feat: implement alternate buffer toggling and unit tests

calculator-app/src/logic.ts

@@ -1,61 +0,0 @@
-import { evaluate } from 'mathjs';
-
-export interface CalculatorState {
-  display: string;
-  equation: string;
-  lastResult: string | null;
-}
-
-export const initialState: CalculatorState = {
-  display: '0',
-  equation: '',
-  lastResult: null,
-};
-
-export function handleInput(state: CalculatorState, input: string): CalculatorState {
-  if (/[0-9]/.test(input)) {
-    if (state.display === '0' || state.lastResult !== null) {
-      return { ...state, display: input, lastResult: null };
-    } else {
-      return { ...state, display: state.display + input };
-    }
-  } else if (input === '.') {
-    if (!state.display.includes('.')) {
-      return { ...state, display: state.display + '.' };
-    }
-  } else if (['+', '-', '*', '/'].includes(input)) {
-    return {
-      ...state,
-      equation: `${state.display} ${input} `,
-      display: '0',
-    };
-  }
-  return state;
-}
-
-export function calculate(state: CalculatorState): CalculatorState {
-  try {
-    const fullEquation = state.equation + state.display;
-    const result = evaluate(fullEquation);
-    const resultStr = result.toString();
-    return {
-      display: resultStr,
-      equation: '',
-      lastResult: resultStr,
-    };
-  } catch (error) {
-    return {
-      display: 'Error',
-      equation: '',
-      lastResult: null,
-    };
-  }
-}
-
-export function deleteLast(state: CalculatorState): CalculatorState {
-  if (state.display.length > 1) {
-    return { ...state, display: state.display.slice(0, -1) };
-  } else {
-    return { ...state, display: '0' };
-  }
-}

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

@@ -1867,32 +1867,6 @@ describe('loadCliConfig with admin.mcp.config', () => {
   });
 });
 
-describe('loadCliConfig deepValidation', () => {
-  beforeEach(() => {
-    vi.spyOn(ExtensionManager.prototype, 'getExtensions').mockReturnValue([]);
-  });
-
-  it('should enable deepValidation by default', async () => {
-    process.argv = ['node', 'script.js'];
-    const argv = await parseArguments(createTestMergedSettings());
-    const settings = createTestMergedSettings();
-    const config = await loadCliConfig(settings, 'test-session', argv);
-    expect(config.isDeepValidationEnabled()).toBe(true);
-  });
-
-  it('should allow disabling deepValidation via settings', async () => {
-    process.argv = ['node', 'script.js'];
-    const argv = await parseArguments(createTestMergedSettings());
-    const settings = createTestMergedSettings({
-      general: {
-        deepValidation: false,
-      },
-    });
-    const config = await loadCliConfig(settings, 'test-session', argv);
-    expect(config.isDeepValidationEnabled()).toBe(false);
-  });
-});
-
 describe('loadCliConfig model selection', () => {
   beforeEach(() => {
     vi.spyOn(ExtensionManager.prototype, 'getExtensions').mockReturnValue([]);

packages/cli/src/config/config.ts

@@ -900,7 +900,6 @@ export async function loadCliConfig(
     memoryBoundaryMarkers: settings.context?.memoryBoundaryMarkers,
     importFormat: settings.context?.importFormat,
     debugMode,
-    deepValidation: settings.general?.deepValidation ?? true,
     question,
     worktreeSettings,
 

packages/cli/src/config/settingsSchema.ts

@@ -236,16 +236,6 @@ const SETTINGS_SCHEMA = {
         description: 'Enable DevTools inspector on launch.',
         showInDialog: false,
       },
-      deepValidation: {
-        type: 'boolean',
-        label: 'Deep Validation',
-        category: 'General',
-        requiresRestart: false,
-        default: true,
-        description:
-          'Run a subagent after the main agent finishes to perform final validation.',
-        showInDialog: true,
-      },
       enableAutoUpdate: {
         type: 'boolean',
         label: 'Enable Auto Update',

packages/cli/src/test-utils/render.tsx

@@ -534,6 +534,7 @@ export const mockAppState: AppState = {
 };
 
 const mockUIActions: UIActions = {
+  toggleAlternateBuffer: vi.fn(),
   handleThemeSelect: vi.fn(),
   closeThemeDialog: vi.fn(),
   handleThemeHighlight: vi.fn(),

