fix(cli): resolve paste issue on Windows terminals. (#15932)

packages/cli/src/ui/AppContainer.tsx

@@ -91,7 +91,6 @@ import { useVim } from './hooks/vim.js';
 import { type LoadableSettingScope, SettingScope } from '../config/settings.js';
 import { type InitializationResult } from '../core/initializer.js';
 import { useFocus } from './hooks/useFocus.js';
-import { useBracketedPaste } from './hooks/useBracketedPaste.js';
 import { useKeypress, type Key } from './hooks/useKeypress.js';
 import { keyMatchers, Command } from './keyMatchers.js';
 import { useLoadingIndicator } from './hooks/useLoadingIndicator.js';
@@ -123,7 +122,6 @@ import { useAlternateBuffer } from './hooks/useAlternateBuffer.js';
 import { useSettings } from './contexts/SettingsContext.js';
 import { terminalCapabilityManager } from './utils/terminalCapabilityManager.js';
 import { useInputHistoryStore } from './hooks/useInputHistoryStore.js';
-import { enableBracketedPaste } from './utils/bracketedPaste.js';
 import { useBanner } from './hooks/useBanner.js';
 
 const WARNING_PROMPT_DURATION_MS = 1000;
@@ -424,8 +422,7 @@ export const AppContainer = (props: AppContainerProps) => {
       disableLineWrapping();
       app.rerender();
     }
-    enableBracketedPaste();
-    terminalCapabilityManager.enableKittyProtocol();
+    terminalCapabilityManager.enableSupportedModes();
     refreshStatic();
   }, [refreshStatic, isAlternateBuffer, app, config]);
 
@@ -925,7 +922,6 @@ Logging in with Google... Restarting Gemini CLI to continue.
   });
 
   const isFocused = useFocus();
-  useBracketedPaste();
 
   // Context file names computation
   const contextFileNames = useMemo(() => {

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

@@ -31,6 +31,7 @@ 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';
@@ -121,6 +122,10 @@ describe('InputPrompt', () => {
 
   beforeEach(() => {
     vi.resetAllMocks();
+    vi.spyOn(
+      terminalCapabilityManager,
+      'isBracketedPasteEnabled',
+    ).mockReturnValue(true);
 
     mockCommandContext = createMockCommandContext();
 

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

@@ -35,6 +35,7 @@ import {
   type SettingDefinition,
   type SettingsSchemaType,
 } from '../../config/settingsSchema.js';
+import { terminalCapabilityManager } from '../../ui/utils/terminalCapabilityManager.js';
 
 // Mock the VimModeContext
 const mockToggleVimEnabled = vi.fn();
@@ -253,6 +254,10 @@ const renderDialog = (
 
 describe('SettingsDialog', () => {
   beforeEach(() => {
+    vi.spyOn(
+      terminalCapabilityManager,
+      'isBracketedPasteEnabled',
+    ).mockReturnValue(true);
     mockToggleVimEnabled.mockResolvedValue(true);
   });
 

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

@@ -19,10 +19,12 @@ import { ESC } from '../utils/input.js';
 import { parseMouseEvent } from '../utils/mouse.js';
 import { FOCUS_IN, FOCUS_OUT } from '../hooks/useFocus.js';
 import { appEvents, AppEvent } from '../../utils/events.js';
+import { terminalCapabilityManager } from '../utils/terminalCapabilityManager.js';
 
 export const BACKSLASH_ENTER_TIMEOUT = 5;
 export const ESC_TIMEOUT = 50;
 export const PASTE_TIMEOUT = 30_000;
+export const FAST_RETURN_TIMEOUT = 30;
 
 // Parse the key itself
 const KEY_INFO_MAP: Record<
@@ -148,7 +150,7 @@ function nonKeyboardEventFilter(
  */
 function bufferBackslashEnter(
   keypressHandler: KeypressHandler,
-): (key: Key | null) => void {
+): KeypressHandler {
   const bufferer = (function* (): Generator<void, void, Key | null> {
     while (true) {
       const key = yield;
@@ -184,7 +186,31 @@ function bufferBackslashEnter(
 
   bufferer.next(); // prime the generator so it starts listening.
 
