async () => {
@@ -300,6 +316,129 @@ describe('Server Config (config.ts)', () => {
     });
   });
 
+  describe('model switching optimization (QWEN_OAUTH)', () => {
+    it('should switch qwen-oauth model in-place without refreshing auth when safe', async () => {
+      const config = new Config(baseParams);
+
+      const mockContentConfig: ContentGeneratorConfig = {
+        authType: AuthType.QWEN_OAUTH,
+        model: 'coder-model',
+        apiKey: 'QWEN_OAUTH_DYNAMIC_TOKEN',
+        baseUrl: DEFAULT_DASHSCOPE_BASE_URL,
+        timeout: 60000,
+        maxRetries: 3,
+      } as ContentGeneratorConfig;
+
+      vi.mocked(resolveContentGeneratorConfigWithSources).mockImplementation(
+        (_config, authType, generationConfig) => ({
+          config: {
+            ...mockContentConfig,
+            authType,
+            model: generationConfig?.model ?? mockContentConfig.model,
+          } as ContentGeneratorConfig,
+          sources: {},
+        }),
+      );
+      vi.mocked(createContentGenerator).mockResolvedValue({
+        generateContent: vi.fn(),
+        generateContentStream: vi.fn(),
+        countTokens: vi.fn(),
+        embedContent: vi.fn(),
+      } as unknown as ContentGenerator);
+
+      // Establish initial qwen-oauth content generator config/content generator.
+      await config.refreshAuth(AuthType.QWEN_OAUTH);
+
+      // Spy after initial refresh to ensure model switch does not re-trigger refreshAuth.
+      const refreshSpy = vi.spyOn(config, 'refreshAuth');
+
+      await config.switchModel(AuthType.QWEN_OAUTH, 'vision-model');
+
+      expect(config.getModel()).toBe('vision-model');
+      expect(refreshSpy).not.toHaveBeenCalled();
+      // Called once during initial refreshAuth + once during handleModelChange diffing.
+      expect(
+        vi.mocked(resolveContentGeneratorConfigWithSources),
+      ).toHaveBeenCalledTimes(2);
+      expect(vi.mocked(createContentGenerator)).toHaveBeenCalledTimes(1);
+    });
+  });
+
+  describe('model switching with different credentials (OpenAI)', () => {
+    it('should refresh auth when switching to model with different envKey', async () => {
+      // This test verifies the fix for switching between modelProvider models
+      // with different envKeys (e.g., deepseek-chat with DEEPSEEK_API_KEY)
+      const configWithModelProviders = new Config({
+        ...baseParams,
+        authType: AuthType.USE_OPENAI,
+        modelProvidersConfig: {
+          openai: [
+            {
+              id: 'model-a',
+              name: 'Model A',
+              baseUrl: 'https://api.example.com/v1',
+              envKey: 'API_KEY_A',
+            },
+            {
+              id: 'model-b',
+              name: 'Model B',
+              baseUrl: 'https://api.example.com/v1',
+              envKey: 'API_KEY_B',
+            },
+          ],
+        },
+      });
+
+      const mockContentConfigA: ContentGeneratorConfig = {
+        authType: AuthType.USE_OPENAI,
+        model: 'model-a',
+        apiKey: 'key-a',
+        baseUrl: 'https://api.example.com/v1',
+      } as ContentGeneratorConfig;
+
+      const mockContentConfigB: ContentGeneratorConfig = {
+        authType: AuthType.USE_OPENAI,
+        model: 'model-b',
+        apiKey: 'key-b',
+        baseUrl: 'https://api.example.com/v1',
+      } as ContentGeneratorConfig;
+
+      vi.mocked(resolveContentGeneratorConfigWithSources).mockImplementation(
+        (_config, _authType, generationConfig) => {
+          const model = generationConfig?.model;
+          return {
+            config:
+              model === 'model-b' ? mockContentConfigB : mockContentConfigA,
+            sources: {},
+          };
+        },
+      );
+
+      vi.mocked(createContentGenerator).mockResolvedValue({
+        generateContent: vi.fn(),
+        generateContentStream: vi.fn(),
+        countTokens: vi.fn(),
+        embedContent: vi.fn(),
+      } as unknown as ContentGenerator);
+
+      // Initialize with model-a
+      await configWithModelProviders.refreshAuth(AuthType.USE_OPENAI);
+
+      // Spy on refreshAuth to verify it's called when switching to model-b
+      const refreshSpy = vi.spyOn(configWithModelProviders, 'refreshAuth');
+
+      // Switch to model-b (different envKey)
+      await configWithModelProviders.switchModel(
+        AuthType.USE_OPENAI,
+        'model-b',
+      );
+
+      // Should trigger full refresh because envKey changed
+      expect(refreshSpy).toHaveBeenCalledWith(AuthType.USE_OPENAI);
+      expect(configWithModelProviders.getModel()).toBe('model-b');
+    });
+  });
+
   it('Config constructor should store userMemory correctly', () => {
     const config = new Config(baseParams);
 

packages/core/src/config/config.ts

@@ -16,9 +16,8 @@ import { ProxyAgent, setGlobalDispatcher } from 'undici';
 import type {
   ContentGenerator,
   ContentGeneratorConfig,
-  AuthType,
 } from '../core/contentGenerator.js';
-import type { FallbackModelHandler } from '../fallback/types.js';
+import type { ContentGeneratorConfigSources } from '../core/contentGenerator.js';
 import type { MCPOAuthConfig } from '../mcp/oauth-provider.js';
 import type { ShellExecutionConfig } from '../services/shellExecutionService.js';
 import type { AnyToolInvocation } from '../tools/tools.js';
@@ -27,8 +26,9 @@ import type { AnyToolInvocation } from '../tools/tools.js';
 import { BaseLlmClient } from '../core/baseLlmClient.js';
 import { GeminiClient } from '../core/client.js';
 import {
+  AuthType,
   createContentGenerator,
-  createContentGeneratorConfig,
+  resolveContentGeneratorConfigWithSources,
 } from '../core/contentGenerator.js';
 import { tokenLimit } from '../core/tokenLimits.js';
 
@@ -94,7 +94,7 @@ import {
   DEFAULT_FILE_FILTERING_OPTIONS,
   DEFAULT_MEMORY_FILE_FILTERING_OPTIONS,
 } from './constants.js';
-import { DEFAULT_QWEN_EMBEDDING_MODEL, DEFAULT_QWEN_MODEL } from './models.js';
+import { DEFAULT_QWEN_EMBEDDING_MODEL } from './models.js';
 import { Storage } from './storage.js';
 import { ChatRecordingService } from '../services/chatRecordingService.js';
 import {
@@ -103,6 +103,12 @@ import {
 } from '../services/sessionService.js';
 import { randomUUID } from 'node:crypto';
 
+import {
+  ModelsConfig,
+  type ModelProvidersConfig,
+  type AvailableModel,
+} from '../models/index.js';
+
 // Re-export types
 export type { AnyToolInvocation, FileFilteringOptions, MCPOAuthConfig };
 export {
@@ -318,6 +324,11 @@ export interface ConfigParameters {
   ideMode?: boolean;
   authType?: AuthType;
   generationConfig?: Partial<ContentGeneratorConfig>;
+  /**
+   * Optional source map for generationConfig fields (e.g. CLI/env/settings attribution).
+   * This is used to produce per-field source badges in the UI.
+   */
+  generationConfigSources?: ContentGeneratorConfigSources;
   cliVersion?: string;
   loadMemoryFromIncludeDirectories?: boolean;
   chatRecording?: boolean;
@@ -353,6 +364,8 @@ export interface ConfigParameters {
   sdkMode?: boolean;
   sessionSubagents?: SubagentConfig[];
   channel?: string;
+  /** Model providers configuration grouped by authType */
+  modelProvidersConfig?: ModelProvidersConfig;
 }
 
 function normalizeConfigOutputFormat(
@@ -394,9 +407,12 @@ export class Config {
   private skillManager!: SkillManager;
   private fileSystemService: FileSystemService;
   private contentGeneratorConfig!: ContentGeneratorConfig;
+  private contentGeneratorConfigSources: ContentGeneratorConfigSources = {};
   private contentGenerator!: ContentGenerator;
-  private _generationConfig: Partial<ContentGeneratorConfig>;
   private readonly embeddingModel: string;
+
+  private _modelsConfig!: ModelsConfig;
+  private readonly modelProvidersConfig?: ModelProvidersConfig;
   private readonly sandbox: SandboxConfig | undefined;
   private readonly targetDir: string;
   private workspaceContext: WorkspaceContext;
@@ -445,7 +461,6 @@ export class Config {
   private readonly folderTrust: boolean;
   private ideMode: boolean;
 
-  private inFallbackMode = false;
   private readonly maxSessionTurns: number;
   private readonly sessionTokenLimit: number;
   private readonly listExtensions: boolean;
@@ -454,8 +469,6 @@ export class Config {
     name: string;
     extensionName: string;
   }>;
-  fallbackModelHandler?: FallbackModelHandler;
-  private quotaErrorOccurred: boolean = false;
   private readonly summarizeToolOutput:
     | Record<string, SummarizeToolOutputSettings>
     | undefined;
@@ -570,13 +583,7 @@ export class Config {
     this.folderTrustFeature = params.folderTrustFeature ?? false;
     this.folderTrust = params.folderTrust ?? false;
     this.ideMode = params.ideMode ?? false;
-    this._generationConfig = {
+    this.modelProvidersConfig = params.modelProvidersConfig;
-      model: params.model,
-      ...(params.generationConfig || {}),
-      baseUrl: params.generationConfig?.baseUrl,
-    };
-    this.contentGeneratorConfig = this
-      ._generationConfig as ContentGeneratorConfig;
     this.cliVersion = params.cliVersion;
 
     this.chatRecordingEnabled = params.chatRecording ?? true;
@@ -619,6 +626,23 @@ export class Config {
       setGeminiMdFilename(params.contextFileName);
     }
 
+    // Create ModelsConfig for centralized model management
+    // Prefer params.authType over generationConfig.authType because:
+    // - params.authType preserves undefined (user hasn't selected yet)
+    // - generationConfig.authType may have a default value from resolvers
+    this._modelsConfig = new ModelsConfig({
+      initialAuthType: params.authType ?? params.generationConfig?.authType,
+      initialModelId: params.model,
+      modelProvidersConfig: this.modelProvidersConfig,
+      generationConfig: {
+        model: params.model,
+        ...(params.generationConfig || {}),
+        baseUrl: params.generationConfig?.baseUrl,
+      },
+      generationConfigSources: params.generationConfigSources,
+      onModelChange: this.handleModelChange.bind(this),
+    });
+
     if (this.telemetrySettings.enabled) {
       initializeTelemetry(this);
     }
@@ -669,45 +693,61 @@ export class Config {
     return this.contentGenerator;
   }
 
+  /**
+   * Get the ModelsConfig instance for model-related operations.
+   * External code (e.g., CLI) can use this to access model configuration.
+   */
+  get modelsConfig(): ModelsConfig {
+    return this._modelsConfig;
+  }
+
   /**
    * Updates the credentials in the generation config.
-   * This is needed when credentials are set after Config construction.
+   * Exclusive for `OpenAIKeyPrompt` to update credentials via `/auth`
+   * Delegates to ModelsConfig.
    */
   updateCredentials(credentials: {
     apiKey?: string;
     baseUrl?: string;
     model?: string;
   }): void {
-    if (credentials.apiKey) {
+    this._modelsConfig.updateCredentials(credentials);
-      this._generationConfig.apiKey = credentials.apiKey;
-    }
-    if (credentials.baseUrl) {
-      this._generationConfig.baseUrl = credentials.baseUrl;
-    }
-    if (credentials.model) {
-      this._generationConfig.model = credentials.model;
-    }
   }
 
+  /**
+   * Refresh authentication and rebuild ContentGenerator.
+   */
   async refreshAuth(authMethod: AuthType, isInitialAuth?: boolean) {
-    const newContentGeneratorConfig = createContentGeneratorConfig(
+    // Sync modelsConfig state for this auth refresh
+    const modelId = this._modelsConfig.getModel();
+    this._modelsConfig.syncAfterAuthRefresh(authMethod, modelId);
+
+    // Check and consume cached credentials flag
+    const requireCached =
+      this._modelsConfig.consumeRequireCachedCredentialsFlag();
+
+    const { config, sources } = resolveContentGeneratorConfigWithSources(
       this,
       authMethod,
-      this._generationConfig,
+      this._modelsConfig.getGenerationConfig(),
+      this._modelsConfig.getGenerationConfigSources(),
+      {
+        strictModelProvider:
+          this._modelsConfig.isStrictModelProviderSelection(),
+      },
     );
+    const newContentGeneratorConfig = config;
     this.contentGenerator = await createContentGenerator(
       newContentGeneratorConfig,
       this,
-      isInitialAuth,
+      requireCached ? true : isInitialAuth,
     );
     // Only assign to instance properties after successful initialization
     this.contentGeneratorConfig = newContentGeneratorConfig;
+    this.contentGeneratorConfigSources = sources;
 
     // Initialize BaseLlmClient now that the ContentGenerator is available
     this.baseLlmClient = new BaseLlmClient(this.contentGenerator, this);
-
-    // Reset the session flag since we're explicitly changing auth and using default model
-    this.inFallbackMode = false;
   }
 
   /**
@@ -767,31 +807,125 @@ export class Config {
     return this.contentGeneratorConfig;
   }
 
-  getModel(): string {
+  getContentGeneratorConfigSources(): ContentGeneratorConfigSources {
-    return this.contentGeneratorConfig?.model || DEFAULT_QWEN_MODEL;
+    // If contentGeneratorConfigSources is empty (before initializeAuth),
+    // get sources from ModelsConfig
+    if (
+      Object.keys(this.contentGeneratorConfigSources).length === 0 &&
+      this._modelsConfig
+    ) {
+      return this._modelsConfig.getGenerationConfigSources();
+    }
+    return this.contentGeneratorConfigSources;
   }
 
+  getModel(): string {
+    return this.contentGeneratorConfig?.model || this._modelsConfig.getModel();
+  }
+
+  /**
+   * Set model programmatically (e.g., VLM auto-switch, fallback).
+   * Delegates to ModelsConfig.
+   */
   async setModel(
     newModel: string,
-    _metadata?: { reason?: string; context?: string },
+    metadata?: { reason?: string; context?: string },
   ): Promise<void> {
+    await this._modelsConfig.setModel(newModel, metadata);
+    // Also update contentGeneratorConfig for hot-update compatibility
     if (this.contentGeneratorConfig) {
       this.contentGeneratorConfig.model = newModel;
     }
-    // TODO: Log _metadata for telemetry if needed
-    // This _metadata can be used for tracking model switches (reason, context)
   }
 
-  isInFallbackMode(): boolean {
+  /**
-    return this.inFallbackMode;
+   * Handle model change from ModelsConfig.
+   * This updates the content generator config with the new model settings.
+   */
+  private async handleModelChange(
+    authType: AuthType,
+    requiresRefresh: boolean,
+  ): Promise<void> {
+    if (!this.contentGeneratorConfig) {
+      return;
     }
 
-  setFallbackMode(active: boolean): void {
+    // Hot update path: only supported for qwen-oauth.
-    this.inFallbackMode = active;
+    // For other auth types we always refresh to recreate the ContentGenerator.
+    //
+    // Rationale:
+    // - Non-qwen providers may need to re-validate credentials / baseUrl / envKey.
+    // - ModelsConfig.applyResolvedModelDefaults can clear or change credentials sources.
+    // - Refresh keeps runtime behavior consistent and centralized.
+    if (authType === AuthType.QWEN_OAUTH && !requiresRefresh) {
+      const { config, sources } = resolveContentGeneratorConfigWithSources(
+        this,
+        authType,
+        this._modelsConfig.getGenerationConfig(),
+        this._modelsConfig.getGenerationConfigSources(),
+        {
+          strictModelProvider:
+            this._modelsConfig.isStrictModelProviderSelection(),
+        },
+      );
+
+      // Hot-update fields (qwen-oauth models share the same auth + client).
+      this.contentGeneratorConfig.model = config.model;
+      this.contentGeneratorConfig.samplingParams = config.samplingParams;
+      this.contentGeneratorConfig.disableCacheControl =
+        config.disableCacheControl;
+
+      if ('model' in sources) {
+        this.contentGeneratorConfigSources['model'] = sources['model'];
+      }
+      if ('samplingParams' in sources) {
+        this.contentGeneratorConfigSources['samplingParams'] =
+          sources['samplingParams'];
+      }
+      if ('disableCacheControl' in sources) {
+        this.contentGeneratorConfigSources['disableCacheControl'] =
+          sources['disableCacheControl'];
+      }
+      return;
     }
 
-  setFallbackModelHandler(handler: FallbackModelHandler): void {
+    // Full refresh path
-    this.fallbackModelHandler = handler;
+    await this.refreshAuth(authType);
+  }
+
+  /**
+   * Get available models for the current authType.
+   * Delegates to ModelsConfig.
+   */
+  getAvailableModels(): AvailableModel[] {
+    return this._modelsConfig.getAvailableModels();
+  }
+
+  /**
+   * Get available models for a specific authType.
+   * Delegates to ModelsConfig.
+   */
+  getAvailableModelsForAuthType(authType: AuthType): AvailableModel[] {
+    return this._modelsConfig.getAvailableModelsForAuthType(authType);
+  }
+
+  /**
+   * Switch authType+model via registry-backed selection.
+   * This triggers a refresh of the ContentGenerator when required (always on authType changes).
+   * For qwen-oauth model switches that are hot-update safe, this may update in place.
+   *
+   * @param authType - Target authentication type
+   * @param modelId - Target model ID
+   * @param options - Additional options like requireCachedCredentials
+   * @param metadata - Metadata for logging/tracking
+   */
+  async switchModel(
+    authType: AuthType,
+    modelId: string,
+    options?: { requireCachedCredentials?: boolean },
+    metadata?: { reason?: string; context?: string },
+  ): Promise<void> {
+    await this._modelsConfig.switchModel(authType, modelId, options, metadata);
   }
 
   getMaxSessionTurns(): number {
@@ -802,14 +936,6 @@ export class Config {
     return this.sessionTokenLimit;
   }
 
-  setQuotaErrorOccurred(value: boolean): void {
-    this.quotaErrorOccurred = value;
-  }
-
-  getQuotaErrorOccurred(): boolean {
-    return this.quotaErrorOccurred;
-  }
-
   getEmbeddingModel(): string {
     return this.embeddingModel;
   }

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

@@ -1,100 +0,0 @@
-/**
- * @license
- * Copyright 2025 Google LLC
- * SPDX-License-Identifier: Apache-2.0
- */
-
-import { describe, it, expect, beforeEach, vi } from 'vitest';
-import { Config } from './config.js';
-import { DEFAULT_GEMINI_MODEL, DEFAULT_GEMINI_FLASH_MODEL } from './models.js';
-import fs from 'node:fs';
-
-vi.mock('node:fs');
-
-// Skip this test because we do not have fall back mechanism.
-describe.skip('Flash Model Fallback Configuration', () => {
-  let config: Config;
-
-  beforeEach(() => {
-    vi.mocked(fs.existsSync).mockReturnValue(true);
-    vi.mocked(fs.statSync).mockReturnValue({
-      isDirectory: () => true,
-    } as fs.Stats);
-    config = new Config({
-      targetDir: '/test',
-      debugMode: false,
-      cwd: '/test',
-      model: DEFAULT_GEMINI_MODEL,
-    });
-
-    // Initialize contentGeneratorConfig for testing
-    (
-      config as unknown as { contentGeneratorConfig: unknown }
-    ).contentGeneratorConfig = {
-      model: DEFAULT_GEMINI_MODEL,
-      authType: 'gemini',
-    };
-  });
-
-  // These tests do not actually test fallback. isInFallbackMode() only returns true,
-  // when setFallbackMode is marked as true. This is to decouple setting a model
-  // with the fallback mechanism. This will be necessary we introduce more
-  // intelligent model routing.
-  describe('setModel', () => {
-    it('should only mark as switched if contentGeneratorConfig exists', async () => {
-      // Create config without initializing contentGeneratorConfig
-      const newConfig = new Config({
-        targetDir: '/test',
-        debugMode: false,
-        cwd: '/test',
-        model: DEFAULT_GEMINI_MODEL,
-      });
-
-      // Should not crash when contentGeneratorConfig is undefined
-      await newConfig.setModel(DEFAULT_GEMINI_FLASH_MODEL);
-      expect(newConfig.isInFallbackMode()).toBe(false);
-    });
-  });
-
-  describe('getModel', () => {
-    it('should return contentGeneratorConfig model if available', async () => {
-      // Simulate initialized content generator config
-      await config.setModel(DEFAULT_GEMINI_FLASH_MODEL);
-      expect(config.getModel()).toBe(DEFAULT_GEMINI_FLASH_MODEL);
-    });
-
-    it('should fall back to initial model if contentGeneratorConfig is not available', () => {
-      // Test with fresh config where contentGeneratorConfig might not be set
-      const newConfig = new Config({
-        targetDir: '/test',
-        debugMode: false,
-        cwd: '/test',
-        model: 'custom-model',
-      });
-
-      expect(newConfig.getModel()).toBe('custom-model');
-    });
-  });
-
-  describe('isInFallbackMode', () => {
-    it('should start as false for new session', () => {
-      expect(config.isInFallbackMode()).toBe(false);
-    });
-
-    it('should remain false if no model switch occurs', () => {
-      // Perform other operations that don't involve model switching
-      expect(config.isInFallbackMode()).toBe(false);
-    });
-
-    it('should persist switched state throughout session', async () => {
-      await config.setModel(DEFAULT_GEMINI_FLASH_MODEL);
-      // Setting state for fallback mode as is expected of clients
-      config.setFallbackMode(true);
-      expect(config.isInFallbackMode()).toBe(true);
-
-      // Should remain true even after getting model
-      config.getModel();
-      expect(config.isInFallbackMode()).toBe(true);
-    });
-  });
-});

