From b6f71ac06084d031680397718d80d685c7dfdeab Mon Sep 17 00:00:00 2001
From: Eduard Stanculet <eduard.stanculet@uipath.com>
Date: Wed, 28 Jan 2026 13:24:25 +0200
Subject: [PATCH] feat: simple serialization defaults

---
 pyproject.toml                            |   2 +-
 src/uipath/core/serialization/__init__.py |   5 +
 src/uipath/core/serialization/json.py     | 150 ++++++
 src/uipath/core/tracing/_utils.py         |  58 +-
 tests/serialization/test_json.py          | 614 ++++++++++++++++++++++
 uv.lock                                   |   2 +-
 6 files changed, 776 insertions(+), 55 deletions(-)
 create mode 100644 src/uipath/core/serialization/__init__.py
 create mode 100644 src/uipath/core/serialization/json.py
 create mode 100644 tests/serialization/test_json.py

diff --git a/pyproject.toml b/pyproject.toml
index 1c9200d..786d5d7 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "uipath-core"
-version = "0.2.1"
+version = "0.2.2"
 description = "UiPath Core abstractions"
 readme = { file = "README.md", content-type = "text/markdown" }
 requires-python = ">=3.11"
diff --git a/src/uipath/core/serialization/__init__.py b/src/uipath/core/serialization/__init__.py
new file mode 100644
index 0000000..aa26e75
--- /dev/null
+++ b/src/uipath/core/serialization/__init__.py
@@ -0,0 +1,5 @@
+"""Serialization utilities for converting Python objects to various formats."""
+
+from .json import serialize_defaults, serialize_json
+
+__all__ = ["serialize_defaults", "serialize_json"]
diff --git a/src/uipath/core/serialization/json.py b/src/uipath/core/serialization/json.py
new file mode 100644
index 0000000..0208454
--- /dev/null
+++ b/src/uipath/core/serialization/json.py
@@ -0,0 +1,150 @@
+"""JSON serialization utilities for converting Python objects to JSON formats."""
+
+import json
+from dataclasses import asdict, is_dataclass
+from datetime import datetime, timezone
+from enum import Enum
+from typing import Any, cast
+from zoneinfo import ZoneInfo
+
+from pydantic import BaseModel
+
+
+def serialize_defaults(
+    obj: Any,
+) -> dict[str, Any] | list[Any] | str | int | float | bool | None:
+    """Convert Python objects to JSON-serializable formats.
+
+    Handles common Python types that are not natively JSON-serializable:
+    - Pydantic models (v1 and v2)
+    - Dataclasses
+    - Enums
+    - Datetime objects
+    - Timezone objects
+    - Named tuples
+    - Sets and tuples
+
+    This function is designed to be used as the `default` parameter in json.dumps():
+    ```python
+    import json
+    result = json.dumps(obj, default=serialize_defaults)
+    ```
+
+    Or use the convenience function `serialize_json()` which wraps this:
+    ```python
+    result = serialize_json(obj)
+    ```
+
+    Args:
+        obj: The object to serialize
+
+    Returns:
+        A JSON-serializable representation of the object:
+        - Pydantic models: dict from model_dump()
+        - Dataclasses: dict from asdict()
+        - Enums: the enum value (recursively serialized)
+        - datetime: ISO format string
+        - timezone/ZoneInfo: timezone name
+        - sets/tuples: converted to lists
+        - named tuples: converted to dict
+        - Primitives (None, bool, int, float, str, list, dict): returned unchanged
+        - Other types: converted to string with str()
+
+    Examples:
+        >>> from datetime import datetime
+        >>> from pydantic import BaseModel
+        >>>
+        >>> class User(BaseModel):
+        ...     name: str
+        ...     created_at: datetime
+        >>>
+        >>> user = User(name="Alice", created_at=datetime.now())
+        >>> import json
+        >>> json.dumps(user, default=serialize_defaults)
+        '{"name": "Alice", "created_at": "2024-01-01T12:00:00"}'
