fix: fix OpenAPI Schema Import Pydantic Validation Errors for Complex Default Values (#27159)

Co-authored-by: Alain <yinxulai@hoymail.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: autofix-ci[bot] <114827586+autofix-ci[bot]@users.noreply.github.com>

api/tests/unit_tests/core/tools/utils/test_parser.py

@@ -109,3 +109,83 @@ def test_parse_openapi_to_tool_bundle_properties_all_of(app):
     assert tool_bundles[0].parameters[0].llm_description == "desc prop1"
     # TODO: support enum in OpenAPI
     # assert set(tool_bundles[0].parameters[0].options) == {"option1", "option2", "option3"}
+
+
+def test_parse_openapi_to_tool_bundle_default_value_type_casting(app):
+    """
+    Test that default values are properly cast to match parameter types.
+    This addresses the issue where array default values like [] cause validation errors
+    when parameter type is inferred as string/number/boolean.
+    """
+    openapi = {
+        "openapi": "3.0.0",
+        "info": {"title": "Test API", "version": "1.0.0"},
+        "servers": [{"url": "https://example.com"}],
+        "paths": {
+            "/product/create": {
+                "post": {
+                    "operationId": "createProduct",
+                    "summary": "Create a product",
+                    "requestBody": {
+                        "content": {
+                            "application/json": {
+                                "schema": {
+                                    "type": "object",
+                                    "properties": {
+                                        "categories": {
+                                            "description": "List of category identifiers",
+                                            "default": [],
+                                            "type": "array",
+                                            "items": {"type": "string"},
+                                        },
+                                        "name": {
+                                            "description": "Product name",
+                                            "default": "Default Product",
+                                            "type": "string",
+                                        },
+                                        "price": {"description": "Product price", "default": 0.0, "type": "number"},
+                                        "available": {
+                                            "description": "Product availability",
+                                            "default": True,
+                                            "type": "boolean",
+                                        },
+                                    },
+                                }
+                            }
+                        }
+                    },
+                    "responses": {"200": {"description": "Default Response"}},
+                }
+            }
+        },
+    }
+
+    with app.test_request_context():
+        tool_bundles = ApiBasedToolSchemaParser.parse_openapi_to_tool_bundle(openapi)
+
+    assert len(tool_bundles) == 1
+    bundle = tool_bundles[0]
+    assert len(bundle.parameters) == 4
+
+    # Find parameters by name
+    params_by_name = {param.name: param for param in bundle.parameters}
+
+    # Check categories parameter (array type with [] default)
+    categories_param = params_by_name["categories"]
+    assert categories_param.type == "array"  # Will be detected by _get_tool_parameter_type
+    assert categories_param.default is None  # Array default [] is converted to None
+
+    # Check name parameter (string type with string default)
+    name_param = params_by_name["name"]
+    assert name_param.type == "string"
+    assert name_param.default == "Default Product"
+
+    # Check price parameter (number type with number default)
+    price_param = params_by_name["price"]
+    assert price_param.type == "number"
+    assert price_param.default == 0.0
+
+    # Check available parameter (boolean type with boolean default)
+    available_param = params_by_name["available"]
+    assert available_param.type == "boolean"
+    assert available_param.default is True