🔧 refactor: customUserVar Error Normalization (#8950)

* fix: localization string had unused template var

* fix: add normalizeHttpError to hopefully stop UI hangs when an error is returned in UserController

- Ensures updateUserPluginsController always returns valid HTTP status codes instead of undefined
- Add normalizeHttpError() helper to safely extract status/message from errors
- Default to 400 status code when Error.status is undefined/invalid

* refactor: move normalizeHttpError to packages/api

api/server/controllers/UserController.js

@@ -1,5 +1,5 @@
 const { logger } = require('@librechat/data-schemas');
-const { webSearchKeys, extractWebSearchEnvVars } = require('@librechat/api');
+const { webSearchKeys, extractWebSearchEnvVars, normalizeHttpError } = require('@librechat/api');
 const {
   getFiles,
   updateUser,
@@ -89,8 +89,8 @@ const updateUserPluginsController = async (req, res) => {
 
       if (userPluginsService instanceof Error) {
         logger.error('[userPluginsService]', userPluginsService);
-        const { status, message } = userPluginsService;
-        res.status(status).send({ message });
+        const { status, message } = normalizeHttpError(userPluginsService);
+        return res.status(status).send({ message });
       }
     }
 
@@ -137,7 +137,7 @@ const updateUserPluginsController = async (req, res) => {
         authService = await updateUserPluginAuth(user.id, keys[i], pluginKey, values[i]);
         if (authService instanceof Error) {
           logger.error('[authService]', authService);
-          ({ status, message } = authService);
+          ({ status, message } = normalizeHttpError(authService));
         }
       }
     } else if (action === 'uninstall') {
@@ -151,7 +151,7 @@ const updateUserPluginsController = async (req, res) => {
             `[authService] Error deleting all auth for MCP tool ${pluginKey}:`,
             authService,
           );
-          ({ status, message } = authService);
+          ({ status, message } = normalizeHttpError(authService));
         }
       } else {
         // This handles:
@@ -163,7 +163,7 @@ const updateUserPluginsController = async (req, res) => {
           authService = await deleteUserPluginAuth(user.id, keys[i]); // Deletes by authField name
           if (authService instanceof Error) {
             logger.error('[authService] Error deleting specific auth key:', authService);
-            ({ status, message } = authService);
+            ({ status, message } = normalizeHttpError(authService));
           }
         }
       }
@@ -193,7 +193,8 @@ const updateUserPluginsController = async (req, res) => {
       return res.status(status).send();
     }
 
-    res.status(status).send({ message });
+    const normalized = normalizeHttpError({ status, message });
+    return res.status(normalized.status).send({ message: normalized.message });
   } catch (err) {
     logger.error('[updateUserPluginsController]', err);
     return res.status(500).json({ message: 'Something went wrong.' });

client/src/locales/en/translation.json

@@ -450,7 +450,7 @@
   "com_nav_maximize_chat_space": "Maximize chat space",
   "com_nav_mcp_configure_server": "Configure {{0}}",
   "com_nav_mcp_status_connecting": "{{0}} - Connecting",
-  "com_nav_mcp_vars_update_error": "Error updating MCP custom user variables: {{0}}",
+  "com_nav_mcp_vars_update_error": "Error updating MCP custom user variables",
   "com_nav_mcp_vars_updated": "MCP custom user variables updated successfully.",
   "com_nav_modular_chat": "Enable switching Endpoints mid-conversation",
   "com_nav_my_files": "My Files",

packages/api/src/utils/http.ts

@@ -0,0 +1,26 @@
+/**
+ * Normalizes an error-like object into an HTTP status and message.
+ * Ensures we always respond with a valid numeric status to avoid UI hangs.
+ */
+export function normalizeHttpError(
+  err: Error | { status?: number; message?: string } | unknown,
+  fallbackStatus = 400,
+) {
+  let status = fallbackStatus;
+  if (err && typeof err === 'object' && 'status' in err && typeof err.status === 'number') {
+    status = err.status;
+  }
+
+  let message = 'An error occurred.';
+  if (
+    err &&
+    typeof err === 'object' &&
+    'message' in err &&
+    typeof err.message === 'string' &&
+    err.message.length > 0
+  ) {
+    message = err.message;
+  }
+
+  return { status, message };
+}

packages/api/src/utils/index.ts

@@ -12,3 +12,4 @@ export * from './openid';
 export * from './tempChatRetention';
 export { default as Tokenizer } from './tokenizer';
 export * from './yaml';
+export * from './http';