fix(core): improve API response error handling and retry logic (#14563)

packages/core/src/utils/fetch.ts

@@ -22,8 +22,9 @@ export class FetchError extends Error {
   constructor(
     message: string,
     public code?: string,
+    options?: ErrorOptions,
   ) {
-    super(message);
+    super(message, options);
     this.name = 'FetchError';
   }
 }
@@ -51,7 +52,7 @@ export async function fetchWithTimeout(
     if (isNodeError(error) && error.code === 'ABORT_ERR') {
       throw new FetchError(`Request timed out after ${timeout}ms`, 'ETIMEDOUT');
     }
-    throw new FetchError(getErrorMessage(error));
+    throw new FetchError(getErrorMessage(error), undefined, { cause: error });
   } finally {
     clearTimeout(timeoutId);
   }

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

@@ -307,7 +307,7 @@ describe('retryWithBackoff', () => {
   });
 
   describe('Fetch error retries', () => {
-    it('should retry on specific fetch error when retryFetchErrors is true', async () => {
+    it("should retry on 'fetch failed' when retryFetchErrors is true", async () => {
       const mockFn = vi.fn();
       mockFn.mockRejectedValueOnce(new TypeError('fetch failed'));
       mockFn.mockResolvedValueOnce('success');
@@ -365,19 +365,48 @@ describe('retryWithBackoff', () => {
       expect(mockFn).toHaveBeenCalledTimes(2);
     });
 
-    it.each([false, undefined])(
-      'should not retry on specific fetch error when retryFetchErrors is %s',
-      async (retryFetchErrors) => {
-        const mockFn = vi.fn().mockRejectedValue(new TypeError('fetch failed'));
+    it("should retry on 'fetch failed' when retryFetchErrors is true (short delays)", async () => {
+      const mockFn = vi
+        .fn()
+        .mockRejectedValueOnce(new TypeError('fetch failed'))
+        .mockResolvedValue('success');
 
-        const promise = retryWithBackoff(mockFn, {
-          retryFetchErrors,
-        });
+      const promise = retryWithBackoff(mockFn, {
+        retryFetchErrors: true,
+        initialDelayMs: 1,
+        maxDelayMs: 1,
+      });
+      await vi.runAllTimersAsync();
+      await expect(promise).resolves.toBe('success');
+    });
 
-        await expect(promise).rejects.toThrow('fetch failed');
-        expect(mockFn).toHaveBeenCalledTimes(1);
-      },
-    );
+    it("should not retry on 'fetch failed' when retryFetchErrors is false", async () => {
+      const mockFn = vi.fn().mockRejectedValue(new TypeError('fetch failed'));
+      const promise = retryWithBackoff(mockFn, {
+        retryFetchErrors: false,
+        initialDelayMs: 1,
+        maxDelayMs: 1,
+      });
+      await expect(promise).rejects.toThrow('fetch failed');
+      expect(mockFn).toHaveBeenCalledTimes(1);
+    });
+
+    it('should retry on network error code (ETIMEDOUT) even when retryFetchErrors is false', async () => {
+      const error = new Error('connect ETIMEDOUT');
+      (error as any).code = 'ETIMEDOUT';
+      const mockFn = vi
+        .fn()
+        .mockRejectedValueOnce(error)
+        .mockResolvedValue('success');
+
+      const promise = retryWithBackoff(mockFn, {
+        retryFetchErrors: false,
+        initialDelayMs: 1,
+        maxDelayMs: 1,
+      });
+      await vi.runAllTimersAsync();
+      await expect(promise).resolves.toBe('success');
+    });
   });
 
   describe('Flash model fallback for OAuth users', () => {

packages/core/src/utils/retry.ts

@@ -35,7 +35,7 @@ const DEFAULT_RETRY_OPTIONS: RetryOptions = {
   maxAttempts: 3,
   initialDelayMs: 5000,
   maxDelayMs: 30000, // 30 seconds
-  shouldRetryOnError: defaultShouldRetry,
+  shouldRetryOnError: isRetryableError,
 };
 
 const RETRYABLE_NETWORK_CODES = [
@@ -79,21 +79,21 @@ const FETCH_FAILED_MESSAGE = 'fetch failed';
  * @param retryFetchErrors Whether to retry on specific fetch errors.
  * @returns True if the error is a transient error, false otherwise.
  */
-function defaultShouldRetry(
+export function isRetryableError(
   error: Error | unknown,
   retryFetchErrors?: boolean,
 ): boolean {
+  // Check for common network error codes
+  const errorCode = getNetworkErrorCode(error);
+  if (errorCode && RETRYABLE_NETWORK_CODES.includes(errorCode)) {
+    return true;
+  }
+
   if (retryFetchErrors && error instanceof Error) {
     // Check for generic fetch failed message (case-insensitive)
     if (error.message.toLowerCase().includes(FETCH_FAILED_MESSAGE)) {
       return true;
     }
-
-    // Check for common network error codes
-    const errorCode = getNetworkErrorCode(error);
-    if (errorCode && RETRYABLE_NETWORK_CODES.includes(errorCode)) {
-      return true;
-    }
   }
 
   // Priority check for ApiError
@@ -147,6 +147,7 @@ export async function retryWithBackoff<T>(
     signal,
   } = {
     ...DEFAULT_RETRY_OPTIONS,
+    shouldRetryOnError: isRetryableError,
     ...cleanOptions,
   };