diff --git a/packages/cli/src/ui/components/InputPrompt.test.tsx b/packages/cli/src/ui/components/InputPrompt.test.tsx
index 7717b1e2f9..0d000fc79f 100644
--- a/packages/cli/src/ui/components/InputPrompt.test.tsx
+++ b/packages/cli/src/ui/components/InputPrompt.test.tsx
@@ -34,7 +34,6 @@ import { useReverseSearchCompletion } from '../hooks/useReverseSearchCompletion.
 import clipboardy from 'clipboardy';
 import * as clipboardUtils from '../utils/clipboardUtils.js';
 import { useKittyKeyboardProtocol } from '../hooks/useKittyKeyboardProtocol.js';
-import { terminalCapabilityManager } from '../utils/terminalCapabilityManager.js';
 import { createMockCommandContext } from '../../test-utils/mockCommandContext.js';
 import stripAnsi from 'strip-ansi';
 import chalk from 'chalk';
@@ -125,10 +124,6 @@ describe('InputPrompt', () => {
 
   beforeEach(() => {
     vi.resetAllMocks();
-    vi.spyOn(
-      terminalCapabilityManager,
-      'isBracketedPasteEnabled',
-    ).mockReturnValue(true);
 
     mockCommandContext = createMockCommandContext();
 
diff --git a/packages/cli/src/ui/components/SettingsDialog.test.tsx b/packages/cli/src/ui/components/SettingsDialog.test.tsx
index 2c0c10e502..d33130744a 100644
--- a/packages/cli/src/ui/components/SettingsDialog.test.tsx
+++ b/packages/cli/src/ui/components/SettingsDialog.test.tsx
@@ -35,7 +35,6 @@ import {
   type SettingDefinition,
   type SettingsSchemaType,
 } from '../../config/settingsSchema.js';
-import { terminalCapabilityManager } from '../../ui/utils/terminalCapabilityManager.js';
 
 // Mock the VimModeContext
 const mockToggleVimEnabled = vi.fn();
@@ -254,10 +253,6 @@ const renderDialog = (
 
 describe('SettingsDialog', () => {
   beforeEach(() => {
-    vi.spyOn(
-      terminalCapabilityManager,
-      'isBracketedPasteEnabled',
-    ).mockReturnValue(true);
     mockToggleVimEnabled.mockResolvedValue(true);
   });
 
diff --git a/packages/cli/src/ui/utils/terminalCapabilityManager.test.ts b/packages/cli/src/ui/utils/terminalCapabilityManager.test.ts
index e10ca2593c..67f16e5db2 100644
--- a/packages/cli/src/ui/utils/terminalCapabilityManager.test.ts
+++ b/packages/cli/src/ui/utils/terminalCapabilityManager.test.ts
@@ -7,6 +7,10 @@
 import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
 import { TerminalCapabilityManager } from './terminalCapabilityManager.js';
 import { EventEmitter } from 'node:events';
+import {
+  enableKittyKeyboardProtocol,
+  enableModifyOtherKeys,
+} from '@google/gemini-cli-core';
 
 // Mock fs
 vi.mock('node:fs', () => ({
@@ -190,7 +194,8 @@ describe('TerminalCapabilityManager', () => {
       stdin.emit('data', Buffer.from('\x1b[?62c'));
 
       await promise;
-      expect(manager.isModifyOtherKeysEnabled()).toBe(true);
+
+      expect(enableModifyOtherKeys).toHaveBeenCalled();
     });
 
     it('should not enable modifyOtherKeys for level 0', async () => {
@@ -203,7 +208,8 @@ describe('TerminalCapabilityManager', () => {
       stdin.emit('data', Buffer.from('\x1b[?62c'));
 
       await promise;
-      expect(manager.isModifyOtherKeysEnabled()).toBe(false);
+
+      expect(enableModifyOtherKeys).not.toHaveBeenCalled();
     });
 
     it('should prefer Kitty over modifyOtherKeys', async () => {
@@ -218,7 +224,9 @@ describe('TerminalCapabilityManager', () => {
 
       await promise;
       expect(manager.isKittyProtocolEnabled()).toBe(true);
-      expect(manager.isModifyOtherKeysEnabled()).toBe(false);
+
+      expect(enableKittyKeyboardProtocol).toHaveBeenCalled();
+      expect(enableModifyOtherKeys).not.toHaveBeenCalled();
     });
 
     it('should enable modifyOtherKeys when Kitty not supported', async () => {
@@ -231,8 +239,9 @@ describe('TerminalCapabilityManager', () => {
       stdin.emit('data', Buffer.from('\x1b[?62c'));
 
