fix(cli-ui): enable Ctrl+Backspace for word deletion in Windows Terminal (#21447)

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

@@ -44,7 +44,7 @@ enum TerminalKeys {
   LEFT_ARROW = '\u001B[D',
   RIGHT_ARROW = '\u001B[C',
   ESCAPE = '\u001B',
-  BACKSPACE = '\u0008',
+  BACKSPACE = '\x7f',
   CTRL_P = '\u0010',
   CTRL_N = '\u000E',
 }

packages/cli/src/ui/components/shared/BaseSettingsDialog.test.tsx

@@ -24,7 +24,7 @@ enum TerminalKeys {
   LEFT_ARROW = '\u001B[D',
   RIGHT_ARROW = '\u001B[C',
   ESCAPE = '\u001B',
-  BACKSPACE = '\u0008',
+  BACKSPACE = '\x7f',
   CTRL_L = '\u000C',
 }
 

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

@@ -9,7 +9,17 @@ import { act } from 'react';
 import { renderHookWithProviders } from '../../test-utils/render.js';
 import { createMockSettings } from '../../test-utils/settings.js';
 import { waitFor } from '../../test-utils/async.js';
-import { vi, afterAll, beforeAll, type Mock } from 'vitest';
+import type { Mock } from 'vitest';
+import {
+  vi,
+  afterAll,
+  beforeAll,
+  describe,
+  it,
+  expect,
+  beforeEach,
+  afterEach,
+} from 'vitest';
 import {
   useKeypressContext,
   ESC_TIMEOUT,
@@ -431,6 +441,80 @@ describe('KeypressContext', () => {
     );
   });
 
+  describe('Windows Terminal Backspace handling', () => {
+    afterEach(() => {
+      vi.unstubAllEnvs();
+    });
+
+    it('should NOT treat \\b as ctrl when WT_SESSION is NOT present and OS is not Windows_NT', async () => {
+      vi.stubEnv('WT_SESSION', '');
+      vi.stubEnv('OS', 'Linux');
+      const { keyHandler } = await setupKeypressTest();
+
+      act(() => {
+        stdin.write('\b');
+      });
+
+      expect(keyHandler).toHaveBeenCalledWith(
+        expect.objectContaining({
+          name: 'backspace',
+          ctrl: false,
+        }),
+      );
+    });
+
+    it('should treat \\b as ctrl when WT_SESSION IS present (even if not Windows_NT)', async () => {
+      vi.stubEnv('WT_SESSION', 'some-id');
+      vi.stubEnv('OS', 'Linux');
+      const { keyHandler } = await setupKeypressTest();
+
+      act(() => {
+        stdin.write('\b');
+      });
+
+      expect(keyHandler).toHaveBeenCalledWith(
+        expect.objectContaining({
+          name: 'backspace',
+          ctrl: true,
+        }),
+      );
+    });
+
+    it('should treat \\b as ctrl when OS is Windows_NT', async () => {
+      vi.stubEnv('WT_SESSION', '');
+      vi.stubEnv('OS', 'Windows_NT');
+      const { keyHandler } = await setupKeypressTest();
+
+      act(() => {
+        stdin.write('\b');
+      });
+
+      expect(keyHandler).toHaveBeenCalledWith(
+        expect.objectContaining({
+          name: 'backspace',
+          ctrl: true,
+        }),
+      );
+    });
+
+    it('should treat \\x7f as regular backspace regardless of WT_SESSION or OS', async () => {
+      vi.stubEnv('WT_SESSION', 'some-id');
+      vi.stubEnv('OS', 'Windows_NT');
+      const { keyHandler } = await setupKeypressTest();
+
+      act(() => {
+        stdin.write('\x7f');
+      });
+
+      expect(keyHandler).toHaveBeenCalledWith(
+        expect.objectContaining({
+          name: 'backspace',
+          ctrl: false,
+        }),
+      );
+    });
+  });
+
   describe('paste mode', () => {
     it.each([
       {

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

@@ -651,8 +651,20 @@ function* emitKeys(
       // tab
       name = 'tab';
       alt = escaped;
-    } else if (ch === '\b' || ch === '\x7f') {
-      // backspace or ctrl+h
+    } else if (ch === '\b') {
+      // ctrl+h / ctrl+backspace (windows terminals send \x08 for ctrl+backspace)
+      name = 'backspace';
+      // In Windows environments, \b is sent for Ctrl+Backspace (standard backspace is translated to \x7f).
+      // We scope this to Windows/WT_SESSION to avoid breaking other unixes where \b is a plain backspace.
+      if (
+        typeof process !== 'undefined' &&
+        (process.env?.['OS'] === 'Windows_NT' || !!process.env?.['WT_SESSION'])
+      ) {
+        ctrl = true;
+      }
+      alt = escaped;
+    } else if (ch === '\x7f') {
+      // backspace
       name = 'backspace';
       alt = escaped;
     } else if (ch === ESC) {