🔧 fix: Ensure getServerToolFunctions Handles Errors (#9895)

* ensure getServerToolFunctions handles errors

* remove reduntant test

packages/api/src/mcp/MCPManager.ts

@@ -97,22 +97,30 @@ export class MCPManager extends UserConnectionManager {
     userId: string,
     serverName: string,
   ): Promise<t.LCAvailableTools | null> {
-    if (this.appConnections?.has(serverName)) {
-      return this.serversRegistry.getToolFunctions(
-        serverName,
-        await this.appConnections.get(serverName),
+    try {
+      if (this.appConnections?.has(serverName)) {
+        return this.serversRegistry.getToolFunctions(
+          serverName,
+          await this.appConnections.get(serverName),
+        );
+      }
+
+      const userConnections = this.getUserConnections(userId);
+      if (!userConnections || userConnections.size === 0) {
+        return null;
+      }
+      if (!userConnections.has(serverName)) {
+        return null;
+      }
+
+      return this.serversRegistry.getToolFunctions(serverName, userConnections.get(serverName)!);
+    } catch (error) {
+      logger.warn(
+        `[getServerToolFunctions] Error getting tool functions for server ${serverName}`,
+        error,
       );
-    }
-
-    const userConnections = this.getUserConnections(userId);
-    if (!userConnections || userConnections.size === 0) {
       return null;
     }
-    if (!userConnections.has(serverName)) {
-      return null;
-    }
-
-    return this.serversRegistry.getToolFunctions(serverName, userConnections.get(serverName)!);
   }
 
   /**

packages/api/src/mcp/__tests__/MCPManager.test.ts

@@ -0,0 +1,169 @@
+import { logger } from '@librechat/data-schemas';
+import type * as t from '~/mcp/types';
+import { MCPManager } from '~/mcp/MCPManager';
+import { MCPServersRegistry } from '~/mcp/MCPServersRegistry';
+import { ConnectionsRepository } from '~/mcp/ConnectionsRepository';
+import { MCPConnection } from '../connection';
+
+// Mock external dependencies
+jest.mock('@librechat/data-schemas', () => ({
+  logger: {
+    info: jest.fn(),
+    warn: jest.fn(),
+    error: jest.fn(),
+    debug: jest.fn(),
+  },
+}));
+
+jest.mock('~/mcp/MCPServersRegistry');
+jest.mock('~/mcp/ConnectionsRepository');
+
+const mockLogger = logger as jest.Mocked<typeof logger>;
+
+describe('MCPManager', () => {
+  const userId = 'test-user-123';
+  const serverName = 'test_server';
+
+  beforeEach(() => {
+    // Reset MCPManager singleton state
+    (MCPManager as unknown as { instance: null }).instance = null;
+    jest.clearAllMocks();
+  });
+
+  function mockRegistry(
+    registryConfig: Partial<MCPServersRegistry>,
+  ): jest.MockedClass<typeof MCPServersRegistry> {
+    const mock = {
+      initialize: jest.fn().mockResolvedValue(undefined),
+      getToolFunctions: jest.fn().mockResolvedValue(null),
+      ...registryConfig,
+    };
+    return (MCPServersRegistry as jest.MockedClass<typeof MCPServersRegistry>).mockImplementation(
+      () => mock as unknown as MCPServersRegistry,
+    );
+  }
+
+  function mockAppConnections(
+    appConnectionsConfig: Partial<ConnectionsRepository>,
+  ): jest.MockedClass<typeof ConnectionsRepository> {
+    const mock = {
+      has: jest.fn().mockReturnValue(false),
+      get: jest.fn().mockResolvedValue({} as unknown as MCPConnection),
+      ...appConnectionsConfig,
+    };
+    return (
+      ConnectionsRepository as jest.MockedClass<typeof ConnectionsRepository>
+    ).mockImplementation(() => mock as unknown as ConnectionsRepository);
+  }
+
+  function newMCPServersConfig(serverNameOverride?: string): t.MCPServers {
+    return {
+      [serverNameOverride ?? serverName]: {
+        type: 'stdio',
+        command: 'test',
+        args: [],
+      },
+    };
+  }
+
+  describe('getServerToolFunctions', () => {
+    it('should catch and handle errors gracefully', async () => {
+      mockRegistry({
+        getToolFunctions: jest.fn(() => {
+          throw new Error('Connection failed');
+        }),
+      });
+
+      mockAppConnections({
+        has: jest.fn().mockReturnValue(true),
+      });
+
+      const manager = await MCPManager.createInstance(newMCPServersConfig());
+
+      const result = await manager.getServerToolFunctions(userId, serverName);
+
+      expect(result).toBeNull();
+      expect(mockLogger.warn).toHaveBeenCalledWith(
+        `[getServerToolFunctions] Error getting tool functions for server ${serverName}`,
+        expect.any(Error),
+      );
+    });
+
+    it('should catch synchronous errors from getUserConnections', async () => {
+      mockRegistry({
+        getToolFunctions: jest.fn().mockResolvedValue({}),
+      });
+
+      mockAppConnections({
+        has: jest.fn().mockReturnValue(false),
+      });
+
+      const manager = await MCPManager.createInstance(newMCPServersConfig());
+
+      const spy = jest.spyOn(manager, 'getUserConnections').mockImplementation(() => {
+        throw new Error('Failed to get user connections');
+      });
+
+      const result = await manager.getServerToolFunctions(userId, serverName);
+
+      expect(result).toBeNull();
+      expect(mockLogger.warn).toHaveBeenCalledWith(
+        `[getServerToolFunctions] Error getting tool functions for server ${serverName}`,
+        expect.any(Error),
+      );
+      expect(spy).toHaveBeenCalled();
+    });
+
+    it('should return tools successfully when no errors occur', async () => {
+      const expectedTools: t.LCAvailableTools = {
+        [`test_tool_mcp_${serverName}`]: {
+          type: 'function',
+          function: {
+            name: `test_tool_mcp_${serverName}`,
+            description: 'Test tool',
+            parameters: { type: 'object' },
+          },
+        },
+      };
+
+      mockRegistry({
+        getToolFunctions: jest.fn().mockResolvedValue(expectedTools),
+      });
+
+      mockAppConnections({
+        has: jest.fn().mockReturnValue(true),
+      });
+
+      const manager = await MCPManager.createInstance(newMCPServersConfig());
+
+      const result = await manager.getServerToolFunctions(userId, serverName);
+
+      expect(result).toEqual(expectedTools);
+      expect(mockLogger.warn).not.toHaveBeenCalled();
+    });
+
+    it('should include specific server name in error messages', async () => {
+      const specificServerName = 'github_mcp_server';
+
+      mockRegistry({
+        getToolFunctions: jest.fn(() => {
+          throw new Error('Server specific error');
+        }),
+      });
+
+      mockAppConnections({
+        has: jest.fn().mockReturnValue(true),
+      });
+
+      const manager = await MCPManager.createInstance(newMCPServersConfig(specificServerName));
+
+      const result = await manager.getServerToolFunctions(userId, specificServerName);
+
+      expect(result).toBeNull();
+      expect(mockLogger.warn).toHaveBeenCalledWith(
+        `[getServerToolFunctions] Error getting tool functions for server ${specificServerName}`,
+        expect.any(Error),
+      );
+    });
+  });
+});