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

@@ -1,83 +0,0 @@
-/**
- * @license
- * Copyright 2025 Google LLC
- * SPDX-License-Identifier: Apache-2.0
- */
-
-import { describe, it, expect } from 'vitest';
-import {
-  getEffectiveModel,
-  DEFAULT_GEMINI_MODEL,
-  DEFAULT_GEMINI_FLASH_MODEL,
-  DEFAULT_GEMINI_FLASH_LITE_MODEL,
-} from './models.js';
-
-describe('getEffectiveModel', () => {
-  describe('When NOT in fallback mode', () => {
-    const isInFallbackMode = false;
-
-    it('should return the Pro model when Pro is requested', () => {
-      const model = getEffectiveModel(isInFallbackMode, DEFAULT_GEMINI_MODEL);
-      expect(model).toBe(DEFAULT_GEMINI_MODEL);
-    });
-
-    it('should return the Flash model when Flash is requested', () => {
-      const model = getEffectiveModel(
-        isInFallbackMode,
-        DEFAULT_GEMINI_FLASH_MODEL,
-      );
-      expect(model).toBe(DEFAULT_GEMINI_FLASH_MODEL);
-    });
-
-    it('should return the Lite model when Lite is requested', () => {
-      const model = getEffectiveModel(
-        isInFallbackMode,
-        DEFAULT_GEMINI_FLASH_LITE_MODEL,
-      );
-      expect(model).toBe(DEFAULT_GEMINI_FLASH_LITE_MODEL);
-    });
-
-    it('should return a custom model name when requested', () => {
-      const customModel = 'custom-model-v1';
-      const model = getEffectiveModel(isInFallbackMode, customModel);
-      expect(model).toBe(customModel);
-    });
-  });
-
-  describe('When IN fallback mode', () => {
-    const isInFallbackMode = true;
-
-    it('should downgrade the Pro model to the Flash model', () => {
-      const model = getEffectiveModel(isInFallbackMode, DEFAULT_GEMINI_MODEL);
-      expect(model).toBe(DEFAULT_GEMINI_FLASH_MODEL);
-    });
-
-    it('should return the Flash model when Flash is requested', () => {
-      const model = getEffectiveModel(
-        isInFallbackMode,
-        DEFAULT_GEMINI_FLASH_MODEL,
-      );
-      expect(model).toBe(DEFAULT_GEMINI_FLASH_MODEL);
-    });
-
-    it('should HONOR the Lite model when Lite is requested', () => {
-      const model = getEffectiveModel(
-        isInFallbackMode,
-        DEFAULT_GEMINI_FLASH_LITE_MODEL,
-      );
-      expect(model).toBe(DEFAULT_GEMINI_FLASH_LITE_MODEL);
-    });
-
-    it('should HONOR any model with "lite" in its name', () => {
-      const customLiteModel = 'gemini-2.5-custom-lite-vNext';
-      const model = getEffectiveModel(isInFallbackMode, customLiteModel);
-      expect(model).toBe(customLiteModel);
-    });
-
-    it('should downgrade any other custom model to the Flash model', () => {
-      const customModel = 'custom-model-v1-unlisted';
-      const model = getEffectiveModel(isInFallbackMode, customModel);
-      expect(model).toBe(DEFAULT_GEMINI_FLASH_MODEL);
-    });
-  });
-});

packages/core/src/config/models.ts

@@ -7,46 +7,3 @@
 export const DEFAULT_QWEN_MODEL = 'coder-model';
 export const DEFAULT_QWEN_FLASH_MODEL = 'coder-model';
 export const DEFAULT_QWEN_EMBEDDING_MODEL = 'text-embedding-v4';
-
-export const DEFAULT_GEMINI_MODEL = 'coder-model';
-export const DEFAULT_GEMINI_FLASH_MODEL = 'gemini-2.5-flash';
-export const DEFAULT_GEMINI_FLASH_LITE_MODEL = 'gemini-2.5-flash-lite';
-
-export const DEFAULT_GEMINI_MODEL_AUTO = 'auto';
-
-export const DEFAULT_GEMINI_EMBEDDING_MODEL = 'gemini-embedding-001';
-
-// Some thinking models do not default to dynamic thinking which is done by a value of -1
-export const DEFAULT_THINKING_MODE = -1;
-
-/**
- * Determines the effective model to use, applying fallback logic if necessary.
- *
- * When fallback mode is active, this function enforces the use of the standard
- * fallback model. However, it makes an exception for "lite" models (any model
- * with "lite" in its name), allowing them to be used to preserve cost savings.
- * This ensures that "pro" models are always downgraded, while "lite" model
- * requests are honored.
- *
- * @param isInFallbackMode Whether the application is in fallback mode.
- * @param requestedModel The model that was originally requested.
- * @returns The effective model name.
- */
-export function getEffectiveModel(
-  isInFallbackMode: boolean,
-  requestedModel: string,
-): string {
-  // If we are not in fallback mode, simply use the requested model.
-  if (!isInFallbackMode) {
-    return requestedModel;
-  }
-
-  // If a "lite" model is requested, honor it. This allows for variations of
-  // lite models without needing to list them all as constants.
-  if (requestedModel.includes('lite')) {
-    return requestedModel;
-  }
-
-  // Default fallback for Gemini CLI.
-  return DEFAULT_GEMINI_FLASH_MODEL;
-}

packages/core/src/core/client.test.ts

@@ -32,7 +32,7 @@ import {
   type ChatCompressionInfo,
 } from './turn.js';
 import { getCoreSystemPrompt } from './prompts.js';
-import { DEFAULT_GEMINI_FLASH_MODEL } from '../config/models.js';
+import { DEFAULT_QWEN_FLASH_MODEL } from '../config/models.js';
 import { FileDiscoveryService } from '../services/fileDiscoveryService.js';
 import { setSimulate429 } from '../utils/testUtils.js';
 import { tokenLimit } from './tokenLimits.js';
@@ -302,8 +302,6 @@ describe('Gemini Client (client.ts)', () => {
       getFileService: vi.fn().mockReturnValue(fileService),
       getMaxSessionTurns: vi.fn().mockReturnValue(0),
       getSessionTokenLimit: vi.fn().mockReturnValue(32000),
-      getQuotaErrorOccurred: vi.fn().mockReturnValue(false),
-      setQuotaErrorOccurred: vi.fn(),
       getNoBrowser: vi.fn().mockReturnValue(false),
       getUsageStatisticsEnabled: vi.fn().mockReturnValue(true),
       getApprovalMode: vi.fn().mockReturnValue(ApprovalMode.DEFAULT),
@@ -317,8 +315,6 @@ describe('Gemini Client (client.ts)', () => {
       getModelRouterService: vi.fn().mockReturnValue({
         route: vi.fn().mockResolvedValue({ model: 'default-routed-model' }),
       }),
-      isInFallbackMode: vi.fn().mockReturnValue(false),
-      setFallbackMode: vi.fn(),
       getCliVersion: vi.fn().mockReturnValue('1.0.0'),
       getChatCompression: vi.fn().mockReturnValue(undefined),
       getSkipNextSpeakerCheck: vi.fn().mockReturnValue(false),
@@ -2262,12 +2258,12 @@ ${JSON.stringify(
         contents,
         generationConfig,
         abortSignal,
-        DEFAULT_GEMINI_FLASH_MODEL,
+        DEFAULT_QWEN_FLASH_MODEL,
       );
 
       expect(mockContentGenerator.generateContent).toHaveBeenCalledWith(
         expect.objectContaining({
-          model: DEFAULT_GEMINI_FLASH_MODEL,
+          model: DEFAULT_QWEN_FLASH_MODEL,
           config: expect.objectContaining({
             abortSignal,
             systemInstruction: getCoreSystemPrompt(''),
@@ -2290,7 +2286,7 @@ ${JSON.stringify(
         contents,
         {},
         new AbortController().signal,
-        DEFAULT_GEMINI_FLASH_MODEL,
+        DEFAULT_QWEN_FLASH_MODEL,
       );
 
       expect(mockContentGenerator.generateContent).not.toHaveBeenCalledWith({
@@ -2300,7 +2296,7 @@ ${JSON.stringify(
       });
       expect(mockContentGenerator.generateContent).toHaveBeenCalledWith(
         {
-          model: DEFAULT_GEMINI_FLASH_MODEL,
+          model: DEFAULT_QWEN_FLASH_MODEL,
           config: expect.any(Object),
           contents,
         },
@@ -2308,28 +2304,7 @@ ${JSON.stringify(
       );
     });
 
-    it('should use the Flash model when fallback mode is active', async () => {
+    // Note: there is currently no "fallback mode" model routing; the model used
-      const contents = [{ role: 'user', parts: [{ text: 'hello' }] }];
+    // is always the one explicitly requested by the caller.
-      const generationConfig = { temperature: 0.5 };
-      const abortSignal = new AbortController().signal;
-      const requestedModel = 'gemini-2.5-pro'; // A non-flash model
-
-      // Mock config to be in fallback mode
-      vi.spyOn(client['config'], 'isInFallbackMode').mockReturnValue(true);
-
-      await client.generateContent(
-        contents,
-        generationConfig,
-        abortSignal,
-        requestedModel,
-      );
-
-      expect(mockGenerateContentFn).toHaveBeenCalledWith(
-        expect.objectContaining({
-          model: DEFAULT_GEMINI_FLASH_MODEL,
-        }),
-        'test-session-id',
-      );
-    });
   });
 });

packages/core/src/core/client.ts

@@ -15,7 +15,6 @@ import type {
 
 // Config
 import { ApprovalMode, type Config } from '../config/config.js';
-import { DEFAULT_GEMINI_FLASH_MODEL } from '../config/models.js';
 
 // Core modules
 import type { ContentGenerator } from './contentGenerator.js';
@@ -542,11 +541,6 @@ export class GeminiClient {
       }
     }
     if (!turn.pendingToolCalls.length && signal && !signal.aborted) {
-      // Check if next speaker check is needed
-      if (this.config.getQuotaErrorOccurred()) {
-        return turn;
-      }
-
       if (this.config.getSkipNextSpeakerCheck()) {
         return turn;
       }
@@ -602,14 +596,11 @@ export class GeminiClient {
       };
 
       const apiCall = () => {
-        const modelToUse = this.config.isInFallbackMode()
+        currentAttemptModel = model;
-          ? DEFAULT_GEMINI_FLASH_MODEL
-          : model;
-        currentAttemptModel = modelToUse;
 
         return this.getContentGeneratorOrFail().generateContent(
           {
-            model: modelToUse,
+            model,
             config: requestConfig,
             contents,
           },

packages/core/src/core/contentGenerator.test.ts

@@ -5,7 +5,11 @@
  */
 
 import { describe, it, expect, vi } from 'vitest';
-import { createContentGenerator, AuthType } from './contentGenerator.js';
+import {
+  createContentGenerator,
+  createContentGeneratorConfig,
+  AuthType,
+} from './contentGenerator.js';
 import { GoogleGenAI } from '@google/genai';
 import type { Config } from '../config/config.js';
 import { LoggingContentGenerator } from './loggingContentGenerator/index.js';
@@ -78,3 +82,32 @@ describe('createContentGenerator', () => {
     expect(generator).toBeInstanceOf(LoggingContentGenerator);
   });
 });
+
+describe('createContentGeneratorConfig', () => {
+  const mockConfig = {
+    getProxy: () => undefined,
+  } as unknown as Config;
+
+  it('should preserve provided fields and set authType for QWEN_OAUTH', () => {
+    const cfg = createContentGeneratorConfig(mockConfig, AuthType.QWEN_OAUTH, {
+      model: 'vision-model',
+      apiKey: 'QWEN_OAUTH_DYNAMIC_TOKEN',
+    });
+    expect(cfg.authType).toBe(AuthType.QWEN_OAUTH);
+    expect(cfg.model).toBe('vision-model');
+    expect(cfg.apiKey).toBe('QWEN_OAUTH_DYNAMIC_TOKEN');
+  });
+
+  it('should not warn or fallback for QWEN_OAUTH (resolution handled by ModelConfigResolver)', () => {
+    const warnSpy = vi
+      .spyOn(console, 'warn')
+      .mockImplementation(() => undefined);
+    const cfg = createContentGeneratorConfig(mockConfig, AuthType.QWEN_OAUTH, {
+      model: 'some-random-model',
+    });
+    expect(cfg.model).toBe('some-random-model');
+    expect(cfg.apiKey).toBeUndefined();
+    expect(warnSpy).not.toHaveBeenCalled();
+    warnSpy.mockRestore();
+  });
+});

packages/core/src/core/contentGenerator.ts

@@ -12,9 +12,24 @@ import type {
   GenerateContentParameters,
   GenerateContentResponse,
 } from '@google/genai';
-import { DEFAULT_QWEN_MODEL } from '../config/models.js';
 import type { Config } from '../config/config.js';
 import { LoggingContentGenerator } from './loggingContentGenerator/index.js';
+import type {
+  ConfigSource,
+  ConfigSourceKind,
+  ConfigSources,
+} from '../utils/configResolver.js';
+import {
+  getDefaultApiKeyEnvVar,
+  getDefaultModelEnvVar,
+  MissingAnthropicBaseUrlEnvError,
+  MissingApiKeyError,
+  MissingBaseUrlError,
+  MissingModelError,
+  StrictMissingCredentialsError,
+  StrictMissingModelIdError,
+} from '../models/modelConfigErrors.js';
+import { PROVIDER_SOURCED_FIELDS } from '../models/modelsConfig.js';
 
 /**
  * Interface abstracting the core functionalities for generating content and counting tokens.
@@ -48,6 +63,7 @@ export enum AuthType {
 export type ContentGeneratorConfig = {
   model: string;
   apiKey?: string;
+  apiKeyEnvKey?: string;
   baseUrl?: string;
   vertexai?: boolean;
   authType?: AuthType | undefined;
@@ -77,102 +93,178 @@ export type ContentGeneratorConfig = {
   schemaCompliance?: 'auto' | 'openapi_30';
 };
 
-export function createContentGeneratorConfig(
+// Keep the public ContentGeneratorConfigSources API, but reuse the generic
+// source-tracking types from utils/configResolver to avoid duplication.
+export type ContentGeneratorConfigSourceKind = ConfigSourceKind;
+export type ContentGeneratorConfigSource = ConfigSource;
+export type ContentGeneratorConfigSources = ConfigSources;
+
+export type ResolvedContentGeneratorConfig = {
+  config: ContentGeneratorConfig;
+  sources: ContentGeneratorConfigSources;
+};
+
+function setSource(
+  sources: ContentGeneratorConfigSources,
+  path: string,
+  source: ContentGeneratorConfigSource,
+): void {
+  sources[path] = source;
+}
+
+function getSeedSource(
+  seed: ContentGeneratorConfigSources | undefined,
+  path: string,
+): ContentGeneratorConfigSource | undefined {
+  return seed?.[path];
+}
+
+/**
+ * Resolve ContentGeneratorConfig while tracking the source of each effective field.
+ *
+ * This function now primarily validates and finalizes the configuration that has
+ * already been resolved by ModelConfigResolver. The env fallback logic has been
+ * moved to the unified resolver to eliminate duplication.
+ *
+ * Note: The generationConfig passed here should already be fully resolved with
+ * proper source tracking from the caller (CLI/SDK layer).
+ */
+export function resolveContentGeneratorConfigWithSources(
   config: Config,
   authType: AuthType | undefined,
   generationConfig?: Partial<ContentGeneratorConfig>,
-): ContentGeneratorConfig {
+  seedSources?: ContentGeneratorConfigSources,
-  let newContentGeneratorConfig: Partial<ContentGeneratorConfig> = {
+  options?: { strictModelProvider?: boolean },
+): ResolvedContentGeneratorConfig {
+  const sources: ContentGeneratorConfigSources = { ...(seedSources || {}) };
+  const strictModelProvider = options?.strictModelProvider === true;
+
+  // Build config with computed fields
+  const newContentGeneratorConfig: Partial<ContentGeneratorConfig> = {
     ...(generationConfig || {}),
     authType,
     proxy: config?.getProxy(),
   };
 
-  if (authType === AuthType.QWEN_OAUTH) {
+  // Set sources for computed fields
-    // For Qwen OAuth, we'll handle the API key dynamically in createContentGenerator
+  setSource(sources, 'authType', {
-    // Set a special marker to indicate this is Qwen OAuth
+    kind: 'computed',
-    return {
+    detail: 'provided by caller',
-      ...newContentGeneratorConfig,
+  });
-      model: DEFAULT_QWEN_MODEL,
+  if (config?.getProxy()) {
-      apiKey: 'QWEN_OAUTH_DYNAMIC_TOKEN',
+    setSource(sources, 'proxy', {
-    } as ContentGeneratorConfig;
+      kind: 'computed',
+      detail: 'Config.getProxy()',
+    });
   }
 
-  if (authType === AuthType.USE_OPENAI) {
+  // Preserve seed sources for fields that were passed in
-    newContentGeneratorConfig = {
+  const seedOrUnknown = (path: string): ContentGeneratorConfigSource =>
-      ...newContentGeneratorConfig,
+    getSeedSource(seedSources, path) ?? { kind: 'unknown' };
-      apiKey: newContentGeneratorConfig.apiKey || process.env['OPENAI_API_KEY'],
-      baseUrl:
-        newContentGeneratorConfig.baseUrl || process.env['OPENAI_BASE_URL'],
-      model: newContentGeneratorConfig.model || process.env['OPENAI_MODEL'],
-    };
 
-    if (!newContentGeneratorConfig.apiKey) {
+  for (const field of PROVIDER_SOURCED_FIELDS) {
-      throw new Error('OPENAI_API_KEY environment variable not found.');
+    if (generationConfig && field in generationConfig && !sources[field]) {
+      setSource(sources, field, seedOrUnknown(field));
+    }
+  }
+
+  // Validate required fields based on authType. This does not perform any
+  // fallback resolution (resolution is handled by ModelConfigResolver).
+  const validation = validateModelConfig(
+    newContentGeneratorConfig as ContentGeneratorConfig,
+    strictModelProvider,
+  );
+  if (!validation.valid) {
+    throw new Error(validation.errors.map((e) => e.message).join('\n'));
   }
 
   return {
-      ...newContentGeneratorConfig,
+    config: newContentGeneratorConfig as ContentGeneratorConfig,
-      model: newContentGeneratorConfig?.model || 'qwen3-coder-plus',
+    sources,
-    } as ContentGeneratorConfig;
-  }
-
-  if (authType === AuthType.USE_ANTHROPIC) {
-    newContentGeneratorConfig = {
-      ...newContentGeneratorConfig,
-      apiKey:
-        newContentGeneratorConfig.apiKey || process.env['ANTHROPIC_API_KEY'],
-      baseUrl:
-        newContentGeneratorConfig.baseUrl || process.env['ANTHROPIC_BASE_URL'],
-      model: newContentGeneratorConfig.model || process.env['ANTHROPIC_MODEL'],
   };
-
-    if (!newContentGeneratorConfig.apiKey) {
-      throw new Error('ANTHROPIC_API_KEY environment variable not found.');
 }
 
-    if (!newContentGeneratorConfig.baseUrl) {
+export interface ModelConfigValidationResult {
-      throw new Error('ANTHROPIC_BASE_URL environment variable not found.');
+  valid: boolean;
+  errors: Error[];
 }
 
-    if (!newContentGeneratorConfig.model) {
+/**
-      throw new Error('ANTHROPIC_MODEL environment variable not found.');
+ * Validate a resolved model configuration.
+ * This is the single validation entry point used across Core.
+ */
+export function validateModelConfig(
+  config: ContentGeneratorConfig,
+  isStrictModelProvider: boolean = false,
+): ModelConfigValidationResult {
+  const errors: Error[] = [];
+
+  // Qwen OAuth doesn't need validation - it uses dynamic tokens
+  if (config.authType === AuthType.QWEN_OAUTH) {
+    return { valid: true, errors: [] };
+  }
+
+  // API key is required for all other auth types
+  if (!config.apiKey) {
+    if (isStrictModelProvider) {
+      errors.push(
+        new StrictMissingCredentialsError(
+          config.authType,
+          config.model,
+          config.apiKeyEnvKey,
+        ),
+      );
+    } else {
+      const envKey =
+        config.apiKeyEnvKey || getDefaultApiKeyEnvVar(config.authType);
+      errors.push(
+        new MissingApiKeyError({
+          authType: config.authType,
+          model: config.model,
+          baseUrl: config.baseUrl,
+          envKey,
+        }),
+      );
     }
   }
 
-  if (authType === AuthType.USE_GEMINI) {
+  // Model is required
-    newContentGeneratorConfig = {
+  if (!config.model) {
-      ...newContentGeneratorConfig,
+    if (isStrictModelProvider) {
-      apiKey: newContentGeneratorConfig.apiKey || process.env['GEMINI_API_KEY'],
+      errors.push(new StrictMissingModelIdError(config.authType));
-      model: newContentGeneratorConfig.model || process.env['GEMINI_MODEL'],
+    } else {
-    };
+      const envKey = getDefaultModelEnvVar(config.authType);
-
+      errors.push(new MissingModelError({ authType: config.authType, envKey }));
-    if (!newContentGeneratorConfig.apiKey) {
-      throw new Error('GEMINI_API_KEY environment variable not found.');
-    }
-
-    if (!newContentGeneratorConfig.model) {
-      throw new Error('GEMINI_MODEL environment variable not found.');
     }
   }
 
