Fix parameter ordering in JsonSchemaGenerator

Incorrect usage of ClassUtils.isAssignable.

Incorrectly reversing the parameters causes the method to always return true when an Object is passed.

Fixes: #3729

Signed-off-by: TheEterna <125226601+TheEterna@users.noreply.github.com>
(cherry picked from commit cd0cc46)

Author: TheEterna

spring-ai-model/src/main/java/org/springframework/ai/util/json/schema/JsonSchemaGenerator.java

@@ -129,7 +129,7 @@ public static String generateForMethodInput(Method method, SchemaOption... schem
 			String parameterName = method.getParameters()[i].getName();
 			Type parameterType = method.getGenericParameterTypes()[i];
 			if (parameterType instanceof Class<?> parameterClass
-					&& ClassUtils.isAssignable(parameterClass, ToolContext.class)) {
+					&& ClassUtils.isAssignable(ToolContext.class, parameterClass)) {
 				// A ToolContext method parameter is not included in the JSON Schema
 				// generation.
 				// It's a special type used by Spring AI to pass contextual data to tools

spring-ai-model/src/test/java/org/springframework/ai/util/json/JsonSchemaGeneratorTests.java

@@ -161,6 +161,29 @@ void generateSchemaForMethodWithOpenApiSchemaAnnotations() throws Exception {
 		assertThat(schema).isEqualToIgnoringWhitespace(expectedJsonSchema);
 	}
 
+	@Test
+	void generateSchemaForMethodWithObjectParam() throws Exception {
+		Method method = TestMethods.class.getDeclaredMethod("objectParamMethod", Object.class);
+
+		String schema = JsonSchemaGenerator.generateForMethodInput(method);
+		String expectedJsonSchema = """
+				{
+				    "$schema": "https://json-schema.org/draft/2020-12/schema",
+				    "type": "object",
+				    "properties": {
+				        "object": {
+				        }
+				    },
+				    "required": [
+				        "object"
+				    ],
+				    "additionalProperties": false
+				}
+				""";
+
+		assertThat(schema).isEqualToIgnoringWhitespace(expectedJsonSchema);
+	}
+
 	@Test
 	void generateSchemaForMethodWithJacksonAnnotations() throws Exception {
 		Method method = TestMethods.class.getDeclaredMethod("jacksonMethod", String.class, String.class);
@@ -662,6 +685,9 @@ static class TestMethods {
 		public void simpleMethod(String name, int age) {
 		}
 
+		public void objectParamMethod(Object object) {
+		}
+
 		public void annotatedMethod(
 				@ToolParam(required = false, description = "The username of the customer") String username,
 				@ToolParam(required = true) String password) {