packages/cli/src/ui/AppContainer.tsx

@@ -68,8 +68,10 @@ import {
   writeToStdout,
   disableMouseEvents,
   enterAlternateScreen,
+  exitAlternateScreen,
   enableMouseEvents,
   disableLineWrapping,
+  enableLineWrapping,
   shouldEnterAlternateScreen,
   startupProfiler,
   SessionStartSource,
@@ -213,7 +215,7 @@ export const AppContainer = (props: AppContainerProps) => {
   });
 
   useMemoryMonitor(historyManager);
-  const isAlternateBuffer = config.getUseAlternateBuffer();
+  const [isAlternateBuffer, setIsAlternateBuffer] = useState(config.getUseAlternateBuffer());
   const [corgiMode, setCorgiMode] = useState(false);
   const [forceRerenderKey, setForceRerenderKey] = useState(0);
   const [debugMessage, setDebugMessage] = useState<string>('');
@@ -1550,6 +1552,23 @@ Logging in with Google... Restarting Gemini CLI to continue.
     type: TransientMessageType;
   }>(WARNING_PROMPT_DURATION_MS);
 
+  const [shownBufferToggleHint, setShownBufferToggleHint] = useState(false);
+
+  useEffect(() => {
+    if (isAlternateBuffer) return;
+
+    const isLongHistory = historyManager.history.length > 15;
+    const isComplexPrompt = buffer.text.length > 200 || buffer.text.includes('\n');
+
+    if ((isLongHistory || isComplexPrompt) && !shownBufferToggleHint) {
+      showTransientMessage({ 
+        text: 'Tip: Press Alt+T to toggle full-screen mode for better scrolling/editing', 
+        type: TransientMessageType.Hint 
+      });
+      setShownBufferToggleHint(true);
+    }
+  }, [historyManager.history.length, buffer.text, isAlternateBuffer, shownBufferToggleHint, showTransientMessage]);
+
   const {
     isFolderTrustDialogOpen,
     discoveryResults: folderDiscoveryResults,
@@ -1700,6 +1719,11 @@ Logging in with Google... Restarting Gemini CLI to continue.
         return true;
       }
 
+      if (keyMatchers[Command.TOGGLE_BUFFER_MODE](key)) {
+        toggleAlternateBuffer();
+        return true;
+      }
+
       if (keyMatchers[Command.QUIT](key)) {
         // If the user presses Ctrl+C, we want to cancel any ongoing requests.
         // This should happen regardless of the count.
@@ -2204,8 +2228,11 @@ Logging in with Google... Restarting Gemini CLI to continue.
     };
   }, [config, refreshStatic]);
 
+  const showIsAlternateBufferHint = (historyManager.history.length > 15 || buffer.text.length > 200 || buffer.text.includes('\n')) && !isAlternateBuffer;
+
   const uiState: UIState = useMemo(
     () => ({
+      isAlternateBuffer,
       history: historyManager.history,
       historyManager,
       isThemeDialogOpen,
@@ -2331,6 +2358,7 @@ Logging in with Google... Restarting Gemini CLI to continue.
       adminSettingsChanged,
       newAgents,
       showIsExpandableHint,
+      showIsAlternateBufferHint,
       hintMode:
         config.isModelSteeringEnabled() && isToolExecuting(pendingHistoryItems),
       hintBuffer: '',
@@ -2457,6 +2485,8 @@ Logging in with Google... Restarting Gemini CLI to continue.
       adminSettingsChanged,
       newAgents,
       showIsExpandableHint,
+      showIsAlternateBufferHint,
+      isAlternateBuffer,
     ],
   );
 
@@ -2465,6 +2495,31 @@ Logging in with Google... Restarting Gemini CLI to continue.
     [setShowPrivacyNotice],
   );
 
+  const toggleAlternateBuffer = useCallback(() => {
+    setIsAlternateBuffer(prev => {
+      const next = !prev;
+      if (next) {
+        enterAlternateScreen();
+        enableMouseEvents();
+        disableLineWrapping();
+      } else {
+        exitAlternateScreen();
+        disableMouseEvents();
+        enableLineWrapping();
+        writeToStdout('\x1b[2J\x1b[H');
+      }
+      process.stdout.emit('resize');
+
+      // Give a tick for resize to process, then trigger remount to force full redraw
+      setImmediate(() => {
+        refreshStatic();
+        setForceRerenderKey((prev) => prev + 1);
+      });
+
+      return next;
+    });
+  }, [setIsAlternateBuffer, refreshStatic, setForceRerenderKey]);
+
   const uiActions: UIActions = useMemo(
     () => ({
       handleThemeSelect,
@@ -2476,6 +2531,7 @@ Logging in with Google... Restarting Gemini CLI to continue.
       handleEditorSelect,
       exitEditorDialog,
       exitPrivacyNotice,
+      toggleAlternateBuffer,
       closeSettingsDialog,
       closeModelDialog,
       openAgentConfigDialog,
@@ -2614,6 +2670,7 @@ Logging in with Google... Restarting Gemini CLI to continue.
       config,
       historyManager,
       getPreferredEditor,
+      toggleAlternateBuffer,
     ],
   );
 