-  if (authType === AuthType.USE_VERTEX_AI) {
+  // Explicit baseUrl is required for Anthropic; Migrated from existing code.
-    newContentGeneratorConfig = {
+  if (config.authType === AuthType.USE_ANTHROPIC && !config.baseUrl) {
-      ...newContentGeneratorConfig,
+    if (isStrictModelProvider) {
-      apiKey: newContentGeneratorConfig.apiKey || process.env['GOOGLE_API_KEY'],
+      errors.push(
-      model: newContentGeneratorConfig.model || process.env['GOOGLE_MODEL'],
+        new MissingBaseUrlError({
-    };
+          authType: config.authType,
-
+          model: config.model,
-    if (!newContentGeneratorConfig.apiKey) {
+        }),
-      throw new Error('GOOGLE_API_KEY environment variable not found.');
+      );
-    }
+    } else if (config.authType === AuthType.USE_ANTHROPIC) {
-
+      errors.push(new MissingAnthropicBaseUrlEnvError());
-    if (!newContentGeneratorConfig.model) {
-      throw new Error('GOOGLE_MODEL environment variable not found.');
     }
   }
 
-  return newContentGeneratorConfig as ContentGeneratorConfig;
+  return { valid: errors.length === 0, errors };
+}
+
+export function createContentGeneratorConfig(
+  config: Config,
+  authType: AuthType | undefined,
+  generationConfig?: Partial<ContentGeneratorConfig>,
+): ContentGeneratorConfig {
+  return resolveContentGeneratorConfigWithSources(
+    config,
+    authType,
+    generationConfig,
+  ).config;
 }
 
 export async function createContentGenerator(
@@ -180,11 +272,12 @@ export async function createContentGenerator(
   gcConfig: Config,
   isInitialAuth?: boolean,
 ): Promise<ContentGenerator> {
-  if (config.authType === AuthType.USE_OPENAI) {
+  const validation = validateModelConfig(config, false);
-    if (!config.apiKey) {
+  if (!validation.valid) {
-      throw new Error('OPENAI_API_KEY environment variable not found.');
+    throw new Error(validation.errors.map((e) => e.message).join('\n'));
   }
 
+  if (config.authType === AuthType.USE_OPENAI) {
     // Import OpenAIContentGenerator dynamically to avoid circular dependencies
     const { createOpenAIContentGenerator } = await import(
       './openaiContentGenerator/index.js'
@@ -223,10 +316,6 @@ export async function createContentGenerator(
   }
 
   if (config.authType === AuthType.USE_ANTHROPIC) {
-    if (!config.apiKey) {
-      throw new Error('ANTHROPIC_API_KEY environment variable not found.');
-    }
-
     const { createAnthropicContentGenerator } = await import(
       './anthropicContentGenerator/index.js'
     );

packages/core/src/core/geminiChat.test.ts

@@ -20,7 +20,6 @@ import {
 } from './geminiChat.js';
 import type { Config } from '../config/config.js';
 import { setSimulate429 } from '../utils/testUtils.js';
-import { DEFAULT_GEMINI_FLASH_MODEL } from '../config/models.js';
 import { AuthType } from './contentGenerator.js';
 import { type RetryOptions } from '../utils/retry.js';
 import { uiTelemetryService } from '../telemetry/uiTelemetry.js';
@@ -117,10 +116,6 @@ describe('GeminiChat', () => {
       }),
       getModel: vi.fn().mockReturnValue('gemini-pro'),
       setModel: vi.fn(),
-      isInFallbackMode: vi.fn().mockReturnValue(false),
-      getQuotaErrorOccurred: vi.fn().mockReturnValue(false),
-      setQuotaErrorOccurred: vi.fn(),
-      flashFallbackHandler: undefined,
       getProjectRoot: vi.fn().mockReturnValue('/test/project/root'),
       getCliVersion: vi.fn().mockReturnValue('1.0.0'),
       storage: {
@@ -1349,9 +1344,8 @@ describe('GeminiChat', () => {
       ],
     } as unknown as GenerateContentResponse;
 
-    it('should use the FLASH model when in fallback mode (sendMessageStream)', async () => {
+    it('should pass the requested model through to generateContentStream', async () => {
       vi.mocked(mockConfig.getModel).mockReturnValue('gemini-pro');
-      vi.mocked(mockConfig.isInFallbackMode).mockReturnValue(true);
       vi.mocked(mockContentGenerator.generateContentStream).mockImplementation(
         async () =>
           (async function* () {
@@ -1370,7 +1364,7 @@ describe('GeminiChat', () => {
 
       expect(mockContentGenerator.generateContentStream).toHaveBeenCalledWith(
         expect.objectContaining({
-          model: DEFAULT_GEMINI_FLASH_MODEL,
+          model: 'test-model',
         }),
         'prompt-id-res3',
       );
@@ -1422,9 +1416,6 @@ describe('GeminiChat', () => {
         authType,
       });
 
-      const isInFallbackModeSpy = vi.spyOn(mockConfig, 'isInFallbackMode');
-      isInFallbackModeSpy.mockReturnValue(false);
-
       vi.mocked(mockContentGenerator.generateContentStream)
         .mockRejectedValueOnce(error429) // Attempt 1 fails
         .mockResolvedValueOnce(
@@ -1441,10 +1432,7 @@ describe('GeminiChat', () => {
           })(),
         );
 
-      mockHandleFallback.mockImplementation(async () => {
+      mockHandleFallback.mockImplementation(async () => true);
-        isInFallbackModeSpy.mockReturnValue(true);
-        return true; // Signal retry
-      });
 
       const stream = await chat.sendMessageStream(
         'test-model',

packages/core/src/core/geminiChat.ts

@@ -19,10 +19,6 @@ import type {
 import { ApiError, createUserContent } from '@google/genai';
 import { retryWithBackoff } from '../utils/retry.js';
 import type { Config } from '../config/config.js';
-import {
-  DEFAULT_GEMINI_FLASH_MODEL,
-  getEffectiveModel,
-} from '../config/models.js';
 import { hasCycleInSchema } from '../tools/tools.js';
 import type { StructuredError } from './turn.js';
 import {
@@ -352,31 +348,15 @@ export class GeminiChat {
     params: SendMessageParameters,
     prompt_id: string,
   ): Promise<AsyncGenerator<GenerateContentResponse>> {
-    const apiCall = () => {
+    const apiCall = () =>
-      const modelToUse = getEffectiveModel(
+      this.config.getContentGenerator().generateContentStream(
-        this.config.isInFallbackMode(),
-        model,
-      );
-
-      if (
-        this.config.getQuotaErrorOccurred() &&
-        modelToUse === DEFAULT_GEMINI_FLASH_MODEL
-      ) {
-        throw new Error(
-          'Please submit a new query to continue with the Flash model.',
-        );
-      }
-
-      return this.config.getContentGenerator().generateContentStream(
         {
-          model: modelToUse,
+          model,
           contents: requestContents,
           config: { ...this.generationConfig, ...params.config },
         },
         prompt_id,
       );
-    };
-
     const onPersistent429Callback = async (
       authType?: string,
       error?: unknown,

packages/core/src/core/openaiContentGenerator/pipeline.test.ts

@@ -46,6 +46,7 @@ describe('ContentGenerationPipeline', () => {
 
     // Mock converter
     mockConverter = {
+      setModel: vi.fn(),
       convertGeminiRequestToOpenAI: vi.fn(),
       convertOpenAIResponseToGemini: vi.fn(),
       convertOpenAIChunkToGemini: vi.fn(),
@@ -99,6 +100,7 @@ describe('ContentGenerationPipeline', () => {
   describe('constructor', () => {
     it('should initialize with correct configuration', () => {
       expect(mockProvider.buildClient).toHaveBeenCalled();
+      // Converter is constructed once and the model is updated per-request via setModel().
       expect(OpenAIContentConverter).toHaveBeenCalledWith(
         'test-model',
         undefined,
@@ -144,6 +146,9 @@ describe('ContentGenerationPipeline', () => {
 
       // Assert
       expect(result).toBe(mockGeminiResponse);
+      expect(
+        (mockConverter as unknown as { setModel: Mock }).setModel,
+      ).toHaveBeenCalledWith('test-model');
       expect(mockConverter.convertGeminiRequestToOpenAI).toHaveBeenCalledWith(
         request,
       );
@@ -164,6 +169,53 @@ describe('ContentGenerationPipeline', () => {
       );
     });
 
+    it('should ignore request.model override and always use configured model', async () => {
+      // Arrange
+      const request: GenerateContentParameters = {
+        model: 'override-model',
+        contents: [{ parts: [{ text: 'Hello' }], role: 'user' }],
+      };
+      const userPromptId = 'test-prompt-id';
+
+      const mockMessages = [
+        { role: 'user', content: 'Hello' },
+      ] as OpenAI.Chat.ChatCompletionMessageParam[];
+      const mockOpenAIResponse = {
+        id: 'response-id',
+        choices: [
+          { message: { content: 'Hello response' }, finish_reason: 'stop' },
+        ],
+        created: Date.now(),
+        model: 'override-model',
+      } as OpenAI.Chat.ChatCompletion;
+      const mockGeminiResponse = new GenerateContentResponse();
+
+      (mockConverter.convertGeminiRequestToOpenAI as Mock).mockReturnValue(
+        mockMessages,
+      );
+      (mockConverter.convertOpenAIResponseToGemini as Mock).mockReturnValue(
+        mockGeminiResponse,
+      );
+      (mockClient.chat.completions.create as Mock).mockResolvedValue(
+        mockOpenAIResponse,
+      );
+
+      // Act
+      const result = await pipeline.execute(request, userPromptId);
+
+      // Assert
+      expect(result).toBe(mockGeminiResponse);
+      expect(
+        (mockConverter as unknown as { setModel: Mock }).setModel,
+      ).toHaveBeenCalledWith('test-model');
+      expect(mockClient.chat.completions.create).toHaveBeenCalledWith(
+        expect.objectContaining({
+          model: 'test-model',
+        }),
+        expect.any(Object),
+      );
+    });
+
     it('should handle tools in request', async () => {
       // Arrange
       const request: GenerateContentParameters = {
@@ -217,6 +269,9 @@ describe('ContentGenerationPipeline', () => {
 
       // Assert
       expect(result).toBe(mockGeminiResponse);
+      expect(
+        (mockConverter as unknown as { setModel: Mock }).setModel,
+      ).toHaveBeenCalledWith('test-model');
       expect(mockConverter.convertGeminiToolsToOpenAI).toHaveBeenCalledWith(
         request.config!.tools,
       );

packages/core/src/core/openaiContentGenerator/pipeline.ts

@@ -40,10 +40,16 @@ export class ContentGenerationPipeline {
     request: GenerateContentParameters,
     userPromptId: string,
   ): Promise<GenerateContentResponse> {
+    // For OpenAI-compatible providers, the configured model is the single source of truth.
+    // We intentionally ignore request.model because upstream callers may pass a model string
+    // that is not valid/available for the OpenAI-compatible backend.
+    const effectiveModel = this.contentGeneratorConfig.model;
+    this.converter.setModel(effectiveModel);
     return this.executeWithErrorHandling(
       request,
       userPromptId,
       false,
+      effectiveModel,
       async (openaiRequest) => {
         const openaiResponse = (await this.client.chat.completions.create(
           openaiRequest,
@@ -64,10 +70,13 @@ export class ContentGenerationPipeline {
     request: GenerateContentParameters,
     userPromptId: string,
   ): Promise<AsyncGenerator<GenerateContentResponse>> {
+    const effectiveModel = this.contentGeneratorConfig.model;
+    this.converter.setModel(effectiveModel);
     return this.executeWithErrorHandling(
       request,
       userPromptId,
       true,
+      effectiveModel,
       async (openaiRequest, context) => {
         // Stage 1: Create OpenAI stream
         const stream = (await this.client.chat.completions.create(
@@ -224,12 +233,13 @@ export class ContentGenerationPipeline {
     request: GenerateContentParameters,
     userPromptId: string,
     streaming: boolean = false,
+    effectiveModel: string,
   ): Promise<OpenAI.Chat.ChatCompletionCreateParams> {
     const messages = this.converter.convertGeminiRequestToOpenAI(request);
 
     // Apply provider-specific enhancements
     const baseRequest: OpenAI.Chat.ChatCompletionCreateParams = {
-      model: this.contentGeneratorConfig.model,
+      model: effectiveModel,
       messages,
       ...this.buildGenerateContentConfig(request),
     };
@@ -342,18 +352,24 @@ export class ContentGenerationPipeline {
     request: GenerateContentParameters,
     userPromptId: string,
     isStreaming: boolean,
+    effectiveModel: string,
     executor: (
       openaiRequest: OpenAI.Chat.ChatCompletionCreateParams,
       context: RequestContext,
     ) => Promise<T>,
   ): Promise<T> {
-    const context = this.createRequestContext(userPromptId, isStreaming);
+    const context = this.createRequestContext(
+      userPromptId,
+      isStreaming,
+      effectiveModel,
+    );
 
     try {
       const openaiRequest = await this.buildRequest(
         request,
         userPromptId,
         isStreaming,
+        effectiveModel,
       );
 
       const result = await executor(openaiRequest, context);
@@ -385,10 +401,11 @@ export class ContentGenerationPipeline {
   private createRequestContext(
     userPromptId: string,
     isStreaming: boolean,
+    effectiveModel: string,
   ): RequestContext {
     return {
       userPromptId,
-      model: this.contentGeneratorConfig.model,
+      model: effectiveModel,
       authType: this.contentGeneratorConfig.authType || 'unknown',
       startTime: Date.now(),
       duration: 0,

packages/core/src/fallback/types.ts

@@ -1,23 +0,0 @@
-/**
- * @license
- * Copyright 2025 Google LLC
- * SPDX-License-Identifier: Apache-2.0
- */
-
-/**
- * Defines the intent returned by the UI layer during a fallback scenario.
- */
-export type FallbackIntent =
-  | 'retry' // Immediately retry the current request with the fallback model.
-  | 'stop' // Switch to fallback for future requests, but stop the current request.
-  | 'auth'; // Stop the current request; user intends to change authentication.
-
-/**
- * The interface for the handler provided by the UI layer (e.g., the CLI)
- * to interact with the user during a fallback scenario.
- */
-export type FallbackModelHandler = (
-  failedModel: string,
-  fallbackModel: string,
-  error?: unknown,
-) => Promise<FallbackIntent | null>;

packages/core/src/index.ts

@@ -9,6 +9,30 @@ export * from './config/config.js';
 export * from './output/types.js';
 export * from './output/json-formatter.js';
 
+// Export models
+export {
+  type ModelCapabilities,
+  type ModelGenerationConfig,
+  type ModelConfig as ProviderModelConfig,
+  type ModelProvidersConfig,
+  type ResolvedModelConfig,
+  type AvailableModel,
+  type ModelSwitchMetadata,
+  QWEN_OAUTH_MODELS,
+  ModelRegistry,
+  ModelsConfig,
+  type ModelsConfigOptions,
+  type OnModelChangeCallback,
+  // Model configuration resolver
+  resolveModelConfig,
+  validateModelConfig,
+  type ModelConfigSourcesInput,
+  type ModelConfigCliInput,
+  type ModelConfigSettingsInput,
+  type ModelConfigResolutionResult,
+  type ModelConfigValidationResult,
+} from './models/index.js';
+
 // Export Core Logic
 export * from './core/client.js';
 export * from './core/contentGenerator.js';
@@ -21,8 +45,6 @@ export * from './core/geminiRequest.js';
 export * from './core/coreToolScheduler.js';
 export * from './core/nonInteractiveToolExecutor.js';
 
-export * from './fallback/types.js';
-
 export * from './qwen/qwenOAuth2.js';
 
 // Export utilities
@@ -55,6 +77,9 @@ export * from './utils/projectSummary.js';
 export * from './utils/promptIdContext.js';
 export * from './utils/thoughtUtils.js';
 
+// Config resolution utilities
+export * from './utils/configResolver.js';
+
 // Export services
 export * from './services/fileDiscoveryService.js';
 export * from './services/gitService.js';

packages/core/src/models/constants.ts

@@ -0,0 +1,134 @@
+/**
+ * @license
+ * Copyright 2025 Qwen Team
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { DEFAULT_QWEN_MODEL } from '../config/models.js';
+
+import type { ModelConfig } from './types.js';
+
+type AuthType = import('../core/contentGenerator.js').AuthType;
+type ContentGeneratorConfig =
+  import('../core/contentGenerator.js').ContentGeneratorConfig;
+
+/**
+ * Field keys for model-scoped generation config.
+ *
+ * Kept in a small standalone module to avoid circular deps. The `import('...')`
+ * usage is type-only and does not emit runtime imports.
+ */
+export const MODEL_GENERATION_CONFIG_FIELDS = [
+  'samplingParams',
+  'timeout',
+  'maxRetries',
+  'disableCacheControl',
+  'schemaCompliance',
+  'reasoning',
+] as const satisfies ReadonlyArray<keyof ContentGeneratorConfig>;
+
+/**
+ * Credential-related fields that are part of ContentGeneratorConfig
+ * but not ModelGenerationConfig.
+ */
+export const CREDENTIAL_FIELDS = [
+  'model',
+  'apiKey',
+  'apiKeyEnvKey',
+  'baseUrl',
+] as const satisfies ReadonlyArray<keyof ContentGeneratorConfig>;
+
+/**
+ * All provider-sourced fields that need to be tracked for source attribution
+ * and cleared when switching from provider to manual credentials.
+ */
+export const PROVIDER_SOURCED_FIELDS = [
+  ...CREDENTIAL_FIELDS,
+  ...MODEL_GENERATION_CONFIG_FIELDS,
+] as const;
+
+/**
+ * Environment variable mappings per authType.
+ */
+export interface AuthEnvMapping {
+  apiKey: string[];
+  baseUrl: string[];
+  model: string[];
+}
+
+export const AUTH_ENV_MAPPINGS = {
+  openai: {
+    apiKey: ['OPENAI_API_KEY'],
+    baseUrl: ['OPENAI_BASE_URL'],
+    model: ['OPENAI_MODEL', 'QWEN_MODEL'],
+  },
+  anthropic: {
+    apiKey: ['ANTHROPIC_API_KEY'],
+    baseUrl: ['ANTHROPIC_BASE_URL'],
+    model: ['ANTHROPIC_MODEL'],
+  },
+  gemini: {
+    apiKey: ['GEMINI_API_KEY'],
+    baseUrl: [],
+    model: ['GEMINI_MODEL'],
+  },
+  'vertex-ai': {
+    apiKey: ['GOOGLE_API_KEY'],
+    baseUrl: [],
+    model: ['GOOGLE_MODEL'],
+  },
+  'qwen-oauth': {
+    apiKey: [],
+    baseUrl: [],
+    model: [],
+  },
+} as const satisfies Record<AuthType, AuthEnvMapping>;
+
+export const DEFAULT_MODELS = {
+  openai: 'qwen3-coder-plus',
+  'qwen-oauth': DEFAULT_QWEN_MODEL,
+} as Partial<Record<AuthType, string>>;
+
+export const QWEN_OAUTH_ALLOWED_MODELS = [
+  DEFAULT_QWEN_MODEL,
+  'vision-model',
+] as const;
+
+/**
+ * Hard-coded Qwen OAuth models that are always available.
+ * These cannot be overridden by user configuration.
+ */
+export const QWEN_OAUTH_MODELS: ModelConfig[] = [
+  {
+    id: 'coder-model',
+    name: 'Qwen Coder',
+    description:
+      'The latest Qwen Coder model from Alibaba Cloud ModelStudio (version: qwen3-coder-plus-2025-09-23)',
+    capabilities: { vision: false },
+    generationConfig: {
+      samplingParams: {
+        temperature: 0.7,
+        top_p: 0.9,
+        max_tokens: 8192,
+      },
+      timeout: 60000,
+      maxRetries: 3,
+    },
+  },
+  {
+    id: 'vision-model',
+    name: 'Qwen Vision',
+    description:
+      'The latest Qwen Vision model from Alibaba Cloud ModelStudio (version: qwen3-vl-plus-2025-09-23)',
+    capabilities: { vision: true },
+    generationConfig: {
+      samplingParams: {
+        temperature: 0.7,
+        top_p: 0.9,
+        max_tokens: 8192,
+      },
+      timeout: 60000,
+      maxRetries: 3,
+    },
+  },
+];

packages/core/src/models/index.ts

@@ -0,0 +1,44 @@
+/**
+ * @license
+ * Copyright 2025 Qwen Team
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+export {
+  type ModelCapabilities,
+  type ModelGenerationConfig,
+  type ModelConfig,
+  type ModelProvidersConfig,
+  type ResolvedModelConfig,
+  type AvailableModel,
+  type ModelSwitchMetadata,
+} from './types.js';
+
+export { ModelRegistry } from './modelRegistry.js';
+
+export {
+  ModelsConfig,
+  type ModelsConfigOptions,
+  type OnModelChangeCallback,
+} from './modelsConfig.js';
+
+export {
+  AUTH_ENV_MAPPINGS,
+  CREDENTIAL_FIELDS,
+  DEFAULT_MODELS,
+  MODEL_GENERATION_CONFIG_FIELDS,
+  PROVIDER_SOURCED_FIELDS,
+  QWEN_OAUTH_ALLOWED_MODELS,
+  QWEN_OAUTH_MODELS,
+} from './constants.js';
+
+// Model configuration resolver
+export {
+  resolveModelConfig,
+  validateModelConfig,
+  type ModelConfigSourcesInput,
+  type ModelConfigCliInput,
+  type ModelConfigSettingsInput,
+  type ModelConfigResolutionResult,
+  type ModelConfigValidationResult,
+} from './modelConfigResolver.js';

