diff --git a/README.md b/README.md
index f480d2d4..cf864f39 100644
--- a/README.md
+++ b/README.md
@@ -136,6 +136,25 @@ for devbox in first_page.devboxes:
 # Remove `await` for non-async usage.
 ```
 
+## File uploads
+
+Request parameters that correspond to file uploads can be passed as `bytes`, a [`PathLike`](https://docs.python.org/3/library/os.html#os.PathLike) instance or a tuple of `(filename, contents, media type)`.
+
+```python
+from pathlib import Path
+from runloop_api_client import Runloop
+
+client = Runloop()
+
+client.devboxes.upload_file(
+    id="id",
+    path="path",
+    file=Path("/path/to/file"),
+)
+```
+
+The async client uses the exact same interface. If you pass a [`PathLike`](https://docs.python.org/3/library/os.html#os.PathLike) instance, the file contents will be read asynchronously automatically.
+
 ## Handling errors
 
 When the library is unable to connect to the API (for example, due to network connection problems or a timeout), a subclass of `runloop_api_client.APIConnectionError` is raised.
diff --git a/src/runloop_api_client/_files.py b/src/runloop_api_client/_files.py
index 715cc207..1b182511 100644
--- a/src/runloop_api_client/_files.py
+++ b/src/runloop_api_client/_files.py
@@ -34,7 +34,7 @@ def assert_is_file_content(obj: object, *, key: str | None = None) -> None:
     if not is_file_content(obj):
         prefix = f"Expected entry at `{key}`" if key is not None else f"Expected file input `{obj!r}`"
         raise RuntimeError(
-            f"{prefix} to be bytes, an io.IOBase instance, PathLike or a tuple but received {type(obj)} instead."
+            f"{prefix} to be bytes, an io.IOBase instance, PathLike or a tuple but received {type(obj)} instead. See https://github.com/runloopai/api-client-python/tree/main#file-uploads"
         ) from None