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

@@ -142,4 +142,38 @@ describe('<StatusRow />', () => {
     await waitUntilReady();
     expect(lastFrame()).toContain('Tip: Test Tip');
   });
+
+  it('renders buffer toggle hint when showIsAlternateBufferHint is true', async () => {
+    (useComposerStatus as Mock).mockReturnValue({
+      isInteractiveShellWaiting: false,
+      showLoadingIndicator: false,
+      showTips: false,
+      showWit: false,
+      modeContentObj: null,
+      showMinimalContext: false,
+    });
+
+    const uiState: Partial<UIState> = {
+      ...defaultUiState,
+      showIsAlternateBufferHint: true,
+    };
+
+    const { lastFrame, waitUntilReady } = await renderWithProviders(
+      <StatusRow
+        showUiDetails={false}
+        isNarrow={false}
+        terminalWidth={100}
+        hideContextSummary={false}
+        hideUiDetailsForSuggestions={false}
+        hasPendingActionRequired={false}
+      />,
+      {
+        width: 100,
+        uiState,
+      },
+    );
+
+    await waitUntilReady();
+    expect(lastFrame()).toContain('[Alt+T] Switch to Full Screen');
+  });
 });

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

@@ -206,7 +206,12 @@ export const StatusRow: React.FC<StatusRowProps> = ({
       return uiState.currentTip;
     }
 
-    // 2. Shortcut Hint (Fallback)
+    // 2. Buffer Toggle Hint
+    if (uiState.showIsAlternateBufferHint) {
+      return '[Alt+T] Switch to Full Screen';
+    }
+
+    // 3. Shortcut Hint (Fallback)
     if (
       settings.merged.ui.showShortcutsHint &&
       !hideUiDetailsForSuggestions &&

packages/cli/src/ui/contexts/KeypressContext.tsx

@@ -205,6 +205,8 @@ const MAC_ALT_KEY_CHARACTER_MAP: Record<string, string> = {
   '\u03A9': 'z', // "Ω" Option+z
   '\u00B8': 'Z', // "¸" Option+Shift+z
   '\u2202': 'd', // "∂" delete word forward
+  '\u2020': 't', // "†" toggle full screen buffer
+  '\u00E5': 'a', // "å" Option+a for alternate buffer
 };
 
 function nonKeyboardEventFilter(

packages/cli/src/ui/contexts/UIActionsContext.tsx

@@ -78,6 +78,7 @@ export interface UIActions {
   setShortcutsHelpVisible: (visible: boolean) => void;
   setCleanUiDetailsVisible: (visible: boolean) => void;
   toggleCleanUiDetailsVisible: () => void;
+  toggleAlternateBuffer: () => void;
   revealCleanUiDetailsTemporarily: (durationMs?: number) => void;
   handleWarning: (message: string) => void;
   setEmbeddedShellFocused: (value: boolean) => void;

packages/cli/src/ui/contexts/UIStateContext.tsx

@@ -118,6 +118,8 @@ export interface UIState {
   isEditorDialogOpen: boolean;
   showPrivacyNotice: boolean;
   corgiMode: boolean;
+  isAlternateBuffer: boolean;
+  showIsAlternateBufferHint: boolean;
   debugMessage: string;
   quittingMessages: HistoryItem[] | null;
   isSettingsDialogOpen: boolean;

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

@@ -11,49 +11,47 @@ import {
   isAlternateBufferEnabled,
 } from './useAlternateBuffer.js';
 import type { Config } from '@google/gemini-cli-core';
+import { useUIState } from '../contexts/UIStateContext.js';
 
-vi.mock('../contexts/ConfigContext.js', () => ({
-  useConfig: vi.fn(),
-}));
+vi.mock('../contexts/UIStateContext.js');
 
