diff --git a/packages/cli/src/gemini.renderOptions.test.tsx b/packages/cli/src/gemini.renderOptions.test.tsx
index 6febf6493..713b9167c 100644
--- a/packages/cli/src/gemini.renderOptions.test.tsx
+++ b/packages/cli/src/gemini.renderOptions.test.tsx
@@ -90,6 +90,7 @@ describe('startInteractiveUI ink render options', () => {
       debugMode: false,
       model: 'gemini-2.5-flash-lite',
       accessibility: { screenReader: false },
+      continueSession: false,
     });
 
     await startInteractiveUI(config, createLoadedSettings(), [], tempDir);
@@ -117,6 +118,7 @@ describe('startInteractiveUI ink render options', () => {
       debugMode: false,
       model: 'gemini-2.5-flash-lite',
       accessibility: { screenReader: true },
+      continueSession: false,
     });
 
     await startInteractiveUI(config, createLoadedSettings(), [], tempDir);
diff --git a/packages/cli/src/ui/commands/__tests__/authCommand.autoswitch.spec.ts b/packages/cli/src/ui/commands/__tests__/authCommand.autoswitch.spec.ts
new file mode 100644
index 000000000..2dd7bd570
--- /dev/null
+++ b/packages/cli/src/ui/commands/__tests__/authCommand.autoswitch.spec.ts
@@ -0,0 +1,191 @@
+/**
+ * @license
+ * Copyright 2025 Vybestack LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect, beforeEach, vi, afterEach } from 'vitest';
+import { AuthCommandExecutor } from '../authCommand.js';
+import { OAuthManager } from '../../../auth/oauth-manager.js';
+import { CommandContext } from '../types.js';
+
+// Mock the runtime settings module (partial mock)
+vi.mock('../../../runtime/runtimeSettings.js', async (importOriginal) => {
+  const actual =
+    await importOriginal<
+      typeof import('../../../runtime/runtimeSettings.js')
+    >();
+  return {
+    ...actual,
+    switchActiveProvider: vi.fn(),
+    getEphemeralSetting: vi.fn(),
+  };
+});
+
+import {
+  switchActiveProvider,
+  getEphemeralSetting,
+} from '../../../runtime/runtimeSettings.js';
+
+const mockSwitchActiveProvider = switchActiveProvider as ReturnType<
+  typeof vi.fn
+>;
+const mockGetEphemeralSetting = getEphemeralSetting as ReturnType<typeof vi.fn>;
+
+describe('Auth Command Auto-Switch Integration', () => {
+  let executor: AuthCommandExecutor;
+  let mockOAuthManager: OAuthManager;
+  let mockContext: CommandContext;
+
+  beforeEach(() => {
+    vi.clearAllMocks();
+
+    mockOAuthManager = {
+      authenticate: vi.fn().mockResolvedValue(undefined),
+      getSupportedProviders: vi
+        .fn()
+        .mockReturnValue(['gemini', 'qwen', 'anthropic', 'codex']),
+    } as unknown as OAuthManager;
+
+    executor = new AuthCommandExecutor(mockOAuthManager);
+
+    mockContext = {
+      services: {
+        config: null,
+        settings: {} as never,
+        git: undefined,
+        logger: {} as never,
+      },
+      ui: {} as never,
+      session: {} as never,
+    };
+
+    // Default: auto-switch enabled
+    mockGetEphemeralSetting.mockReturnValue(true);
+    mockSwitchActiveProvider.mockResolvedValue({
+      changed: true,
+      previousProvider: 'gemini',
+      nextProvider: 'anthropic',
+    });
+  });
+
+  afterEach(() => {
+    vi.resetAllMocks();
+  });
+
+  describe('@requirement REQ-001: Auto-switch after auth', () => {
+    it('switches provider after successful OAuth login', async () => {
+      const result = await executor.execute(mockContext, 'anthropic login');
+
+      expect(mockOAuthManager.authenticate).toHaveBeenCalledWith(
+        'anthropic',
+        undefined,
+      );
+      expect(mockSwitchActiveProvider).toHaveBeenCalledWith('anthropic');
+      expect(result).toEqual({
+        type: 'message',
+        messageType: 'info',
+        content: '[OK] Authenticated with anthropic and set as active provider',
+      });
+    });
+
+    it('includes bucket info in success message', async () => {
+      const result = await executor.execute(
+        mockContext,
+        'anthropic login work',
+      );
+
+      expect(mockOAuthManager.authenticate).toHaveBeenCalledWith(
+        'anthropic',
+        'work',
+      );
+      expect(mockSwitchActiveProvider).toHaveBeenCalledWith('anthropic');
+      expect(result).toEqual({
+        type: 'message',
+        messageType: 'info',
+        content:
+          '[OK] Authenticated with anthropic (bucket: work) and set as active provider',
+      });
+    });
+  });
+
+  describe('@requirement REQ-008: Configurable auto-switch', () => {
+    it('skips auto-switch when setting is disabled', async () => {
+      mockGetEphemeralSetting.mockReturnValue(false);
+
+      const result = await executor.execute(mockContext, 'anthropic login');
+
+      expect(mockOAuthManager.authenticate).toHaveBeenCalledWith(
+        'anthropic',
+        undefined,
+      );
+      expect(mockSwitchActiveProvider).not.toHaveBeenCalled();
+      expect(result).toEqual({
+        type: 'message',
+        messageType: 'info',
+        content: 'Successfully authenticated anthropic',
+      });
+    });
+
+    it('defaults to enabled when setting is undefined', async () => {
+      mockGetEphemeralSetting.mockReturnValue(undefined);
+
+      await executor.execute(mockContext, 'anthropic login');
+
+      expect(mockSwitchActiveProvider).toHaveBeenCalledWith('anthropic');
+    });
+  });
+
+  describe('@requirement REQ-010: Graceful error handling', () => {
+    it('succeeds auth even when switch fails', async () => {
+      mockSwitchActiveProvider.mockRejectedValue(
+        new Error('Provider not found'),
+      );
+
+      const result = await executor.execute(mockContext, 'anthropic login');
+
+      expect(mockOAuthManager.authenticate).toHaveBeenCalled();
+      expect(result.type).toBe('message');
+      expect((result as { messageType: string }).messageType).toBe('info');
+      expect((result as { content: string }).content).toContain(
+        'Successfully authenticated',
+      );
+      expect((result as { content: string }).content).toContain(
+        'auto-switch to provider failed',
+      );
+    });
+  });
+
+  describe('@requirement REQ-004.2: Override existing provider', () => {
+    it('switches even when provider already set', async () => {
+      mockSwitchActiveProvider.mockResolvedValue({
+        changed: true,
+        previousProvider: 'openai',
+        nextProvider: 'anthropic',
+      });
+
+      const result = await executor.execute(mockContext, 'anthropic login');
+
+      expect(mockSwitchActiveProvider).toHaveBeenCalledWith('anthropic');
+      expect((result as { content: string }).content).toContain(
+        'set as active provider',
+      );
+    });
+
+    it('shows simple message when already on same provider', async () => {
+      mockSwitchActiveProvider.mockResolvedValue({
+        changed: false,
+        previousProvider: 'anthropic',
+        nextProvider: 'anthropic',
+      });
+
+      const result = await executor.execute(mockContext, 'anthropic login');
+
+      expect(result).toEqual({
+        type: 'message',
+        messageType: 'info',
+        content: 'Successfully authenticated anthropic',
+      });
+    });
+  });
+});
diff --git a/packages/cli/src/ui/commands/__tests__/authCommand.bucket.spec.ts b/packages/cli/src/ui/commands/__tests__/authCommand.bucket.spec.ts
index ee20d7790..ac24a1f06 100644
--- a/packages/cli/src/ui/commands/__tests__/authCommand.bucket.spec.ts
+++ b/packages/cli/src/ui/commands/__tests__/authCommand.bucket.spec.ts
@@ -18,6 +18,23 @@ import { AuthCommandExecutor } from '../authCommand.js';
 import { OAuthManager } from '../../../auth/oauth-manager.js';
 import { CommandContext } from '../types.js';
 
