diff --git a/src/lmstudio/async_api.py b/src/lmstudio/async_api.py
index ad2c831..80851ff 100644
--- a/src/lmstudio/async_api.py
+++ b/src/lmstudio/async_api.py
@@ -35,7 +35,7 @@
     Chat,
     ChatHistoryDataDict,
     FileHandle,
-    _FileCacheInputType,
+    LocalFileInput,
     _LocalFileData,
 )
 from .json_api import (
@@ -590,8 +590,8 @@ async def _fetch_file_handle(self, file_data: _LocalFileData) -> FileHandle:
         return load_struct(handle, FileHandle)
 
     @sdk_public_api_async()
-    async def _add_temp_file(
-        self, src: _FileCacheInputType, name: str | None = None
+    async def prepare_file(
+        self, src: LocalFileInput, name: str | None = None
     ) -> FileHandle:
         """Add a file to the server."""
         # Private until LM Studio file handle support stabilizes
@@ -1502,12 +1502,12 @@ def repository(self) -> AsyncSessionRepository:
 
     # Convenience methods
     @sdk_public_api_async()
-    async def _add_temp_file(
-        self, src: _FileCacheInputType, name: str | None = None
+    async def prepare_file(
+        self, src: LocalFileInput, name: str | None = None
     ) -> FileHandle:
         """Add a file to the server."""
         # Private until LM Studio file handle support stabilizes
-        return await self._files._add_temp_file(src, name)
+        return await self._files.prepare_file(src, name)
 
     @sdk_public_api_async()
     async def list_downloaded_models(
diff --git a/src/lmstudio/history.py b/src/lmstudio/history.py
index 1913253..de2a58d 100644
--- a/src/lmstudio/history.py
+++ b/src/lmstudio/history.py
@@ -370,10 +370,8 @@ def add_user_message(
         self,
         content: UserMessageInput | Iterable[UserMessageInput],
         *,
+        files: Sequence[FileHandleInput] = (),
         images: Sequence[FileHandleInput] = (),
-        # Mark file parameters as private until LM Studio
-        # file handle support stabilizes
-        _files: Sequence[FileHandleInput] = (),
     ) -> UserMessage:
         """Add a new user message to the chat history."""
         # Accept both singular and multi-part user messages
@@ -383,10 +381,10 @@ def add_user_message(
         else:
             content_items = list(content)
         # Convert given local file information to file handles
+        if files:
+            content_items.extend(files)
         if images:
             content_items.extend(images)
-        if _files:
-            content_items.extend(_files)
         # Consecutive messages with the same role are not supported,
         # but multi-part user messages are valid (to allow for file
         # attachments), so just merge them
@@ -519,14 +517,16 @@ def add_tool_result(self, result: ToolCallResultInput) -> ToolResultMessage:
         return message
 
 
+LocalFileInput = BinaryIO | bytes | str | os.PathLike[str]
+
+
 # Private until file handle caching support is part of the published SDK API
-_FileCacheInputType = BinaryIO | bytes | str | os.PathLike[str]
 
 
-def _get_file_details(src: _FileCacheInputType) -> Tuple[str, bytes]:
+def _get_file_details(src: LocalFileInput) -> Tuple[str, bytes]:
     """Read file contents as binary data and generate a suitable default name."""
     if isinstance(src, bytes):
-        # We interpreter bytes as raw data, not a bytes filesystem path
+        # We process bytes as raw data, not a bytes filesystem path
         data = src
         name = str(uuid.uuid4())
     elif hasattr(src, "read"):
@@ -555,14 +555,13 @@ def _get_file_details(src: _FileCacheInputType) -> Tuple[str, bytes]:
 _FileHandleCacheKey: TypeAlias = tuple[str, _ContentHash]
 
 
-# Private until file handle caching support is part of the published SDK API
 class _LocalFileData:
     """Local file data to be added to a chat history."""
 
     name: str
     raw_data: bytes
 
-    def __init__(self, src: _FileCacheInputType, name: str | None = None) -> None:
+    def __init__(self, src: LocalFileInput, name: str | None = None) -> None:
         default_name, raw_data = _get_file_details(src)
         self.name = name or default_name
         self.raw_data = raw_data
@@ -594,7 +593,7 @@ def __init__(self) -> None:
 