-const mockUseConfig = vi.mocked(
-  await import('../contexts/ConfigContext.js').then((m) => m.useConfig),
-);
+const mockUseUIState = vi.mocked(useUIState);
 
 describe('useAlternateBuffer', () => {
   beforeEach(() => {
     vi.clearAllMocks();
   });
 
-  it('should return false when config.getUseAlternateBuffer returns false', async () => {
-    mockUseConfig.mockReturnValue({
-      getUseAlternateBuffer: () => false,
-    } as unknown as ReturnType<typeof mockUseConfig>);
+  it('should return false when uiState.isAlternateBuffer is false', async () => {
+    mockUseUIState.mockReturnValue({
+      isAlternateBuffer: false,
+    } as unknown as ReturnType<typeof mockUseUIState>);
 
     const { result } = await renderHook(() => useAlternateBuffer());
     expect(result.current).toBe(false);
   });
 
-  it('should return true when config.getUseAlternateBuffer returns true', async () => {
-    mockUseConfig.mockReturnValue({
-      getUseAlternateBuffer: () => true,
-    } as unknown as ReturnType<typeof mockUseConfig>);
+  it('should return true when uiState.isAlternateBuffer is true', async () => {
+    mockUseUIState.mockReturnValue({
+      isAlternateBuffer: true,
+    } as unknown as ReturnType<typeof mockUseUIState>);
 
     const { result } = await renderHook(() => useAlternateBuffer());
     expect(result.current).toBe(true);
   });
 
-  it('should return the immutable config value, not react to settings changes', async () => {
-    const mockConfig = {
-      getUseAlternateBuffer: () => true,
-    } as unknown as ReturnType<typeof mockUseConfig>;
-
-    mockUseConfig.mockReturnValue(mockConfig);
+  it('should react to state changes', async () => {
+    mockUseUIState.mockReturnValue({
+      isAlternateBuffer: false,
+    } as unknown as ReturnType<typeof mockUseUIState>);
 
     const { result, rerender } = await renderHook(() => useAlternateBuffer());
 
-    // Value should remain true even after rerender
-    expect(result.current).toBe(true);
+    expect(result.current).toBe(false);
+
+    mockUseUIState.mockReturnValue({
+      isAlternateBuffer: true,
+    } as unknown as ReturnType<typeof mockUseUIState>);
 
     rerender();
 

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

@@ -4,14 +4,14 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-import { useConfig } from '../contexts/ConfigContext.js';
+import { useUIState } from '../contexts/UIStateContext.js';
 import type { Config } from '@google/gemini-cli-core';
 
 export const isAlternateBufferEnabled = (config: Config): boolean =>
   config.getUseAlternateBuffer();
 
-// This is read from Config so that the UI reads the same value per application session
+// This is read from UIState so that the UI can toggle dynamically
 export const useAlternateBuffer = (): boolean => {
-  const config = useConfig();
-  return isAlternateBufferEnabled(config);
+  const uiState = useUIState();
+  return uiState.isAlternateBuffer;
 };

packages/cli/src/ui/key/keyBindings.ts

@@ -95,6 +95,7 @@ export enum Command {
   RESTART_APP = 'app.restart',
   SUSPEND_APP = 'app.suspend',
   SHOW_SHELL_INPUT_UNFOCUS_WARNING = 'app.showShellUnfocusWarning',
+  TOGGLE_BUFFER_MODE = 'app.toggleBufferMode',
 
   // Background Shell Controls
   BACKGROUND_SHELL_ESCAPE = 'background.escape',
@@ -392,6 +393,7 @@ export const defaultKeyBindingConfig: KeyBindingConfig = new Map([
   [Command.RESTART_APP, [new KeyBinding('r'), new KeyBinding('shift+r')]],
   [Command.SUSPEND_APP, [new KeyBinding('ctrl+z')]],
   [Command.SHOW_SHELL_INPUT_UNFOCUS_WARNING, [new KeyBinding('tab')]],
+  [Command.TOGGLE_BUFFER_MODE, [new KeyBinding('alt+a')]],
 
