diff --git a/packages/cli/src/ui/components/messages/ToolConfirmationMessage.test.tsx b/packages/cli/src/ui/components/messages/ToolConfirmationMessage.test.tsx
index ec623f69a4..1e11742e30 100644
--- a/packages/cli/src/ui/components/messages/ToolConfirmationMessage.test.tsx
+++ b/packages/cli/src/ui/components/messages/ToolConfirmationMessage.test.tsx
@@ -4,16 +4,18 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-import { describe, it, expect, vi } from 'vitest';
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
 import { ToolConfirmationMessage } from './ToolConfirmationMessage.js';
-import type {
-  SerializableConfirmationDetails,
-  ToolCallConfirmationDetails,
-  Config,
+import {
+  type SerializableConfirmationDetails,
+  type ToolCallConfirmationDetails,
+  type Config,
+  ToolConfirmationOutcome,
 } from '@google/gemini-cli-core';
 import { renderWithProviders } from '../../../test-utils/render.js';
 import { createMockSettings } from '../../../test-utils/settings.js';
 import { useToolActions } from '../../contexts/ToolActionsContext.js';
+import { act } from 'react';
 
 vi.mock('../../contexts/ToolActionsContext.js', async (importOriginal) => {
   const actual =
@@ -644,4 +646,125 @@ describe('ToolConfirmationMessage', () => {
     expect(output).not.toContain('Invocation Arguments:');
     unmount();
   });
+
+  describe('ESCAPE key behavior', () => {
+    beforeEach(() => {
+      vi.useFakeTimers();
+    });
+
+    afterEach(() => {
+      vi.useRealTimers();
+      vi.restoreAllMocks();
+    });
+
+    it('should call confirm(Cancel) and reset constrainHeight when ESC is pressed', async () => {
+      const mockConfirm = vi.fn().mockResolvedValue(undefined);
+      const mockSetConstrainHeight = vi.fn();
+      const mockRefreshStatic = vi.fn();
+
+      vi.mocked(useToolActions).mockReturnValue({
+        confirm: mockConfirm,
+        cancel: vi.fn(),
+        isDiffingEnabled: false,
+      });
+
+      const confirmationDetails: SerializableConfirmationDetails = {
+        type: 'info',
+        title: 'Confirm Web Fetch',
+        prompt: 'https://example.com',
+        urls: ['https://example.com'],
+      };
+
+      const { stdin, waitUntilReady, unmount } = renderWithProviders(
+        <ToolConfirmationMessage
+          callId="test-call-id"
+          confirmationDetails={confirmationDetails}
+          config={mockConfig}
+          getPreferredEditor={vi.fn()}
+          availableTerminalHeight={30}
+          terminalWidth={80}
+        />,
+        {
+          uiState: { constrainHeight: false },
+          uiActions: {
+            setConstrainHeight: mockSetConstrainHeight,
+            refreshStatic: mockRefreshStatic,
+          },
+        },
+      );
+      await waitUntilReady();
+
+      // Simulate ESC key
+      stdin.write('\x1b');
+
+      await act(async () => {
+        await vi.runAllTimersAsync();
+      });
+
+      expect(mockConfirm).toHaveBeenCalledWith(
+        'test-call-id',
+        ToolConfirmationOutcome.Cancel,
+        undefined,
+      );
+      expect(mockSetConstrainHeight).toHaveBeenCalledWith(true);
+      expect(mockRefreshStatic).toHaveBeenCalled();
+
+      unmount();
+    });
+
+    it('should NOT reset constrainHeight if it is already true when ESC is pressed', async () => {
+      const mockConfirm = vi.fn().mockResolvedValue(undefined);
+      const mockSetConstrainHeight = vi.fn();
+      const mockRefreshStatic = vi.fn();
+
+      vi.mocked(useToolActions).mockReturnValue({
+        confirm: mockConfirm,
+        cancel: vi.fn(),
+        isDiffingEnabled: false,
+      });
+
+      const confirmationDetails: SerializableConfirmationDetails = {
+        type: 'info',
+        title: 'Confirm Web Fetch',
+        prompt: 'https://example.com',
+        urls: ['https://example.com'],
+      };
+
+      const { stdin, waitUntilReady, unmount } = renderWithProviders(
+        <ToolConfirmationMessage
+          callId="test-call-id"
+          confirmationDetails={confirmationDetails}
+          config={mockConfig}
+          getPreferredEditor={vi.fn()}
+          availableTerminalHeight={30}
+          terminalWidth={80}
+        />,
+        {
+          uiState: { constrainHeight: true },
+          uiActions: {
+            setConstrainHeight: mockSetConstrainHeight,
+            refreshStatic: mockRefreshStatic,
+          },
+        },
+      );
+      await waitUntilReady();
+
+      // Simulate ESC key
+      stdin.write('\x1b');
+
+      await act(async () => {
+        await vi.runAllTimersAsync();
+      });
+
+      expect(mockConfirm).toHaveBeenCalledWith(
+        'test-call-id',
+        ToolConfirmationOutcome.Cancel,
+        undefined,
+      );
+      expect(mockSetConstrainHeight).not.toHaveBeenCalled();
+      expect(mockRefreshStatic).not.toHaveBeenCalled();
+
+      unmount();
+    });
+  });
 });
diff --git a/packages/cli/src/ui/components/messages/ToolConfirmationMessage.tsx b/packages/cli/src/ui/components/messages/ToolConfirmationMessage.tsx
index 113852cb8d..534b459f66 100644
--- a/packages/cli/src/ui/components/messages/ToolConfirmationMessage.tsx
+++ b/packages/cli/src/ui/components/messages/ToolConfirmationMessage.tsx
@@ -5,7 +5,7 @@
  */
 