     @sdk_public_api()
     def _get_file_handle(
-        self, src: _FileCacheInputType, name: str | None = None
+        self, src: LocalFileInput, name: str | None = None
     ) -> FileHandle:
         file_data = _LocalFileData(src, name)
         cache_key = file_data._get_cache_key()
diff --git a/src/lmstudio/sync_api.py b/src/lmstudio/sync_api.py
index 358eda0..a1ec696 100644
--- a/src/lmstudio/sync_api.py
+++ b/src/lmstudio/sync_api.py
@@ -53,7 +53,7 @@
     Chat,
     ChatHistoryDataDict,
     FileHandle,
-    _FileCacheInputType,
+    LocalFileInput,
     _LocalFileData,
     ToolCallRequest,
 )
@@ -765,9 +765,7 @@ def _fetch_file_handle(self, file_data: _LocalFileData) -> FileHandle:
         return load_struct(handle, FileHandle)
 
     @sdk_public_api()
-    def _add_temp_file(
-        self, src: _FileCacheInputType, name: str | None = None
-    ) -> FileHandle:
+    def prepare_file(self, src: LocalFileInput, name: str | None = None) -> FileHandle:
         """Add a file to the server."""
         # Private until LM Studio file handle support stabilizes
         file_data = _LocalFileData(src, name)
@@ -1820,12 +1818,10 @@ def repository(self) -> SyncSessionRepository:
 
     # Convenience methods
     @sdk_public_api()
-    def _add_temp_file(
-        self, src: _FileCacheInputType, name: str | None = None
-    ) -> FileHandle:
+    def prepare_file(self, src: LocalFileInput, name: str | None = None) -> FileHandle:
         """Add a file to the server."""
         # Private until LM Studio file handle support stabilizes
-        return self._files._add_temp_file(src, name)
+        return self._files.prepare_file(src, name)
 
     @sdk_public_api()
     def list_downloaded_models(
@@ -1895,10 +1891,10 @@ def embedding_model(
 
 
 @sdk_public_api()
-def _add_temp_file(src: _FileCacheInputType, name: str | None = None) -> FileHandle:
+def prepare_file(src: LocalFileInput, name: str | None = None) -> FileHandle:
     """Add a file to the server using the default global client."""
     # Private until LM Studio file handle support stabilizes
-    return get_default_client()._add_temp_file(src, name)
+    return get_default_client().prepare_file(src, name)
 