   // Background Shell Controls
   [Command.BACKGROUND_SHELL_ESCAPE, [new KeyBinding('escape')]],
@@ -609,6 +611,7 @@ export const commandDescriptions: Readonly<Record<Command, string>> = {
   [Command.SHOW_IDE_CONTEXT_DETAIL]: 'Show IDE context details.',
   [Command.TOGGLE_MARKDOWN]: 'Toggle Markdown rendering.',
   [Command.TOGGLE_COPY_MODE]: 'Toggle copy mode when in alternate buffer mode.',
+  [Command.TOGGLE_BUFFER_MODE]: 'Toggle between regular and full screen (alternate buffer) mode.',
   [Command.TOGGLE_YOLO]: 'Toggle YOLO (auto-approval) mode for tool calls.',
   [Command.CYCLE_APPROVAL_MODE]:
     'Cycle through approval modes: default (prompt), auto_edit (auto-approve edits), and plan (read-only). Plan mode is skipped when the agent is busy.',

packages/core/src/agents/deep-validation-agent.ts

@@ -1,82 +0,0 @@
-/**
- * @license
- * Copyright 2026 Google LLC
- * SPDX-License-Identifier: Apache-2.0
- */
-
-import { z } from 'zod';
-import type { AgentLoopContext } from '../config/agent-loop-context.js';
-import type { LocalAgentDefinition } from './types.js';
-
-const DeepValidationAgentSchema = z.object({
-  report: z.string().describe('The final validation report.'),
-  isSatisfied: z.boolean().describe('Whether the original prompt was fully satisfied.'),
-});
-
-/**
- * A specialized subagent that performs final validation after the main agent finishes.
- * It reflects on the original prompt and determines if it was satisfied by reviewing
- * the changes and running the application and tests.
- */
-export const DeepValidationAgent = (
-  context: AgentLoopContext,
-  originalPrompt: string,
-): LocalAgentDefinition<typeof DeepValidationAgentSchema> => ({
-  kind: 'local',
-  name: 'deep-validation',
-  displayName: 'Deep Validation Agent',
-  internal: true,
-  description:
-    'A specialized subagent that performs final validation. It reflects on the original prompt and determines if it was satisfied by reviewing the changes and running the application and tests, if applicable.',
-  inputConfig: {
-    inputSchema: {
-      type: 'object',
-      properties: {
-        originalPrompt: {
-          type: 'string',
-          description: 'The original user request or prompt that was executed.',
-        },
-      },
-      required: ['originalPrompt'],
-    },
-  },
-  outputConfig: {
-    outputName: 'validationResult',
-    description: 'The final validation report and satisfaction status.',
-    schema: DeepValidationAgentSchema,
-  },
-  modelConfig: {
-    model: 'inherit',
-  },
-  get toolConfig() {
-    const tools = context.toolRegistry?.getAllToolNames() ?? [];
-    return {
-      tools,
-    };
-  },
-  get promptConfig() {
-    return {
-      systemPrompt: `You are the Deep Validation subagent. Your job is to perform final validation after the main agent finishes.
-The user's original request was: ${originalPrompt}
-You must deterministically determine if the request was satisfied.
-Review the changes using git, check the code, and run the application, any existing linters, formatters, and tests if applicable.
-Make a comprehensive and prioritized list of any validation failures and then fix them in priority order. Take care not to leave the code worse than you found it.
-
-Use the following order to guide your prioritization of fixes:
-- Unfulfilled aspects of the original request.
-- Issues blocking correct operation of the solution, such as runtime failures, test failures, etc.
-- Conventions
-- Linters
-- Best practices for the ecosystem.
-
-Try to keep your changes targeted and as minimal as possible while still resolving the validation issue.
-
-Return a final validation report detailing your findings and a boolean indicating if the request was fully satisfied.`,
-      query: `Please validate the original request: ${originalPrompt}`,
-    };
-  },
-  runConfig: {
-    maxTimeMinutes: 10,
-    maxTurns: 10,
-  },
-});

packages/core/src/agents/local-invocation.ts

@@ -56,7 +56,7 @@ export class LocalSubagentInvocation extends BaseToolInvocation<
    * @param messageBus Message bus for policy enforcement.
    */
   constructor(
-    private readonly definition: LocalAgentDefinition<any>,
+    private readonly definition: LocalAgentDefinition,
     private readonly context: AgentLoopContext,
     params: AgentInputs,
     messageBus: MessageBus,

packages/core/src/agents/registry.test.ts

@@ -272,7 +272,6 @@ describe('AgentRegistry', () => {
             codebase_investigator: { enabled: false },
             cli_help: { enabled: false },
             generalist: { enabled: false },
-            'deep-validation': { enabled: false },
           },
         },
       });

