feat: consolidate remote MCP servers to use url in config (#13762)

packages/core/src/utils/errors.test.ts

@@ -0,0 +1,42 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { describe, it, expect } from 'vitest';
+import { isAuthenticationError, UnauthorizedError } from './errors.js';
+
+describe('isAuthenticationError', () => {
+  it('should detect error with code: 401 property (MCP SDK style)', () => {
+    const error = { code: 401, message: 'Unauthorized' };
+    expect(isAuthenticationError(error)).toBe(true);
+  });
+
+  it('should detect UnauthorizedError instance', () => {
+    const error = new UnauthorizedError('Authentication required');
+    expect(isAuthenticationError(error)).toBe(true);
+  });
+
+  it('should return false for 404 errors', () => {
+    const error = { code: 404, message: 'Not Found' };
+    expect(isAuthenticationError(error)).toBe(false);
+  });
+
+  it('should handle null and undefined gracefully', () => {
+    expect(isAuthenticationError(null)).toBe(false);
+    expect(isAuthenticationError(undefined)).toBe(false);
+  });
+
+  it('should handle non-error objects', () => {
+    expect(isAuthenticationError('string error')).toBe(false);
+    expect(isAuthenticationError(123)).toBe(false);
+    expect(isAuthenticationError({})).toBe(false);
+  });
+
+  it('should detect 401 in various message formats', () => {
+    expect(isAuthenticationError(new Error('401 Unauthorized'))).toBe(true);
+    expect(isAuthenticationError(new Error('HTTP 401'))).toBe(true);
+    expect(isAuthenticationError(new Error('Status code: 401'))).toBe(true);
+  });
+});

packages/core/src/utils/errors.ts

@@ -117,3 +117,42 @@ function parseResponseData(error: GaxiosError): ResponseData {
   }
   return error.response?.data as ResponseData;
 }
+
+/**
+ * Checks if an error is a 401 authentication error.
+ * Uses structured error properties from MCP SDK errors.
+ *
+ * @param error The error to check
+ * @returns true if this is a 401/authentication error
+ */
+export function isAuthenticationError(error: unknown): boolean {
+  // Check for MCP SDK errors with code property
+  // (SseError and StreamableHTTPError both have numeric 'code' property)
+  if (error && typeof error === 'object' && 'code' in error) {
+    const errorCode = (error as { code: unknown }).code;
+    if (errorCode === 401) {
+      return true;
+    }
+  }
+
+  // Check for UnauthorizedError class (from MCP SDK or our own)
+  if (
+    error instanceof Error &&
+    error.constructor.name === 'UnauthorizedError'
+  ) {
+    return true;
+  }
+
+  if (error instanceof UnauthorizedError) {
+    return true;
+  }
+
+  // Fallback: Check for MCP SDK's plain Error messages with HTTP 401
+  // The SDK sometimes throws: new Error(`Error POSTing to endpoint (HTTP 401): ...`)
+  const message = getErrorMessage(error);
+  if (message.includes('401')) {
+    return true;
+  }
+
+  return false;
+}