+// Mock the runtime settings module to avoid needing full CLI runtime context
+vi.mock('../../../runtime/runtimeSettings.js', async (importOriginal) => {
+  const actual =
+    await importOriginal<
+      typeof import('../../../runtime/runtimeSettings.js')
+    >();
+  return {
+    ...actual,
+    switchActiveProvider: vi.fn().mockResolvedValue({
+      changed: false,
+      previousProvider: 'anthropic',
+      nextProvider: 'anthropic',
+    }),
+    getEphemeralSetting: vi.fn().mockReturnValue(true),
+  };
+});
+
 // Mock OAuth manager for bucket operations
 const mockOAuthManager = {
   registerProvider: vi.fn(),
diff --git a/packages/cli/src/ui/commands/authCommand.ts b/packages/cli/src/ui/commands/authCommand.ts
index 78f2b304d..e61b70e69 100644
--- a/packages/cli/src/ui/commands/authCommand.ts
+++ b/packages/cli/src/ui/commands/authCommand.ts
@@ -26,6 +26,10 @@ import {
   type CompleterFn,
 } from './schema/types.js';
 import { withFuzzyFilter } from '../utils/fuzzyFilter.js';
+import {
+  switchActiveProvider,
+  getEphemeralSetting,
+} from '../../runtime/runtimeSettings.js';
 
 const logger = new DebugLogger('llxprt:ui:auth-command');
 
@@ -404,6 +408,7 @@ export class AuthCommandExecutor {
 
   /**
    * Login to a provider with optional bucket parameter
+   * @requirement REQ-001 Auto-switch provider after successful auth
    */
   private async loginWithBucket(
     provider: string,
@@ -414,6 +419,44 @@ export class AuthCommandExecutor {
       await this.oauthManager.authenticate(provider, bucket);
 
       const bucketInfo = bucket ? ` (bucket: ${bucket})` : '';
+
+      // Check if auto-switch is enabled (default: true)
+      const autoSwitchEnabled =
+        getEphemeralSetting('auth.autoSwitchProvider') ?? true;
+
+      if (autoSwitchEnabled) {
+        try {
+          // Attempt to switch to the authenticated provider
+          const switchResult = await switchActiveProvider(provider);
+
+          if (switchResult.changed) {
+            return {
+              type: 'message',
+              messageType: 'info',
+              content: `[OK] Authenticated with ${provider}${bucketInfo} and set as active provider`,
+            };
+          }
+          // Provider was already active, just show auth success
+          return {
+            type: 'message',
+            messageType: 'info',
+            content: `Successfully authenticated ${provider}${bucketInfo}`,
+          };
+        } catch (switchError) {
+          // Log warning but don't fail auth
+          logger.debug(
+            `Auto-switch to ${provider} failed after auth:`,
+            switchError,
+          );
+          return {
+            type: 'message',
+            messageType: 'info',
+            content: `Successfully authenticated ${provider}${bucketInfo} (Note: auto-switch to provider failed, use /provider ${provider} to switch manually)`,
+          };
+        }
+      }
+
+      // Auto-switch disabled, just return auth success
       return {
         type: 'message',
         messageType: 'info',