packages/core/src/agents/registry.ts

@@ -14,7 +14,6 @@ import { loadAgentsFromDirectory } from './agentLoader.js';
 import { CodebaseInvestigatorAgent } from './codebase-investigator.js';
 import { CliHelpAgent } from './cli-help-agent.js';
 import { GeneralistAgent } from './generalist-agent.js';
-import { DeepValidationAgent } from './deep-validation-agent.js';
 import { BrowserAgentDefinition } from './browser/browserAgentDefinition.js';
 import { MemoryManagerAgent } from './memory-manager-agent.js';
 import { A2AAuthProviderFactory } from './auth-provider/factory.js';
@@ -244,7 +243,7 @@ export class AgentRegistry {
 
     if (this.config.getDebugMode()) {
       debugLogger.log(
-        `[AgentRegistry] Loaded with ${this.getAllDefinitions().length} agents.`,
+        `[AgentRegistry] Loaded with ${this.agents.size} agents.`,
       );
     }
   }
@@ -253,7 +252,6 @@ export class AgentRegistry {
     this.registerLocalAgent(CodebaseInvestigatorAgent(this.config));
     this.registerLocalAgent(CliHelpAgent(this.config));
     this.registerLocalAgent(GeneralistAgent(this.config));
-    this.registerLocalAgent(DeepValidationAgent(this.config, '${originalPrompt}'));
 
     // Register the browser agent if enabled in settings.
     // Tools are configured dynamically at invocation time via browserAgentFactory.
@@ -671,7 +669,7 @@ export class AgentRegistry {
    * Returns all active agent definitions.
    */
   getAllDefinitions(): AgentDefinition[] {
-    return Array.from(this.agents.values()).filter((d) => !d.internal);
+    return Array.from(this.agents.values());
   }
 
   /**

packages/core/src/agents/types.ts

@@ -193,7 +193,6 @@ export interface BaseAgentDefinition<
   displayName?: string;
   description: string;
   experimental?: boolean;
-  internal?: boolean;
   inputConfig: InputConfig;
   outputConfig?: OutputConfig<TOutput>;
   metadata?: {

packages/core/src/config/config.ts

@@ -43,15 +43,7 @@ import { EnterPlanModeTool } from '../tools/enter-plan-mode.js';
 import { GeminiClient } from '../core/client.js';
 import { BaseLlmClient } from '../core/baseLlmClient.js';
 import { LocalLiteRtLmClient } from '../core/localLiteRtLmClient.js';
-import {
-  type HookDefinition,
-  HookEventName,
-  HookType,
-  type AfterAgentInput,
-  type HookInput,
-} from '../hooks/types.js';
-import { DeepValidationAgent } from '../agents/deep-validation-agent.js';
-import { LocalSubagentInvocation } from '../agents/local-invocation.js';
+import type { HookDefinition, HookEventName } from '../hooks/types.js';
 import { FileDiscoveryService } from '../services/fileDiscoveryService.js';
 import { GitService } from '../services/gitService.js';
 import {
@@ -583,7 +575,6 @@ export interface ConfigParameters {
   toolSandboxing?: boolean;
   targetDir: string;
   debugMode: boolean;
-  deepValidation?: boolean;
   question?: string;
 
   coreTools?: string[];
@@ -749,7 +740,6 @@ export class Config implements McpContext, AgentLoopContext {
   private readonly targetDir: string;
   private workspaceContext: WorkspaceContext;
   private readonly debugMode: boolean;
-  private readonly deepValidation: boolean;
   private readonly question: string | undefined;
   private readonly worktreeSettings: WorktreeSettings | undefined;
   readonly enableConseca: boolean;
@@ -1019,7 +1009,6 @@ export class Config implements McpContext, AgentLoopContext {
     this.workspaceContext = new WorkspaceContext(this.targetDir, []);
     this.pendingIncludeDirectories = params.includeDirectories ?? [];
     this.debugMode = params.debugMode;
-    this.deepValidation = params.deepValidation ?? false;
     this.question = params.question;
     this.worktreeSettings = params.worktreeSettings;
 
@@ -1454,53 +1443,10 @@ export class Config implements McpContext, AgentLoopContext {
       }
     }
 