packages/core/src/models/modelConfigErrors.ts

@@ -0,0 +1,125 @@
+/**
+ * @license
+ * Copyright 2025 Qwen Team
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+export function getDefaultApiKeyEnvVar(authType: string | undefined): string {
+  switch (authType) {
+    case 'openai':
+      return 'OPENAI_API_KEY';
+    case 'anthropic':
+      return 'ANTHROPIC_API_KEY';
+    case 'gemini':
+      return 'GEMINI_API_KEY';
+    case 'vertex-ai':
+      return 'GOOGLE_API_KEY';
+    default:
+      return 'API_KEY';
+  }
+}
+
+export function getDefaultModelEnvVar(authType: string | undefined): string {
+  switch (authType) {
+    case 'openai':
+      return 'OPENAI_MODEL';
+    case 'anthropic':
+      return 'ANTHROPIC_MODEL';
+    case 'gemini':
+      return 'GEMINI_MODEL';
+    case 'vertex-ai':
+      return 'GOOGLE_MODEL';
+    default:
+      return 'MODEL';
+  }
+}
+
+export abstract class ModelConfigError extends Error {
+  abstract readonly code: string;
+
+  protected constructor(message: string) {
+    super(message);
+    this.name = new.target.name;
+    Object.setPrototypeOf(this, new.target.prototype);
+  }
+}
+
+export class StrictMissingCredentialsError extends ModelConfigError {
+  readonly code = 'STRICT_MISSING_CREDENTIALS';
+
+  constructor(
+    authType: string | undefined,
+    model: string | undefined,
+    envKey?: string,
+  ) {
+    const providerKey = authType || '(unknown)';
+    const modelName = model || '(unknown)';
+    super(
+      `Missing credentials for modelProviders model '${modelName}'. ` +
+        (envKey
+          ? `Current configured envKey: '${envKey}'. Set that environment variable, or update modelProviders.${providerKey}[].envKey.`
+          : `Configure modelProviders.${providerKey}[].envKey and set that environment variable.`),
+    );
+  }
+}
+
+export class StrictMissingModelIdError extends ModelConfigError {
+  readonly code = 'STRICT_MISSING_MODEL_ID';
+
+  constructor(authType: string | undefined) {
+    super(
+      `Missing model id for strict modelProviders resolution (authType: ${authType}).`,
+    );
+  }
+}
+
+export class MissingApiKeyError extends ModelConfigError {
+  readonly code = 'MISSING_API_KEY';
+
+  constructor(params: {
+    authType: string | undefined;
+    model: string | undefined;
+    baseUrl: string | undefined;
+    envKey: string;
+  }) {
+    super(
+      `Missing API key for ${params.authType} auth. ` +
+        `Current model: '${params.model || '(unknown)'}', baseUrl: '${params.baseUrl || '(default)'}'. ` +
+        `Provide an API key via settings (security.auth.apiKey), ` +
+        `or set the environment variable '${params.envKey}'.`,
+    );
+  }
+}
+
+export class MissingModelError extends ModelConfigError {
+  readonly code = 'MISSING_MODEL';
+
+  constructor(params: { authType: string | undefined; envKey: string }) {
+    super(
+      `Missing model for ${params.authType} auth. ` +
+        `Set the environment variable '${params.envKey}'.`,
+    );
+  }
+}
+
+export class MissingBaseUrlError extends ModelConfigError {
+  readonly code = 'MISSING_BASE_URL';
+
+  constructor(params: {
+    authType: string | undefined;
+    model: string | undefined;
+  }) {
+    super(
+      `Missing baseUrl for modelProviders model '${params.model || '(unknown)'}' (authType: ${params.authType}). ` +
+        `Configure modelProviders.${params.authType || '(unknown)'}[].baseUrl.`,
+    );
+  }
+}
+
+export class MissingAnthropicBaseUrlEnvError extends ModelConfigError {
+  readonly code = 'MISSING_ANTHROPIC_BASE_URL_ENV';
+
+  constructor() {
+    super('ANTHROPIC_BASE_URL environment variable not found.');
+  }
+}

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

@@ -0,0 +1,355 @@
+/**
+ * @license
+ * Copyright 2025 Qwen Team
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect } from 'vitest';
+import {
+  resolveModelConfig,
+  validateModelConfig,
+} from './modelConfigResolver.js';
+import { AuthType } from '../core/contentGenerator.js';
+import { DEFAULT_QWEN_MODEL } from '../config/models.js';
+
+describe('modelConfigResolver', () => {
+  describe('resolveModelConfig', () => {
+    describe('OpenAI auth type', () => {
+      it('resolves from CLI with highest priority', () => {
+        const result = resolveModelConfig({
+          authType: AuthType.USE_OPENAI,
+          cli: {
+            model: 'cli-model',
+            apiKey: 'cli-key',
+            baseUrl: 'https://cli.example.com',
+          },
+          settings: {
+            model: 'settings-model',
+            apiKey: 'settings-key',
+            baseUrl: 'https://settings.example.com',
+          },
+          env: {
+            OPENAI_MODEL: 'env-model',
+            OPENAI_API_KEY: 'env-key',
+            OPENAI_BASE_URL: 'https://env.example.com',
+          },
+        });
+
+        expect(result.config.model).toBe('cli-model');
+        expect(result.config.apiKey).toBe('cli-key');
+        expect(result.config.baseUrl).toBe('https://cli.example.com');
+
+        expect(result.sources['model'].kind).toBe('cli');
+        expect(result.sources['apiKey'].kind).toBe('cli');
+        expect(result.sources['baseUrl'].kind).toBe('cli');
+      });
+
+      it('falls back to env when CLI not provided', () => {
+        const result = resolveModelConfig({
+          authType: AuthType.USE_OPENAI,
+          cli: {},
+          settings: {
+            model: 'settings-model',
+          },
+          env: {
+            OPENAI_MODEL: 'env-model',
+            OPENAI_API_KEY: 'env-key',
+          },
+        });
+
+        expect(result.config.model).toBe('env-model');
+        expect(result.config.apiKey).toBe('env-key');
+
+        expect(result.sources['model'].kind).toBe('env');
+        expect(result.sources['apiKey'].kind).toBe('env');
+      });
+
+      it('falls back to settings when env not provided', () => {
+        const result = resolveModelConfig({
+          authType: AuthType.USE_OPENAI,
+          cli: {},
+          settings: {
+            model: 'settings-model',
+            apiKey: 'settings-key',
+            baseUrl: 'https://settings.example.com',
+          },
+          env: {},
+        });
+
+        expect(result.config.model).toBe('settings-model');
+        expect(result.config.apiKey).toBe('settings-key');
+        expect(result.config.baseUrl).toBe('https://settings.example.com');
+
+        expect(result.sources['model'].kind).toBe('settings');
+        expect(result.sources['apiKey'].kind).toBe('settings');
+        expect(result.sources['baseUrl'].kind).toBe('settings');
+      });
+
+      it('uses default model when nothing provided', () => {
+        const result = resolveModelConfig({
+          authType: AuthType.USE_OPENAI,
+          cli: {},
+          settings: {},
+          env: {
+            OPENAI_API_KEY: 'some-key', // need key to be valid
+          },
+        });
+
+        expect(result.config.model).toBe('qwen3-coder-plus');
+        expect(result.sources['model'].kind).toBe('default');
+      });
+
+      it('prioritizes modelProvider over CLI', () => {
+        const result = resolveModelConfig({
+          authType: AuthType.USE_OPENAI,
+          cli: {
+            model: 'cli-model',
+          },
+          settings: {},
+          env: {
+            MY_CUSTOM_KEY: 'provider-key',
+          },
+          modelProvider: {
+            id: 'provider-model',
+            name: 'Provider Model',
+            authType: AuthType.USE_OPENAI,
+            envKey: 'MY_CUSTOM_KEY',
+            baseUrl: 'https://provider.example.com',
+            generationConfig: {},
+            capabilities: {},
+          },
+        });
+
+        expect(result.config.model).toBe('provider-model');
+        expect(result.config.apiKey).toBe('provider-key');
+        expect(result.config.baseUrl).toBe('https://provider.example.com');
+
+        expect(result.sources['model'].kind).toBe('modelProviders');
+        expect(result.sources['apiKey'].kind).toBe('env');
+        expect(result.sources['apiKey'].via?.kind).toBe('modelProviders');
+      });
+
+      it('reads QWEN_MODEL as fallback for OPENAI_MODEL', () => {
+        const result = resolveModelConfig({
+          authType: AuthType.USE_OPENAI,
+          cli: {},
+          settings: {},
+          env: {
+            QWEN_MODEL: 'qwen-model',
+            OPENAI_API_KEY: 'key',
+          },
+        });
+
+        expect(result.config.model).toBe('qwen-model');
+        expect(result.sources['model'].envKey).toBe('QWEN_MODEL');
+      });
+    });
+
+    describe('Qwen OAuth auth type', () => {
+      it('uses default model for Qwen OAuth', () => {
+        const result = resolveModelConfig({
+          authType: AuthType.QWEN_OAUTH,
+          cli: {},
+          settings: {},
+          env: {},
+        });
+
+        expect(result.config.model).toBe(DEFAULT_QWEN_MODEL);
+        expect(result.config.apiKey).toBe('QWEN_OAUTH_DYNAMIC_TOKEN');
+        expect(result.sources['apiKey'].kind).toBe('computed');
+      });
+
+      it('allows vision-model for Qwen OAuth', () => {
+        const result = resolveModelConfig({
+          authType: AuthType.QWEN_OAUTH,
+          cli: {
+            model: 'vision-model',
+          },
+          settings: {},
+          env: {},
+        });
+
+        expect(result.config.model).toBe('vision-model');
+        expect(result.sources['model'].kind).toBe('cli');
+      });
+
+      it('warns and falls back for unsupported Qwen OAuth models', () => {
+        const result = resolveModelConfig({
+          authType: AuthType.QWEN_OAUTH,
+          cli: {
+            model: 'unsupported-model',
+          },
+          settings: {},
+          env: {},
+        });
+
+        expect(result.config.model).toBe(DEFAULT_QWEN_MODEL);
+        expect(result.warnings).toHaveLength(1);
+        expect(result.warnings[0]).toContain('unsupported-model');
+      });
+    });
+
+    describe('Anthropic auth type', () => {
+      it('resolves Anthropic config from env', () => {
+        const result = resolveModelConfig({
+          authType: AuthType.USE_ANTHROPIC,
+          cli: {},
+          settings: {},
+          env: {
+            ANTHROPIC_API_KEY: 'anthropic-key',
+            ANTHROPIC_BASE_URL: 'https://anthropic.example.com',
+            ANTHROPIC_MODEL: 'claude-3',
+          },
+        });
+
+        expect(result.config.model).toBe('claude-3');
+        expect(result.config.apiKey).toBe('anthropic-key');
+        expect(result.config.baseUrl).toBe('https://anthropic.example.com');
+      });
+    });
+
+    describe('generation config resolution', () => {
+      it('merges generation config from settings', () => {
+        const result = resolveModelConfig({
+          authType: AuthType.USE_OPENAI,
+          cli: {},
+          settings: {
+            apiKey: 'key',
+            generationConfig: {
+              timeout: 60000,
+              maxRetries: 5,
+              samplingParams: {
+                temperature: 0.7,
+              },
+            },
+          },
+          env: {},
+        });
+
+        expect(result.config.timeout).toBe(60000);
+        expect(result.config.maxRetries).toBe(5);
+        expect(result.config.samplingParams?.temperature).toBe(0.7);
+
+        expect(result.sources['timeout'].kind).toBe('settings');
+        expect(result.sources['samplingParams'].kind).toBe('settings');
+      });
+
+      it('modelProvider config overrides settings', () => {
+        const result = resolveModelConfig({
+          authType: AuthType.USE_OPENAI,
+          cli: {},
+          settings: {
+            generationConfig: {
+              timeout: 30000,
+            },
+          },
+          env: {
+            MY_KEY: 'key',
+          },
+          modelProvider: {
+            id: 'model',
+            name: 'Model',
+            authType: AuthType.USE_OPENAI,
+            envKey: 'MY_KEY',
+            baseUrl: 'https://api.example.com',
+            generationConfig: {
+              timeout: 60000,
+            },
+            capabilities: {},
+          },
+        });
+
+        expect(result.config.timeout).toBe(60000);
+        expect(result.sources['timeout'].kind).toBe('modelProviders');
+      });
+    });
+
+    describe('proxy handling', () => {
+      it('includes proxy in config when provided', () => {
+        const result = resolveModelConfig({
+          authType: AuthType.USE_OPENAI,
+          cli: {},
+          settings: { apiKey: 'key' },
+          env: {},
+          proxy: 'http://proxy.example.com:8080',
+        });
+
+        expect(result.config.proxy).toBe('http://proxy.example.com:8080');
+        expect(result.sources['proxy'].kind).toBe('computed');
+      });
+    });
+  });
+
+  describe('validateModelConfig', () => {
+    it('passes for valid OpenAI config', () => {
+      const result = validateModelConfig({
+        authType: AuthType.USE_OPENAI,
+        model: 'gpt-4',
+        apiKey: 'sk-xxx',
+      });
+
+      expect(result.valid).toBe(true);
+      expect(result.errors).toHaveLength(0);
+    });
+
+    it('fails when API key missing', () => {
+      const result = validateModelConfig({
+        authType: AuthType.USE_OPENAI,
+        model: 'gpt-4',
+      });
+
+      expect(result.valid).toBe(false);
+      expect(result.errors).toHaveLength(1);
+      expect(result.errors[0].message).toContain('Missing API key');
+    });
+
+    it('fails when model missing', () => {
+      const result = validateModelConfig({
+        authType: AuthType.USE_OPENAI,
+        model: '',
+        apiKey: 'sk-xxx',
+      });
+
+      expect(result.valid).toBe(false);
+      expect(result.errors).toHaveLength(1);
+      expect(result.errors[0].message).toContain('Missing model');
+    });
+
+    it('always passes for Qwen OAuth', () => {
+      const result = validateModelConfig({
+        authType: AuthType.QWEN_OAUTH,
+        model: DEFAULT_QWEN_MODEL,
+        apiKey: 'QWEN_OAUTH_DYNAMIC_TOKEN',
+      });
+
+      expect(result.valid).toBe(true);
+    });
+
+    it('requires baseUrl for Anthropic', () => {
+      const result = validateModelConfig({
+        authType: AuthType.USE_ANTHROPIC,
+        model: 'claude-3',
+        apiKey: 'key',
+        // missing baseUrl
+      });
+
+      expect(result.valid).toBe(false);
+      expect(result.errors[0].message).toContain('ANTHROPIC_BASE_URL');
+    });
+
+    it('uses strict error messages for modelProvider', () => {
+      const result = validateModelConfig(
+        {
+          authType: AuthType.USE_OPENAI,
+          model: 'my-model',
+          // missing apiKey
+        },
+        true, // isStrictModelProvider
+      );
+
+      expect(result.valid).toBe(false);
+      expect(result.errors[0].message).toContain('modelProviders');
+      expect(result.errors[0].message).toContain('envKey');
+    });
+  });
+});

packages/core/src/models/modelConfigResolver.ts

@@ -0,0 +1,362 @@
+/**
+ * @license
+ * Copyright 2025 Qwen Team
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * ModelConfigResolver - Unified resolver for model-related configuration.
+ *
+ * This module consolidates all model configuration resolution logic,
+ * eliminating duplicate code between CLI and Core layers.
+ *
+ * Configuration priority (highest to lowest):
+ * 1. modelProvider - Explicit selection from ModelProviders config
+ * 2. CLI arguments - Command line flags (--model, --openaiApiKey, etc.)
+ * 3. Environment variables - OPENAI_API_KEY, OPENAI_MODEL, etc.
+ * 4. Settings - User/workspace settings file
+ * 5. Defaults - Built-in default values
+ */
+
+import { AuthType } from '../core/contentGenerator.js';
+import type { ContentGeneratorConfig } from '../core/contentGenerator.js';
+import { DEFAULT_QWEN_MODEL } from '../config/models.js';
+import {
+  resolveField,
+  resolveOptionalField,
+  layer,
+  envLayer,
+  cliSource,
+  settingsSource,
+  modelProvidersSource,
+  defaultSource,
+  computedSource,
+  type ConfigSource,
+  type ConfigSources,
+  type ConfigLayer,
+} from '../utils/configResolver.js';
+import {
+  AUTH_ENV_MAPPINGS,
+  DEFAULT_MODELS,
+  QWEN_OAUTH_ALLOWED_MODELS,
+  MODEL_GENERATION_CONFIG_FIELDS,
+} from './constants.js';
+import type { ResolvedModelConfig } from './types.js';
+export {
+  validateModelConfig,
+  type ModelConfigValidationResult,
+} from '../core/contentGenerator.js';
+
+/**
+ * CLI-provided configuration values
+ */
+export interface ModelConfigCliInput {
+  model?: string;
+  apiKey?: string;
+  baseUrl?: string;
+}
+
+/**
+ * Settings-provided configuration values
+ */
+export interface ModelConfigSettingsInput {
+  /** Model name from settings.model.name */
+  model?: string;
+  /** API key from settings.security.auth.apiKey */
+  apiKey?: string;
+  /** Base URL from settings.security.auth.baseUrl */
+  baseUrl?: string;
+  /** Generation config from settings.model.generationConfig */
+  generationConfig?: Partial<ContentGeneratorConfig>;
+}
+
+/**
+ * All input sources for model configuration resolution
+ */
+export interface ModelConfigSourcesInput {
+  /** Authentication type */
+  authType: AuthType;
+
+  /** CLI arguments (highest priority for user-provided values) */
+  cli?: ModelConfigCliInput;
+
+  /** Settings file configuration */
+  settings?: ModelConfigSettingsInput;
+
+  /** Environment variables (injected for testability) */
+  env: Record<string, string | undefined>;
+
+  /** Resolved model from ModelProviders (explicit selection, highest priority) */
+  modelProvider?: ResolvedModelConfig;
+
+  /** Proxy URL (computed from Config) */
+  proxy?: string;
+}
+
+/**
+ * Result of model configuration resolution
+ */
+export interface ModelConfigResolutionResult {
+  /** The fully resolved configuration */
+  config: ContentGeneratorConfig;
+  /** Source attribution for each field */
+  sources: ConfigSources;
+  /** Warnings generated during resolution */
+  warnings: string[];
+}
+
+/**
+ * Resolve model configuration from all input sources.
+ *
+ * This is the single entry point for model configuration resolution.
+ * It replaces the duplicate logic in:
+ * - packages/cli/src/utils/modelProviderUtils.ts (resolveCliGenerationConfig)
+ * - packages/core/src/core/contentGenerator.ts (resolveContentGeneratorConfigWithSources)
+ *
+ * @param input - All configuration sources
+ * @returns Resolved configuration with source tracking
+ */
+export function resolveModelConfig(
+  input: ModelConfigSourcesInput,
+): ModelConfigResolutionResult {
+  const { authType, cli, settings, env, modelProvider, proxy } = input;
+  const warnings: string[] = [];
+  const sources: ConfigSources = {};
+
+  // Special handling for Qwen OAuth
+  if (authType === AuthType.QWEN_OAUTH) {
+    return resolveQwenOAuthConfig(input, warnings);
+  }
+
+  // Get auth-specific env var mappings
+  const envMapping =
+    AUTH_ENV_MAPPINGS[authType] || AUTH_ENV_MAPPINGS[AuthType.USE_OPENAI];
+
+  // Build layers for each field in priority order
+  // Priority: modelProvider > cli > env > settings > default
+
+  // ---- Model ----
+  const modelLayers: Array<ConfigLayer<string>> = [];
+
+  if (modelProvider) {
+    modelLayers.push(
+      layer(
+        modelProvider.id,
+        modelProvidersSource(authType, modelProvider.id, 'model.id'),
+      ),
+    );
+  }
+  if (cli?.model) {
+    modelLayers.push(layer(cli.model, cliSource('--model')));
+  }
+  for (const envKey of envMapping.model) {
+    modelLayers.push(envLayer(env, envKey));
+  }
+  if (settings?.model) {
+    modelLayers.push(layer(settings.model, settingsSource('model.name')));
+  }
+
+  const defaultModel = DEFAULT_MODELS[authType] || '';
+  const modelResult = resolveField(
+    modelLayers,
+    defaultModel,
+    defaultSource(defaultModel),
+  );
+  sources['model'] = modelResult.source;
+
+  // ---- API Key ----
+  const apiKeyLayers: Array<ConfigLayer<string>> = [];
+
+  // For modelProvider, read from the specified envKey
+  if (modelProvider?.envKey) {
+    const apiKeyFromEnv = env[modelProvider.envKey];
+    if (apiKeyFromEnv) {
+      apiKeyLayers.push(
+        layer(apiKeyFromEnv, {
+          kind: 'env',
+          envKey: modelProvider.envKey,
+          via: modelProvidersSource(authType, modelProvider.id, 'envKey'),
+        }),
+      );
+    }
+  }
+  if (cli?.apiKey) {
+    apiKeyLayers.push(layer(cli.apiKey, cliSource('--openaiApiKey')));
+  }
+  for (const envKey of envMapping.apiKey) {
+    apiKeyLayers.push(envLayer(env, envKey));
+  }
+  if (settings?.apiKey) {
+    apiKeyLayers.push(
+      layer(settings.apiKey, settingsSource('security.auth.apiKey')),
+    );
+  }
+
+  const apiKeyResult = resolveOptionalField(apiKeyLayers);
+  if (apiKeyResult) {
+    sources['apiKey'] = apiKeyResult.source;
+  }
+
+  // ---- Base URL ----
+  const baseUrlLayers: Array<ConfigLayer<string>> = [];
+
+  if (modelProvider?.baseUrl) {
+    baseUrlLayers.push(
+      layer(
+        modelProvider.baseUrl,
+        modelProvidersSource(authType, modelProvider.id, 'baseUrl'),
+      ),
+    );
+  }
+  if (cli?.baseUrl) {
+    baseUrlLayers.push(layer(cli.baseUrl, cliSource('--openaiBaseUrl')));
+  }
+  for (const envKey of envMapping.baseUrl) {
+    baseUrlLayers.push(envLayer(env, envKey));
+  }
+  if (settings?.baseUrl) {
+    baseUrlLayers.push(
+      layer(settings.baseUrl, settingsSource('security.auth.baseUrl')),
+    );
+  }
+
+  const baseUrlResult = resolveOptionalField(baseUrlLayers);
+  if (baseUrlResult) {
+    sources['baseUrl'] = baseUrlResult.source;
+  }
+
+  // ---- API Key Env Key (for error messages) ----
+  let apiKeyEnvKey: string | undefined;
+  if (modelProvider?.envKey) {
+    apiKeyEnvKey = modelProvider.envKey;
+    sources['apiKeyEnvKey'] = modelProvidersSource(
+      authType,
+      modelProvider.id,
+      'envKey',
+    );
+  }
+
+  // ---- Generation Config (from settings or modelProvider) ----
+  const generationConfig = resolveGenerationConfig(
+    settings?.generationConfig,
+    modelProvider?.generationConfig,
+    authType,
+    modelProvider?.id,
+    sources,
+  );
+
+  // Build final config
+  const config: ContentGeneratorConfig = {
+    authType,
+    model: modelResult.value,
+    apiKey: apiKeyResult?.value,
+    apiKeyEnvKey,
+    baseUrl: baseUrlResult?.value,
+    proxy,
+    ...generationConfig,
+  };
+
+  // Add proxy source
+  if (proxy) {
+    sources['proxy'] = computedSource('Config.getProxy()');
+  }
+
+  // Add authType source
+  sources['authType'] = computedSource('provided by caller');
+
+  return { config, sources, warnings };
+}
+
+/**
+ * Special resolver for Qwen OAuth authentication.
+ * Qwen OAuth has fixed model options and uses dynamic tokens.
+ */
+function resolveQwenOAuthConfig(
+  input: ModelConfigSourcesInput,
+  warnings: string[],
+): ModelConfigResolutionResult {
+  const { cli, settings, proxy } = input;
+  const sources: ConfigSources = {};
+
+  // Qwen OAuth only allows specific models
+  const allowedModels = new Set<string>(QWEN_OAUTH_ALLOWED_MODELS);
+
+  // Determine requested model
+  const requestedModel = cli?.model || settings?.model;
+  let resolvedModel: string;
+  let modelSource: ConfigSource;
+
+  if (requestedModel && allowedModels.has(requestedModel)) {
+    resolvedModel = requestedModel;
+    modelSource = cli?.model
+      ? cliSource('--model')
+      : settingsSource('model.name');
+  } else {
+    if (requestedModel) {
+      warnings.push(
+        `Unsupported Qwen OAuth model '${requestedModel}', falling back to '${DEFAULT_QWEN_MODEL}'.`,
+      );
+    }
+    resolvedModel = DEFAULT_QWEN_MODEL;
+    modelSource = defaultSource(`fallback to '${DEFAULT_QWEN_MODEL}'`);
+  }
+
+  sources['model'] = modelSource;
+  sources['apiKey'] = computedSource('Qwen OAuth dynamic token');
+  sources['authType'] = computedSource('provided by caller');
+
+  if (proxy) {
+    sources['proxy'] = computedSource('Config.getProxy()');
+  }
+
+  // Resolve generation config from settings
+  const generationConfig = resolveGenerationConfig(
+    settings?.generationConfig,
+    undefined,
+    AuthType.QWEN_OAUTH,
+    resolvedModel,
+    sources,
+  );
+
+  const config: ContentGeneratorConfig = {
+    authType: AuthType.QWEN_OAUTH,
+    model: resolvedModel,
+    apiKey: 'QWEN_OAUTH_DYNAMIC_TOKEN',
+    proxy,
+    ...generationConfig,
+  };
+
+  return { config, sources, warnings };
+}
+
+/**
+ * Resolve generation config fields (samplingParams, timeout, etc.)
+ */
+function resolveGenerationConfig(
+  settingsConfig: Partial<ContentGeneratorConfig> | undefined,
+  modelProviderConfig: Partial<ContentGeneratorConfig> | undefined,
+  authType: AuthType,
+  modelId: string | undefined,
+  sources: ConfigSources,
+): Partial<ContentGeneratorConfig> {
+  const result: Partial<ContentGeneratorConfig> = {};
+
+  for (const field of MODEL_GENERATION_CONFIG_FIELDS) {
+    // ModelProvider config takes priority
+    if (modelProviderConfig && field in modelProviderConfig) {
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      (result as any)[field] = modelProviderConfig[field];
+      sources[field] = modelProvidersSource(
+        authType,
+        modelId || '',
+        `generationConfig.${field}`,
+      );
+    } else if (settingsConfig && field in settingsConfig) {
+      // eslint-disable-next-line @typescript-eslint/no-explicit-any
+      (result as any)[field] = settingsConfig[field];
+      sources[field] = settingsSource(`model.generationConfig.${field}`);
+    }
+  }
+
+  return result;
+}