 import type React from 'react';
-import { useMemo, useCallback, useState } from 'react';
+import { useEffect, useMemo, useCallback, useState } from 'react';
 import { Box, Text } from 'ink';
 import { DiffRenderer } from './DiffRenderer.js';
 import { RenderInline } from '../../utils/InlineMarkdownRenderer.js';
@@ -21,6 +21,8 @@ import {
 import type { RadioSelectItem } from '../shared/RadioButtonSelect.js';
 import { useToolActions } from '../../contexts/ToolActionsContext.js';
 import { RadioButtonSelect } from '../shared/RadioButtonSelect.js';
+import { useUIActions } from '../../contexts/UIActionsContext.js';
+import { useUIState } from '../../contexts/UIStateContext.js';
 import { MaxSizedBox, MINIMUM_MAX_HEIGHT } from '../shared/MaxSizedBox.js';
 import {
   sanitizeForDisplay,
@@ -70,6 +72,8 @@ export const ToolConfirmationMessage: React.FC<
 }) => {
   const keyMatchers = useKeyMatchers();
   const { confirm, isDiffingEnabled } = useToolActions();
+  const uiActions = useUIActions();
+  const { constrainHeight } = useUIState();
   const [mcpDetailsExpansionState, setMcpDetailsExpansionState] = useState<{
     callId: string;
     expanded: boolean;
@@ -77,6 +81,7 @@ export const ToolConfirmationMessage: React.FC<
     callId,
     expanded: false,
   });
+  const [isCancelling, setIsCancelling] = useState(false);
   const isMcpToolDetailsExpanded =
     mcpDetailsExpansionState.callId === callId
       ? mcpDetailsExpansionState.expanded
@@ -179,7 +184,7 @@ export const ToolConfirmationMessage: React.FC<
         return true;
       }
       if (keyMatchers[Command.ESCAPE](key)) {
-        handleConfirm(ToolConfirmationOutcome.Cancel);
+        setIsCancelling(true);
         return true;
       }
       if (keyMatchers[Command.QUIT](key)) {
@@ -192,6 +197,16 @@ export const ToolConfirmationMessage: React.FC<
     { isActive: isFocused, priority: true },
   );
 
+  useEffect(() => {
+    if (isCancelling) {
+      if (!constrainHeight) {
+        uiActions.setConstrainHeight(true);
+        uiActions.refreshStatic();
+      }
+      handleConfirm(ToolConfirmationOutcome.Cancel);
+    }
+  }, [isCancelling, constrainHeight, uiActions, handleConfirm]);
+
   const handleSelect = useCallback(
     (item: ToolConfirmationOutcome) => handleConfirm(item),
     [handleConfirm],