-    // Initialize hook system if enabled or if deepValidation is enabled
-    if (this.getEnableHooks() || this.deepValidation) {
+    // Initialize hook system if enabled
+    if (this.getEnableHooks()) {
       this.hookSystem = new HookSystem(this);
       await this.hookSystem.initialize();
-
-      // Register Deep Validation hook if enabled
-      if (this.deepValidation) {
-        this.hookSystem.registerHook(
-          {
-            type: HookType.Runtime,
-            name: 'deep-validation-hook',
-            action: async (input: HookInput) => {
-              const afterAgentInput = input as AfterAgentInput;
-              const invocation = new LocalSubagentInvocation(
-                DeepValidationAgent(this, afterAgentInput.prompt),
-                this,
-                { originalPrompt: afterAgentInput.prompt },
-                this.messageBus,
-              );
-
-              const result = await invocation.execute(new AbortController().signal);
-              const progress = result.returnDisplay as any;
-              const subagentResult = progress?.result;
-
-              let validationResult: { report: string; isSatisfied: boolean };
-              try {
-                validationResult = JSON.parse(subagentResult);
-              } catch {
-                validationResult = {
-                  report: subagentResult || 'Failed to parse validation report.',
-                  isSatisfied: false,
-                };
-              }
-
-              const satisfactionMessage = validationResult.isSatisfied
-                ? '✅ Deep validation satisfied.'
-                : '⚠️ Deep validation NOT satisfied.';
-
-              return {
-                continue: true,
-                systemMessage: `${satisfactionMessage}\n\n${validationResult.report}`,
-              };
-            },
-          },
-          HookEventName.AfterAgent,
-        );
-      }
     }
 
     if (this.experimentalJitContext) {
@@ -2051,11 +1997,6 @@ export class Config implements McpContext, AgentLoopContext {
   getDebugMode(): boolean {
     return this.debugMode;
   }
-
-  isDeepValidationEnabled(): boolean {
-    return this.deepValidation;
-  }
-
   getQuestion(): string | undefined {
     return this.question;
   }
@@ -3567,7 +3508,7 @@ export class Config implements McpContext, AgentLoopContext {
     const discoveredNames = this.agentRegistry.getAllDiscoveredAgentNames();
     for (const agentName of discoveredNames) {
       const definition = this.agentRegistry.getDiscoveredDefinition(agentName);
-      if (!definition || definition.internal) {
+      if (!definition) {
         continue;
       }
       try {

packages/core/src/config/deep-validation.test.ts

@@ -1,121 +0,0 @@
-/**
- * @license
- * Copyright 2026 Google LLC
- * SPDX-License-Identifier: Apache-2.0
- */
-
-import { describe, it, expect, vi, beforeEach } from 'vitest';
-import { Config } from './config.js';
-import { HookEventName } from '../hooks/types.js';
-import { LocalSubagentInvocation } from '../agents/local-invocation.js';
-
-vi.mock('../agents/local-invocation.js', () => ({
-  LocalSubagentInvocation: vi.fn(),
-}));
-
-vi.mock('../agents/deep-validation-agent.js', () => ({
-  DeepValidationAgent: vi.fn().mockReturnValue({
-    kind: 'local',
-    name: 'deep-validation',
-    displayName: 'Deep Validation Agent',
-    description: 'test description',
-    inputConfig: { inputSchema: {} },
-    outputConfig: { outputName: 'validationResult', schema: { safeParse: vi.fn() } },
-    promptConfig: { systemPrompt: 'test prompt', query: 'test query' },
-    modelConfig: { model: 'inherit' },
-    runConfig: {},
-  }),
-}));
-
-describe('Deep Validation Integration', () => {
-  let config: Config;
-
-  beforeEach(() => {
-    vi.clearAllMocks();
-  });
-
-  it('should register AfterAgent hook when deepValidation is enabled', async () => {
-    config = new Config({
-      sessionId: 'test-session',
-      targetDir: '/tmp',
-      debugMode: false,
-      cwd: '/tmp',
-      model: 'test-model',
-      enableHooks: true,
-      deepValidation: true,
-    } as any);
-
-    await config.initialize();
-
-    const hookSystem = config.getHookSystem();
-    expect(hookSystem).toBeDefined();
-
-    const hooks = hookSystem?.getAllHooks();
-    expect(hooks).toBeDefined();
-    expect(hooks?.some(h => h.config.name === 'deep-validation-hook' && h.eventName === HookEventName.AfterAgent)).toBe(true);
-  });
-
-  it('should NOT register AfterAgent hook when deepValidation is disabled', async () => {
-    config = new Config({
-      sessionId: 'test-session',
-      targetDir: '/tmp',
-      debugMode: false,
-      cwd: '/tmp',
-      model: 'test-model',
-      enableHooks: true,
-      deepValidation: false,
-    } as any);
-
-    await config.initialize();
-
-    const hookSystem = config.getHookSystem();
-    const hooks = hookSystem?.getAllHooks();
-    expect(hooks?.some(h => h.config.name === 'deep-validation-hook')).toBeFalsy();
-  });
-
-  it('should execute DeepValidationAgent when hook is triggered', async () => {
-    config = new Config({
-      sessionId: 'test-session',
-      targetDir: '/tmp',
-      debugMode: false,
-      cwd: '/tmp',
-      model: 'test-model',
-      enableHooks: true,
-      deepValidation: true,
-    } as any);
-
-    const mockExecute = vi.fn().mockResolvedValue({
-      returnDisplay: {
-        result: JSON.stringify({
-          report: 'All good',
-          isSatisfied: true,
-        }),
-      },
-    });
-
-    (LocalSubagentInvocation as any).mockImplementation(() => ({
-      execute: mockExecute,
-    }));
-
-    await config.initialize();
-
-    const hookSystem = config.getHookSystem();
-    const deepValidationEntry = hookSystem?.getAllHooks()?.find(h => h.config.name === 'deep-validation-hook');
-
-    expect(deepValidationEntry).toBeDefined();
-
-    if (deepValidationEntry && 'action' in deepValidationEntry.config) {
-      const result = await (deepValidationEntry.config as any).action({ prompt: 'original prompt' } as any);
-      
-      expect(LocalSubagentInvocation).toHaveBeenCalled();
-      expect(mockExecute).toHaveBeenCalled();
-      expect(result).toMatchObject({
-        continue: true,
-        systemMessage: expect.stringContaining('✅ Deep validation satisfied.'),
-      });
-      expect(result).toMatchObject({
-        systemMessage: expect.stringContaining('All good'),
-      });
-    }
-  });
-});

