Allow prompt queueing during MCP initialization (#17395)

packages/cli/src/ui/AppContainer.tsx

@@ -106,6 +106,7 @@ import { registerCleanup, runExitCleanup } from '../utils/cleanup.js';
 import { RELAUNCH_EXIT_CODE } from '../utils/processUtils.js';
 import type { SessionInfo } from '../utils/sessionUtils.js';
 import { useMessageQueue } from './hooks/useMessageQueue.js';
+import { useMcpStatus } from './hooks/useMcpStatus.js';
 import { useApprovalModeIndicator } from './hooks/useApprovalModeIndicator.js';
 import { useSessionStats } from './contexts/SessionContext.js';
 import { useGitBranchName } from './hooks/useGitBranchName.js';
@@ -131,6 +132,7 @@ import {
   QUEUE_ERROR_DISPLAY_DURATION_MS,
 } from './constants.js';
 import { LoginWithGoogleRestartDialog } from './auth/LoginWithGoogleRestartDialog.js';
+import { isSlashCommand } from './utils/commandUtils.js';
 
 function isToolExecuting(pendingHistoryItems: HistoryItemWithoutId[]) {
   return pendingHistoryItems.some((item) => {
@@ -910,6 +912,8 @@ Logging in with Google... Restarting Gemini CLI to continue.
     isActive: !embeddedShellFocused,
   });
 
+  const { isMcpReady } = useMcpStatus(config);
+
   const {
     messageQueue,
     addMessage,
@@ -920,6 +924,7 @@ Logging in with Google... Restarting Gemini CLI to continue.
     isConfigInitialized,
     streamingState,
     submitQuery,
+    isMcpReady,
   });
 
   cancelHandlerRef.current = useCallback(
@@ -961,10 +966,31 @@ Logging in with Google... Restarting Gemini CLI to continue.
 
   const handleFinalSubmit = useCallback(
     (submittedValue: string) => {
-      addMessage(submittedValue);
+      const isSlash = isSlashCommand(submittedValue.trim());
+      const isIdle = streamingState === StreamingState.Idle;
+
+      if (isSlash || (isIdle && isMcpReady)) {
+        void submitQuery(submittedValue);
+      } else {
+        // Check messageQueue.length === 0 to only notify on the first queued item
+        if (isIdle && !isMcpReady && messageQueue.length === 0) {
+          coreEvents.emitFeedback(
+            'info',
+            'Waiting for MCP servers to initialize... Slash commands are still available and prompts will be queued.',
+          );
+        }
+        addMessage(submittedValue);
+      }
       addInput(submittedValue); // Track input for up-arrow history
     },
-    [addMessage, addInput],
+    [
+      addMessage,
+      addInput,
+      submitQuery,
+      isMcpReady,
+      streamingState,
+      messageQueue.length,
+    ],
   );
 
   const handleClearScreen = useCallback(() => {