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

@@ -0,0 +1,390 @@
+/**
+ * @license
+ * Copyright 2025 Qwen Team
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect, beforeEach, vi } from 'vitest';
+import { ModelRegistry, QWEN_OAUTH_MODELS } from './modelRegistry.js';
+import { AuthType } from '../core/contentGenerator.js';
+import type { ModelProvidersConfig } from './types.js';
+
+describe('ModelRegistry', () => {
+  describe('initialization', () => {
+    it('should always include hard-coded qwen-oauth models', () => {
+      const registry = new ModelRegistry();
+
+      const qwenModels = registry.getModelsForAuthType(AuthType.QWEN_OAUTH);
+      expect(qwenModels.length).toBe(QWEN_OAUTH_MODELS.length);
+      expect(qwenModels[0].id).toBe('coder-model');
+      expect(qwenModels[1].id).toBe('vision-model');
+    });
+
+    it('should initialize with empty config', () => {
+      const registry = new ModelRegistry();
+      expect(registry.getModelsForAuthType(AuthType.QWEN_OAUTH).length).toBe(
+        QWEN_OAUTH_MODELS.length,
+      );
+      expect(registry.getModelsForAuthType(AuthType.USE_OPENAI).length).toBe(0);
+    });
+
+    it('should initialize with custom models config', () => {
+      const modelProvidersConfig: ModelProvidersConfig = {
+        openai: [
+          {
+            id: 'gpt-4-turbo',
+            name: 'GPT-4 Turbo',
+            baseUrl: 'https://api.openai.com/v1',
+          },
+        ],
+      };
+
+      const registry = new ModelRegistry(modelProvidersConfig);
+
+      const openaiModels = registry.getModelsForAuthType(AuthType.USE_OPENAI);
+      expect(openaiModels.length).toBe(1);
+      expect(openaiModels[0].id).toBe('gpt-4-turbo');
+    });
+
+    it('should ignore qwen-oauth models in config (hard-coded)', () => {
+      const modelProvidersConfig: ModelProvidersConfig = {
+        'qwen-oauth': [
+          {
+            id: 'custom-qwen',
+            name: 'Custom Qwen',
+          },
+        ],
+      };
+
+      const registry = new ModelRegistry(modelProvidersConfig);
+
+      // Should still use hard-coded qwen-oauth models
+      const qwenModels = registry.getModelsForAuthType(AuthType.QWEN_OAUTH);
+      expect(qwenModels.length).toBe(QWEN_OAUTH_MODELS.length);
+      expect(qwenModels.find((m) => m.id === 'custom-qwen')).toBeUndefined();
+    });
+  });
+
+  describe('getModelsForAuthType', () => {
+    let registry: ModelRegistry;
+
+    beforeEach(() => {
+      const modelProvidersConfig: ModelProvidersConfig = {
+        openai: [
+          {
+            id: 'gpt-4-turbo',
+            name: 'GPT-4 Turbo',
+            description: 'Most capable GPT-4',
+            baseUrl: 'https://api.openai.com/v1',
+            capabilities: { vision: true },
+          },
+          {
+            id: 'gpt-3.5-turbo',
+            name: 'GPT-3.5 Turbo',
+            capabilities: { vision: false },
+          },
+        ],
+      };
+      registry = new ModelRegistry(modelProvidersConfig);
+    });
+
+    it('should return models for existing authType', () => {
+      const models = registry.getModelsForAuthType(AuthType.USE_OPENAI);
+      expect(models.length).toBe(2);
+    });
+
+    it('should return empty array for non-existent authType', () => {
+      const models = registry.getModelsForAuthType(AuthType.USE_VERTEX_AI);
+      expect(models.length).toBe(0);
+    });
+
+    it('should return AvailableModel format with correct fields', () => {
+      const models = registry.getModelsForAuthType(AuthType.USE_OPENAI);
+      const gpt4 = models.find((m) => m.id === 'gpt-4-turbo');
+
+      expect(gpt4).toBeDefined();
+      expect(gpt4?.label).toBe('GPT-4 Turbo');
+      expect(gpt4?.description).toBe('Most capable GPT-4');
+      expect(gpt4?.isVision).toBe(true);
+      expect(gpt4?.authType).toBe(AuthType.USE_OPENAI);
+    });
+  });
+
+  describe('getModel', () => {
+    let registry: ModelRegistry;
+
+    beforeEach(() => {
+      const modelProvidersConfig: ModelProvidersConfig = {
+        openai: [
+          {
+            id: 'gpt-4-turbo',
+            name: 'GPT-4 Turbo',
+            baseUrl: 'https://api.openai.com/v1',
+            generationConfig: {
+              samplingParams: {
+                temperature: 0.8,
+                max_tokens: 4096,
+              },
+            },
+          },
+        ],
+      };
+      registry = new ModelRegistry(modelProvidersConfig);
+    });
+
+    it('should return resolved model config', () => {
+      const model = registry.getModel(AuthType.USE_OPENAI, 'gpt-4-turbo');
+
+      expect(model).toBeDefined();
+      expect(model?.id).toBe('gpt-4-turbo');
+      expect(model?.name).toBe('GPT-4 Turbo');
+      expect(model?.authType).toBe(AuthType.USE_OPENAI);
+      expect(model?.baseUrl).toBe('https://api.openai.com/v1');
+    });
+
+    it('should preserve generationConfig without applying defaults', () => {
+      const model = registry.getModel(AuthType.USE_OPENAI, 'gpt-4-turbo');
+
+      expect(model?.generationConfig.samplingParams?.temperature).toBe(0.8);
+      expect(model?.generationConfig.samplingParams?.max_tokens).toBe(4096);
+      // No defaults are applied - only the configured values are present
+      expect(model?.generationConfig.samplingParams?.top_p).toBeUndefined();
+      expect(model?.generationConfig.timeout).toBeUndefined();
+    });
+
+    it('should return undefined for non-existent model', () => {
+      const model = registry.getModel(AuthType.USE_OPENAI, 'non-existent');
+      expect(model).toBeUndefined();
+    });
+
+    it('should return undefined for non-existent authType', () => {
+      const model = registry.getModel(AuthType.USE_VERTEX_AI, 'some-model');
+      expect(model).toBeUndefined();
+    });
+  });
+
+  describe('hasModel', () => {
+    let registry: ModelRegistry;
+
+    beforeEach(() => {
+      registry = new ModelRegistry({
+        openai: [{ id: 'gpt-4', name: 'GPT-4' }],
+      });
+    });
+
+    it('should return true for existing model', () => {
+      expect(registry.hasModel(AuthType.USE_OPENAI, 'gpt-4')).toBe(true);
+    });
+
+    it('should return false for non-existent model', () => {
+      expect(registry.hasModel(AuthType.USE_OPENAI, 'non-existent')).toBe(
+        false,
+      );
+    });
+
+    it('should return false for non-existent authType', () => {
+      expect(registry.hasModel(AuthType.USE_VERTEX_AI, 'gpt-4')).toBe(false);
+    });
+  });
+
+  describe('getDefaultModelForAuthType', () => {
+    it('should return coder-model for qwen-oauth', () => {
+      const registry = new ModelRegistry();
+      const defaultModel = registry.getDefaultModelForAuthType(
+        AuthType.QWEN_OAUTH,
+      );
+      expect(defaultModel?.id).toBe('coder-model');
+    });
+
+    it('should return first model for other authTypes', () => {
+      const registry = new ModelRegistry({
+        openai: [
+          { id: 'gpt-4', name: 'GPT-4' },
+          { id: 'gpt-3.5', name: 'GPT-3.5' },
+        ],
+      });
+
+      const defaultModel = registry.getDefaultModelForAuthType(
+        AuthType.USE_OPENAI,
+      );
+      expect(defaultModel?.id).toBe('gpt-4');
+    });
+  });
+
+  describe('validation', () => {
+    it('should throw error for model without id', () => {
+      expect(
+        () =>
+          new ModelRegistry({
+            openai: [{ id: '', name: 'No ID' }],
+          }),
+      ).toThrow('missing required field: id');
+    });
+  });
+
+  describe('default base URLs', () => {
+    it('should apply default dashscope URL for qwen-oauth', () => {
+      const registry = new ModelRegistry();
+      const model = registry.getModel(AuthType.QWEN_OAUTH, 'coder-model');
+      expect(model?.baseUrl).toBe(
+        'https://dashscope.aliyuncs.com/compatible-mode/v1',
+      );
+    });
+
+    it('should apply default openai URL when not specified', () => {
+      const registry = new ModelRegistry({
+        openai: [{ id: 'gpt-4', name: 'GPT-4' }],
+      });
+
+      const model = registry.getModel(AuthType.USE_OPENAI, 'gpt-4');
+      expect(model?.baseUrl).toBe('https://api.openai.com/v1');
+    });
+
+    it('should use custom baseUrl when specified', () => {
+      const registry = new ModelRegistry({
+        openai: [
+          {
+            id: 'deepseek',
+            name: 'DeepSeek',
+            baseUrl: 'https://api.deepseek.com/v1',
+          },
+        ],
+      });
+
+      const model = registry.getModel(AuthType.USE_OPENAI, 'deepseek');
+      expect(model?.baseUrl).toBe('https://api.deepseek.com/v1');
+    });
+  });
+
+  describe('authType key validation', () => {
+    it('should accept valid authType keys', () => {
+      const registry = new ModelRegistry({
+        openai: [{ id: 'gpt-4', name: 'GPT-4' }],
+        gemini: [{ id: 'gemini-pro', name: 'Gemini Pro' }],
+      });
+
+      const openaiModels = registry.getModelsForAuthType(AuthType.USE_OPENAI);
+      expect(openaiModels.length).toBe(1);
+      expect(openaiModels[0].id).toBe('gpt-4');
+
+      const geminiModels = registry.getModelsForAuthType(AuthType.USE_GEMINI);
+      expect(geminiModels.length).toBe(1);
+      expect(geminiModels[0].id).toBe('gemini-pro');
+    });
+
+    it('should skip invalid authType keys with warning', () => {
+      const consoleWarnSpy = vi
+        .spyOn(console, 'warn')
+        .mockImplementation(() => undefined);
+
+      const registry = new ModelRegistry({
+        openai: [{ id: 'gpt-4', name: 'GPT-4' }],
+        'invalid-key': [{ id: 'some-model', name: 'Some Model' }],
+      } as unknown as ModelProvidersConfig);
+
+      expect(consoleWarnSpy).toHaveBeenCalledWith(
+        expect.stringContaining('[ModelRegistry] Invalid authType key'),
+      );
+      expect(consoleWarnSpy).toHaveBeenCalledWith(
+        expect.stringContaining('invalid-key'),
+      );
+      expect(consoleWarnSpy).toHaveBeenCalledWith(
+        expect.stringContaining('Expected one of:'),
+      );
+
+      // Valid key should be registered
+      expect(registry.getModelsForAuthType(AuthType.USE_OPENAI).length).toBe(1);
+
+      // Invalid key should be skipped (no crash)
+      const openaiModels = registry.getModelsForAuthType(AuthType.USE_OPENAI);
+      expect(openaiModels.length).toBe(1);
+
+      consoleWarnSpy.mockRestore();
+    });
+
+    it('should handle mixed valid and invalid keys', () => {
+      const consoleWarnSpy = vi
+        .spyOn(console, 'warn')
+        .mockImplementation(() => undefined);
+
+      const registry = new ModelRegistry({
+        openai: [{ id: 'gpt-4', name: 'GPT-4' }],
+        'bad-key-1': [{ id: 'model-1', name: 'Model 1' }],
+        gemini: [{ id: 'gemini-pro', name: 'Gemini Pro' }],
+        'bad-key-2': [{ id: 'model-2', name: 'Model 2' }],
+      } as unknown as ModelProvidersConfig);
+
+      // Should warn twice for the two invalid keys
+      expect(consoleWarnSpy).toHaveBeenCalledTimes(2);
+      expect(consoleWarnSpy).toHaveBeenCalledWith(
+        expect.stringContaining('bad-key-1'),
+      );
+      expect(consoleWarnSpy).toHaveBeenCalledWith(
+        expect.stringContaining('bad-key-2'),
+      );
+
+      // Valid keys should be registered
+      expect(registry.getModelsForAuthType(AuthType.USE_OPENAI).length).toBe(1);
+      expect(registry.getModelsForAuthType(AuthType.USE_GEMINI).length).toBe(1);
+
+      // Invalid keys should be skipped
+      const openaiModels = registry.getModelsForAuthType(AuthType.USE_OPENAI);
+      expect(openaiModels.length).toBe(1);
+
+      const geminiModels = registry.getModelsForAuthType(AuthType.USE_GEMINI);
+      expect(geminiModels.length).toBe(1);
+
+      consoleWarnSpy.mockRestore();
+    });
+
+    it('should list all valid AuthType values in warning message', () => {
+      const consoleWarnSpy = vi
+        .spyOn(console, 'warn')
+        .mockImplementation(() => undefined);
+
+      new ModelRegistry({
+        'invalid-auth': [{ id: 'model', name: 'Model' }],
+      } as unknown as ModelProvidersConfig);
+
+      expect(consoleWarnSpy).toHaveBeenCalledWith(
+        expect.stringContaining('openai'),
+      );
+      expect(consoleWarnSpy).toHaveBeenCalledWith(
+        expect.stringContaining('qwen-oauth'),
+      );
+      expect(consoleWarnSpy).toHaveBeenCalledWith(
+        expect.stringContaining('gemini'),
+      );
+      expect(consoleWarnSpy).toHaveBeenCalledWith(
+        expect.stringContaining('vertex-ai'),
+      );
+      expect(consoleWarnSpy).toHaveBeenCalledWith(
+        expect.stringContaining('anthropic'),
+      );
+
+      consoleWarnSpy.mockRestore();
+    });
+
+    it('should work correctly with getModelsForAuthType after validation', () => {
+      const consoleWarnSpy = vi
+        .spyOn(console, 'warn')
+        .mockImplementation(() => undefined);
+
+      const registry = new ModelRegistry({
+        openai: [
+          { id: 'gpt-4', name: 'GPT-4' },
+          { id: 'gpt-3.5', name: 'GPT-3.5' },
+        ],
+        'invalid-key': [{ id: 'invalid-model', name: 'Invalid Model' }],
+      } as unknown as ModelProvidersConfig);
+
+      const models = registry.getModelsForAuthType(AuthType.USE_OPENAI);
+      expect(models.length).toBe(2);
+      expect(models.find((m) => m.id === 'gpt-4')).toBeDefined();
+      expect(models.find((m) => m.id === 'gpt-3.5')).toBeDefined();
+      expect(models.find((m) => m.id === 'invalid-model')).toBeUndefined();
+
+      consoleWarnSpy.mockRestore();
+    });
+  });
+});