+        >>> # Or use the convenience function
+        >>> serialize_json(user)
+        '{"name": "Alice", "created_at": "2024-01-01T12:00:00"}'
+    """
+    # Handle Pydantic BaseModel instances
+    if hasattr(obj, "model_dump") and not isinstance(obj, type):
+        return obj.model_dump(exclude_none=True, mode="json")
+
+    # Handle Pydantic model classes - convert to schema representation
+    if isinstance(obj, type) and issubclass(obj, BaseModel):
+        return {
+            "__class__": obj.__name__,
+            "__module__": obj.__module__,
+            "schema": obj.model_json_schema(),
+        }
+
+    # Handle Pydantic v1 models
+    if hasattr(obj, "dict") and not isinstance(obj, type):
+        return obj.dict()
+
+    # Handle objects with to_dict method
+    if hasattr(obj, "to_dict") and not isinstance(obj, type):
+        return obj.to_dict()
+
+    # Handle dataclasses
+    if is_dataclass(obj) and not isinstance(obj, type):
+        return asdict(obj)
+
+    # Handle enums - recursively serialize the value
+    if isinstance(obj, Enum):
+        return serialize_defaults(obj.value)
+
+    # Handle sets and tuples
+    if isinstance(obj, (set, tuple)):
+        # Check if it's a named tuple (has _asdict method)
+        if hasattr(obj, "_asdict") and callable(
+            obj._asdict  # pyright: ignore[reportAttributeAccessIssue]
+        ):
+            return cast(
+                dict[str, Any],
+                obj._asdict(),  # pyright: ignore[reportAttributeAccessIssue]
+            )
+        # Convert to list
+        return list(obj)
+
+    # Handle datetime objects
+    if isinstance(obj, datetime):
+        return obj.isoformat()
+
+    # Handle timezone objects
+    if isinstance(obj, (timezone, ZoneInfo)):
+        return obj.tzname(None)
+
+    # Allow JSON-serializable primitives to pass through unchanged
+    if obj is None or isinstance(obj, (bool, int, float, str, list, dict)):
+        return obj
+
+    # Fallback: convert to string
+    return str(obj)
+
+
+def serialize_json(obj: Any) -> str:
+    """Serialize Python object to JSON string.
+
+    This is a convenience function that wraps json.dumps() with serialize_defaults()
+    as the default handler for non-JSON-serializable types.
+
+    Args:
+        obj: The object to serialize to JSON
+
+    Returns:
+        JSON string representation of the object
+
+    Examples:
+        >>> from datetime import datetime
+        >>> from pydantic import BaseModel
+        >>>
+        >>> class Task(BaseModel):
+        ...     name: str
+        ...     created: datetime
+        >>>
+        >>> task = Task(name="Review PR", created=datetime(2024, 1, 15, 10, 30))
+        >>> serialize_json(task)
+        '{"name": "Review PR", "created": "2024-01-15T10:30:00"}'
+    """
+    return json.dumps(obj, default=serialize_defaults)
diff --git a/src/uipath/core/tracing/_utils.py b/src/uipath/core/tracing/_utils.py
index afe3540..841aa67 100644
--- a/src/uipath/core/tracing/_utils.py
+++ b/src/uipath/core/tracing/_utils.py
@@ -3,14 +3,11 @@
 import inspect
 import json
 from collections.abc import Callable
-from dataclasses import asdict, is_dataclass
-from datetime import datetime, timezone
-from enum import Enum
-from typing import Any, Mapping, Optional, cast
-from zoneinfo import ZoneInfo
+from typing import Any, Mapping, Optional
 
 from opentelemetry.trace import Span
-from pydantic import BaseModel
+
+from uipath.core.serialization import serialize_json
 
 
 def get_supported_params(
@@ -31,64 +28,19 @@ def get_supported_params(
     return supported
 
 
-def _simple_serialize_defaults(
-    obj: Any,
-) -> dict[str, Any] | list[Any] | str | int | float | bool | None:
-    # Handle Pydantic BaseModel instances
