🔒 feat: Add MCP server domain restrictions for remote transports (#11013)

* 🔒 feat: Add MCP server domain restrictions for remote transports

* 🔒 feat: Implement comprehensive MCP error handling and domain validation

- Added `handleMCPError` function to centralize error responses for domain restrictions and inspection failures.
- Introduced custom error classes: `MCPDomainNotAllowedError` and `MCPInspectionFailedError` for better error management.
- Updated MCP server controllers to utilize the new error handling mechanism.
- Enhanced domain validation logic in `createMCPTools` and `createMCPTool` functions to prevent operations on disallowed domains.
- Added tests for runtime domain validation scenarios to ensure correct behavior.

* chore: import order

* 🔒 feat: Enhance domain validation in MCP tools with user role-based restrictions

- Integrated `getAppConfig` to fetch allowed domains based on user roles in `createMCPTools` and `createMCPTool` functions.
- Removed the deprecated `getAllowedDomains` method from `MCPServersRegistry`.
- Updated tests to verify domain restrictions are applied correctly based on user roles.
- Ensured that domain validation logic is consistent and efficient across tool creation processes.

* 🔒 test: Refactor MCP tests to utilize configurable app settings

- Introduced a mock for `getAppConfig` to enhance test flexibility.
- Removed redundant mock definition to streamline test setup.
- Ensured tests are aligned with the latest domain validation logic.

---------

Co-authored-by: Atef Bellaaj <slalom.bellaaj@external.daimlertruck.com>
Co-authored-by: Danny Avila <danny@librechat.ai>

packages/api/src/mcp/registry/MCPServerInspector.ts

@@ -2,7 +2,9 @@ import { Constants } from 'librechat-data-provider';
 import type { JsonSchemaType } from '@librechat/data-schemas';
 import type { MCPConnection } from '~/mcp/connection';
 import type * as t from '~/mcp/types';
+import { isMCPDomainAllowed, extractMCPServerDomain } from '~/auth/domain';
 import { MCPConnectionFactory } from '~/mcp/MCPConnectionFactory';
+import { MCPDomainNotAllowedError } from '~/mcp/errors';
 import { detectOAuthRequirement } from '~/mcp/oauth';
 import { isEnabled } from '~/utils';
 
@@ -24,13 +26,22 @@ export class MCPServerInspector {
    * @param serverName - The name of the server (used for tool function naming)
    * @param rawConfig - The raw server configuration
    * @param connection - The MCP connection
+   * @param allowedDomains - Optional list of allowed domains for remote transports
    * @returns A fully processed and enriched configuration with server metadata
    */
   public static async inspect(
     serverName: string,
     rawConfig: t.MCPOptions,
     connection?: MCPConnection,
+    allowedDomains?: string[] | null,
   ): Promise<t.ParsedServerConfig> {
+    // Validate domain against allowlist BEFORE attempting connection
+    const isDomainAllowed = await isMCPDomainAllowed(rawConfig, allowedDomains);
+    if (!isDomainAllowed) {
+      const domain = extractMCPServerDomain(rawConfig);
+      throw new MCPDomainNotAllowedError(domain ?? 'unknown');
+    }
+
     const start = Date.now();
     const inspector = new MCPServerInspector(serverName, rawConfig, connection);
     await inspector.inspectServer();