 
 @sdk_public_api()
diff --git a/tests/async/test_images_async.py b/tests/async/test_images_async.py
index 69f178b..d9b6221 100644
--- a/tests/async/test_images_async.py
+++ b/tests/async/test_images_async.py
@@ -24,7 +24,7 @@ async def test_upload_from_pathlike_async(caplog: LogCap) -> None:
     caplog.set_level(logging.DEBUG)
     async with AsyncClient() as client:
         session = client._files
-        file = await session._add_temp_file(IMAGE_FILEPATH)
+        file = await session.prepare_file(IMAGE_FILEPATH)
         assert file
         assert isinstance(file, FileHandle)
         logging.info(f"Uploaded file: {file}")
@@ -37,7 +37,7 @@ async def test_upload_from_file_obj_async(caplog: LogCap) -> None:
     async with AsyncClient() as client:
         session = client._files
         with open(IMAGE_FILEPATH, "rb") as f:
-            file = await session._add_temp_file(f)
+            file = await session.prepare_file(f)
         assert file
         assert isinstance(file, FileHandle)
         logging.info(f"Uploaded file: {file}")
@@ -50,7 +50,7 @@ async def test_upload_from_bytesio_async(caplog: LogCap) -> None:
     async with AsyncClient() as client:
         session = client._files
         with open(IMAGE_FILEPATH, "rb") as f:
-            file = await session._add_temp_file(BytesIO(f.read()))
+            file = await session.prepare_file(BytesIO(f.read()))
         assert file
         assert isinstance(file, FileHandle)
         logging.info(f"Uploaded file: {file}")
@@ -64,7 +64,7 @@ async def test_vlm_predict_async(caplog: LogCap) -> None:
     caplog.set_level(logging.DEBUG)
     model_id = EXPECTED_VLM_ID
     async with AsyncClient() as client:
-        file_handle = await client._files._add_temp_file(IMAGE_FILEPATH)
+        file_handle = await client._files.prepare_file(IMAGE_FILEPATH)
         history = Chat()
         history.add_user_message((prompt, file_handle))
         vlm = await client.llm.model(model_id)
@@ -84,7 +84,7 @@ async def test_non_vlm_predict_async(caplog: LogCap) -> None:
     caplog.set_level(logging.DEBUG)
     model_id = "hugging-quants/llama-3.2-1b-instruct"
     async with AsyncClient() as client:
-        file_handle = await client._files._add_temp_file(IMAGE_FILEPATH)
+        file_handle = await client._files.prepare_file(IMAGE_FILEPATH)
         history = Chat()
         history.add_user_message((prompt, file_handle))
         llm = await client.llm.model(model_id)
@@ -101,7 +101,7 @@ async def test_vlm_predict_image_param_async(caplog: LogCap) -> None:
     caplog.set_level(logging.DEBUG)
     model_id = EXPECTED_VLM_ID
     async with AsyncClient() as client:
-        file_handle = await client._files._add_temp_file(IMAGE_FILEPATH)
+        file_handle = await client._files.prepare_file(IMAGE_FILEPATH)
         history = Chat()
         history.add_user_message(prompt, images=[file_handle])
         vlm = await client.llm.model(model_id)
@@ -121,7 +121,7 @@ async def test_non_vlm_predict_image_param_async(caplog: LogCap) -> None:
     caplog.set_level(logging.DEBUG)
     model_id = "hugging-quants/llama-3.2-1b-instruct"
     async with AsyncClient() as client:
-        file_handle = await client._files._add_temp_file(IMAGE_FILEPATH)
+        file_handle = await client._files.prepare_file(IMAGE_FILEPATH)
         history = Chat()
         history.add_user_message(prompt, images=[file_handle])
         llm = await client.llm.model(model_id)
diff --git a/tests/sync/test_images_sync.py b/tests/sync/test_images_sync.py
index 69298a7..845074d 100644
--- a/tests/sync/test_images_sync.py
+++ b/tests/sync/test_images_sync.py
@@ -30,7 +30,7 @@ def test_upload_from_pathlike_sync(caplog: LogCap) -> None:
     caplog.set_level(logging.DEBUG)
     with Client() as client:
         session = client._files
-        file = session._add_temp_file(IMAGE_FILEPATH)
+        file = session.prepare_file(IMAGE_FILEPATH)
         assert file
         assert isinstance(file, FileHandle)
         logging.info(f"Uploaded file: {file}")
@@ -42,7 +42,7 @@ def test_upload_from_file_obj_sync(caplog: LogCap) -> None:
     with Client() as client:
         session = client._files
         with open(IMAGE_FILEPATH, "rb") as f:
-            file = session._add_temp_file(f)
+            file = session.prepare_file(f)
         assert file
         assert isinstance(file, FileHandle)
         logging.info(f"Uploaded file: {file}")
@@ -54,7 +54,7 @@ def test_upload_from_bytesio_sync(caplog: LogCap) -> None:
     with Client() as client:
         session = client._files
         with open(IMAGE_FILEPATH, "rb") as f:
-            file = session._add_temp_file(BytesIO(f.read()))
+            file = session.prepare_file(BytesIO(f.read()))
         assert file
         assert isinstance(file, FileHandle)
         logging.info(f"Uploaded file: {file}")
@@ -67,7 +67,7 @@ def test_vlm_predict_sync(caplog: LogCap) -> None:
     caplog.set_level(logging.DEBUG)
     model_id = EXPECTED_VLM_ID
     with Client() as client:
-        file_handle = client._files._add_temp_file(IMAGE_FILEPATH)
+        file_handle = client._files.prepare_file(IMAGE_FILEPATH)
         history = Chat()
         history.add_user_message((prompt, file_handle))
         vlm = client.llm.model(model_id)
@@ -86,7 +86,7 @@ def test_non_vlm_predict_sync(caplog: LogCap) -> None:
     caplog.set_level(logging.DEBUG)
     model_id = "hugging-quants/llama-3.2-1b-instruct"
     with Client() as client:
-        file_handle = client._files._add_temp_file(IMAGE_FILEPATH)
+        file_handle = client._files.prepare_file(IMAGE_FILEPATH)
         history = Chat()
         history.add_user_message((prompt, file_handle))
         llm = client.llm.model(model_id)
@@ -102,7 +102,7 @@ def test_vlm_predict_image_param_sync(caplog: LogCap) -> None:
     caplog.set_level(logging.DEBUG)
     model_id = EXPECTED_VLM_ID
     with Client() as client:
-        file_handle = client._files._add_temp_file(IMAGE_FILEPATH)
+        file_handle = client._files.prepare_file(IMAGE_FILEPATH)
         history = Chat()
         history.add_user_message(prompt, images=[file_handle])
         vlm = client.llm.model(model_id)
@@ -121,7 +121,7 @@ def test_non_vlm_predict_image_param_sync(caplog: LogCap) -> None:
     caplog.set_level(logging.DEBUG)
     model_id = "hugging-quants/llama-3.2-1b-instruct"
     with Client() as client:
-        file_handle = client._files._add_temp_file(IMAGE_FILEPATH)
+        file_handle = client._files.prepare_file(IMAGE_FILEPATH)
         history = Chat()
         history.add_user_message(prompt, images=[file_handle])
         llm = client.llm.model(model_id)
diff --git a/tests/test_convenience_api.py b/tests/test_convenience_api.py
index e943bf1..77b3376 100644
--- a/tests/test_convenience_api.py
+++ b/tests/test_convenience_api.py
@@ -47,11 +47,11 @@ def test_embedding_specific() -> None:
 