-    if hasattr(obj, "model_dump") and not isinstance(obj, type):
-        return obj.model_dump(exclude_none=True, mode="json")
-
-    # Handle classes - convert to schema representation
-    if isinstance(obj, type) and issubclass(obj, BaseModel):
-        return {
-            "__class__": obj.__name__,
-            "__module__": obj.__module__,
-            "schema": obj.model_json_schema(),
-        }
-    if hasattr(obj, "dict") and not isinstance(obj, type):
-        return obj.dict()
-    if hasattr(obj, "to_dict") and not isinstance(obj, type):
-        return obj.to_dict()
-
-    # Handle dataclasses
-    if is_dataclass(obj) and not isinstance(obj, type):
-        return asdict(obj)
-
-    # Handle enums
-    if isinstance(obj, Enum):
-        return _simple_serialize_defaults(obj.value)
-
-    if isinstance(obj, (set, tuple)):
-        if hasattr(obj, "_asdict") and callable(obj._asdict):  # pyright: ignore[reportAttributeAccessIssue]
-            return cast(dict[str, Any], obj._asdict())  # pyright: ignore[reportAttributeAccessIssue]
-        return list(obj)
-
-    if isinstance(obj, datetime):
-        return obj.isoformat()
-
-    if isinstance(obj, (timezone, ZoneInfo)):
-        return obj.tzname(None)
-
-    # Allow JSON-serializable primitives to pass through unchanged
-    if obj is None or isinstance(obj, (bool, int, float, str)):
-        return obj
-
-    return str(obj)
-
-
 def format_args_for_trace_json(
     signature: inspect.Signature, *args: Any, **kwargs: Any
 ) -> str:
     """Return a JSON string of inputs from the function signature."""
     result = format_args_for_trace(signature, *args, **kwargs)
-    return json.dumps(result, default=_simple_serialize_defaults)
+    return serialize_json(result)
 
 
 def format_object_for_trace_json(
     input_object: Any,
 ) -> str:
     """Return a JSON string of inputs from the function signature."""
-    return json.dumps(input_object, default=_simple_serialize_defaults)
+    return serialize_json(input_object)
 
 
 def format_args_for_trace(
diff --git a/tests/serialization/test_json.py b/tests/serialization/test_json.py
new file mode 100644
index 0000000..663b292
--- /dev/null
+++ b/tests/serialization/test_json.py
@@ -0,0 +1,614 @@
+"""Tests for serialization utilities."""
+
+import json
+from collections import namedtuple
+from dataclasses import dataclass
+from datetime import datetime, timezone
+from enum import Enum
+from typing import Any
+from zoneinfo import ZoneInfo
+
+import pytest
+from pydantic import BaseModel
+
+from uipath.core.serialization import serialize_json
+
+
+def _has_tzdata() -> bool:
+    """Check if timezone data is available."""
+    try:
+        ZoneInfo("America/New_York")
+        return True
+    except Exception:
+        return False
+
+
+class Color(Enum):
+    """Test enum."""
+
+    RED = "red"
+    GREEN = "green"
+    BLUE = 3
+
+
+class Priority(Enum):
+    """Test enum with int values."""
+
+    LOW = 1
+    MEDIUM = 2
+    HIGH = 3
+
+
+class SimpleModel(BaseModel):
+    """Simple Pydantic v2 model."""
+
+    name: str
+    value: int
+
+
+class NestedModel(BaseModel):
+    """Pydantic model with nested model."""
+
+    id: str
+    inner: SimpleModel
+    items: list[SimpleModel]
+
+
+@dataclass
+class SimpleDataclass:
+    """Simple dataclass for testing."""
+
+    name: str
+    count: int
+
+
+@dataclass
+class NestedDataclass:
+    """Dataclass with nested dataclass."""
+
+    id: str
+    inner: SimpleDataclass
+
+
+Point = namedtuple("Point", ["x", "y"])
+
+
+class TestSimpleSerializeDefaults:
+    """Tests for serialize_defaults and serialize_json functions."""
+
+    def test_serializes_none(self) -> None:
+        """Test None serialization via json.dumps."""
