diff --git a/dashscope/finetune/reinforcement/component/observability/genai/_core.py b/dashscope/finetune/reinforcement/component/observability/genai/_core.py
index 3c0fe794..08091c6c 100644
--- a/dashscope/finetune/reinforcement/component/observability/genai/_core.py
+++ b/dashscope/finetune/reinforcement/component/observability/genai/_core.py
@@ -59,12 +59,19 @@
         ToolCall,
     )
 
+    try:  # Reasoning part exists in loongsuite-util-genai >= 0.4.0.
+        from opentelemetry.util.genai import types as _genai_types
+
+        Reasoning = getattr(_genai_types, "Reasoning", None)
+    except ImportError:  # pragma: no cover - older genai util
+        Reasoning = None  # type: ignore[assignment,misc]
+
     GENAI_AVAILABLE = True
 except ImportError:  # pragma: no cover
     get_extended_telemetry_handler = None  # type: ignore[assignment]
     ExecuteToolInvocation = None  # type: ignore[assignment]
     # type: ignore[assignment]
-    InputMessage = OutputMessage = Text = ToolCall = None
+    InputMessage = OutputMessage = Reasoning = Text = ToolCall = None
     GENAI_AVAILABLE = False
 
 _logger = logging.getLogger(__name__)
diff --git a/dashscope/finetune/reinforcement/component/observability/genai/messages.py b/dashscope/finetune/reinforcement/component/observability/genai/messages.py
index 44abe0f5..ab09826a 100644
--- a/dashscope/finetune/reinforcement/component/observability/genai/messages.py
+++ b/dashscope/finetune/reinforcement/component/observability/genai/messages.py
@@ -454,6 +454,23 @@ def openai_chat_messages_to_input_messages(
     return out
 
 
+def _reasoning_part(msg: Any) -> Any:
+    """Return a ``Reasoning`` part when the message carries thinking content.
+
+    ``None`` when the GenAI util is unavailable or the field is absent, so
+    callers keep their existing part ordering logic.
+    """
+    if _core.Reasoning is None or msg is None:
+        return None
+    if isinstance(msg, Dict):
+        reasoning = msg.get("reasoning_content")
+    else:
+        reasoning = getattr(msg, "reasoning_content", None)
+    if not isinstance(reasoning, str) or not reasoning:
+        return None
+    return _core.Reasoning(content=reasoning)
+
+
 def openai_completion_to_output_messages(  # pylint: disable=too-many-branches
     completion: Any,
 ) -> List[Any]:
@@ -513,6 +530,9 @@ def openai_completion_to_output_messages(  # pylint: disable=too-many-branches
                 tool_calls = getattr(msg, "tool_calls", None)
             if tool_calls:
                 parts.extend(tool_calls_to_parts(tool_calls))
+            reasoning_part = _reasoning_part(msg)
+            if reasoning_part is not None:
+                parts.insert(0, reasoning_part)
         if not parts:
             parts.append(_core.Text(content=""))
         result.append(
@@ -561,6 +581,9 @@ def dashscope_response_to_output_messages(response: Any) -> List[Any]:
                     )
                 if tool_calls:
                     parts.extend(tool_calls_to_parts(tool_calls))
+                reasoning_part = _reasoning_part(msg)
+                if reasoning_part is not None:
+                    parts.insert(0, reasoning_part)
             if not parts:
                 parts.append(_core.Text(content=""))
             result.append(
diff --git a/dashscope/finetune/reinforcement/component/observability/genai/tools.py b/dashscope/finetune/reinforcement/component/observability/genai/tools.py
index c0d48b85..bdf20b9a 100644
--- a/dashscope/finetune/reinforcement/component/observability/genai/tools.py
+++ b/dashscope/finetune/reinforcement/component/observability/genai/tools.py
@@ -535,7 +535,7 @@ def _bind_tool_arguments(
         bound = sig.bind_partial(*args, **kwargs)
         bound.apply_defaults()
         param_names = list(sig.parameters.keys())
-        raw = Dict(bound.arguments)
+        raw = dict(bound.arguments)
         if param_names and param_names[0] in ("self", "cls"):
             raw = {k: v for k, v in raw.items() if k not in ("self", "cls")}
         return _json_serializable(raw)