       await promise;
-      expect(manager.isModifyOtherKeysEnabled()).toBe(true);
+
       expect(manager.isKittyProtocolEnabled()).toBe(false);
+      expect(enableModifyOtherKeys).toHaveBeenCalled();
     });
 
     it('should handle split modifyOtherKeys response chunks', async () => {
@@ -246,7 +255,8 @@ describe('TerminalCapabilityManager', () => {
       stdin.emit('data', Buffer.from('\x1b[?62c'));
 
       await promise;
-      expect(manager.isModifyOtherKeysEnabled()).toBe(true);
+
+      expect(enableModifyOtherKeys).toHaveBeenCalled();
     });
 
     it('should detect modifyOtherKeys with other capabilities', async () => {
@@ -263,7 +273,23 @@ describe('TerminalCapabilityManager', () => {
 
       expect(manager.getTerminalBackgroundColor()).toBe('#1a1a1a');
       expect(manager.getTerminalName()).toBe('tmux');
-      expect(manager.isModifyOtherKeysEnabled()).toBe(true);
+
+      expect(enableModifyOtherKeys).toHaveBeenCalled();
+    });
+
+    it('should infer modifyOtherKeys support from Device Attributes (DA1) alone', async () => {
+      const manager = TerminalCapabilityManager.getInstance();
+      const promise = manager.detectCapabilities();
+
+      // Simulate only DA1 response (no specific MOK or Kitty response)
+      stdin.emit('data', Buffer.from('\x1b[?62c'));
+
+      await promise;
+
+      expect(manager.isKittyProtocolEnabled()).toBe(false);
+      // It should fall back to modifyOtherKeys because DA1 proves it's an ANSI terminal
+
+      expect(enableModifyOtherKeys).toHaveBeenCalled();
     });
   });
 });
diff --git a/packages/cli/src/ui/utils/terminalCapabilityManager.ts b/packages/cli/src/ui/utils/terminalCapabilityManager.ts
index 7b09a33e4e..50a69ee707 100644
--- a/packages/cli/src/ui/utils/terminalCapabilityManager.ts
+++ b/packages/cli/src/ui/utils/terminalCapabilityManager.ts
@@ -43,14 +43,13 @@ export class TerminalCapabilityManager {
   // eslint-disable-next-line no-control-regex
   private static readonly MODIFY_OTHER_KEYS_REGEX = /\x1b\[>4;(\d+)m/;
 
+  private detectionComplete = false;
   private terminalBackgroundColor: TerminalBackgroundColor;
   private kittySupported = false;
   private kittyEnabled = false;
-  private detectionComplete = false;
   private terminalName: string | undefined;
-  private modifyOtherKeysSupported = false;
-  private modifyOtherKeysEnabled = false;
-  private bracketedPasteEnabled = false;
+  private modifyOtherKeysSupported?: boolean;
+  private deviceAttributesSupported = false;
 
   private constructor() {}
 
@@ -187,6 +186,7 @@ export class TerminalCapabilityManager {
           );
           if (match) {
             deviceAttributesReceived = true;
+            this.deviceAttributesSupported = true;
             cleanup();
           }
         }
@@ -215,13 +215,17 @@ export class TerminalCapabilityManager {
       if (this.kittySupported) {
         enableKittyKeyboardProtocol();
         this.kittyEnabled = true;
-      } else if (this.modifyOtherKeysSupported) {
+      } else if (
+        this.modifyOtherKeysSupported === true ||
+        // If device attributes were received it's safe to try enabling
+        // anyways, since it will be ignored if unsupported
+        (this.modifyOtherKeysSupported === undefined &&
+          this.deviceAttributesSupported)
+      ) {
         enableModifyOtherKeys();
-        this.modifyOtherKeysEnabled = true;
       }
       // Always enable bracketed paste since it'll be ignored if unsupported.
       enableBracketedPasteMode();
-      this.bracketedPasteEnabled = true;
     } catch (e) {
       debugLogger.warn('Failed to enable keyboard protocols:', e);
     }
@@ -239,14 +243,6 @@ export class TerminalCapabilityManager {
     return this.kittyEnabled;
   }
 
-  isBracketedPasteEnabled(): boolean {
-    return this.bracketedPasteEnabled;
-  }
-
-  isModifyOtherKeysEnabled(): boolean {
-    return this.modifyOtherKeysEnabled;
-  }
-
   private parseColor(rHex: string, gHex: string, bHex: string): string {
     const parseComponent = (hex: string) => {
       const val = parseInt(hex, 16);