+        data = {"value": None}
+        result = serialize_json(data)
+        parsed = json.loads(result)
+        assert parsed["value"] is None
+
+    def test_serializes_primitives(self) -> None:
+        """Test primitive types pass through json.dumps unchanged."""
+        data = {
+            "bool_true": True,
+            "bool_false": False,
+            "integer": 42,
+            "float": 3.14,
+            "string": "hello",
+        }
+        result = serialize_json(data)
+        parsed = json.loads(result)
+        assert parsed["bool_true"] is True
+        assert parsed["bool_false"] is False
+        assert parsed["integer"] == 42
+        assert parsed["float"] == 3.14
+        assert parsed["string"] == "hello"
+
+    def test_serializes_pydantic_model(self) -> None:
+        """Test Pydantic BaseModel serialization via json.dumps."""
+        model = SimpleModel(name="test", value=42)
+        result = serialize_json(model)
+        parsed = json.loads(result)
+        assert isinstance(parsed, dict)
+        assert parsed["name"] == "test"
+        assert parsed["value"] == 42
+
+    def test_serializes_nested_pydantic_model(self) -> None:
+        """Test nested Pydantic models via json.dumps."""
+        inner = SimpleModel(name="inner", value=10)
+        model = NestedModel(
+            id="123",
+            inner=inner,
+            items=[
+                SimpleModel(name="item1", value=1),
+                SimpleModel(name="item2", value=2),
+            ],
+        )
+        result = serialize_json(model)
+        parsed = json.loads(result)
+        assert isinstance(parsed, dict)
+        assert parsed["id"] == "123"
+        assert parsed["inner"]["name"] == "inner"
+        assert len(parsed["items"]) == 2
+        assert parsed["items"][0]["name"] == "item1"
+        assert parsed["items"][1]["value"] == 2
+
+    def test_serializes_pydantic_model_excludes_none(self) -> None:
+        """Test Pydantic model with None values excluded via json.dumps."""
+
+        class OptionalModel(BaseModel):
+            required: str
+            optional: str | None = None
+
+        model = OptionalModel(required="value")
+        result = serialize_json(model)
+        parsed = json.loads(result)
+        assert isinstance(parsed, dict)
+        assert parsed["required"] == "value"
+        # exclude_none=True should exclude the None field
+        assert "optional" not in parsed
+
+    def test_serializes_pydantic_model_class(self) -> None:
+        """Test Pydantic model class (not instance) serialization via json.dumps."""
+        data = {"model_class": SimpleModel}
+        result = serialize_json(data)
+        parsed = json.loads(result)
+        assert isinstance(parsed["model_class"], dict)
+        assert parsed["model_class"]["__class__"] == "SimpleModel"
+        assert parsed["model_class"]["__module__"] == "test_json"
+        assert "schema" in parsed["model_class"]
+        assert isinstance(parsed["model_class"]["schema"], dict)
+
+    def test_serializes_dataclass(self) -> None:
+        """Test dataclass serialization via json.dumps."""
+        obj = SimpleDataclass(name="test", count=5)
+        result = serialize_json(obj)
+        parsed = json.loads(result)
+        assert isinstance(parsed, dict)
+        assert parsed["name"] == "test"
+        assert parsed["count"] == 5
+
+    def test_serializes_nested_dataclass(self) -> None:
+        """Test nested dataclass serialization via json.dumps."""
+        inner = SimpleDataclass(name="inner", count=10)
+        obj = NestedDataclass(id="123", inner=inner)
+        result = serialize_json(obj)
+        parsed = json.loads(result)
+        assert isinstance(parsed, dict)
+        assert parsed["id"] == "123"
+        assert parsed["inner"]["name"] == "inner"
+        assert parsed["inner"]["count"] == 10
+
+    def test_serializes_enum_string_value(self) -> None:
+        """Test enum with string value via json.dumps."""
+        data = {"color": Color.RED}
+        result = serialize_json(data)
+        parsed = json.loads(result)
+        assert parsed["color"] == "red"
+
+    def test_serializes_enum_int_value(self) -> None:
+        """Test enum with int value via json.dumps."""
