🔧 fix: Handle Missing MCP Config Gracefully in Config/Plugin Routes (#9438)

* 🛠️ fix: Update Plugins and Config Routes to Handle No MCP Config

* refactor: Rename cachedMCPPlugins to mcpPlugins for clarity in PluginController

api/server/controllers/PluginController.js

@@ -74,14 +74,23 @@ const getAvailableTools = async (req, res) => {
     const cachedToolsArray = await cache.get(CacheKeys.TOOLS);
     const cachedUserTools = await getCachedTools({ userId });
 
+    const appConfig = req.config ?? (await getAppConfig({ role: req.user?.role }));
+
+    /** @type {TPlugin[]} */
+    let mcpPlugins;
+    if (appConfig?.mcpConfig) {
       const mcpManager = getMCPManager();
-    const userPlugins =
+      mcpPlugins =
         cachedUserTools != null
           ? convertMCPToolsToPlugins({ functionTools: cachedUserTools, mcpManager })
           : undefined;
+    }
 
-    if (cachedToolsArray != null && userPlugins != null) {
-      const dedupedTools = filterUniquePlugins([...userPlugins, ...cachedToolsArray]);
+    if (
+      cachedToolsArray != null &&
+      (appConfig?.mcpConfig != null ? mcpPlugins != null && mcpPlugins.length > 0 : true)
+    ) {
+      const dedupedTools = filterUniquePlugins([...(mcpPlugins ?? []), ...cachedToolsArray]);
       res.status(200).json(dedupedTools);
       return;
     }
@@ -93,9 +102,9 @@ const getAvailableTools = async (req, res) => {
     /** @type {import('@librechat/api').LCManifestTool[]} */
     let pluginManifest = availableTools;
 
-    const appConfig = req.config ?? (await getAppConfig({ role: req.user?.role }));
     if (appConfig?.mcpConfig != null) {
       try {
+        const mcpManager = getMCPManager();
         const mcpTools = await mcpManager.getAllToolFunctions(userId);
         prelimCachedTools = prelimCachedTools ?? {};
         for (const [toolKey, toolData] of Object.entries(mcpTools)) {
@@ -175,7 +184,7 @@ const getAvailableTools = async (req, res) => {
     const finalTools = filterUniquePlugins(toolsOutput);
     await cache.set(CacheKeys.TOOLS, finalTools);
 
-    const dedupedTools = filterUniquePlugins([...(userPlugins ?? []), ...finalTools]);
+    const dedupedTools = filterUniquePlugins([...(mcpPlugins ?? []), ...finalTools]);
     res.status(200).json(dedupedTools);
   } catch (error) {
     logger.error('[getAvailableTools]', error);

api/server/controllers/PluginController.spec.js

@@ -174,10 +174,19 @@ describe('PluginController', () => {
       mockCache.get.mockResolvedValue(null);
       getCachedTools.mockResolvedValueOnce(mockUserTools);
       mockReq.config = {
-        mcpConfig: null,
+        mcpConfig: {
+          server1: {},
+        },
         paths: { structuredTools: '/mock/path' },
       };
 
+      // Mock MCP manager to return empty tools initially (since getAllToolFunctions is called)
+      const mockMCPManager = {
+        getAllToolFunctions: jest.fn().mockResolvedValue({}),
+        getRawConfig: jest.fn().mockReturnValue({}),
+      };
+      require('~/config').getMCPManager.mockReturnValue(mockMCPManager);
+
       // Mock second call to return tool definitions (includeGlobal: true)
       getCachedTools.mockResolvedValueOnce(mockUserTools);
 
@@ -505,7 +514,7 @@ describe('PluginController', () => {
       expect(mockRes.json).toHaveBeenCalledWith([]);
     });
 
-    it('should handle cachedToolsArray and userPlugins both being defined', async () => {
+    it('should handle `cachedToolsArray` and `mcpPlugins` both being defined', async () => {
       const cachedTools = [{ name: 'CachedTool', pluginKey: 'cached-tool', description: 'Cached' }];
       // Use MCP delimiter for the user tool so convertMCPToolsToPlugins works
       const userTools = {
@@ -522,10 +531,19 @@ describe('PluginController', () => {
       mockCache.get.mockResolvedValue(cachedTools);
       getCachedTools.mockResolvedValueOnce(userTools);
       mockReq.config = {
-        mcpConfig: null,
+        mcpConfig: {
+          server1: {},
+        },
         paths: { structuredTools: '/mock/path' },
       };
 
+      // Mock MCP manager to return empty tools initially
+      const mockMCPManager = {
+        getAllToolFunctions: jest.fn().mockResolvedValue({}),
+        getRawConfig: jest.fn().mockReturnValue({}),
+      };
+      require('~/config').getMCPManager.mockReturnValue(mockMCPManager);
+
       // The controller expects a second call to getCachedTools
       getCachedTools.mockResolvedValueOnce({
         'cached-tool': { type: 'function', function: { name: 'cached-tool' } },

api/server/routes/config.js

@@ -125,6 +125,9 @@ router.get('/', async function (req, res) {
     payload.mcpServers = {};
     const getMCPServers = () => {
       try {
+        if (appConfig?.mcpConfig == null) {
+          return;
+        }
         const mcpManager = getMCPManager();
         if (!mcpManager) {
           return;