packages/core/src/models/modelRegistry.ts

@@ -0,0 +1,180 @@
+/**
+ * @license
+ * Copyright 2025 Qwen Team
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { AuthType } from '../core/contentGenerator.js';
+import { DEFAULT_OPENAI_BASE_URL } from '../core/openaiContentGenerator/constants.js';
+import {
+  type ModelConfig,
+  type ModelProvidersConfig,
+  type ResolvedModelConfig,
+  type AvailableModel,
+} from './types.js';
+import { DEFAULT_QWEN_MODEL } from '../config/models.js';
+import { QWEN_OAUTH_MODELS } from './constants.js';
+
+export { QWEN_OAUTH_MODELS } from './constants.js';
+
+/**
+ * Validates if a string key is a valid AuthType enum value.
+ * @param key - The key to validate
+ * @returns The validated AuthType or undefined if invalid
+ */
+function validateAuthTypeKey(key: string): AuthType | undefined {
+  // Check if the key is a valid AuthType enum value
+  if (Object.values(AuthType).includes(key as AuthType)) {
+    return key as AuthType;
+  }
+
+  // Invalid key
+  return undefined;
+}
+
+/**
+ * Central registry for managing model configurations.
+ * Models are organized by authType.
+ */
+export class ModelRegistry {
+  private modelsByAuthType: Map<AuthType, Map<string, ResolvedModelConfig>>;
+
+  private getDefaultBaseUrl(authType: AuthType): string {
+    switch (authType) {
+      case AuthType.QWEN_OAUTH:
+        return 'DYNAMIC_QWEN_OAUTH_BASE_URL';
+      case AuthType.USE_OPENAI:
+        return DEFAULT_OPENAI_BASE_URL;
+      default:
+        return '';
+    }
+  }
+
+  constructor(modelProvidersConfig?: ModelProvidersConfig) {
+    this.modelsByAuthType = new Map();
+
+    // Always register qwen-oauth models (hard-coded, cannot be overridden)
+    this.registerAuthTypeModels(AuthType.QWEN_OAUTH, QWEN_OAUTH_MODELS);
+
+    // Register user-configured models for other authTypes
+    if (modelProvidersConfig) {
+      for (const [rawKey, models] of Object.entries(modelProvidersConfig)) {
+        const authType = validateAuthTypeKey(rawKey);
+
+        if (!authType) {
+          console.warn(
+            `[ModelRegistry] Invalid authType key "${rawKey}" in modelProviders config. Expected one of: ${Object.values(AuthType).join(', ')}. Skipping.`,
+          );
+          continue;
+        }
+
+        // Skip qwen-oauth as it uses hard-coded models
+        if (authType === AuthType.QWEN_OAUTH) {
+          continue;
+        }
+
+        this.registerAuthTypeModels(authType, models);
+      }
+    }
+  }
+
+  /**
+   * Register models for an authType
+   */
+  private registerAuthTypeModels(
+    authType: AuthType,
+    models: ModelConfig[],
+  ): void {
+    const modelMap = new Map<string, ResolvedModelConfig>();
+
+    for (const config of models) {
+      const resolved = this.resolveModelConfig(config, authType);
+      modelMap.set(config.id, resolved);
+    }
+
+    this.modelsByAuthType.set(authType, modelMap);
+  }
+
+  /**
+   * Get all models for a specific authType.
+   * This is used by /model command to show only relevant models.
+   */
+  getModelsForAuthType(authType: AuthType): AvailableModel[] {
+    const models = this.modelsByAuthType.get(authType);
+    if (!models) return [];
+
+    return Array.from(models.values()).map((model) => ({
+      id: model.id,
+      label: model.name,
+      description: model.description,
+      capabilities: model.capabilities,
+      authType: model.authType,
+      isVision: model.capabilities?.vision ?? false,
+    }));
+  }
+
+  /**
+   * Get model configuration by authType and modelId
+   */
+  getModel(
+    authType: AuthType,
+    modelId: string,
+  ): ResolvedModelConfig | undefined {
+    const models = this.modelsByAuthType.get(authType);
+    return models?.get(modelId);
+  }
+
+  /**
+   * Check if model exists for given authType
+   */
+  hasModel(authType: AuthType, modelId: string): boolean {
+    const models = this.modelsByAuthType.get(authType);
+    return models?.has(modelId) ?? false;
+  }
+
+  /**
+   * Get default model for an authType.
+   * For qwen-oauth, returns the coder model.
+   * For others, returns the first configured model.
+   */
+  getDefaultModelForAuthType(
+    authType: AuthType,
+  ): ResolvedModelConfig | undefined {
+    if (authType === AuthType.QWEN_OAUTH) {
+      return this.getModel(authType, DEFAULT_QWEN_MODEL);
+    }
+    const models = this.modelsByAuthType.get(authType);
+    if (!models || models.size === 0) return undefined;
+    return Array.from(models.values())[0];
+  }
+
+  /**
+   * Resolve model config by applying defaults
+   */
+  private resolveModelConfig(
+    config: ModelConfig,
+    authType: AuthType,
+  ): ResolvedModelConfig {
+    this.validateModelConfig(config, authType);
+
+    return {
+      ...config,
+      authType,
+      name: config.name || config.id,
+      baseUrl: config.baseUrl || this.getDefaultBaseUrl(authType),
+      generationConfig: config.generationConfig ?? {},
+      capabilities: config.capabilities || {},
+    };
+  }
+
+  /**
+   * Validate model configuration
+   */
+  private validateModelConfig(config: ModelConfig, authType: AuthType): void {
+    if (!config.id) {
+      throw new Error(
+        `Model config in authType '${authType}' missing required field: id`,
+      );
+    }
+  }
+}

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

@@ -0,0 +1,451 @@
+/**
+ * @license
+ * Copyright 2025 Qwen Team
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect } from 'vitest';
+import { ModelsConfig } from './modelsConfig.js';
+import { AuthType } from '../core/contentGenerator.js';
+import type { ModelProvidersConfig } from './types.js';
+
+describe('ModelsConfig', () => {
+  function deepClone<T>(value: T): T {
+    if (value === null || typeof value !== 'object') return value;
+    if (Array.isArray(value)) return value.map((v) => deepClone(v)) as T;
+    const out: Record<string, unknown> = {};
+    for (const key of Object.keys(value as Record<string, unknown>)) {
+      out[key] = deepClone((value as Record<string, unknown>)[key]);
+    }
+    return out as T;
+  }
+
+  it('should fully rollback state when switchModel fails after applying defaults (authType change)', async () => {
+    const modelProvidersConfig: ModelProvidersConfig = {
+      openai: [
+        {
+          id: 'openai-a',
+          name: 'OpenAI A',
+          baseUrl: 'https://api.openai.example.com/v1',
+          envKey: 'OPENAI_API_KEY',
+          generationConfig: {
+            samplingParams: { temperature: 0.2, max_tokens: 123 },
+            timeout: 111,
+            maxRetries: 1,
+          },
+        },
+      ],
+      anthropic: [
+        {
+          id: 'anthropic-b',
+          name: 'Anthropic B',
+          baseUrl: 'https://api.anthropic.example.com/v1',
+          envKey: 'ANTHROPIC_API_KEY',
+          generationConfig: {
+            samplingParams: { temperature: 0.7, max_tokens: 456 },
+            timeout: 222,
+            maxRetries: 2,
+          },
+        },
+      ],
+    };
+
+    const modelsConfig = new ModelsConfig({
+      initialAuthType: AuthType.USE_OPENAI,
+      modelProvidersConfig,
+    });
+
+    // Establish a known baseline state via a successful switch.
+    await modelsConfig.switchModel(AuthType.USE_OPENAI, 'openai-a');
+    const baselineAuthType = modelsConfig.getCurrentAuthType();
+    const baselineModel = modelsConfig.getModel();
+    const baselineStrict = modelsConfig.isStrictModelProviderSelection();
+    const baselineGc = deepClone(modelsConfig.getGenerationConfig());
+    const baselineSources = deepClone(
+      modelsConfig.getGenerationConfigSources(),
+    );
+
+    modelsConfig.setOnModelChange(async () => {
+      throw new Error('refresh failed');
+    });
+
+    await expect(
+      modelsConfig.switchModel(AuthType.USE_ANTHROPIC, 'anthropic-b'),
+    ).rejects.toThrow('refresh failed');
+
+    // Ensure state is fully rolled back (selection + generation config + flags).
+    expect(modelsConfig.getCurrentAuthType()).toBe(baselineAuthType);
+    expect(modelsConfig.getModel()).toBe(baselineModel);
+    expect(modelsConfig.isStrictModelProviderSelection()).toBe(baselineStrict);
+
+    const gc = modelsConfig.getGenerationConfig();
+    expect(gc).toMatchObject({
+      model: baselineGc.model,
+      baseUrl: baselineGc.baseUrl,
+      apiKeyEnvKey: baselineGc.apiKeyEnvKey,
+      samplingParams: baselineGc.samplingParams,
+      timeout: baselineGc.timeout,
+      maxRetries: baselineGc.maxRetries,
+    });
+
+    const sources = modelsConfig.getGenerationConfigSources();
+    expect(sources).toEqual(baselineSources);
+  });
+
+  it('should fully rollback state when switchModel fails after applying defaults', async () => {
+    const modelProvidersConfig: ModelProvidersConfig = {
+      openai: [
+        {
+          id: 'model-a',
+          name: 'Model A',
+          baseUrl: 'https://api.example.com/v1',
+          envKey: 'API_KEY_A',
+        },
+        {
+          id: 'model-b',
+          name: 'Model B',
+          baseUrl: 'https://api.example.com/v1',
+          envKey: 'API_KEY_B',
+        },
+      ],
+    };
+
+    const modelsConfig = new ModelsConfig({
+      initialAuthType: AuthType.USE_OPENAI,
+      modelProvidersConfig,
+    });
+
+    await modelsConfig.switchModel(AuthType.USE_OPENAI, 'model-a');
+    const baselineModel = modelsConfig.getModel();
+    const baselineGc = deepClone(modelsConfig.getGenerationConfig());
+    const baselineSources = deepClone(
+      modelsConfig.getGenerationConfigSources(),
+    );
+
+    modelsConfig.setOnModelChange(async () => {
+      throw new Error('hot-update failed');
+    });
+
+    await expect(
+      modelsConfig.switchModel(AuthType.USE_OPENAI, 'model-b'),
+    ).rejects.toThrow('hot-update failed');
+
+    expect(modelsConfig.getModel()).toBe(baselineModel);
+    expect(modelsConfig.getGenerationConfig()).toMatchObject({
+      model: baselineGc.model,
+      baseUrl: baselineGc.baseUrl,
+      apiKeyEnvKey: baselineGc.apiKeyEnvKey,
+    });
+    expect(modelsConfig.getGenerationConfigSources()).toEqual(baselineSources);
+  });
+
+  it('should preserve an explicit apiKey when switching models if envKey is missing in the environment', async () => {
+    const modelProvidersConfig: ModelProvidersConfig = {
+      openai: [
+        {
+          id: 'model-a',
+          name: 'Model A',
+          baseUrl: 'https://api.example.com/v1',
+          envKey: 'API_KEY_SHARED',
+        },
+        {
+          id: 'model-b',
+          name: 'Model B',
+          baseUrl: 'https://api.example.com/v1',
+          envKey: 'API_KEY_SHARED',
+        },
+      ],
+    };
+
+    const modelsConfig = new ModelsConfig({
+      initialAuthType: AuthType.USE_OPENAI,
+      initialModelId: 'model-a',
+      modelProvidersConfig,
+    });
+
+    // Simulate key prompt flow / explicit key provided via CLI/settings.
+    modelsConfig.updateCredentials({ apiKey: 'manual-key', model: 'model-a' });
+
+    await modelsConfig.switchModel(AuthType.USE_OPENAI, 'model-b');
+
+    const gc = modelsConfig.getGenerationConfig();
+    expect(gc.model).toBe('model-b');
+    expect(gc.apiKey).toBe('manual-key');
+    expect(gc.apiKeyEnvKey).toBe('API_KEY_SHARED');
+  });
+
+  it('should preserve settings generationConfig when model is updated via updateCredentials even if it matches modelProviders', () => {
+    const modelProvidersConfig: ModelProvidersConfig = {
+      openai: [
+        {
+          id: 'model-a',
+          name: 'Model A',
+          baseUrl: 'https://api.example.com/v1',
+          envKey: 'API_KEY_A',
+          generationConfig: {
+            samplingParams: { temperature: 0.1, max_tokens: 123 },
+            timeout: 111,
+            maxRetries: 1,
+          },
+        },
+      ],
+    };
+
+    // Simulate settings.model.generationConfig being resolved into ModelsConfig.generationConfig
+    const modelsConfig = new ModelsConfig({
+      initialAuthType: AuthType.USE_OPENAI,
+      initialModelId: 'model-a',
+      modelProvidersConfig,
+      generationConfig: {
+        model: 'model-a',
+        samplingParams: { temperature: 0.9, max_tokens: 999 },
+        timeout: 9999,
+        maxRetries: 9,
+      },
+      generationConfigSources: {
+        model: { kind: 'settings', detail: 'settings.model.name' },
+        samplingParams: {
+          kind: 'settings',
+          detail: 'settings.model.generationConfig.samplingParams',
+        },
+        timeout: {
+          kind: 'settings',
+          detail: 'settings.model.generationConfig.timeout',
+        },
+        maxRetries: {
+          kind: 'settings',
+          detail: 'settings.model.generationConfig.maxRetries',
+        },
+      },
+    });
+
+    // User manually updates the model via updateCredentials (e.g. key prompt flow).
+    // Even if the model ID matches a modelProviders entry, we must not apply provider defaults
+    // that would overwrite settings.model.generationConfig.
+    modelsConfig.updateCredentials({ model: 'model-a' });
+
+    modelsConfig.syncAfterAuthRefresh(
+      AuthType.USE_OPENAI,
+      modelsConfig.getModel(),
+    );
+
+    const gc = modelsConfig.getGenerationConfig();
+    expect(gc.model).toBe('model-a');
+    expect(gc.samplingParams?.temperature).toBe(0.9);
+    expect(gc.samplingParams?.max_tokens).toBe(999);
+    expect(gc.timeout).toBe(9999);
+    expect(gc.maxRetries).toBe(9);
+  });
+
+  it('should preserve settings generationConfig across multiple auth refreshes after updateCredentials', () => {
+    const modelProvidersConfig: ModelProvidersConfig = {
+      openai: [
+        {
+          id: 'model-a',
+          name: 'Model A',
+          baseUrl: 'https://api.example.com/v1',
+          envKey: 'API_KEY_A',
+          generationConfig: {
+            samplingParams: { temperature: 0.1, max_tokens: 123 },
+            timeout: 111,
+            maxRetries: 1,
+          },
+        },
+      ],
+    };
+
+    const modelsConfig = new ModelsConfig({
+      initialAuthType: AuthType.USE_OPENAI,
+      initialModelId: 'model-a',
+      modelProvidersConfig,
+      generationConfig: {
+        model: 'model-a',
+        samplingParams: { temperature: 0.9, max_tokens: 999 },
+        timeout: 9999,
+        maxRetries: 9,
+      },
+      generationConfigSources: {
+        model: { kind: 'settings', detail: 'settings.model.name' },
+        samplingParams: {
+          kind: 'settings',
+          detail: 'settings.model.generationConfig.samplingParams',
+        },
+        timeout: {
+          kind: 'settings',
+          detail: 'settings.model.generationConfig.timeout',
+        },
+        maxRetries: {
+          kind: 'settings',
+          detail: 'settings.model.generationConfig.maxRetries',
+        },
+      },
+    });
+
+    modelsConfig.updateCredentials({
+      apiKey: 'manual-key',
+      baseUrl: 'https://manual.example.com/v1',
+      model: 'model-a',
+    });
+
+    // First auth refresh
+    modelsConfig.syncAfterAuthRefresh(
+      AuthType.USE_OPENAI,
+      modelsConfig.getModel(),
+    );
+    // Second auth refresh should still preserve settings generationConfig
+    modelsConfig.syncAfterAuthRefresh(
+      AuthType.USE_OPENAI,
+      modelsConfig.getModel(),
+    );
+
+    const gc = modelsConfig.getGenerationConfig();
+    expect(gc.model).toBe('model-a');
+    expect(gc.samplingParams?.temperature).toBe(0.9);
+    expect(gc.samplingParams?.max_tokens).toBe(999);
+    expect(gc.timeout).toBe(9999);
+    expect(gc.maxRetries).toBe(9);
+  });
+
+  it('should clear provider-sourced config when updateCredentials is called after switchModel', async () => {
+    const modelProvidersConfig: ModelProvidersConfig = {
+      openai: [
+        {
+          id: 'provider-model',
+          name: 'Provider Model',
+          baseUrl: 'https://provider.example.com/v1',
+          envKey: 'PROVIDER_API_KEY',
+          generationConfig: {
+            samplingParams: { temperature: 0.1, max_tokens: 100 },
+            timeout: 1000,
+            maxRetries: 2,
+          },
+        },
+      ],
+    };
+
+    const modelsConfig = new ModelsConfig({
+      initialAuthType: AuthType.USE_OPENAI,
+      modelProvidersConfig,
+    });
+
+    // Step 1: Switch to a provider model - this applies provider config
+    await modelsConfig.switchModel(AuthType.USE_OPENAI, 'provider-model');
+
+    // Verify provider config is applied
+    let gc = modelsConfig.getGenerationConfig();
+    expect(gc.model).toBe('provider-model');
+    expect(gc.baseUrl).toBe('https://provider.example.com/v1');
+    expect(gc.samplingParams?.temperature).toBe(0.1);
+    expect(gc.samplingParams?.max_tokens).toBe(100);
+    expect(gc.timeout).toBe(1000);
+    expect(gc.maxRetries).toBe(2);
+
+    // Verify sources are from modelProviders
+    let sources = modelsConfig.getGenerationConfigSources();
+    expect(sources['model']?.kind).toBe('modelProviders');
+    expect(sources['baseUrl']?.kind).toBe('modelProviders');
+    expect(sources['samplingParams']?.kind).toBe('modelProviders');
+    expect(sources['timeout']?.kind).toBe('modelProviders');
+    expect(sources['maxRetries']?.kind).toBe('modelProviders');
+
+    // Step 2: User manually sets credentials via updateCredentials
+    // This should clear all provider-sourced config
+    modelsConfig.updateCredentials({
+      apiKey: 'manual-api-key',
+      model: 'custom-model',
+    });
+
+    // Verify provider-sourced config is cleared
+    gc = modelsConfig.getGenerationConfig();
+    expect(gc.model).toBe('custom-model'); // Set by updateCredentials
+    expect(gc.apiKey).toBe('manual-api-key'); // Set by updateCredentials
+    expect(gc.baseUrl).toBeUndefined(); // Cleared (was from provider)
+    expect(gc.samplingParams).toBeUndefined(); // Cleared (was from provider)
+    expect(gc.timeout).toBeUndefined(); // Cleared (was from provider)
+    expect(gc.maxRetries).toBeUndefined(); // Cleared (was from provider)
+
+    // Verify sources are updated
+    sources = modelsConfig.getGenerationConfigSources();
+    expect(sources['model']?.kind).toBe('programmatic');
+    expect(sources['apiKey']?.kind).toBe('programmatic');
+    expect(sources['baseUrl']).toBeUndefined(); // Source cleared
+    expect(sources['samplingParams']).toBeUndefined(); // Source cleared
+    expect(sources['timeout']).toBeUndefined(); // Source cleared
+    expect(sources['maxRetries']).toBeUndefined(); // Source cleared
+  });
+
+  it('should preserve non-provider config when updateCredentials clears provider config', async () => {
+    const modelProvidersConfig: ModelProvidersConfig = {
+      openai: [
+        {
+          id: 'provider-model',
+          name: 'Provider Model',
+          baseUrl: 'https://provider.example.com/v1',
+          envKey: 'PROVIDER_API_KEY',
+          generationConfig: {
+            samplingParams: { temperature: 0.1, max_tokens: 100 },
+            timeout: 1000,
+            maxRetries: 2,
+          },
+        },
+      ],
+    };
+
+    // Initialize with settings-sourced config
+    const modelsConfig = new ModelsConfig({
+      initialAuthType: AuthType.USE_OPENAI,
+      modelProvidersConfig,
+      generationConfig: {
+        samplingParams: { temperature: 0.8, max_tokens: 500 },
+        timeout: 5000,
+      },
+      generationConfigSources: {
+        samplingParams: {
+          kind: 'settings',
+          detail: 'settings.model.generationConfig.samplingParams',
+        },
+        timeout: {
+          kind: 'settings',
+          detail: 'settings.model.generationConfig.timeout',
+        },
+      },
+    });
+
+    // Switch to provider model - this overwrites with provider config
+    await modelsConfig.switchModel(AuthType.USE_OPENAI, 'provider-model');
+
+    // Verify provider config is applied (overwriting settings)
+    let gc = modelsConfig.getGenerationConfig();
+    expect(gc.samplingParams?.temperature).toBe(0.1);
+    expect(gc.timeout).toBe(1000);
+
+    // User manually sets credentials - clears provider-sourced config
+    modelsConfig.updateCredentials({
+      apiKey: 'manual-key',
+    });
+
+    // Provider-sourced config should be cleared
+    gc = modelsConfig.getGenerationConfig();
+    expect(gc.samplingParams).toBeUndefined();
+    expect(gc.timeout).toBeUndefined();
+    // The original settings-sourced config is NOT restored automatically;
+    // it should be re-resolved by other layers in refreshAuth
+  });
+
+  it('should always force Qwen OAuth apiKey placeholder when applying model defaults', async () => {
+    // Simulate a stale/explicit apiKey existing before switching models.
+    const modelsConfig = new ModelsConfig({
+      initialAuthType: AuthType.QWEN_OAUTH,
+      generationConfig: {
+        apiKey: 'manual-key-should-not-leak',
+      },
+    });
+
+    // Switching within qwen-oauth triggers applyResolvedModelDefaults().
+    await modelsConfig.switchModel(AuthType.QWEN_OAUTH, 'vision-model');
+
+    const gc = modelsConfig.getGenerationConfig();
+    expect(gc.apiKey).toBe('QWEN_OAUTH_DYNAMIC_TOKEN');
+    expect(gc.apiKeyEnvKey).toBeUndefined();
+  });
+});

