Python: Fix HTML tags silently dropped in prompt templates

python/semantic_kernel/contents/chat_history.py

@@ -350,11 +350,23 @@ def from_rendered_prompt(cls: type[_T], rendered_prompt: str) -> _T:
         for item in xml_prompt:
             if item.tag == CHAT_MESSAGE_CONTENT_TAG:
                 messages.append(ChatMessageContent.from_element(item))
+                if item.tail and item.tail.strip():
+                    messages.append(ChatMessageContent(role=AuthorRole.USER, content=unescape(item.tail.strip())))
             elif item.tag == CHAT_HISTORY_TAG:
                 for message in item:
                     messages.append(ChatMessageContent.from_element(message))
-            if item.tail and item.tail.strip():
-                messages.append(ChatMessageContent(role=AuthorRole.USER, content=unescape(item.tail.strip())))
+                if item.tail and item.tail.strip():
+                    messages.append(ChatMessageContent(role=AuthorRole.USER, content=unescape(item.tail.strip())))
+            else:
+                # Unrecognized XML element (e.g. HTML tags like <p>, <div>, etc.)
+                # Serialize it back to string and append to the last message's content
+                # or create a new user message, so that HTML tags in prompts are preserved.
+                raw = tostring(item, encoding="unicode", short_empty_elements=False)
+                tail = item.tail or ""
+                if messages:
+                    messages[-1].content = (messages[-1].content or "") + raw + tail
+                else:
+                    messages.append(ChatMessageContent(role=AuthorRole.USER, content=raw + tail))
         if len(messages) == 1 and messages[0].role == AuthorRole.SYSTEM:
             messages[0].role = AuthorRole.USER
         return cls(messages=messages)

python/tests/unit/contents/test_chat_history.py

@@ -628,3 +628,42 @@ def __str__(self) -> str:
     ])
     chat_history.add_tool_message([FunctionResultContent(id="test1", result=custom_result)])
     assert "CustomResultTestValue" in chat_history.serialize()
+
+
+def test_chat_history_from_rendered_prompt_with_html_tags():
+    """Test that HTML tags like <p> in prompts are preserved and not silently dropped.
+
+    Regression test for https://github.com/microsoft/semantic-kernel/issues/13632
+    """
+    rendered = 'Translate following message from English language into the Spanish language - "<p>What is your name?</p>"'
+    chat_history = ChatHistory.from_rendered_prompt(rendered)
+    assert len(chat_history.messages) == 1
+    assert chat_history.messages[0].role == AuthorRole.USER
+    assert "<p>" in chat_history.messages[0].content
+    assert "What is your name?" in chat_history.messages[0].content
+    assert "</p>" in chat_history.messages[0].content
+
+
+def test_chat_history_from_rendered_prompt_with_multiple_html_tags():
+    """Test that multiple HTML tags in prompts are preserved."""
+    rendered = "Here is <b>bold</b> and <i>italic</i> text"
+    chat_history = ChatHistory.from_rendered_prompt(rendered)
+    assert len(chat_history.messages) == 1
+    assert chat_history.messages[0].role == AuthorRole.USER
+    assert "<b>bold</b>" in chat_history.messages[0].content
+    assert "<i>italic</i>" in chat_history.messages[0].content
+
+
+def test_chat_history_from_rendered_prompt_html_with_message_tags():
+    """Test that HTML tags work alongside recognized message tags."""
+    rendered = '<message role="system">You are helpful</message>Translate: <p>Hello</p> please'
+    chat_history = ChatHistory.from_rendered_prompt(rendered)
+    assert chat_history.messages[0].role == AuthorRole.SYSTEM
+    assert chat_history.messages[0].content == "You are helpful"
+    # The HTML content and surrounding text should be preserved
+    found_html = False
+    for msg in chat_history.messages[1:]:
+        if "<p>" in (msg.content or "") and "Hello" in (msg.content or ""):
+            found_html = True
+            break
+    assert found_html, f"HTML tag <p>Hello</p> not found in messages: {[m.content for m in chat_history.messages]}"