packages/core/src/core/client.ts

@@ -809,7 +809,7 @@ export class GeminiClient {
 
     // Update cumulative response in hook state
     // We do this immediately after the stream finishes for THIS turn.
-    const hooksEnabled = this.config.getHookSystem() !== undefined;
+    const hooksEnabled = this.config.getEnableHooks();
     if (hooksEnabled) {
       const responseText = turn.getResponseText() || '';
       const hookState = this.hookStateMap.get(prompt_id);
@@ -900,7 +900,7 @@ export class GeminiClient {
       this.config.resetTurn();
     }
 
-    const hooksEnabled = this.config.getHookSystem() !== undefined;
+    const hooksEnabled = this.config.getEnableHooks();
     const messageBus = this.context.messageBus;
 
     if (this.lastPromptId !== prompt_id) {

packages/core/src/hooks/hookRegistry.test.ts

@@ -70,7 +70,7 @@ describe('HookRegistry', () => {
     mockConfig = {
       storage: mockStorage,
       getExtensions: vi.fn().mockReturnValue([]),
-      getHooks: vi.fn(), getEnableHooks: vi.fn().mockReturnValue(true).mockReturnValue({}),
+      getHooks: vi.fn().mockReturnValue({}),
       getProjectHooks: vi.fn().mockReturnValue({}),
       getDisabledHooks: vi.fn().mockReturnValue([]),
       isTrustedFolder: vi.fn().mockReturnValue(true),

packages/core/src/hooks/hookRegistry.ts

@@ -73,10 +73,7 @@ export class HookRegistry {
       (entry) => entry.source === ConfigSource.Runtime,
     );
     this.entries = [...runtimeHooks];
-
-    if (this.config.getEnableHooks()) {
-      this.processHooksFromConfig();
-    }
+    this.processHooksFromConfig();
 
     debugLogger.debug(
       `Hook registry initialized with ${this.entries.length} hook entries`,

schemas/settings.schema.json

@@ -77,13 +77,6 @@
           "default": false,
           "type": "boolean"
         },
-        "deepValidation": {
-          "title": "Deep Validation",
-          "description": "Run a subagent after the main agent finishes to perform final validation.",
-          "markdownDescription": "Run a subagent after the main agent finishes to perform final validation. This subagent will reflect on the original prompt, review changes, and run tests to ensure satisfaction.\n\n- Category: `General`\n- Requires restart: `no`\n- Default: `false`",
-          "default": false,
-          "type": "boolean"
-        },
         "enableAutoUpdate": {
           "title": "Enable Auto Update",
           "description": "Enable automatic updates.",