-  return (key: Key | null) => bufferer.next(key);
+  return (key: Key) => bufferer.next(key);
+}
+
+/**
+ * Converts return keys pressed quickly after other keys into plain
+ * insertable return characters.
+ *
+ * This is to accomodate older terminals that paste text without bracketing.
+ */
+function bufferFastReturn(keypressHandler: KeypressHandler): KeypressHandler {
+  let lastKeyTime = 0;
+  return (key: Key) => {
+    const now = Date.now();
+    if (key.name === 'return' && now - lastKeyTime <= FAST_RETURN_TIMEOUT) {
+      keypressHandler({
+        ...key,
+        name: '',
+        sequence: '\r',
+        insertable: true,
+      });
+    } else {
+      keypressHandler(key);
+    }
+    lastKeyTime = now;
+  };
 }
 
 /**
@@ -192,9 +218,7 @@ function bufferBackslashEnter(
  * Will flush the buffer if no data is received for PASTE_TIMEOUT ms or
  * when a null key is received.
  */
-function bufferPaste(
-  keypressHandler: KeypressHandler,
-): (key: Key | null) => void {
+function bufferPaste(keypressHandler: KeypressHandler): KeypressHandler {
   const bufferer = (function* (): Generator<void, void, Key | null> {
     while (true) {
       let key = yield;
@@ -238,7 +262,7 @@ function bufferPaste(
   })();
   bufferer.next(); // prime the generator so it starts listening.
 
-  return (key: Key | null) => bufferer.next(key);
+  return (key: Key) => bufferer.next(key);
 }
 
 /**
@@ -592,10 +616,13 @@ export function KeypressProvider({
 
     process.stdin.setEncoding('utf8'); // Make data events emit strings
 
-    const mouseFilterer = nonKeyboardEventFilter(broadcast);
-    const backslashBufferer = bufferBackslashEnter(mouseFilterer);
-    const pasteBufferer = bufferPaste(backslashBufferer);
-    let dataListener = createDataListener(pasteBufferer);
+    let processor = nonKeyboardEventFilter(broadcast);
+    if (!terminalCapabilityManager.isBracketedPasteEnabled()) {
+      processor = bufferFastReturn(processor);
+    }
+    processor = bufferBackslashEnter(processor);
+    processor = bufferPaste(processor);
+    let dataListener = createDataListener(processor);
 
     if (debugKeystrokeLogging) {
       const old = dataListener;

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

@@ -1,38 +0,0 @@
-/**
- * @license
- * Copyright 2025 Google LLC
- * SPDX-License-Identifier: Apache-2.0
- */
-
-import { useEffect } from 'react';
-import {
-  disableBracketedPaste,
-  enableBracketedPaste,
-} from '../utils/bracketedPaste.js';
-
-/**
- * Enables and disables bracketed paste mode in the terminal.
- *
- * This hook ensures that bracketed paste mode is enabled when the component
- * mounts and disabled when it unmounts or when the process exits.
- */
-export const useBracketedPaste = () => {
-  const cleanup = () => {
-    disableBracketedPaste();
-  };
-
-  useEffect(() => {
-    enableBracketedPaste();
-
-    process.on('exit', cleanup);
-    process.on('SIGINT', cleanup);
-    process.on('SIGTERM', cleanup);
-
-    return () => {
-      cleanup();
-      process.removeListener('exit', cleanup);
-      process.removeListener('SIGINT', cleanup);
-      process.removeListener('SIGTERM', cleanup);
-    };
-  }, []);
-};

packages/cli/src/ui/utils/bracketedPaste.ts

@@ -1,18 +0,0 @@
-/**
- * @license
- * Copyright 2025 Google LLC
- * SPDX-License-Identifier: Apache-2.0
- */
-
-import { writeToStdout } from '@google/gemini-cli-core';
-
-const ENABLE_BRACKETED_PASTE = '\x1b[?2004h';
-const DISABLE_BRACKETED_PASTE = '\x1b[?2004l';
-
-export const enableBracketedPaste = () => {
-  writeToStdout(ENABLE_BRACKETED_PASTE);
-};
-
-export const disableBracketedPaste = () => {
-  writeToStdout(DISABLE_BRACKETED_PASTE);
-};

packages/cli/src/ui/utils/terminalCapabilityManager.test.ts

@@ -23,6 +23,8 @@ vi.mock('@google/gemini-cli-core', () => ({
   disableKittyKeyboardProtocol: vi.fn(),
   enableModifyOtherKeys: vi.fn(),
   disableModifyOtherKeys: vi.fn(),
+  enableBracketedPasteMode: vi.fn(),
+  disableBracketedPasteMode: vi.fn(),
 }));
 
