diff --git a/models/spring-ai-anthropic/src/main/java/org/springframework/ai/anthropic/api/AnthropicApi.java b/models/spring-ai-anthropic/src/main/java/org/springframework/ai/anthropic/api/AnthropicApi.java
index fb51c348e4a..7ca9fced140 100644
--- a/models/spring-ai-anthropic/src/main/java/org/springframework/ai/anthropic/api/AnthropicApi.java
+++ b/models/spring-ai-anthropic/src/main/java/org/springframework/ai/anthropic/api/AnthropicApi.java
@@ -51,6 +51,7 @@
  * @author Christian Tzolov
  * @author Mariusz Bernacki
  * @author Thomas Vitale
+ * @author Jihoon Kim
  * @since 1.0.0
  */
 public class AnthropicApi {
@@ -138,8 +139,9 @@ public AnthropicApi(String baseUrl, String anthropicApiKey, String anthropicVers
 		this.webClient = webClientBuilder.baseUrl(baseUrl)
 			.defaultHeaders(jsonContentHeaders)
 			.defaultStatusHandler(HttpStatusCode::isError,
-					resp -> Mono.just(new RuntimeException("Response exception, Status: [" + resp.statusCode()
-							+ "], Body:[" + resp.bodyToMono(java.lang.String.class) + "]")))
+					resp -> resp.bodyToMono(String.class)
+						.flatMap(it -> Mono.error(new RuntimeException(
+								"Response exception, Status: [" + resp.statusCode() + "], Body:[" + it + "]"))))
 			.build();
 	}
 
diff --git a/models/spring-ai-anthropic/src/test/java/org/springframework/ai/anthropic/api/AnthropicApiIT.java b/models/spring-ai-anthropic/src/test/java/org/springframework/ai/anthropic/api/AnthropicApiIT.java
index d830980771b..f3f72e3745e 100644
--- a/models/spring-ai-anthropic/src/test/java/org/springframework/ai/anthropic/api/AnthropicApiIT.java
+++ b/models/spring-ai-anthropic/src/test/java/org/springframework/ai/anthropic/api/AnthropicApiIT.java
@@ -28,11 +28,12 @@
 import org.springframework.ai.anthropic.api.AnthropicApi.ContentBlock;
 import org.springframework.ai.anthropic.api.AnthropicApi.Role;
 import org.springframework.http.ResponseEntity;
-
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.assertj.core.api.Assertions.assertThat;
 
 /**
  * @author Christian Tzolov
+ * @author Jihoon Kim
  */
 @EnabledIfEnvironmentVariable(named = "ANTHROPIC_API_KEY", matches = ".+")
 public class AnthropicApiIT {
@@ -70,4 +71,21 @@ void chatCompletionStream() {
 		bla.stream().forEach(r -> System.out.println(r));
 	}
 
+	@Test
+	void chatCompletionStreamError() {
+		AnthropicMessage chatCompletionMessage = new AnthropicMessage(List.of(new ContentBlock("Tell me a Joke?")),
+				Role.USER);
+		AnthropicApi api = new AnthropicApi("FAKE_KEY_FOR_ERROR_RESPONSE");
+
+		Flux<ChatCompletionResponse> response = api.chatCompletionStream(new ChatCompletionRequest(
+				AnthropicApi.ChatModel.CLAUDE_3_OPUS.getValue(), List.of(chatCompletionMessage), null, 100, 0.8, true));
+
+		assertThat(response).isNotNull();
+
+		assertThatThrownBy(() -> response.collectList().block()).isInstanceOf(RuntimeException.class)
+			.hasMessageStartingWith("Response exception, Status: [")
+			.hasMessageContaining(
+					"{\"type\":\"error\",\"error\":{\"type\":\"authentication_error\",\"message\":\"invalid x-api-key\"}}");
+	}
+
 }