diff --git a/src/fastmcp/tools/tool.py b/src/fastmcp/tools/tool.py
index a4b20d5bb..d1fd03f64 100644
--- a/src/fastmcp/tools/tool.py
+++ b/src/fastmcp/tools/tool.py
@@ -546,13 +546,12 @@ def _convert_to_content(
 
     # If any item is a ContentBlock, convert non-ContentBlock items to TextContent
     # without aggregating them
-    if any(isinstance(item, ContentBlock) for item in result):
+    if any(isinstance(item, ContentBlock | Image | Audio | File) for item in result):
         return [
             _convert_to_single_content_block(item, serializer)
             if not isinstance(item, ContentBlock)
             else item
             for item in result
         ]
-
     # If none of the items are ContentBlocks, aggregate all items into a single TextContent
     return [TextContent(type="text", text=_serialize_with_fallback(result, serializer))]
diff --git a/tests/tools/test_tool.py b/tests/tools/test_tool.py
index ac6a78041..dc815b5bf 100644
--- a/tests/tools/test_tool.py
+++ b/tests/tools/test_tool.py
@@ -1087,6 +1087,9 @@ class TestConvertResultToContent:
         converted = _convert_to_content(result)
         assert converted == expected
 
+        converted = _convert_to_content([result, result])
+        assert converted == expected * 2
+
     def test_convert_mixed_content(self):
         result = [
             "hello",