+        data = {"priority": Priority.HIGH}
+        result = serialize_json(data)
+        parsed = json.loads(result)
+        assert parsed["priority"] == 3
+
+    def test_serializes_enum_mixed_value(self) -> None:
+        """Test enum with mixed types via json.dumps."""
+        data = {"color1": Color.GREEN, "color2": Color.BLUE}
+        result = serialize_json(data)
+        parsed = json.loads(result)
+        assert parsed["color1"] == "green"
+        assert parsed["color2"] == 3
+
+    def test_serializes_datetime(self) -> None:
+        """Test datetime serialization via json.dumps."""
+        dt = datetime(2024, 1, 15, 10, 30, 45)
+        data = {"timestamp": dt}
+        result = serialize_json(data)
+        parsed = json.loads(result)
+        assert isinstance(parsed["timestamp"], str)
+        assert "2024-01-15" in parsed["timestamp"]
+        assert "10:30:45" in parsed["timestamp"]
+
+    def test_serializes_datetime_with_timezone(self) -> None:
+        """Test datetime with timezone via json.dumps."""
+        dt = datetime(2024, 1, 15, 10, 30, 45, tzinfo=timezone.utc)
+        data = {"timestamp": dt}
+        result = serialize_json(data)
+        parsed = json.loads(result)
+        assert isinstance(parsed["timestamp"], str)
+        assert parsed["timestamp"] == "2024-01-15T10:30:45+00:00"
+
+    def test_serializes_timezone(self) -> None:
+        """Test timezone object serialization via json.dumps."""
+        tz = timezone.utc
+        data = {"timezone": tz}
+        result = serialize_json(data)
+        parsed = json.loads(result)
+        assert parsed["timezone"] == "UTC"
+
+    @pytest.mark.skipif(not _has_tzdata(), reason="Timezone data not available")
+    def test_serializes_zoneinfo(self) -> None:
+        """Test ZoneInfo serialization via json.dumps."""
+        tz = ZoneInfo("America/New_York")
+        data = {"timezone": tz}
+        result = serialize_json(data)
+        parsed = json.loads(result)
+        # ZoneInfo returns timezone name or None
+        assert isinstance(parsed["timezone"], (str, type(None)))
+
+    def test_serializes_set(self) -> None:
+        """Test set serialization via json.dumps."""
+        obj = {1, 2, 3}
+        data = {"numbers": obj}
+        result = serialize_json(data)
+        parsed = json.loads(result)
+        assert isinstance(parsed["numbers"], list)
+        assert set(parsed["numbers"]) == {1, 2, 3}
+
+    def test_serializes_tuple(self) -> None:
+        """Test tuple serialization via json.dumps."""
+        obj = (1, 2, 3)
+        data = {"numbers": obj}
+        result = serialize_json(data)
+        parsed = json.loads(result)
+        assert isinstance(parsed["numbers"], list)
+        assert parsed["numbers"] == [1, 2, 3]
+
+    def test_serializes_named_tuple(self) -> None:
+        """Test named tuple serialization via json.dumps.
+
+        Note: Python's json encoder treats namedtuples as regular tuples,
+        so they serialize as lists [x, y] rather than dicts {"x": x, "y": y}.
+        The serialize_defaults function is not called for namedtuples
+        because they're natively JSON-serializable as tuples.
+        """
+        point = Point(x=10, y=20)
+        data = {"point": point}
+        result = serialize_json(data)
+        parsed = json.loads(result)
+        # Namedtuples serialize as lists through json.dumps
+        assert isinstance(parsed["point"], list)
+        assert parsed["point"] == [10, 20]
+
+    def test_serializes_object_with_to_dict(self) -> None:
+        """Test object with to_dict method via json.dumps."""
+
+        class CustomObject:
+            def to_dict(self) -> dict[str, Any]:
+                return {"custom": "value"}
+
+        obj = CustomObject()
+        data = {"obj": obj}
+        result = serialize_json(data)
+        parsed = json.loads(result)
+        assert parsed["obj"] == {"custom": "value"}
+
+    def test_serializes_unknown_object_to_str(self) -> None:
+        """Test unknown object falls back to str() via json.dumps."""
