diff --git a/python/packages/chatkit/agent_framework_chatkit/_converter.py b/python/packages/chatkit/agent_framework_chatkit/_converter.py
index c4fe24670f2..88f75598b5b 100644
--- a/python/packages/chatkit/agent_framework_chatkit/_converter.py
+++ b/python/packages/chatkit/agent_framework_chatkit/_converter.py
@@ -81,33 +81,40 @@ async def user_message_to_input(
         """
         # Extract text content from the user message
         text_content = ""
+        contents: list[Content] = []
+
+        def append_text_content() -> None:
+            nonlocal text_content
+            if stripped_text := text_content.strip():
+                contents.append(Content.from_text(text=stripped_text))
+            text_content = ""
+
         if item.content:
             for content_part in item.content:
                 if isinstance(content_part, UserMessageTextContent):
                     text_content += content_part.text
+                elif isinstance(content_part, UserMessageTagContent):
+                    tag_content = self.tag_to_message_content(content_part)
+                    if tag_content.type == "text":
+                        text_content += tag_content.text or ""
+                    else:
+                        append_text_content()
+                        contents.append(tag_content)
+
+        append_text_content()
 
-        # Convert attachments to Content
-        data_contents: list[Content] = []
+        # Append attachments after the ordered message content.
         if item.attachments:
             for attachment in item.attachments:
                 content = await self.attachment_to_message_content(attachment)
                 if content is not None:
-                    data_contents.append(content)
+                    contents.append(content)
 
         # Create the message with text and attachments
-        if not text_content.strip() and not data_contents:
+        if not contents:
             return None
 
-        # If only text and no attachments, use text parameter for simplicity
-        if text_content.strip() and not data_contents:
-            user_message = Message(role="user", contents=[text_content.strip()])
-        else:
-            # Build contents list with both text and attachments
-            contents: list[Content] = []
-            if text_content.strip():
-                contents.append(Content.from_text(text=text_content.strip()))
-            contents.extend(data_contents)
-            user_message = Message(role="user", contents=contents)
+        user_message = Message(role="user", contents=contents)
 
         # Handle quoted text if this is the last message
         messages = [user_message]
diff --git a/python/packages/chatkit/tests/test_converter.py b/python/packages/chatkit/tests/test_converter.py
index 730fd6ec6e1..a0fb0244549 100644
--- a/python/packages/chatkit/tests/test_converter.py
+++ b/python/packages/chatkit/tests/test_converter.py
@@ -7,8 +7,8 @@
 from unittest.mock import Mock
 
 import pytest
-from agent_framework import Message
-from chatkit.types import InferenceOptions, UserMessageTextContent
+from agent_framework import Content, Message
+from chatkit.types import InferenceOptions, UserMessageTagContent, UserMessageTextContent
 from pydantic import AnyUrl
 
 from agent_framework_chatkit import ThreadItemConverter, simple_to_agent_input
@@ -110,6 +110,98 @@ async def test_to_agent_input_multiple_content_parts(self, converter):
         assert len(result) == 1
         assert result[0].text == "Hello world!"
 
+    async def test_to_agent_input_keeps_tag_inline_with_text(self, converter):
+        """Test converting user message tags in their original text position."""
+        from chatkit.types import UserMessageItem
+
+        input_item = UserMessageItem(
+            id="msg_tag",
+            thread_id="thread_1",
+            created_at=datetime.now(),
+            type="user_message",
+            content=[
+                UserMessageTextContent(text="Ask "),
+                UserMessageTagContent(
+                    type="input_tag",
+                    id="tag_1",
+                    text="john",
+                    data={"name": "John Doe"},
+                    interactive=False,
+                ),
+                UserMessageTextContent(text=" about the report."),
+            ],
+            attachments=[],
+            inference_options=InferenceOptions(),
+        )
+
+        result = await converter.to_agent_input(input_item)
+
+        assert len(result) == 1
+        assert result[0].text == "Ask <TAG>Name:John Doe</TAG> about the report."
+
+    async def test_to_agent_input_keeps_tag_only_message(self, converter):
+        """Test that a user message containing only a tag is not discarded."""
+        from chatkit.types import UserMessageItem
+
+        input_item = UserMessageItem(
+            id="msg_tag_only",
+            thread_id="thread_1",
+            created_at=datetime.now(),
+            type="user_message",
+            content=[
+                UserMessageTagContent(
+                    type="input_tag",
+                    id="tag_1",
+                    text="john",
+                    data={"name": "John Doe"},
+                    interactive=False,
+                )
+            ],
+            attachments=[],
+            inference_options=InferenceOptions(),
+        )
+
+        result = await converter.to_agent_input(input_item)
+
+        assert len(result) == 1
+        assert result[0].text == "<TAG>Name:John Doe</TAG>"
+
+    async def test_to_agent_input_preserves_non_text_tag_position(self):
+        """Test that custom non-text tag conversions remain between adjacent text."""
+        from chatkit.types import UserMessageItem
+
+        class UriTagConverter(ThreadItemConverter):
+            def tag_to_message_content(self, tag: UserMessageTagContent) -> Content:
+                return Content.from_uri(uri=f"https://example.com/users/{tag.text}", media_type="text/html")
+
+        input_item = UserMessageItem(
+            id="msg_uri_tag",
+            thread_id="thread_1",
+            created_at=datetime.now(),
+            type="user_message",
+            content=[
+                UserMessageTextContent(text="Ask"),
+                UserMessageTagContent(
+                    type="input_tag",
+                    id="tag_1",
+                    text="john",
+                    data={"name": "John Doe"},
+                    interactive=False,
+                ),
+                UserMessageTextContent(text="about the report."),
+            ],
+            attachments=[],
+            inference_options=InferenceOptions(),
+        )
+
+        result = await UriTagConverter().to_agent_input(input_item)
+
+        assert len(result) == 1
+        assert [content.type for content in result[0].contents] == ["text", "uri", "text"]
+        assert result[0].contents[0].text == "Ask"
+        assert result[0].contents[1].uri == "https://example.com/users/john"
+        assert result[0].contents[2].text == "about the report."
+
     async def test_to_agent_input_with_quoted_text_for_last_message(self, converter):
         """Test quoted text is prepended as context for the last user message."""
         from chatkit.types import UserMessageItem