diff --git a/packages/core/src/utils/retry.test.ts b/packages/core/src/utils/retry.test.ts
index 2af05fb148..fe607e6914 100644
--- a/packages/core/src/utils/retry.test.ts
+++ b/packages/core/src/utils/retry.test.ts
@@ -307,11 +307,50 @@ describe('retryWithBackoff', () => {
   });
 
   describe('Fetch error retries', () => {
-    const fetchErrorMsg = 'exception TypeError: fetch failed sending request';
-
     it('should retry on specific fetch error when retryFetchErrors is true', async () => {
       const mockFn = vi.fn();
-      mockFn.mockRejectedValueOnce(new Error(fetchErrorMsg));
+      mockFn.mockRejectedValueOnce(new TypeError('fetch failed'));
+      mockFn.mockResolvedValueOnce('success');
+
+      const promise = retryWithBackoff(mockFn, {
+        retryFetchErrors: true,
+        initialDelayMs: 10,
+      });
+
+      await vi.runAllTimersAsync();
+
+      const result = await promise;
+      expect(result).toBe('success');
+      expect(mockFn).toHaveBeenCalledTimes(2);
+    });
+
+    it('should retry on common network error codes (ECONNRESET)', async () => {
+      const mockFn = vi.fn();
+      const error = new Error('read ECONNRESET');
+      (error as any).code = 'ECONNRESET';
+      mockFn.mockRejectedValueOnce(error);
+      mockFn.mockResolvedValueOnce('success');
+
+      const promise = retryWithBackoff(mockFn, {
+        retryFetchErrors: true,
+        initialDelayMs: 10,
+      });
+
+      await vi.runAllTimersAsync();
+
+      const result = await promise;
+      expect(result).toBe('success');
+      expect(mockFn).toHaveBeenCalledTimes(2);
+    });
+
+    it('should retry on common network error codes in cause (ETIMEDOUT)', async () => {
+      const mockFn = vi.fn();
+      const cause = new Error('Connect Timeout');
+      (cause as any).code = 'ETIMEDOUT';
+      const error = new Error('fetch failed');
+      (error as any).cause = cause;
+
+      mockFn.mockRejectedValueOnce(error);
       mockFn.mockResolvedValueOnce('success');
 
       const promise = retryWithBackoff(mockFn, {
@@ -329,13 +368,13 @@ describe('retryWithBackoff', () => {
     it.each([false, undefined])(
       'should not retry on specific fetch error when retryFetchErrors is %s',
       async (retryFetchErrors) => {
-        const mockFn = vi.fn().mockRejectedValue(new Error(fetchErrorMsg));
+        const mockFn = vi.fn().mockRejectedValue(new TypeError('fetch failed'));
 
         const promise = retryWithBackoff(mockFn, {
           retryFetchErrors,
         });
 
-        await expect(promise).rejects.toThrow(fetchErrorMsg);
+        await expect(promise).rejects.toThrow('fetch failed');
         expect(mockFn).toHaveBeenCalledTimes(1);
       },
     );
diff --git a/packages/core/src/utils/retry.ts b/packages/core/src/utils/retry.ts
index d196a00283..99ed75ea7e 100644
--- a/packages/core/src/utils/retry.ts
+++ b/packages/core/src/utils/retry.ts
@@ -16,9 +16,6 @@ import { delay, createAbortError } from './delay.js';
 import { debugLogger } from './debugLogger.js';
 import { getErrorStatus, ModelNotFoundError } from './httpErrors.js';
 
-const FETCH_FAILED_MESSAGE =
-  'exception TypeError: fetch failed sending request';
-
 export interface RetryOptions {
   maxAttempts: number;
   initialDelayMs: number;
@@ -41,6 +38,40 @@ const DEFAULT_RETRY_OPTIONS: RetryOptions = {
   shouldRetryOnError: defaultShouldRetry,
 };
 
+const RETRYABLE_NETWORK_CODES = [
+  'ECONNRESET',
+  'ETIMEDOUT',
+  'EPIPE',
+  'ENOTFOUND',
+  'EAI_AGAIN',
+  'ECONNREFUSED',
+];
+
+function getNetworkErrorCode(error: unknown): string | undefined {
+  const getCode = (obj: unknown): string | undefined => {
+    if (typeof obj !== 'object' || obj === null) {
+      return undefined;
+    }
+    if ('code' in obj && typeof (obj as { code: unknown }).code === 'string') {
+      return (obj as { code: string }).code;
+    }
+    return undefined;
+  };
+
+  const directCode = getCode(error);
+  if (directCode) {
+    return directCode;
+  }
+
+  if (typeof error === 'object' && error !== null && 'cause' in error) {
+    return getCode((error as { cause: unknown }).cause);
+  }
+
+  return undefined;
+}
+
+const FETCH_FAILED_MESSAGE = 'fetch failed';
+
 /**
  * Default predicate function to determine if a retry should be attempted.
  * Retries on 429 (Too Many Requests) and 5xx server errors.
@@ -52,12 +83,17 @@ function defaultShouldRetry(
   error: Error | unknown,
   retryFetchErrors?: boolean,
 ): boolean {
-  if (
-    retryFetchErrors &&
-    error instanceof Error &&
-    error.message.includes(FETCH_FAILED_MESSAGE)
-  ) {
-    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