+
+        class CustomClass:
+            def __str__(self) -> str:
+                return "custom_string"
+
+        obj = CustomClass()
+        data = {"obj": obj}
+        result = serialize_json(data)
+        parsed = json.loads(result)
+        assert parsed["obj"] == "custom_string"
+
+    def test_with_json_dumps(self) -> None:
+        """Test integration with json.dumps()."""
+
+        class ComplexObject(BaseModel):
+            name: str
+            created_at: datetime
+            priority: Priority
+
+        obj = ComplexObject(
+            name="task",
+            created_at=datetime(2024, 1, 15, 10, 30),
+            priority=Priority.HIGH,
+        )
+
+        # Should not raise TypeError
+        result = serialize_json(obj)
+        parsed = json.loads(result)
+
+        assert parsed["name"] == "task"
+        assert "2024-01-15" in parsed["created_at"]
+        assert parsed["priority"] == 3
+
+    def test_with_json_dumps_complex_nested(self) -> None:
+        """Test with complex nested structure."""
+        data = {
+            "model": SimpleModel(name="test", value=42),
+            "dataclass": SimpleDataclass(name="dc", count=5),
+            "enum": Color.RED,
+            "datetime": datetime(2024, 1, 1),
+            "set": {1, 2, 3},
+            "tuple": (4, 5, 6),
+        }
+
+        result = serialize_json(data)
+        parsed = json.loads(result)
+
+        assert parsed["model"]["name"] == "test"
+        assert parsed["dataclass"]["name"] == "dc"
+        assert parsed["enum"] == "red"
+        assert "2024-01-01" in parsed["datetime"]
+        assert set(parsed["set"]) == {1, 2, 3}
+        assert parsed["tuple"] == [4, 5, 6]
+
+    def test_with_list_of_pydantic_models(self) -> None:
+        """Test with list of Pydantic models (common MCP scenario)."""
+        models = [
+            SimpleModel(name="first", value=1),
+            SimpleModel(name="second", value=2),
+            SimpleModel(name="third", value=3),
+        ]
+
+        # This should not raise TypeError
+        result = serialize_json(models)
+        parsed = json.loads(result)
+
+        assert len(parsed) == 3
+        assert parsed[0]["name"] == "first"
+        assert parsed[1]["value"] == 2
+
+    def test_recursive_enum_serialization(self) -> None:
+        """Test that enum values are recursively serialized via json.dumps."""
+
+        class NestedEnum(Enum):
+            """Enum with complex value."""
+
+            COMPLEX = {"key": "value"}
+
+        data = {"enum": NestedEnum.COMPLEX}
+        result = serialize_json(data)
+        parsed = json.loads(result)
+        # The enum value itself (a dict) should be returned as-is
+        assert parsed["enum"] == {"key": "value"}
+        assert isinstance(parsed["enum"], dict)
+
+    def test_dataclass_class_returns_string(self) -> None:
+        """Test that dataclass class (not instance) falls back to str via json.dumps."""
+        data = {"dataclass_class": SimpleDataclass}
+        result = serialize_json(data)
+        parsed = json.loads(result)
+        assert isinstance(parsed["dataclass_class"], str)
+        assert "SimpleDataclass" in parsed["dataclass_class"]
+
+    def test_empty_collections(self) -> None:
+        """Test empty collections via json.dumps."""
+        data: dict[str, Any] = {"empty_set": set(), "empty_tuple": (), "empty_list": []}
+        result = serialize_json(data)
+        parsed = json.loads(result)
+        assert parsed["empty_set"] == []
+        assert parsed["empty_tuple"] == []
+        assert parsed["empty_list"] == []
+
+    def test_with_dict_method(self) -> None:
+        """Test object with dict() method (Pydantic v1 compatibility) via json.dumps."""
