diff --git a/openhands-sdk/openhands/sdk/event/llm_convertible/action.py b/openhands-sdk/openhands/sdk/event/llm_convertible/action.py
index d2bd9ada3..0bd03cbb1 100644
--- a/openhands-sdk/openhands/sdk/event/llm_convertible/action.py
+++ b/openhands-sdk/openhands/sdk/event/llm_convertible/action.py
@@ -5,6 +5,7 @@
 
 from openhands.sdk.event.base import N_CHAR_PREVIEW, EventID, LLMConvertibleEvent
 from openhands.sdk.event.types import SourceType, ToolCallID
+from openhands.sdk.event.utils import render_responses_reasoning_block
 from openhands.sdk.llm import (
     Message,
     MessageToolCall,
@@ -87,15 +88,9 @@ def visualize(self) -> Text:
             content.append("\n\n")
 
         # Responses API reasoning (plaintext only; never render encrypted_content)
-        reasoning_item = self.responses_reasoning_item
-        if reasoning_item is not None:
-            content.append("Reasoning:\n", style="bold")
-            if reasoning_item.summary:
-                for s in reasoning_item.summary:
-                    content.append(f"- {s}\n")
-            if reasoning_item.content:
-                for b in reasoning_item.content:
-                    content.append(f"{b}\n")
+        reasoning_text = render_responses_reasoning_block(self.responses_reasoning_item)
+        if reasoning_text:
+            content.append(reasoning_text)
 
         # Display action information using action's visualize method
         if self.action:
diff --git a/openhands-sdk/openhands/sdk/event/llm_convertible/message.py b/openhands-sdk/openhands/sdk/event/llm_convertible/message.py
index c71b27ac2..d6126dfea 100644
--- a/openhands-sdk/openhands/sdk/event/llm_convertible/message.py
+++ b/openhands-sdk/openhands/sdk/event/llm_convertible/message.py
@@ -7,6 +7,7 @@
 
 from openhands.sdk.event.base import N_CHAR_PREVIEW, EventID, LLMConvertibleEvent
 from openhands.sdk.event.types import SourceType
+from openhands.sdk.event.utils import render_responses_reasoning_block
 from openhands.sdk.llm import (
     ImageContent,
     Message,
@@ -74,15 +75,11 @@ def visualize(self) -> Text:
             content.append("[no text content]")
 
         # Responses API reasoning (plaintext only; never render encrypted_content)
-        reasoning_item = self.llm_message.responses_reasoning_item
-        if reasoning_item is not None:
-            content.append("\n\nReasoning:\n", style="bold")
-            if reasoning_item.summary:
-                for s in reasoning_item.summary:
-                    content.append(f"- {s}\n")
-            if reasoning_item.content:
-                for b in reasoning_item.content:
-                    content.append(f"{b}\n")
+        reasoning_text = render_responses_reasoning_block(
+            self.llm_message.responses_reasoning_item, leading_newlines=True
+        )
+        if reasoning_text:
+            content.append(reasoning_text)
 
         # Add skill information if present
         if self.activated_skills:
diff --git a/openhands-sdk/openhands/sdk/event/utils.py b/openhands-sdk/openhands/sdk/event/utils.py
new file mode 100644
index 000000000..683bd064c
--- /dev/null
+++ b/openhands-sdk/openhands/sdk/event/utils.py
@@ -0,0 +1,37 @@
+from rich.text import Text
+
+from openhands.sdk.llm import ReasoningItemModel
+
+
+def render_responses_reasoning_block(
+    reasoning_item: ReasoningItemModel | None,
+    *,
+    leading_newlines: bool = False,
+) -> Text | None:
+    """Build a Rich Text block for Responses API reasoning.
+
+    Only renders when either summary or content is present. Returns None
+    when there is nothing to render.
+    """
+    if reasoning_item is None:
+        return None
+
+    has_summary = bool(reasoning_item.summary)
+    has_content = bool(reasoning_item.content)
+    if not (has_summary or has_content):
+        return None
+
+    t = Text()
+    if leading_newlines:
+        t.append("\n\n")
+    t.append("Reasoning:\n", style="bold")
+
+    if has_summary:
+        for s in list(reasoning_item.summary or []):
+            t.append(f"- {s}\n")
+
+    if has_content:
+        for b in list(reasoning_item.content or []):
+            t.append(f"{b}\n")
+
+    return t
diff --git a/tests/sdk/conversation/test_visualizer.py b/tests/sdk/conversation/test_visualizer.py
index d878be3cb..94413bc34 100644
--- a/tests/sdk/conversation/test_visualizer.py
+++ b/tests/sdk/conversation/test_visualizer.py
@@ -138,6 +138,17 @@ def test_action_event_visualize():
 
     result = event.visualize
     assert isinstance(result, Text)
+    # If no Responses reasoning is present, Reasoning: should not be printed
+    event_no_reason = ActionEvent(
+        thought=[TextContent(text="I need to list files")],
+        action=action,
+        tool_name="terminal",
+        tool_call_id="call_124",
+        tool_call=create_tool_call("call_124", "terminal", {"command": "ls -la"}),
+        llm_response_id="response_457",
+    )
+    text_no_reason = event_no_reason.visualize.plain
+    assert "Reasoning:" not in text_no_reason
 
     text_content = result.plain
     assert "Reasoning:" in text_content