diff --git a/crates/proc-macro-srv-cli/src/main.rs b/crates/proc-macro-srv-cli/src/main.rs
index ea16cfff4b99..0f23a7daafa2 100644
--- a/crates/proc-macro-srv-cli/src/main.rs
+++ b/crates/proc-macro-srv-cli/src/main.rs
@@ -1,3 +1,5 @@
+//! A standalone binary for `proc-macro-srv`.
+
 use proc_macro_srv::cli;
 
 fn main() {