+
+        class OldStyleModel:
+            def dict(self) -> dict[str, Any]:
+                return {"old": "style"}
+
+        obj = OldStyleModel()
+        data = {"obj": obj}
+        result = serialize_json(data)
+        parsed = json.loads(result)
+        assert parsed["obj"] == {"old": "style"}
+
+    def test_dict_of_pydantic_models(self) -> None:
+        """Test dictionary containing Pydantic models as values."""
+        data = {
+            "user1": SimpleModel(name="Alice", value=100),
+            "user2": SimpleModel(name="Bob", value=200),
+            "user3": SimpleModel(name="Charlie", value=300),
+        }
+
+        result = serialize_json(data)
+        parsed = json.loads(result)
+
+        assert isinstance(parsed, dict)
+        assert parsed["user1"]["name"] == "Alice"
+        assert parsed["user1"]["value"] == 100
+        assert parsed["user2"]["name"] == "Bob"
+        assert parsed["user2"]["value"] == 200
+        assert parsed["user3"]["name"] == "Charlie"
+        assert parsed["user3"]["value"] == 300
+
+    def test_dict_of_dataclass_models(self) -> None:
+        """Test dictionary containing dataclass instances as values."""
+        data = {
+            "item1": SimpleDataclass(name="First", count=1),
+            "item2": SimpleDataclass(name="Second", count=2),
+            "item3": SimpleDataclass(name="Third", count=3),
+        }
+
+        result = serialize_json(data)
+        parsed = json.loads(result)
+
+        assert isinstance(parsed, dict)
+        assert parsed["item1"]["name"] == "First"
+        assert parsed["item1"]["count"] == 1
+        assert parsed["item2"]["name"] == "Second"
+        assert parsed["item2"]["count"] == 2
+        assert parsed["item3"]["name"] == "Third"
+        assert parsed["item3"]["count"] == 3
+
+    def test_normal_class_fallback_to_str(self) -> None:
+        """Test normal class (not Pydantic, dataclass, or enum) falls back to str()."""
+
+        class RegularClass:
+            def __init__(self, value: str) -> None:
+                self.value = value
+
+            def __str__(self) -> str:
+                return f"RegularClass({self.value})"
+
+        obj = RegularClass("test_value")
+        data = {"object": obj, "name": "test"}
+        json_result = serialize_json(data)
+        parsed = json.loads(json_result)
+        assert parsed["object"] == "RegularClass(test_value)"
+        assert parsed["name"] == "test"
+
+    def test_list_of_dataclass(self) -> None:
+        """Test list containing dataclass instances."""
+        data = [
+            SimpleDataclass(name="First", count=1),
+            SimpleDataclass(name="Second", count=2),
+            SimpleDataclass(name="Third", count=3),
+        ]
+
+        result = serialize_json(data)
+        parsed = json.loads(result)
+
+        assert isinstance(parsed, list)
+        assert len(parsed) == 3
+        assert parsed[0]["name"] == "First"
+        assert parsed[0]["count"] == 1
+        assert parsed[1]["name"] == "Second"
+        assert parsed[2]["count"] == 3
+
+    def test_list_of_pydantic_models(self) -> None:
+        """Test list containing Pydantic model instances."""
+        data = [
+            SimpleModel(name="Alice", value=100),
+            SimpleModel(name="Bob", value=200),
+            SimpleModel(name="Charlie", value=300),
+        ]
+
+        result = serialize_json(data)
+        parsed = json.loads(result)
+
+        assert isinstance(parsed, list)
+        assert len(parsed) == 3
+        assert parsed[0]["name"] == "Alice"
+        assert parsed[0]["value"] == 100
+        assert parsed[1]["name"] == "Bob"
+        assert parsed[2]["value"] == 300
+
+    def test_list_of_normal_classes(self) -> None:
+        """Test list containing normal class instances (fallback to str)."""
