feat(cli): Prevent queuing of slash and shell commands (#11094)

Co-authored-by: Jacob Richman <jacob314@gmail.com>

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

@@ -89,6 +89,8 @@ export const Composer = () => {
             </Text>
           ) : uiState.showEscapePrompt ? (
             <Text color={theme.text.secondary}>Press Esc again to clear.</Text>
+          ) : uiState.queueErrorMessage ? (
+            <Text color={theme.status.error}>{uiState.queueErrorMessage}</Text>
           ) : (
             !settings.merged.ui?.hideContextSummary && (
               <ContextSummaryDisplay
@@ -149,6 +151,8 @@ export const Composer = () => {
               ? "  Press 'i' for INSERT mode and 'Esc' for NORMAL mode."
               : '  Type your message or @path/to/file'
           }
+          setQueueErrorMessage={uiActions.setQueueErrorMessage}
+          streamingState={uiState.streamingState}
         />
       )}
 

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

@@ -28,6 +28,7 @@ import { useKittyKeyboardProtocol } from '../hooks/useKittyKeyboardProtocol.js';
 import { createMockCommandContext } from '../../test-utils/mockCommandContext.js';
 import stripAnsi from 'strip-ansi';
 import chalk from 'chalk';
+import { StreamingState } from '../types.js';
 
 vi.mock('../hooks/useShellHistory.js');
 vi.mock('../hooks/useCommandCompletion.js');
@@ -2167,7 +2168,58 @@ describe('InputPrompt', () => {
     expect(mockBuffer.handleInput).toHaveBeenCalled();
     unmount();
   });
+  it('should prevent slash commands from being queued while streaming', async () => {
+    props.onSubmit = vi.fn();
+    props.buffer.text = '/help';
+    props.setQueueErrorMessage = vi.fn();
+    props.streamingState = StreamingState.Responding;
+    const { stdin, unmount } = renderWithProviders(<InputPrompt {...props} />);
+    await wait();
+    stdin.write('/help');
+    stdin.write('\r');
+    await wait();
+
+    expect(props.onSubmit).not.toHaveBeenCalled();
+    expect(props.setQueueErrorMessage).toHaveBeenCalledWith(
+      'Slash commands cannot be queued',
+    );
+    unmount();
+  });
+  it('should prevent shell commands from being queued while streaming', async () => {
+    props.onSubmit = vi.fn();
+    props.buffer.text = 'ls';
+    props.setQueueErrorMessage = vi.fn();
+    props.streamingState = StreamingState.Responding;
+    props.shellModeActive = true;
+    const { stdin, unmount } = renderWithProviders(<InputPrompt {...props} />);
+    await wait();
+    stdin.write('ls');
+    stdin.write('\r');
+    await wait();
+
+    expect(props.onSubmit).not.toHaveBeenCalled();
+    expect(props.setQueueErrorMessage).toHaveBeenCalledWith(
+      'Shell commands cannot be queued',
+    );
+    unmount();
+  });
+  it('should allow regular messages to be queued while streaming', async () => {
+    props.onSubmit = vi.fn();
+    props.buffer.text = 'regular message';
+    props.setQueueErrorMessage = vi.fn();
+    props.streamingState = StreamingState.Responding;
+    const { stdin, unmount } = renderWithProviders(<InputPrompt {...props} />);
+    await wait();
+    stdin.write('regular message');
+    stdin.write('\r');
+    await wait();
+
+    expect(props.onSubmit).toHaveBeenCalledWith('regular message');
+    expect(props.setQueueErrorMessage).not.toHaveBeenCalled();
+    unmount();
+  });
 });
+
 function clean(str: string | undefined): string {
   if (!str) return '';
   // Remove ANSI escape codes and trim whitespace

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

@@ -38,6 +38,8 @@ import * as path from 'node:path';
 import { SCREEN_READER_USER_PREFIX } from '../textConstants.js';
 import { useShellFocusState } from '../contexts/ShellFocusContext.js';
 import { useUIState } from '../contexts/UIStateContext.js';
+import { StreamingState } from '../types.js';
+import { isSlashCommand } from '../utils/commandUtils.js';
 
 /**
  * Returns if the terminal can be trusted to handle paste events atomically
@@ -71,6 +73,8 @@ export interface InputPromptProps {
   onEscapePromptChange?: (showPrompt: boolean) => void;
   vimHandleInput?: (key: Key) => boolean;
   isEmbeddedShellFocused?: boolean;
+  setQueueErrorMessage: (message: string | null) => void;
+  streamingState: StreamingState;
 }
 
 // The input content, input container, and input suggestions list may have different widths
@@ -107,6 +111,8 @@ export const InputPrompt: React.FC<InputPromptProps> = ({
   onEscapePromptChange,
   vimHandleInput,
   isEmbeddedShellFocused,
+  setQueueErrorMessage,
+  streamingState,
 }) => {
   const kittyProtocol = useKittyKeyboardProtocol();
   const isShellFocused = useShellFocusState();
@@ -221,6 +227,31 @@ export const InputPrompt: React.FC<InputPromptProps> = ({
     ],
   );
 
+  const handleSubmit = useCallback(
+    (submittedValue: string) => {
+      const trimmedMessage = submittedValue.trim();
+      const isSlash = isSlashCommand(trimmedMessage);
+
+      const isShell = shellModeActive;
+      if (
+        (isSlash || isShell) &&
+        streamingState === StreamingState.Responding
+      ) {
+        setQueueErrorMessage(
+          `${isShell ? 'Shell' : 'Slash'} commands cannot be queued`,
+        );
+        return;
+      }
+      handleSubmitAndClear(trimmedMessage);
+    },
+    [
+      handleSubmitAndClear,
+      shellModeActive,
+      streamingState,
+      setQueueErrorMessage,
+    ],
+  );
+
   const customSetTextAndResetCompletionSignal = useCallback(
     (newText: string) => {
       buffer.setText(newText);
@@ -514,7 +545,7 @@ export const InputPrompt: React.FC<InputPromptProps> = ({
 
       // If the command is a perfect match, pressing enter should execute it.
       if (completion.isPerfectMatch && keyMatchers[Command.RETURN](key)) {
-        handleSubmitAndClear(buffer.text);
+        handleSubmit(buffer.text);
         return;
       }
 
@@ -625,7 +656,7 @@ export const InputPrompt: React.FC<InputPromptProps> = ({
             buffer.backspace();
             buffer.newline();
           } else {
-            handleSubmitAndClear(buffer.text);
+            handleSubmit(buffer.text);
           }
         }
         return;
@@ -706,6 +737,7 @@ export const InputPrompt: React.FC<InputPromptProps> = ({
       onClearScreen,
       inputHistory,
       handleSubmitAndClear,
+      handleSubmit,
       shellHistory,
       reverseSearchCompletion,
       handleClipboardImage,