Fix BeanOutputConverter List type format mismatch

spring-ai-model/src/main/java/org/springframework/ai/converter/BeanOutputConverter.java

@@ -16,7 +16,9 @@
 
 package org.springframework.ai.converter;
 
+import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
+import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 
@@ -234,9 +236,16 @@ protected void postProcessSchema(@NonNull JsonNode jsonNode) {
 	@Override
 	public T convert(String text) {
 		try {
-			// Clean the text using the configured text cleaner
 			text = this.textCleaner.clean(text);
 
+			if (text != null && isListType(this.type) && text.startsWith("{")) {
+				JsonNode node = this.jsonMapper.readTree(text);
+				if (node.isObject() && node.has("items") && node.get("items").isArray() && node.has("type")
+						&& "array".equals(node.get("type").asText())) {
+					text = this.jsonMapper.writeValueAsString(node.get("items"));
+				}
+			}
+
 			return (T) this.jsonMapper.readValue(text, this.jsonMapper.constructType(this.type));
 		}
 		catch (JacksonException e) {
@@ -246,6 +255,25 @@ public T convert(String text) {
 		}
 	}
 
+	/**
+	 * Checks whether the given type is a {@link List} or a subtype of it.
+	 * @param type the type to check
+	 * @return {@code true} if the type is a List type, {@code false} otherwise
+	 */
+	private static boolean isListType(Type type) {
+		Class<?> rawType;
+		if (type instanceof ParameterizedType pt) {
+			rawType = (Class<?>) pt.getRawType();
+		}
+		else if (type instanceof Class<?> c) {
+			rawType = c;
+		}
+		else {
+			return false;
+		}
+		return List.class.isAssignableFrom(rawType);
+	}
+
 	/**
 	 * Configures and returns a JSON mapper for JSON operations.
 	 * @return Configured JSON mapper.

spring-ai-model/src/test/java/org/springframework/ai/converter/BeanOutputConverterTest.java

@@ -33,6 +33,7 @@
 import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
 import org.slf4j.LoggerFactory;
+import tools.jackson.core.JacksonException;
 import tools.jackson.databind.DeserializationFeature;
 import tools.jackson.databind.JsonNode;
 import tools.jackson.databind.json.JsonMapper;
@@ -195,6 +196,44 @@ void convertTypeReferenceArray() {
 			assertThat(testClass.get(0).getSomeString()).isEqualTo("some value");
 		}
 
+		@Test
+		void convertListTypeFromSchemaShapedResponse() {
+			var converter = new BeanOutputConverter<>(new ParameterizedTypeReference<List<TestClass>>() {
+
+			});
+
+			String schemaShapedResponse = """
+					{"type":"array","items":[{"someString":"value1"},{"someString":"value2"}]}
+					""";
+			List<TestClass> result = converter.convert(schemaShapedResponse);
+			assertThat(result).hasSize(2);
+			assertThat(result.get(0).getSomeString()).isEqualTo("value1");
+			assertThat(result.get(1).getSomeString()).isEqualTo("value2");
+		}
+
+		@Test
+		void convertListTypeFromSchemaShapedResponseWithEmptyArray() {
+			var converter = new BeanOutputConverter<>(new ParameterizedTypeReference<List<TestClass>>() {
+
+			});
+			String schemaShapedResponse = """
+					{"type":"array","items":[]}
+					""";
+			List<TestClass> result = converter.convert(schemaShapedResponse);
+			assertThat(result).isEmpty();
+		}
+
+		@Test
+		void convertListTypeIgnoresObjectWithItemsField() {
+			var converter = new BeanOutputConverter<>(new ParameterizedTypeReference<List<TestClass>>() {
+
+			});
+			String objectWithItemsField = """
+					{"type":"object","items":{"someString":"value1"}}
+					""";
+			assertThatThrownBy(() -> converter.convert(objectWithItemsField)).isInstanceOf(JacksonException.class);
+		}
+
 		@Test
 		void convertClassTypeWithJsonAnnotations() {
 			var converter = new BeanOutputConverter<>(TestClassWithJsonAnnotations.class);