packages/core/src/models/modelsConfig.ts

@@ -0,0 +1,697 @@
+/**
+ * @license
+ * Copyright 2025 Qwen Team
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import process from 'node:process';
+
+import { AuthType } from '../core/contentGenerator.js';
+import type { ContentGeneratorConfig } from '../core/contentGenerator.js';
+import type { ContentGeneratorConfigSources } from '../core/contentGenerator.js';
+import { DEFAULT_QWEN_MODEL } from '../config/models.js';
+
+import { ModelRegistry } from './modelRegistry.js';
+import {
+  type ModelProvidersConfig,
+  type ResolvedModelConfig,
+  type AvailableModel,
+  type ModelSwitchMetadata,
+} from './types.js';
+import {
+  MODEL_GENERATION_CONFIG_FIELDS,
+  CREDENTIAL_FIELDS,
+  PROVIDER_SOURCED_FIELDS,
+} from './constants.js';
+
+export {
+  MODEL_GENERATION_CONFIG_FIELDS,
+  CREDENTIAL_FIELDS,
+  PROVIDER_SOURCED_FIELDS,
+};
+
+/**
+ * Callback for when the model changes.
+ * Used by Config to refresh auth/ContentGenerator when needed.
+ */
+export type OnModelChangeCallback = (
+  authType: AuthType,
+  requiresRefresh: boolean,
+) => Promise<void>;
+
+/**
+ * Options for creating ModelsConfig
+ */
+export interface ModelsConfigOptions {
+  /** Initial authType from settings */
+  initialAuthType?: AuthType;
+  /** Initial model ID from settings */
+  initialModelId?: string;
+  /** Model providers configuration */
+  modelProvidersConfig?: ModelProvidersConfig;
+  /** Generation config from CLI/settings */
+  generationConfig?: Partial<ContentGeneratorConfig>;
+  /** Source tracking for generation config */
+  generationConfigSources?: ContentGeneratorConfigSources;
+  /** Callback when model changes require refresh */
+  onModelChange?: OnModelChangeCallback;
+}
+
+/**
+ * ModelsConfig manages all model selection logic and state.
+ *
+ * This class encapsulates:
+ * - ModelRegistry for model configuration storage
+ * - Current authType and modelId selection
+ * - Generation config management
+ * - Model switching logic
+ *
+ * Config uses this as a thin entry point for all model-related operations.
+ */
+export class ModelsConfig {
+  private readonly modelRegistry: ModelRegistry;
+
+  // Current selection state
+  private currentAuthType: AuthType;
+  private currentModelId: string;
+
+  // Generation config state
+  private _generationConfig: Partial<ContentGeneratorConfig>;
+  private generationConfigSources: ContentGeneratorConfigSources;
+
+  // Flag for strict model provider selection
+  private strictModelProviderSelection: boolean = false;
+
+  // One-shot flag for qwen-oauth credential caching
+  private requireCachedQwenCredentialsOnce: boolean = false;
+
+  // One-shot flag indicating credentials were manually set via updateCredentials()
+  // When true, syncAfterAuthRefresh should NOT override these credentials with
+  // modelProviders defaults (even if the model ID matches a registry entry).
+  //
+  // This must be persistent across auth refreshes, because refreshAuth() can be
+  // triggered multiple times after a credential prompt flow. We only clear this
+  // flag when we explicitly apply modelProvider defaults (i.e. when the user
+  // switches to a registry model via switchModel).
+  private hasManualCredentials: boolean = false;
+
+  // Callback for notifying Config of model changes
+  private onModelChange?: OnModelChangeCallback;
+
+  // Flag indicating whether authType was explicitly provided (not defaulted)
+  private readonly authTypeWasExplicitlyProvided: boolean;
+
+  private static deepClone<T>(value: T): T {
+    if (value === null || typeof value !== 'object') {
+      return value;
+    }
+    if (Array.isArray(value)) {
+      return value.map((v) => ModelsConfig.deepClone(v)) as T;
+    }
+    const out: Record<string, unknown> = {};
+    for (const key of Object.keys(value as Record<string, unknown>)) {
+      out[key] = ModelsConfig.deepClone(
+        (value as Record<string, unknown>)[key],
+      );
+    }
+    return out as T;
+  }
+
+  private snapshotState(): {
+    currentAuthType: AuthType;
+    currentModelId: string;
+    generationConfig: Partial<ContentGeneratorConfig>;
+    generationConfigSources: ContentGeneratorConfigSources;
+    strictModelProviderSelection: boolean;
+    requireCachedQwenCredentialsOnce: boolean;
+    hasManualCredentials: boolean;
+  } {
+    return {
+      currentAuthType: this.currentAuthType,
+      currentModelId: this.currentModelId,
+      generationConfig: ModelsConfig.deepClone(this._generationConfig),
+      generationConfigSources: ModelsConfig.deepClone(
+        this.generationConfigSources,
+      ),
+      strictModelProviderSelection: this.strictModelProviderSelection,
+      requireCachedQwenCredentialsOnce: this.requireCachedQwenCredentialsOnce,
+      hasManualCredentials: this.hasManualCredentials,
+    };
+  }
+
+  private restoreState(
+    snapshot: ReturnType<ModelsConfig['snapshotState']>,
+  ): void {
+    this.currentAuthType = snapshot.currentAuthType;
+    this.currentModelId = snapshot.currentModelId;
+    this._generationConfig = snapshot.generationConfig;
+    this.generationConfigSources = snapshot.generationConfigSources;
+    this.strictModelProviderSelection = snapshot.strictModelProviderSelection;
+    this.requireCachedQwenCredentialsOnce =
+      snapshot.requireCachedQwenCredentialsOnce;
+    this.hasManualCredentials = snapshot.hasManualCredentials;
+  }
+
+  constructor(options: ModelsConfigOptions = {}) {
+    this.modelRegistry = new ModelRegistry(options.modelProvidersConfig);
+    this.onModelChange = options.onModelChange;
+
+    // Initialize generation config
+    this._generationConfig = {
+      model: options.initialModelId,
+      ...(options.generationConfig || {}),
+    };
+    this.generationConfigSources = options.generationConfigSources || {};
+
+    // Track if authType was explicitly provided
+    this.authTypeWasExplicitlyProvided = options.initialAuthType !== undefined;
+
+    // Initialize selection state
+    this.currentAuthType = options.initialAuthType || AuthType.QWEN_OAUTH;
+    this.currentModelId = options.initialModelId || '';
+
+    // Validate and initialize default selection
+    this.initializeDefaultSelection();
+  }
+
+  /**
+   * Initialize default selection based on settings/environment.
+   *
+   * Note: The generationConfig passed to ModelsConfig should already be fully
+   * resolved by ModelConfigResolver, which handles CLI args, env vars, and settings.
+   * This method primarily validates and sets up internal state.
+   */
+  private initializeDefaultSelection(): void {
+    // If generationConfig already has a model (resolved by ModelConfigResolver),
+    // use that as the current selection
+    if (this._generationConfig.model) {
+      this.currentModelId = this._generationConfig.model;
+      return;
+    }
+
+    // Check if persisted model selection is valid
+    if (
+      this.currentModelId &&
+      this.modelRegistry.hasModel(this.currentAuthType, this.currentModelId)
+    ) {
+      return;
+    }
+
+    // Use registry default
+    const defaultModel = this.modelRegistry.getDefaultModelForAuthType(
+      this.currentAuthType,
+    );
+    if (defaultModel) {
+      this.currentModelId = defaultModel.id;
+      if (!this._generationConfig.model) {
+        this._generationConfig.model = defaultModel.id;
+      }
+    }
+  }
+
+  /**
+   * Get current model ID
+   */
+  getModel(): string {
+    return (
+      this._generationConfig.model || this.currentModelId || DEFAULT_QWEN_MODEL
+    );
+  }
+
+  /**
+   * Get current authType
+   */
+  getCurrentAuthType(): AuthType {
+    return this.currentAuthType;
+  }
+
+  /**
+   * Check if authType was explicitly provided (via CLI or settings).
+   * If false, the default QWEN_OAUTH is being used.
+   */
+  wasAuthTypeExplicitlyProvided(): boolean {
+    return this.authTypeWasExplicitlyProvided;
+  }
+
+  /**
+   * Get available models for current authType
+   */
+  getAvailableModels(): AvailableModel[] {
+    return this.modelRegistry.getModelsForAuthType(this.currentAuthType);
+  }
+
+  /**
+   * Get available models for a specific authType
+   */
+  getAvailableModelsForAuthType(authType: AuthType): AvailableModel[] {
+    return this.modelRegistry.getModelsForAuthType(authType);
+  }
+
+  /**
+   * Check if a model exists for the given authType
+   */
+  hasModel(authType: AuthType, modelId: string): boolean {
+    return this.modelRegistry.hasModel(authType, modelId);
+  }
+
+  /**
+   * Set model programmatically (e.g., VLM auto-switch, fallback).
+   * Supports both registry models and raw model IDs.
+   */
+  async setModel(
+    newModel: string,
+    metadata?: ModelSwitchMetadata,
+  ): Promise<void> {
+    // Special case: qwen-oauth VLM auto-switch - hot update in place
+    if (
+      this.currentAuthType === AuthType.QWEN_OAUTH &&
+      (newModel === DEFAULT_QWEN_MODEL || newModel === 'vision-model')
+    ) {
+      this.strictModelProviderSelection = false;
+      this._generationConfig.model = newModel;
+      this.currentModelId = newModel;
+      this.generationConfigSources['model'] = {
+        kind: 'programmatic',
+        detail: metadata?.reason || 'setModel',
+      };
+      return;
+    }
+
+    // If model exists in registry, use full switch logic
+    if (this.modelRegistry.hasModel(this.currentAuthType, newModel)) {
+      await this.switchModel(this.currentAuthType, newModel);
+      return;
+    }
+
+    // Raw model override: update generation config in-place
+    this.strictModelProviderSelection = false;
+    this._generationConfig.model = newModel;
+    this.currentModelId = newModel;
+    this.generationConfigSources['model'] = {
+      kind: 'programmatic',
+      detail: metadata?.reason || 'setModel',
+    };
+  }
+
+  /**
+   * Switch model (and optionally authType) via registry-backed selection.
+   * This is a superset of the previous split APIs for model-only vs authType+model switching.
+   */
+  async switchModel(
+    authType: AuthType,
+    modelId: string,
+    options?: { requireCachedCredentials?: boolean },
+    _metadata?: ModelSwitchMetadata,
+  ): Promise<void> {
+    const snapshot = this.snapshotState();
+    if (authType === AuthType.QWEN_OAUTH && options?.requireCachedCredentials) {
+      this.requireCachedQwenCredentialsOnce = true;
+    }
+
+    try {
+      const isAuthTypeChange = authType !== this.currentAuthType;
+      this.currentAuthType = authType;
+
+      const model = this.modelRegistry.getModel(authType, modelId);
+      if (!model) {
+        throw new Error(
+          `Model '${modelId}' not found for authType '${authType}'`,
+        );
+      }
+
+      // Apply model defaults
+      this.applyResolvedModelDefaults(model);
+
+      // Update selection state
+      this.currentModelId = modelId;
+
+      const requiresRefresh = isAuthTypeChange
+        ? true
+        : this.checkRequiresRefresh(snapshot.currentModelId);
+
+      if (this.onModelChange) {
+        await this.onModelChange(authType, requiresRefresh);
+      }
+    } catch (error) {
+      // Rollback on error
+      this.restoreState(snapshot);
+      throw error;
+    }
+  }
+
+  /**
+   * Get generation config for ContentGenerator creation
+   */
+  getGenerationConfig(): Partial<ContentGeneratorConfig> {
+    return this._generationConfig;
+  }
+
+  /**
+   * Get generation config sources for debugging/UI
+   */
+  getGenerationConfigSources(): ContentGeneratorConfigSources {
+    return this.generationConfigSources;
+  }
+
+  /**
+   * Update credentials in generation config.
+   * Sets a flag to prevent syncAfterAuthRefresh from overriding these credentials.
+   *
+   * When credentials are manually set, we clear all provider-sourced configuration
+   * to maintain provider atomicity (either fully applied or not at all).
+   * Other layers (CLI, env, settings, defaults) will participate in resolve.
+   */
+  updateCredentials(credentials: {
+    apiKey?: string;
+    baseUrl?: string;
+    model?: string;
+  }): void {
+    /**
+     * If any fields are updated here, we treat the resulting config as manually overridden
+     * and avoid applying modelProvider defaults during the next auth refresh.
+     *
+     * Clear all provider-sourced configuration to maintain provider atomicity.
+     * This ensures that when user manually sets credentials, the provider config
+     * is either fully applied (via switchModel) or not at all.
+     */
+    if (credentials.apiKey || credentials.baseUrl || credentials.model) {
+      this.hasManualCredentials = true;
+      this.clearProviderSourcedConfig();
+    }
+
+    if (credentials.apiKey) {
+      this._generationConfig.apiKey = credentials.apiKey;
+      this.generationConfigSources['apiKey'] = {
+        kind: 'programmatic',
+        detail: 'updateCredentials',
+      };
+    }
+    if (credentials.baseUrl) {
+      this._generationConfig.baseUrl = credentials.baseUrl;
+      this.generationConfigSources['baseUrl'] = {
+        kind: 'programmatic',
+        detail: 'updateCredentials',
+      };
+    }
+    if (credentials.model) {
+      this._generationConfig.model = credentials.model;
+      this.currentModelId = credentials.model;
+      this.generationConfigSources['model'] = {
+        kind: 'programmatic',
+        detail: 'updateCredentials',
+      };
+    }
+    // When credentials are manually set, disable strict model provider selection
+    // so validation doesn't require envKey-based credentials
+    this.strictModelProviderSelection = false;
+    // Clear apiKeyEnvKey to prevent validation from requiring environment variable
+    this._generationConfig.apiKeyEnvKey = undefined;
+  }
+
+  /**
+   * Clear configuration fields that were sourced from modelProviders.
+   * This ensures provider config atomicity when user manually sets credentials.
+   * Other layers (CLI, env, settings, defaults) will participate in resolve.
+   */
+  private clearProviderSourcedConfig(): void {
+    for (const field of PROVIDER_SOURCED_FIELDS) {
+      const source = this.generationConfigSources[field];
+      if (source?.kind === 'modelProviders') {
+        // Clear the value - let other layers resolve it
+        delete (this._generationConfig as Record<string, unknown>)[field];
+        delete this.generationConfigSources[field];
+      }
+    }
+  }
+
+  /**
+   * Get whether strict model provider selection is enabled
+   */
+  isStrictModelProviderSelection(): boolean {
+    return this.strictModelProviderSelection;
+  }
+
+  /**
+   * Reset strict model provider selection flag
+   */
+  resetStrictModelProviderSelection(): void {
+    this.strictModelProviderSelection = false;
+  }
+
+  /**
+   * Check and consume the one-shot cached credentials flag
+   */
+  consumeRequireCachedCredentialsFlag(): boolean {
+    const value = this.requireCachedQwenCredentialsOnce;
+    this.requireCachedQwenCredentialsOnce = false;
+    return value;
+  }
+
+  /**
+   * Apply resolved model config to generation config
+   */
+  private applyResolvedModelDefaults(model: ResolvedModelConfig): void {
+    this.strictModelProviderSelection = true;
+    const previousApiKey = this._generationConfig.apiKey;
+    const previousApiKeyEnvKey = this._generationConfig.apiKeyEnvKey;
+    const hadManualCredentials = this.hasManualCredentials;
+    // We're explicitly applying modelProvider defaults now, so manual overrides
+    // should no longer block syncAfterAuthRefresh from applying provider defaults.
+    this.hasManualCredentials = false;
+
+    this._generationConfig.model = model.id;
+    this.generationConfigSources['model'] = {
+      kind: 'modelProviders',
+      authType: model.authType,
+      modelId: model.id,
+      detail: 'model.id',
+    };
+
+    // Clear credentials to avoid reusing previous model's API key
+
+    // For Qwen OAuth, apiKey must always be a placeholder. It will be dynamically
+    // replaced when building requests. Do not preserve any previous key or read
+    // from envKey.
+    //
+    // (OpenAI client instantiation requires an apiKey even though it will be
+    // replaced later.)
+    if (this.currentAuthType === AuthType.QWEN_OAUTH) {
+      this._generationConfig.apiKey = 'QWEN_OAUTH_DYNAMIC_TOKEN';
+      this.generationConfigSources['apiKey'] = {
+        kind: 'computed',
+        detail: 'Qwen OAuth placeholder token',
+      };
+      this._generationConfig.apiKeyEnvKey = undefined;
+      delete this.generationConfigSources['apiKeyEnvKey'];
+    } else {
+      this._generationConfig.apiKey = undefined;
+      this._generationConfig.apiKeyEnvKey = undefined;
+    }
+
+    // Read API key from environment variable if envKey is specified
+    if (model.envKey !== undefined) {
+      const apiKey = process.env[model.envKey];
+      if (apiKey) {
+        this._generationConfig.apiKey = apiKey;
+        this.generationConfigSources['apiKey'] = {
+          kind: 'env',
+          envKey: model.envKey,
+          via: {
+            kind: 'modelProviders',
+            authType: model.authType,
+            modelId: model.id,
+            detail: 'envKey',
+          },
+        };
+      } else {
+        // If the user provided an API key via CLI/settings/updateCredentials, keep it.
+        // We only refuse to reuse a previous key when it is explicitly tied to a
+        // different envKey (e.g. switching between two configured accounts).
+        const canPreservePreviousKey =
+          !!previousApiKey &&
+          (hadManualCredentials ||
+            previousApiKeyEnvKey === undefined ||
+            previousApiKeyEnvKey === model.envKey);
+
+        if (canPreservePreviousKey) {
+          this._generationConfig.apiKey = previousApiKey;
+          this.generationConfigSources['apiKey'] = {
+            kind: 'computed',
+            detail: `preserved previous apiKey (missing env: ${model.envKey})`,
+          };
+        } else {
+          console.warn(
+            `[ModelsConfig] Environment variable '${model.envKey}' is not set for model '${model.id}'. ` +
+              `API key will not be available.`,
+          );
+        }
+      }
+      this._generationConfig.apiKeyEnvKey = model.envKey;
+      this.generationConfigSources['apiKeyEnvKey'] = {
+        kind: 'modelProviders',
+        authType: model.authType,
+        modelId: model.id,
+        detail: 'envKey',
+      };
+    }
+
+    // Base URL
+    this._generationConfig.baseUrl = model.baseUrl;
+    this.generationConfigSources['baseUrl'] = {
+      kind: 'modelProviders',
+      authType: model.authType,
+      modelId: model.id,
+      detail: 'baseUrl',
+    };
+
+    // Generation config
+    const gc = model.generationConfig;
+    this._generationConfig.samplingParams = { ...(gc.samplingParams || {}) };
+    this.generationConfigSources['samplingParams'] = {
+      kind: 'modelProviders',
+      authType: model.authType,
+      modelId: model.id,
+      detail: 'generationConfig.samplingParams',
+    };
+
+    this._generationConfig.timeout = gc.timeout;
+    this.generationConfigSources['timeout'] = {
+      kind: 'modelProviders',
+      authType: model.authType,
+      modelId: model.id,
+      detail: 'generationConfig.timeout',
+    };
+
+    this._generationConfig.maxRetries = gc.maxRetries;
+    this.generationConfigSources['maxRetries'] = {
+      kind: 'modelProviders',
+      authType: model.authType,
+      modelId: model.id,
+      detail: 'generationConfig.maxRetries',
+    };
+
+    this._generationConfig.disableCacheControl = gc.disableCacheControl;
+    this.generationConfigSources['disableCacheControl'] = {
+      kind: 'modelProviders',
+      authType: model.authType,
+      modelId: model.id,
+      detail: 'generationConfig.disableCacheControl',
+    };
+
+    this._generationConfig.schemaCompliance = gc.schemaCompliance;
+    this.generationConfigSources['schemaCompliance'] = {
+      kind: 'modelProviders',
+      authType: model.authType,
+      modelId: model.id,
+      detail: 'generationConfig.schemaCompliance',
+    };
+
+    this._generationConfig.reasoning = gc.reasoning;
+    this.generationConfigSources['reasoning'] = {
+      kind: 'modelProviders',
+      authType: model.authType,
+      modelId: model.id,
+      detail: 'generationConfig.reasoning',
+    };
+  }
+
+  /**
+   * Check if model switch requires ContentGenerator refresh.
+   *
+   * Note: This method is ONLY called by switchModel() for same-authType model switches.
+   * Cross-authType switches use switchModel(authType, modelId), which always requires full refresh.
+   *
+   * When this method is called:
+   * - this.currentAuthType is already the target authType
+   * - We're checking if switching between two models within the SAME authType needs refresh
+   *
+   * Examples:
+   * - Qwen OAuth: coder-model -> vision-model (same authType, hot-update safe)
+   * - OpenAI: model-a -> model-b with same envKey (same authType, hot-update safe)
+   * - OpenAI: gpt-4 -> deepseek-chat with different envKey (same authType, needs refresh)
+   *
+   * Cross-authType scenarios:
+   * - OpenAI -> Qwen OAuth: handled by switchModel(authType, modelId), always refreshes
+   * - Qwen OAuth -> OpenAI: handled by switchModel(authType, modelId), always refreshes
+   */
+  private checkRequiresRefresh(previousModelId: string): boolean {
+    // For Qwen OAuth, model switches within the same authType can always be hot-updated
+    // (coder-model <-> vision-model don't require ContentGenerator recreation)
+    if (this.currentAuthType === AuthType.QWEN_OAUTH) {
+      return false;
+    }
+
+    // Get previous and current model configs
+    const previousModel = this.modelRegistry.getModel(
+      this.currentAuthType,
+      previousModelId,
+    );
+    const currentModel = this.modelRegistry.getModel(
+      this.currentAuthType,
+      this.currentModelId,
+    );
+
+    // If either model is not in registry, require refresh to be safe
+    if (!previousModel || !currentModel) {
+      return true;
+    }
+
+    // Check if critical fields changed that require ContentGenerator recreation
+    const criticalFieldsChanged =
+      previousModel.envKey !== currentModel.envKey ||
+      previousModel.baseUrl !== currentModel.baseUrl;
+
+    if (criticalFieldsChanged) {
+      return true;
+    }
+
+    // For other auth types with strict model provider selection,
+    // if no critical fields changed, we can still hot-update
+    // (e.g., switching between two OpenAI models with same envKey and baseUrl)
+    return false;
+  }
+
+  /**
+   * Called by Config.refreshAuth to sync state after auth refresh.
+   *
+   * IMPORTANT: If credentials were manually set via updateCredentials(),
+   * we should NOT override them with modelProvider defaults.
+   * This handles the case where user inputs credentials via OpenAIKeyPrompt
+   * after removing environment variables for a previously selected model.
+   */
+  syncAfterAuthRefresh(authType: AuthType, modelId?: string): void {
+    // Check if we have manually set credentials that should be preserved
+    const preserveManualCredentials = this.hasManualCredentials;
+
+    // If credentials were manually set, don't apply modelProvider defaults
+    // Just update the authType and preserve the manually set credentials
+    if (preserveManualCredentials) {
+      this.strictModelProviderSelection = false;
+      this.currentAuthType = authType;
+      if (modelId) {
+        this.currentModelId = modelId;
+      }
+      return;
+    }
+
+    this.strictModelProviderSelection = false;
+
+    if (modelId && this.modelRegistry.hasModel(authType, modelId)) {
+      const resolved = this.modelRegistry.getModel(authType, modelId);
+      if (resolved) {
+        this.applyResolvedModelDefaults(resolved);
+        this.currentAuthType = authType;
+        this.currentModelId = modelId;
+      }
+    } else {
+      this.currentAuthType = authType;
+    }
+  }
+
+  /**
+   * Update callback for model changes
+   */
+  setOnModelChange(callback: OnModelChangeCallback): void {
+    this.onModelChange = callback;
+  }
+}

