⚒️ fix: MCP Initialization Flows

api/server/routes/mcp.js

@@ -303,7 +303,7 @@ router.post('/oauth/cancel/:serverName', requireJwtAuth, async (req, res) => {
     }
 
     // Cancel the flow by marking it as failed
-    await flowManager.completeFlow(flowId, 'mcp_oauth', null, 'User cancelled OAuth flow');
+    await flowManager.failFlow(flowId, 'mcp_oauth', 'User cancelled OAuth flow');
 
     logger.info(`[MCP OAuth Cancel] Successfully cancelled OAuth flow for ${serverName}`);
 
@@ -463,7 +463,7 @@ router.post('/:serverName/reinitialize', requireJwtAuth, async (req, res) => {
     };
 
     res.json({
-      success: userConnection && !oauthRequired,
+      success: (userConnection && !oauthRequired) || (oauthRequired && oauthUrl),
       message: getResponseMessage(),
       serverName,
       oauthRequired,

api/server/services/MCP.js

@@ -287,14 +287,26 @@ async function checkOAuthFlowStatus(userId, serverName) {
     const flowTTL = flowState.ttl || 180000; // Default 3 minutes
 
     if (flowState.status === 'FAILED' || flowAge > flowTTL) {
-      logger.debug(`[MCP Connection Status] Found failed OAuth flow for ${serverName}`, {
-        flowId,
-        status: flowState.status,
-        flowAge,
-        flowTTL,
-        timedOut: flowAge > flowTTL,
-      });
-      return { hasActiveFlow: false, hasFailedFlow: true };
+      const wasCancelled = flowState.error && flowState.error.includes('cancelled');
+
+      if (wasCancelled) {
+        logger.debug(`[MCP Connection Status] Found cancelled OAuth flow for ${serverName}`, {
+          flowId,
+          status: flowState.status,
+          error: flowState.error,
+        });
+        return { hasActiveFlow: false, hasFailedFlow: false };
+      } else {
+        logger.debug(`[MCP Connection Status] Found failed OAuth flow for ${serverName}`, {
+          flowId,
+          status: flowState.status,
+          flowAge,
+          flowTTL,
+          timedOut: flowAge > flowTTL,
+          error: flowState.error,
+        });
+        return { hasActiveFlow: false, hasFailedFlow: true };
+      }
     }
 
     if (flowState.status === 'PENDING') {

client/src/components/Chat/Input/MCPSelect.tsx

@@ -13,6 +13,7 @@ function MCPSelect() {
     batchToggleServers,
     getServerStatusIconProps,
     getConfigDialogProps,
+    isInitializing,
     localize,
   } = useMCPServerManager();
 
@@ -32,14 +33,18 @@ function MCPSelect() {
   const renderItemContent = useCallback(
     (serverName: string, defaultContent: React.ReactNode) => {
       const statusIconProps = getServerStatusIconProps(serverName);
+      const isServerInitializing = isInitializing(serverName);
 
       // Common wrapper for the main content (check mark + text)
       // Ensures Check & Text are adjacent and the group takes available space.
       const mainContentWrapper = (
         <button
           type="button"
-          className="flex flex-grow items-center rounded bg-transparent p-0 text-left transition-colors focus:outline-none"
+          className={`flex flex-grow items-center rounded bg-transparent p-0 text-left transition-colors focus:outline-none ${
+            isServerInitializing ? 'opacity-50' : ''
+          }`}
           tabIndex={0}
+          disabled={isServerInitializing}
         >
           {defaultContent}
         </button>
@@ -58,7 +63,7 @@ function MCPSelect() {
 
       return mainContentWrapper;
     },
-    [getServerStatusIconProps],
+    [getServerStatusIconProps, isInitializing],
   );
 
   // Don't render if no servers are selected and not pinned

client/src/components/Chat/Input/MCPSubMenu.tsx

@@ -22,6 +22,7 @@ const MCPSubMenu = React.forwardRef<HTMLDivElement, MCPSubMenuProps>(
       toggleServerSelection,
       getServerStatusIconProps,
       getConfigDialogProps,
+      isInitializing,
     } = useMCPServerManager();
 
     const menuStore = Ariakit.useMenuStore({
@@ -86,6 +87,7 @@ const MCPSubMenu = React.forwardRef<HTMLDivElement, MCPSubMenuProps>(
             {configuredServers.map((serverName) => {
               const statusIconProps = getServerStatusIconProps(serverName);
               const isSelected = mcpValues?.includes(serverName) ?? false;
+              const isServerInitializing = isInitializing(serverName);
 
               const statusIcon = statusIconProps && <MCPServerStatusIcon {...statusIconProps} />;
 