+
+        class Item:
+            def __init__(self, id: int, label: str) -> None:
+                self.id = id
+                self.label = label
+
+            def __str__(self) -> str:
+                return f"Item(id={self.id}, label={self.label})"
+
+        data = [
+            Item(1, "First"),
+            Item(2, "Second"),
+            Item(3, "Third"),
+        ]
+
+        result = serialize_json(data)
+        parsed = json.loads(result)
+
+        assert isinstance(parsed, list)
+        assert len(parsed) == 3
+        assert parsed[0] == "Item(id=1, label=First)"
+        assert parsed[1] == "Item(id=2, label=Second)"
+        assert parsed[2] == "Item(id=3, label=Third)"
+
+    def test_list_of_mixed_types(self) -> None:
+        """Test list containing mixed types: Pydantic, dataclass, normal class, primitives."""
+
+        class CustomItem:
+            def __init__(self, name: str) -> None:
+                self.name = name
+
+            def __str__(self) -> str:
+                return f"CustomItem({self.name})"
+
+        data = [
+            SimpleModel(name="pydantic", value=1),
+            SimpleDataclass(name="dataclass", count=2),
+            CustomItem("custom"),
+            "plain_string",
+            42,
+            True,
+            None,
+            Color.RED,
+        ]
+
+        result = serialize_json(data)
+        parsed = json.loads(result)
+
+        assert isinstance(parsed, list)
+        assert len(parsed) == 8
+        # Pydantic model
+        assert parsed[0]["name"] == "pydantic"
+        assert parsed[0]["value"] == 1
+        # Dataclass
+        assert parsed[1]["name"] == "dataclass"
+        assert parsed[1]["count"] == 2
+        # Normal class (str fallback)
+        assert parsed[2] == "CustomItem(custom)"
+        # Primitives
+        assert parsed[3] == "plain_string"
+        assert parsed[4] == 42
+        assert parsed[5] is True
+        assert parsed[6] is None
+        # Enum
+        assert parsed[7] == "red"
+
+    def test_list_of_lists_mixed(self) -> None:
+        """Test nested lists containing mixed types."""
+
+        class Widget:
+            def __init__(self, id: int) -> None:
+                self.id = id
+
+            def __str__(self) -> str:
+                return f"Widget({self.id})"
+
+        data = [
+            [SimpleModel(name="model1", value=1), SimpleModel(name="model2", value=2)],
+            [
+                SimpleDataclass(name="dc1", count=10),
+                SimpleDataclass(name="dc2", count=20),
+            ],
+            [Widget(1), Widget(2), Widget(3)],
+            ["string1", "string2"],
+            [1, 2, 3, 4],
+            [Color.RED, Color.GREEN, Priority.HIGH],
+            [True, False, None],
+        ]
+
+        result = serialize_json(data)
+        parsed = json.loads(result)
+
+        assert isinstance(parsed, list)
+        assert len(parsed) == 7
+
+        # First sublist: Pydantic models
+        assert len(parsed[0]) == 2
+        assert parsed[0][0]["name"] == "model1"
+        assert parsed[0][1]["value"] == 2
+
+        # Second sublist: Dataclasses
+        assert len(parsed[1]) == 2
+        assert parsed[1][0]["name"] == "dc1"
+        assert parsed[1][1]["count"] == 20
+
+        # Third sublist: Normal classes
+        assert len(parsed[2]) == 3
+        assert parsed[2][0] == "Widget(1)"
+        assert parsed[2][2] == "Widget(3)"
+
+        # Fourth sublist: Strings
+        assert parsed[3] == ["string1", "string2"]
+
+        # Fifth sublist: Integers
+        assert parsed[4] == [1, 2, 3, 4]
+
+        # Sixth sublist: Enums
+        assert parsed[5] == ["red", "green", 3]
+
+        # Seventh sublist: Booleans and None
+        assert parsed[6] == [True, False, None]
diff --git a/uv.lock b/uv.lock
index 855d460..75e1d3c 100644
--- a/uv.lock
+++ b/uv.lock
@@ -991,7 +991,7 @@ wheels = [
 
 [[package]]
 name = "uipath-core"
-version = "0.2.1"
+version = "0.2.2"
 source = { editable = "." }
 dependencies = [
     { name = "opentelemetry-instrumentation" },