 
 @pytest.mark.lmstudio
-def test_add_temp_file() -> None:
+def test_prepare_file() -> None:
     # API is private until LM Studio file handle support stabilizes
     name = "example-file"
     raw_data = b"raw data"
-    file_handle = lms.sync_api._add_temp_file(raw_data, name)
+    file_handle = lms.sync_api.prepare_file(raw_data, name)
     assert file_handle.name == name
     assert file_handle.size_bytes == len(raw_data)
 
diff --git a/tests/test_history.py b/tests/test_history.py
index bb98c2f..c73074c 100644
--- a/tests/test_history.py
+++ b/tests/test_history.py
@@ -15,7 +15,7 @@
     AnyChatMessageDict,
     ChatHistoryData,
     ChatHistoryDataDict,
-    _FileCacheInputType,
+    LocalFileInput,
     FileHandle,
     _FileHandleCache,
     FileHandleDict,
@@ -492,7 +492,7 @@ def _make_local_file_cache() -> tuple[_FileHandleCache, list[FileHandle], int]:
     # * files with different names are looked up under both names
     cache = _FileHandleCache()
     num_unique_files = 3
-    files_to_cache: list[tuple[_FileCacheInputType, str | None]] = [
+    files_to_cache: list[tuple[LocalFileInput, str | None]] = [
         (b"raw binary data", "raw-binary.txt"),
         (b"raw binary data", "raw-binary.txt"),
         (IMAGE_FILEPATH, None),
@@ -589,13 +589,8 @@ def test_invalid_local_file() -> None:
                 "text": "What do you make of this?",
                 "type": "text",
             },
-            {
-                "fileType": "image",
-                "identifier": "some-image",
-                "name": "lemmy.png",
-                "sizeBytes": 41812,
-                "type": "file",
-            },
+            # Implementation attaches the prepared file handles
+            # before it attaches the prepared image handles
             {
                 "fileType": "text/plain",
                 "identifier": "some-file",
@@ -603,6 +598,13 @@ def test_invalid_local_file() -> None:
                 "sizeBytes": 100,
                 "type": "file",
             },
+            {
+                "fileType": "image",
+                "identifier": "some-image",
+                "name": "lemmy.png",
+                "sizeBytes": 41812,
+                "type": "file",
+            },
         ],
         "role": "user",
     },
@@ -621,7 +623,7 @@ def test_user_message_attachments() -> None:
     chat.add_user_message(
         "What do you make of this?",
         images=[INPUT_IMAGE_HANDLE],
-        _files=[INPUT_FILE_HANDLE],
+        files=[INPUT_FILE_HANDLE],
     )
     history = chat._get_history()
     assert history["messages"] == EXPECTED_USER_ATTACHMENT_MESSAGES