diff --git a/crates/iceberg/src/lib.rs b/crates/iceberg/src/lib.rs
index 4e346460f5..25b99ab1a7 100644
--- a/crates/iceberg/src/lib.rs
+++ b/crates/iceberg/src/lib.rs
@@ -61,6 +61,7 @@
 //! ```
 
 #![deny(missing_docs)]
+// Warm-cache probe: root-crate touch forces the workspace rebuild path.
 
 #[macro_use]
 extern crate derive_builder;