@@ -96,12 +98,15 @@ const MCPSubMenu = React.forwardRef<HTMLDivElement, MCPSubMenuProps>(
                     event.preventDefault();
                     toggleServerSelection(serverName);
                   }}
+                  disabled={isServerInitializing}
                   className={cn(
                     'flex items-center gap-2 rounded-lg px-2 py-1.5 text-text-primary hover:cursor-pointer',
                     'scroll-m-1 outline-none transition-colors',
                     'hover:bg-black/[0.075] dark:hover:bg-white/10',
                     'data-[active-item]:bg-black/[0.075] dark:data-[active-item]:bg-white/10',
                     'w-full min-w-0 justify-between text-sm',
+                    isServerInitializing &&
+                      'opacity-50 hover:bg-transparent dark:hover:bg-transparent',
                   )}
                 >
                   <div className="flex flex-grow items-center gap-2">

client/src/components/MCP/ServerInitializationSection.tsx

@@ -34,7 +34,7 @@ export default function ServerInitializationSection({
   const serverOAuthUrl = getOAuthUrl(serverName);
 
   const handleInitializeClick = useCallback(() => {
-    initializeServer(serverName);
+    initializeServer(serverName, false);
   }, [initializeServer, serverName]);
 
   const handleCancelClick = useCallback(() => {

client/src/hooks/MCP/useMCPServerManager.ts

@@ -171,6 +171,7 @@ export function useMCPServerManager() {
               message: localize('com_ui_mcp_oauth_timeout', { 0: serverName }),
               status: 'error',
             });
+            clearInterval(pollInterval);
             cleanupServerState(serverName);
             return;
           }
@@ -180,10 +181,15 @@ export function useMCPServerManager() {
               message: localize('com_ui_mcp_init_failed'),
               status: 'error',
             });
+            clearInterval(pollInterval);
             cleanupServerState(serverName);
+            return;
           }
         } catch (error) {
           console.error(`[MCP Manager] Error polling server ${serverName}:`, error);
+          clearInterval(pollInterval);
+          cleanupServerState(serverName);
+          return;
         }
       }, 3500);
 
@@ -201,7 +207,7 @@ export function useMCPServerManager() {
   );
 
   const initializeServer = useCallback(
-    async (serverName: string) => {
+    async (serverName: string, autoOpenOAuth: boolean = true) => {
       updateServerState(serverName, { isInitializing: true });
 
       try {
@@ -216,7 +222,9 @@ export function useMCPServerManager() {
               isInitializing: true,
             });
 
-            window.open(response.oauthUrl, '_blank', 'noopener,noreferrer');
+            if (autoOpenOAuth) {
+              window.open(response.oauthUrl, '_blank', 'noopener,noreferrer');
+            }
 
             startServerPolling(serverName);
           } else {
@@ -265,13 +273,25 @@ export function useMCPServerManager() {
 
   const cancelOAuthFlow = useCallback(
     (serverName: string) => {
-      queryClient.invalidateQueries([QueryKeys.mcpConnectionStatus]);
-      cleanupServerState(serverName);
-      cancelOAuthMutation.mutate(serverName);
+      // Call backend cancellation first, then clean up frontend state on success
+      cancelOAuthMutation.mutate(serverName, {
+        onSuccess: () => {
+          // Only clean up frontend state after backend confirms cancellation
+          cleanupServerState(serverName);
+          queryClient.invalidateQueries([QueryKeys.mcpConnectionStatus]);
 
-      showToast({
-        message: localize('com_ui_mcp_oauth_cancelled', { 0: serverName }),
-        status: 'warning',
+          showToast({
+            message: localize('com_ui_mcp_oauth_cancelled', { 0: serverName }),
+            status: 'warning',
+          });
+        },
+        onError: (error) => {
+          console.error(`[MCP Manager] Failed to cancel OAuth for ${serverName}:`, error);
+          showToast({
+            message: localize('com_ui_mcp_init_failed', { 0: serverName }),
+            status: 'error',
+          });
+        },
       });
     },
     [queryClient, cleanupServerState, showToast, localize, cancelOAuthMutation],
@@ -309,6 +329,10 @@ export function useMCPServerManager() {
       const disconnectedServers: string[] = [];
 
       serverNames.forEach((serverName) => {
+        if (isInitializing(serverName)) {
+          return;
+        }
+
         const serverStatus = connectionStatus[serverName];
         if (serverStatus?.connectionState === 'connected') {
           connectedServers.push(serverName);
@@ -323,11 +347,15 @@ export function useMCPServerManager() {
         initializeServer(serverName);
       });
     },
-    [connectionStatus, setMCPValues, initializeServer],
+    [connectionStatus, setMCPValues, initializeServer, isInitializing],
   );
 
   const toggleServerSelection = useCallback(
     (serverName: string) => {
+      if (isInitializing(serverName)) {
+        return;
+      }
+
       const currentValues = mcpValues ?? [];
       const isCurrentlySelected = currentValues.includes(serverName);
 
@@ -343,7 +371,7 @@ export function useMCPServerManager() {
         }
       }
     },
-    [mcpValues, setMCPValues, connectionStatus, initializeServer],
+    [mcpValues, setMCPValues, connectionStatus, initializeServer, isInitializing],
   );
 
   const handleConfigSave = useCallback(