fix(cursor): isolate slash commands before message queue batching

Parse summarize/clear at enqueue time (runCursor) with pushIsolateAndClear
so waitForMessagesAndGetAsString never merges a slash with the next prompt.
Adds queue policy tests for invalid /clear + following message.

Addresses PR tiann#747 review.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: heavygee

cli/src/cursor/cursorUserMessageQueue.test.ts

@@ -0,0 +1,35 @@
+import { describe, expect, it } from 'vitest';
+import { MessageQueue2 } from '@/utils/MessageQueue2';
+import { parseCursorSpecialCommand } from './cursorSpecialCommands';
+import { enqueueCursorUserMessage } from './cursorUserMessageQueue';
+import type { EnhancedMode } from './loop';
+
+const mode: EnhancedMode = { permissionMode: 'default' };
+
+describe('enqueueCursorUserMessage', () => {
+    it('does not batch invalid /clear with a following prompt', async () => {
+        const queue = new MessageQueue2<EnhancedMode>((m) => m.permissionMode);
+        enqueueCursorUserMessage(queue, '/clear now', mode, 'a');
+        enqueueCursorUserMessage(queue, 'continue work', mode, 'b');
+
+        const first = await queue.waitForMessagesAndGetAsString();
+        expect(first?.message).toBe('/clear now');
+        expect(parseCursorSpecialCommand(first!.message).type).toBe('invalid');
+
+        const second = await queue.waitForMessagesAndGetAsString();
+        expect(second?.message).toBe('continue work');
+    });
+
+    it('isolates /summarize from a following same-mode prompt', async () => {
+        const queue = new MessageQueue2<EnhancedMode>((m) => m.permissionMode);
+        enqueueCursorUserMessage(queue, '/summarize keep recap', mode, 'a');
+        enqueueCursorUserMessage(queue, 'next task', mode, 'b');
+
+        const first = await queue.waitForMessagesAndGetAsString();
+        expect(first?.message).toBe('/summarize keep recap');
+        expect(parseCursorSpecialCommand(first!.message).type).toBe('summarize');
+
+        const second = await queue.waitForMessagesAndGetAsString();
+        expect(second?.message).toBe('next task');
+    });
+});

cli/src/cursor/cursorUserMessageQueue.ts

@@ -0,0 +1,21 @@
+import type { EnhancedMode } from './loop';
+import { parseCursorSpecialCommand } from './cursorSpecialCommands';
+import type { MessageQueue2 } from '@/utils/MessageQueue2';
+
+/**
+ * Enqueue a Cursor user message. Special slash commands are isolated so they are
+ * never newline-batched with adjacent same-mode prompts.
+ */
+export function enqueueCursorUserMessage(
+    messageQueue: MessageQueue2<EnhancedMode>,
+    formattedText: string,
+    enhancedMode: EnhancedMode,
+    localId?: string
+): void {
+    const specialCommand = parseCursorSpecialCommand(formattedText);
+    if (specialCommand.type !== null) {
+        messageQueue.pushIsolateAndClear(formattedText.trim(), enhancedMode, localId);
+        return;
+    }
+    messageQueue.push(formattedText, enhancedMode, localId);
+}

cli/src/cursor/runCursor.ts

@@ -11,6 +11,7 @@ import { createModeChangeHandler, createRunnerLifecycle, setControlledByUser } f
 import { registerSessionConfigRpc } from '@/agent/sessionConfigRpc';
 import { formatMessageWithAttachments } from '@/utils/attachmentFormatter';
 import { getInvokedCwd } from '@/utils/invokedCwd';
+import { enqueueCursorUserMessage } from './cursorUserMessageQueue';
 
 const formatFailureReason = (message: string): string => {
     const maxLength = 200;
@@ -96,7 +97,7 @@ export async function runCursor(opts: {
             model: currentModel
         };
         const formattedText = formatMessageWithAttachments(message.content.text, message.content.attachments);
-        messageQueue.push(formattedText, enhancedMode, localId);
+        enqueueCursorUserMessage(messageQueue, formattedText, enhancedMode, localId);
     });
 
     session.onCancelQueuedMessage((localId) => {