diff --git a/wgpu/src/lib.rs b/wgpu/src/lib.rs
index 1c26225c11..448c826dfe 100644
--- a/wgpu/src/lib.rs
+++ b/wgpu/src/lib.rs
@@ -885,6 +885,8 @@ pub enum BindingResource<'a> {
 }
 
 /// Operation to perform to the output attachment at the start of a renderpass.
+///
+/// The render target must be cleared at least once before it's content be loaded.
 #[derive(Copy, Clone, Debug, Hash, Eq, PartialEq)]
 #[cfg_attr(feature = "trace", derive(Serialize))]
 #[cfg_attr(feature = "replay", derive(Deserialize))]