 describe('TerminalCapabilityManager', () => {
@@ -264,4 +266,46 @@ describe('TerminalCapabilityManager', () => {
       expect(manager.isModifyOtherKeysEnabled()).toBe(true);
     });
   });
+
+  describe('bracketed paste detection', () => {
+    it('should detect bracketed paste support (mode set)', async () => {
+      const manager = TerminalCapabilityManager.getInstance();
+      const promise = manager.detectCapabilities();
+
+      // Simulate bracketed paste response: \x1b[?2004;1$y
+      stdin.emit('data', Buffer.from('\x1b[?2004;1$y'));
+      // Complete detection with DA1
+      stdin.emit('data', Buffer.from('\x1b[?62c'));
+
+      await promise;
+      expect(manager.isBracketedPasteSupported()).toBe(true);
+      expect(manager.isBracketedPasteEnabled()).toBe(true);
+    });
+
+    it('should detect bracketed paste support (mode reset)', async () => {
+      const manager = TerminalCapabilityManager.getInstance();
+      const promise = manager.detectCapabilities();
+
+      // Simulate bracketed paste response: \x1b[?2004;2$y
+      stdin.emit('data', Buffer.from('\x1b[?2004;2$y'));
+      // Complete detection with DA1
+      stdin.emit('data', Buffer.from('\x1b[?62c'));
+
+      await promise;
+      expect(manager.isBracketedPasteSupported()).toBe(true);
+      expect(manager.isBracketedPasteEnabled()).toBe(true);
+    });
+
+    it('should not enable bracketed paste if not supported', async () => {
+      const manager = TerminalCapabilityManager.getInstance();
+      const promise = manager.detectCapabilities();
+
+      // Complete detection with DA1 only
+      stdin.emit('data', Buffer.from('\x1b[?62c'));
+
+      await promise;
+      expect(manager.isBracketedPasteSupported()).toBe(false);
+      expect(manager.isBracketedPasteEnabled()).toBe(false);
+    });
+  });
 });

packages/cli/src/ui/utils/terminalCapabilityManager.ts

@@ -11,6 +11,8 @@ import {
   disableKittyKeyboardProtocol,
   enableModifyOtherKeys,
   disableModifyOtherKeys,
+  enableBracketedPasteMode,
+  disableBracketedPasteMode,
 } from '@google/gemini-cli-core';
 
 export type TerminalBackgroundColor = string | undefined;
@@ -23,6 +25,7 @@ export class TerminalCapabilityManager {
   private static readonly TERMINAL_NAME_QUERY = '\x1b[>q';
   private static readonly DEVICE_ATTRIBUTES_QUERY = '\x1b[c';
   private static readonly MODIFY_OTHER_KEYS_QUERY = '\x1b[>4;?m';
+  private static readonly BRACKETED_PASTE_QUERY = '\x1b[?2004$p';
 
   // Kitty keyboard flags: CSI ? flags u
   // eslint-disable-next-line no-control-regex
@@ -40,6 +43,10 @@ export class TerminalCapabilityManager {
   // modifyOtherKeys response: CSI > 4 ; level m
   // eslint-disable-next-line no-control-regex
   private static readonly MODIFY_OTHER_KEYS_REGEX = /\x1b\[>4;(\d+)m/;
+  // DECRQM response for bracketed paste: CSI ? 2004 ; Ps $ y
+  // Ps = 1 (set), 2 (reset), 3 (permanently set), 4 (permanently reset)
+  // eslint-disable-next-line no-control-regex
+  private static readonly BRACKETED_PASTE_REGEX = /\x1b\[\?2004;([1-4])\$y/;
 
   private terminalBackgroundColor: TerminalBackgroundColor;
   private kittySupported = false;
@@ -48,6 +55,8 @@ export class TerminalCapabilityManager {
   private terminalName: string | undefined;
   private modifyOtherKeysSupported = false;
   private modifyOtherKeysEnabled = false;
+  private bracketedPasteSupported = false;
+  private bracketedPasteEnabled = false;
 
   private constructor() {}
 
@@ -75,6 +84,21 @@ export class TerminalCapabilityManager {
       return;
     }
 
+    const cleanupOnExit = () => {
+      if (this.kittySupported) {
+        this.disableKittyProtocol();
+      }
+      if (this.modifyOtherKeysSupported) {
+        this.disableModifyOtherKeys();
+      }
+      if (this.bracketedPasteSupported) {
+        this.disableBracketedPaste();
+      }
+    };
+    process.on('exit', () => cleanupOnExit);
+    process.on('SIGTERM', () => cleanupOnExit);
+    process.on('SIGINT', cleanupOnExit);
+
     return new Promise((resolve) => {
       const originalRawMode = process.stdin.isRaw;
       if (!originalRawMode) {
@@ -87,6 +111,7 @@ export class TerminalCapabilityManager {
       let deviceAttributesReceived = false;
       let bgReceived = false;
       let modifyOtherKeysReceived = false;
+      let bracketedPasteReceived = false;
       // eslint-disable-next-line prefer-const
       let timeoutId: NodeJS.Timeout;
 
@@ -100,27 +125,14 @@ export class TerminalCapabilityManager {
         }
         this.detectionComplete = true;
 