packages/core/src/models/types.ts

@@ -0,0 +1,101 @@
+/**
+ * @license
+ * Copyright 2025 Qwen Team
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import type {
+  AuthType,
+  ContentGeneratorConfig,
+} from '../core/contentGenerator.js';
+
+/**
+ * Model capabilities configuration
+ */
+export interface ModelCapabilities {
+  /** Supports image/vision inputs */
+  vision?: boolean;
+}
+
+/**
+ * Model-scoped generation configuration.
+ *
+ * Keep this consistent with {@link ContentGeneratorConfig} so modelProviders can
+ * feed directly into content generator resolution without shape conversion.
+ */
+export type ModelGenerationConfig = Pick<
+  ContentGeneratorConfig,
+  | 'samplingParams'
+  | 'timeout'
+  | 'maxRetries'
+  | 'disableCacheControl'
+  | 'schemaCompliance'
+  | 'reasoning'
+>;
+
+/**
+ * Model configuration for a single model within an authType
+ */
+export interface ModelConfig {
+  /** Unique model ID within authType (e.g., "qwen-coder", "gpt-4-turbo") */
+  id: string;
+  /** Display name (defaults to id) */
+  name?: string;
+  /** Model description */
+  description?: string;
+  /** Environment variable name to read API key from (e.g., "OPENAI_API_KEY") */
+  envKey?: string;
+  /** API endpoint override */
+  baseUrl?: string;
+  /** Model capabilities, reserve for future use. Now we do not read this to determine multi-modal support or other capabilities. */
+  capabilities?: ModelCapabilities;
+  /** Generation configuration (sampling parameters) */
+  generationConfig?: ModelGenerationConfig;
+}
+
+/**
+ * Model providers configuration grouped by authType
+ */
+export type ModelProvidersConfig = {
+  [authType: string]: ModelConfig[];
+};
+
+/**
+ * Resolved model config with all defaults applied
+ */
+export interface ResolvedModelConfig extends ModelConfig {
+  /** AuthType this model belongs to (always present from map key) */
+  authType: AuthType;
+  /** Display name (always present, defaults to id) */
+  name: string;
+  /** Environment variable name to read API key from (optional, provider-specific) */
+  envKey?: string;
+  /** API base URL (always present, has default per authType) */
+  baseUrl: string;
+  /** Generation config (always present, merged with defaults) */
+  generationConfig: ModelGenerationConfig;
+  /** Capabilities (always present, defaults to {}) */
+  capabilities: ModelCapabilities;
+}
+
+/**
+ * Model info for UI display
+ */
+export interface AvailableModel {
+  id: string;
+  label: string;
+  description?: string;
+  capabilities?: ModelCapabilities;
+  authType: AuthType;
+  isVision?: boolean;
+}
+
+/**
+ * Metadata for model switch operations
+ */
+export interface ModelSwitchMetadata {
+  /** Reason for the switch */
+  reason?: string;
+  /** Additional context */
+  context?: string;
+}

packages/core/src/subagents/subagent.test.ts

@@ -22,10 +22,11 @@ import {
   type Mock,
 } from 'vitest';
 import { Config, type ConfigParameters } from '../config/config.js';
-import { DEFAULT_GEMINI_MODEL } from '../config/models.js';
+import { DEFAULT_QWEN_MODEL } from '../config/models.js';
 import {
   createContentGenerator,
   createContentGeneratorConfig,
+  resolveContentGeneratorConfigWithSources,
   AuthType,
 } from '../core/contentGenerator.js';
 import { GeminiChat } from '../core/geminiChat.js';
@@ -42,7 +43,33 @@ import type {
 import { SubagentTerminateMode } from './types.js';
 
 vi.mock('../core/geminiChat.js');
-vi.mock('../core/contentGenerator.js');
+vi.mock('../core/contentGenerator.js', async (importOriginal) => {
+  const actual =
+    await importOriginal<typeof import('../core/contentGenerator.js')>();
+  const { DEFAULT_QWEN_MODEL } = await import('../config/models.js');
+  return {
+    ...actual,
+    createContentGenerator: vi.fn().mockResolvedValue({
+      generateContent: vi.fn(),
+      generateContentStream: vi.fn(),
+      countTokens: vi.fn().mockResolvedValue({ totalTokens: 100 }),
+      embedContent: vi.fn(),
+      useSummarizedThinking: vi.fn().mockReturnValue(false),
+    }),
+    createContentGeneratorConfig: vi.fn().mockReturnValue({
+      model: DEFAULT_QWEN_MODEL,
+      authType: actual.AuthType.USE_GEMINI,
+    }),
+    resolveContentGeneratorConfigWithSources: vi.fn().mockReturnValue({
+      config: {
+        model: DEFAULT_QWEN_MODEL,
+        authType: actual.AuthType.USE_GEMINI,
+        apiKey: 'test-api-key',
+      },
+      sources: {},
+    }),
+  };
+});
 vi.mock('../utils/environmentContext.js', () => ({
   getEnvironmentContext: vi.fn().mockResolvedValue([{ text: 'Env Context' }]),
   getInitialChatHistory: vi.fn(async (_config, extraHistory) => [
@@ -65,7 +92,7 @@ async function createMockConfig(
   toolRegistryMocks = {},
 ): Promise<{ config: Config; toolRegistry: ToolRegistry }> {
   const configParams: ConfigParameters = {
-    model: DEFAULT_GEMINI_MODEL,
+    model: DEFAULT_QWEN_MODEL,
     targetDir: '.',
     debugMode: false,
     cwd: process.cwd(),
@@ -89,7 +116,7 @@ async function createMockConfig(
 
   // Mock getContentGeneratorConfig to return a valid config
   vi.spyOn(config, 'getContentGeneratorConfig').mockReturnValue({
-    model: DEFAULT_GEMINI_MODEL,
+    model: DEFAULT_QWEN_MODEL,
     authType: AuthType.USE_GEMINI,
   });
 
@@ -192,9 +219,17 @@ describe('subagent.ts', () => {
         // eslint-disable-next-line @typescript-eslint/no-explicit-any
       } as any);
       vi.mocked(createContentGeneratorConfig).mockReturnValue({
-        model: DEFAULT_GEMINI_MODEL,
+        model: DEFAULT_QWEN_MODEL,
         authType: undefined,
       });
+      vi.mocked(resolveContentGeneratorConfigWithSources).mockReturnValue({
+        config: {
+          model: DEFAULT_QWEN_MODEL,
+          authType: AuthType.USE_GEMINI,
+          apiKey: 'test-api-key',
+        },
+        sources: {},
+      });
 
       mockSendMessageStream = vi.fn();
       vi.mocked(GeminiChat).mockImplementation(

packages/core/src/utils/configResolver.test.ts

@@ -0,0 +1,141 @@
+/**
+ * @license
+ * Copyright 2025 Qwen Team
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect } from 'vitest';
+import {
+  resolveField,
+  resolveOptionalField,
+  layer,
+  envLayer,
+  cliSource,
+  settingsSource,
+  defaultSource,
+} from './configResolver.js';
+
+describe('configResolver', () => {
+  describe('resolveField', () => {
+    it('returns first present value from layers', () => {
+      const result = resolveField(
+        [
+          layer(undefined, cliSource('--model')),
+          envLayer({ MODEL: 'from-env' }, 'MODEL'),
+          layer('from-settings', settingsSource('model.name')),
+        ],
+        'default-model',
+      );
+
+      expect(result.value).toBe('from-env');
+      expect(result.source).toEqual({ kind: 'env', envKey: 'MODEL' });
+    });
+
+    it('returns default when all layers are undefined', () => {
+      const result = resolveField(
+        [layer(undefined, cliSource('--model')), envLayer({}, 'MODEL')],
+        'default-model',
+        defaultSource('default-model'),
+      );
+
+      expect(result.value).toBe('default-model');
+      expect(result.source).toEqual({
+        kind: 'default',
+        detail: 'default-model',
+      });
+    });
+
+    it('respects layer priority order', () => {
+      const result = resolveField(
+        [
+          layer('cli-value', cliSource('--model')),
+          envLayer({ MODEL: 'env-value' }, 'MODEL'),
+          layer('settings-value', settingsSource('model.name')),
+        ],
+        'default',
+      );
+
+      expect(result.value).toBe('cli-value');
+      expect(result.source.kind).toBe('cli');
+    });
+
+    it('skips empty strings', () => {
+      const result = resolveField(
+        [
+          layer('', cliSource('--model')),
+          envLayer({ MODEL: 'env-value' }, 'MODEL'),
+        ],
+        'default',
+      );
+
+      expect(result.value).toBe('env-value');
+    });
+  });
+
+  describe('resolveOptionalField', () => {
+    it('returns undefined when no value present', () => {
+      const result = resolveOptionalField([
+        layer(undefined, cliSource('--key')),
+        envLayer({}, 'KEY'),
+      ]);
+
+      expect(result).toBeUndefined();
+    });
+
+    it('returns first present value', () => {
+      const result = resolveOptionalField([
+        layer(undefined, cliSource('--key')),
+        envLayer({ KEY: 'found' }, 'KEY'),
+      ]);
+
+      expect(result).toBeDefined();
+      expect(result!.value).toBe('found');
+      expect(result!.source.kind).toBe('env');
+    });
+  });
+
+  describe('envLayer', () => {
+    it('creates layer from environment variable', () => {
+      const env = { MY_VAR: 'my-value' };
+      const result = envLayer(env, 'MY_VAR');
+
+      expect(result.value).toBe('my-value');
+      expect(result.source).toEqual({ kind: 'env', envKey: 'MY_VAR' });
+    });
+
+    it('handles missing environment variable', () => {
+      const env = {};
+      const result = envLayer(env, 'MISSING_VAR');
+
+      expect(result.value).toBeUndefined();
+      expect(result.source).toEqual({ kind: 'env', envKey: 'MISSING_VAR' });
+    });
+
+    it('supports transform function', () => {
+      const env = { PORT: '3000' };
+      const result = envLayer(env, 'PORT', (v) => parseInt(v, 10));
+
+      expect(result.value).toBe(3000);
+    });
+  });
+
+  describe('source factory functions', () => {
+    it('creates CLI source', () => {
+      expect(cliSource('--model')).toEqual({ kind: 'cli', detail: '--model' });
+    });
+
+    it('creates settings source', () => {
+      expect(settingsSource('model.name')).toEqual({
+        kind: 'settings',
+        settingsPath: 'model.name',
+      });
+    });
+
+    it('creates default source', () => {
+      expect(defaultSource('my-default')).toEqual({
+        kind: 'default',
+        detail: 'my-default',
+      });
+    });
+  });
+});

packages/core/src/utils/configResolver.ts

@@ -0,0 +1,222 @@
+/**
+ * @license
+ * Copyright 2025 Qwen Team
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * Generic multi-source configuration resolver utilities.
+ *
+ * This module provides reusable tools for resolving configuration values
+ * from multiple sources (CLI, env, settings, etc.) with priority ordering
+ * and source tracking.
+ */
+
+/**
+ * Known source kinds for configuration values.
+ * Extensible for domain-specific needs.
+ */
+export type ConfigSourceKind =
+  | 'cli'
+  | 'env'
+  | 'settings'
+  | 'modelProviders'
+  | 'default'
+  | 'computed'
+  | 'programmatic'
+  | 'unknown';
+
+/**
+ * Source metadata for a configuration value.
+ * Tracks where the value came from for debugging and UI display.
+ */
+export interface ConfigSource {
+  /** The kind/category of the source */
+  kind: ConfigSourceKind;
+  /** Additional detail about the source (e.g., '--model' for CLI) */
+  detail?: string;
+  /** Environment variable key if kind is 'env' */
+  envKey?: string;
+  /** Settings path if kind is 'settings' (e.g., 'model.name') */
+  settingsPath?: string;
+  /** Auth type if relevant (for modelProviders) */
+  authType?: string;
+  /** Model ID if relevant (for modelProviders) */
+  modelId?: string;
+  /** Indirect source - when a value is derived via another source */
+  via?: Omit<ConfigSource, 'via'>;
+}
+
+/**
+ * Map of field names to their sources
+ */
+export type ConfigSources = Record<string, ConfigSource>;
+
+/**
+ * A configuration layer represents a potential source for a value.
+ * Layers are evaluated in priority order (first non-undefined wins).
+ */
+export interface ConfigLayer<T> {
+  /** The value from this layer (undefined means not present) */
+  value: T | undefined;
+  /** Source metadata for this layer */
+  source: ConfigSource;
+}
+
+/**
+ * Result of resolving a single field
+ */
+export interface ResolvedField<T> {
+  /** The resolved value */
+  value: T;
+  /** Source metadata indicating where the value came from */
+  source: ConfigSource;
+}
+
+/**
+ * Resolve a single configuration field from multiple layers.
+ *
+ * Layers are evaluated in order. The first layer with a defined,
+ * non-empty value wins. If no layer has a value, the default is used.
+ *
+ * @param layers - Configuration layers in priority order (highest first)
+ * @param defaultValue - Default value if no layer provides one
+ * @param defaultSource - Source metadata for the default value
+ * @returns The resolved value and its source
+ *
+ * @example
+ * ```typescript
+ * const model = resolveField(
+ *   [
+ *     { value: argv.model, source: { kind: 'cli', detail: '--model' } },
+ *     { value: env['OPENAI_MODEL'], source: { kind: 'env', envKey: 'OPENAI_MODEL' } },
+ *     { value: settings.model, source: { kind: 'settings', settingsPath: 'model.name' } },
+ *   ],
+ *   'default-model',
+ *   { kind: 'default', detail: 'default-model' }
+ * );
+ * ```
+ */
+export function resolveField<T>(
+  layers: Array<ConfigLayer<T>>,
+  defaultValue: T,
+  defaultSource: ConfigSource = { kind: 'default' },
+): ResolvedField<T> {
+  for (const layer of layers) {
+    if (isValuePresent(layer.value)) {
+      return { value: layer.value, source: layer.source };
+    }
+  }
+  return { value: defaultValue, source: defaultSource };
+}
+
+/**
+ * Resolve a field that may not have a default (optional field).
+ *
+ * @param layers - Configuration layers in priority order
+ * @returns The resolved value and source, or undefined if not found
+ */
+export function resolveOptionalField<T>(
+  layers: Array<ConfigLayer<T>>,
+): ResolvedField<T> | undefined {
+  for (const layer of layers) {
+    if (isValuePresent(layer.value)) {
+      return { value: layer.value, source: layer.source };
+    }
+  }
+  return undefined;
+}
+
+/**
+ * Check if a value is "present" (not undefined, not null, not empty string).
+ *
+ * @param value - The value to check
+ * @returns true if the value should be considered present
+ */
+function isValuePresent<T>(value: T | undefined | null): value is T {
+  if (value === undefined || value === null) {
+    return false;
+  }
+  // Treat empty strings as not present
+  if (typeof value === 'string' && value.trim() === '') {
+    return false;
+  }
+  return true;
+}
+
+/**
+ * Create a CLI source descriptor
+ */
+export function cliSource(detail: string): ConfigSource {
+  return { kind: 'cli', detail };
+}
+
+/**
+ * Create an environment variable source descriptor
+ */
+function envSource(envKey: string): ConfigSource {
+  return { kind: 'env', envKey };
+}
+
+/**
+ * Create a settings source descriptor
+ */
+export function settingsSource(settingsPath: string): ConfigSource {
+  return { kind: 'settings', settingsPath };
+}
+
+/**
+ * Create a modelProviders source descriptor
+ */
+export function modelProvidersSource(
+  authType: string,
+  modelId: string,
+  detail?: string,
+): ConfigSource {
+  return { kind: 'modelProviders', authType, modelId, detail };
+}
+
+/**
+ * Create a default value source descriptor
+ */
+export function defaultSource(detail?: string): ConfigSource {
+  return { kind: 'default', detail };
+}
+
+/**
+ * Create a computed value source descriptor
+ */
+export function computedSource(detail?: string): ConfigSource {
+  return { kind: 'computed', detail };
+}
+
+/**
+ * Create a layer from an environment variable
+ */
+export function envLayer<T = string>(
+  env: Record<string, string | undefined>,
+  key: string,
+  transform?: (value: string) => T,
+): ConfigLayer<T> {
+  const rawValue = env[key];
+  const value =
+    rawValue !== undefined
+      ? transform
+        ? transform(rawValue)
+        : (rawValue as unknown as T)
+      : undefined;
+  return {
+    value,
+    source: envSource(key),
+  };
+}
+
+/**
+ * Create a layer with a static value and source
+ */
+export function layer<T>(
+  value: T | undefined,
+  source: ConfigSource,
+): ConfigLayer<T> {
+  return { value, source };
+}

packages/core/src/utils/flashFallback.test.ts

@@ -1,75 +0,0 @@
-/**
- * @license
- * Copyright 2025 Google LLC
- * SPDX-License-Identifier: Apache-2.0
- */
-
-import { describe, it, expect, beforeEach, vi } from 'vitest';
-import { Config } from '../config/config.js';
-import fs from 'node:fs';
-import {
-  setSimulate429,
-  disableSimulationAfterFallback,
-  shouldSimulate429,
-  resetRequestCounter,
-} from './testUtils.js';
-import { DEFAULT_GEMINI_FLASH_MODEL } from '../config/models.js';
-// Import the new types (Assuming this test file is in packages/core/src/utils/)
-import type { FallbackModelHandler } from '../fallback/types.js';
-
-vi.mock('node:fs');
-
-// Update the description to reflect that this tests the retry utility's integration
-describe('Retry Utility Fallback Integration', () => {
-  let config: Config;
-
-  beforeEach(() => {
-    vi.mocked(fs.existsSync).mockReturnValue(true);
-    vi.mocked(fs.statSync).mockReturnValue({
-      isDirectory: () => true,
-    } as fs.Stats);
-    config = new Config({
-      targetDir: '/test',
-      debugMode: false,
-      cwd: '/test',
-      model: 'gemini-2.5-pro',
-    });
-
-    // Reset simulation state for each test
-    setSimulate429(false);
-    resetRequestCounter();
-  });
-
-  // This test validates the Config's ability to store and execute the handler contract.
-  it('should execute the injected FallbackHandler contract correctly', async () => {
-    // Set up a minimal handler for testing, ensuring it matches the new type.
-    const fallbackHandler: FallbackModelHandler = async () => 'retry';
-
-    // Use the generalized setter
-    config.setFallbackModelHandler(fallbackHandler);
-
-    // Call the handler directly via the config property
-    const result = await config.fallbackModelHandler!(
-      'gemini-2.5-pro',
-      DEFAULT_GEMINI_FLASH_MODEL,
-    );
-
-    // Verify it returns the correct intent
-    expect(result).toBe('retry');
-  });
-
-  // This test validates the test utilities themselves.
-  it('should properly disable simulation state after fallback (Test Utility)', () => {
-    // Enable simulation
-    setSimulate429(true);
-
-    // Verify simulation is enabled
-    expect(shouldSimulate429()).toBe(true);
-
-    // Disable simulation after fallback
-    disableSimulationAfterFallback();
-
-    // Verify simulation is now disabled
-    expect(shouldSimulate429()).toBe(false);
-  });
-});

packages/core/src/utils/llm-edit-fixer.ts

@@ -8,7 +8,7 @@ import { createHash } from 'node:crypto';
 import { type Content, Type } from '@google/genai';
 import { type BaseLlmClient } from '../core/baseLlmClient.js';
 import { LruCache } from './LruCache.js';
-import { DEFAULT_GEMINI_FLASH_MODEL } from '../config/models.js';
+import { DEFAULT_QWEN_FLASH_MODEL } from '../config/models.js';
 import { promptIdContext } from './promptIdContext.js';
 
 const MAX_CACHE_SIZE = 50;
@@ -149,7 +149,7 @@ export async function FixLLMEditWithInstruction(
     contents,
     schema: SearchReplaceEditSchema,
     abortSignal,
-    model: DEFAULT_GEMINI_FLASH_MODEL,
+    model: DEFAULT_QWEN_FLASH_MODEL,
     systemInstruction: EDIT_SYS_PROMPT,
     promptId,
     maxAttempts: 1,

packages/core/src/utils/summarizer.ts

@@ -11,7 +11,7 @@ import type {
   GenerateContentResponse,
 } from '@google/genai';
 import type { GeminiClient } from '../core/client.js';
-import { DEFAULT_GEMINI_FLASH_LITE_MODEL } from '../config/models.js';
+import { DEFAULT_QWEN_FLASH_MODEL } from '../config/models.js';
 import { getResponseText, partToString } from './partUtils.js';
 
 /**
@@ -86,7 +86,7 @@ export async function summarizeToolOutput(
       contents,
       toolOutputSummarizerConfig,
       abortSignal,
-      DEFAULT_GEMINI_FLASH_LITE_MODEL,
+      DEFAULT_QWEN_FLASH_MODEL,
     )) as unknown as GenerateContentResponse;
     return getResponseText(parsedResponse) || textToSummarize;
   } catch (error) {