-        // Auto-enable kitty if supported
-        if (this.kittySupported) {
-          this.enableKittyProtocol();
-          process.on('exit', () => this.disableKittyProtocol());
-          process.on('SIGTERM', () => this.disableKittyProtocol());
-        } else if (this.modifyOtherKeysSupported) {
-          this.enableModifyOtherKeys();
-          process.on('exit', () => this.disableModifyOtherKeys());
-          process.on('SIGTERM', () => this.disableModifyOtherKeys());
-        }
+        this.enableSupportedModes();
 
         resolve();
       };
 
-      const onTimeout = () => {
-        cleanup();
-      };
-
       // A somewhat long timeout is acceptable as all terminals should respond
       // to the device attributes query used as a sentinel.
-      timeoutId = setTimeout(onTimeout, 1000);
+      timeoutId = setTimeout(cleanup, 1000);
 
       const onData = (data: Buffer) => {
         buffer += data.toString();
@@ -149,6 +161,32 @@ export class TerminalCapabilityManager {
           this.kittySupported = true;
         }
 
+        // check for modifyOtherKeys support
+        if (!modifyOtherKeysReceived) {
+          const match = buffer.match(
+            TerminalCapabilityManager.MODIFY_OTHER_KEYS_REGEX,
+          );
+          if (match) {
+            modifyOtherKeysReceived = true;
+            const level = parseInt(match[1], 10);
+            this.modifyOtherKeysSupported = level >= 2;
+            debugLogger.log(
+              `Detected modifyOtherKeys support: ${this.modifyOtherKeysSupported} (level ${level})`,
+            );
+          }
+        }
+
+        // check for bracketed paste support
+        if (!bracketedPasteReceived) {
+          const match = buffer.match(
+            TerminalCapabilityManager.BRACKETED_PASTE_REGEX,
+          );
+          if (match) {
+            bracketedPasteReceived = true;
+            this.bracketedPasteSupported = true;
+          }
+        }
+
         // Check for Terminal Name/Version response.
         if (!terminalNameReceived) {
           const match = buffer.match(
@@ -174,21 +212,6 @@ export class TerminalCapabilityManager {
             cleanup();
           }
         }
-
-        // check for modifyOtherKeys support
-        if (!modifyOtherKeysReceived) {
-          const match = buffer.match(
-            TerminalCapabilityManager.MODIFY_OTHER_KEYS_REGEX,
-          );
-          if (match) {
-            modifyOtherKeysReceived = true;
-            const level = parseInt(match[1], 10);
-            this.modifyOtherKeysSupported = level >= 2;
-            debugLogger.log(
-              `Detected modifyOtherKeys support: ${this.modifyOtherKeysSupported} (level ${level})`,
-            );
-          }
-        }
       };
 
       process.stdin.on('data', onData);
@@ -200,6 +223,7 @@ export class TerminalCapabilityManager {
             TerminalCapabilityManager.OSC_11_QUERY +
             TerminalCapabilityManager.TERMINAL_NAME_QUERY +
             TerminalCapabilityManager.MODIFY_OTHER_KEYS_QUERY +
+            TerminalCapabilityManager.BRACKETED_PASTE_QUERY +
             TerminalCapabilityManager.DEVICE_ATTRIBUTES_QUERY,
         );
       } catch (e) {
@@ -209,6 +233,17 @@ export class TerminalCapabilityManager {
     });
   }
 
+  enableSupportedModes() {
+    if (this.kittySupported) {
+      this.enableKittyProtocol();
+    } else if (this.modifyOtherKeysSupported) {
+      this.enableModifyOtherKeys();
+    }
+    if (this.bracketedPasteSupported) {
+      this.enableBracketedPaste();
+    }
+  }
+
   getTerminalBackgroundColor(): TerminalBackgroundColor {
     return this.terminalBackgroundColor;
   }
@@ -221,6 +256,36 @@ export class TerminalCapabilityManager {
     return this.kittyEnabled;
   }
 
+  isBracketedPasteSupported(): boolean {
+    return this.bracketedPasteSupported;
+  }
+
+  isBracketedPasteEnabled(): boolean {
+    return this.bracketedPasteEnabled;
+  }
+
+  enableBracketedPaste(): void {
+    try {
+      if (this.bracketedPasteSupported) {
+        enableBracketedPasteMode();
+        this.bracketedPasteEnabled = true;
+      }
+    } catch (e) {
+      debugLogger.warn('Failed to enable bracketed paste mode:', e);
+    }
+  }
+
+  disableBracketedPaste(): void {
+    try {
+      if (this.bracketedPasteEnabled) {
+        disableBracketedPasteMode();
+        this.bracketedPasteEnabled = false;
+      }
+    } catch (e) {
+      debugLogger.warn('Failed to disable bracketed paste mode:', e);
+    }
+  }
+
   enableKittyProtocol(): void {
     try {
       if (this.kittySupported) {