diff --git a/src/usage.rs b/src/usage.rs
index 6c878c4..3b36150 100644
--- a/src/usage.rs
+++ b/src/usage.rs
@@ -186,6 +186,8 @@ pub fn extract_usage(config: &Config, path: &Path, cmd: &str) -> Usage {
         command = command.arg(Arg::new("args").trailing_var_arg(true).num_args(..).allow_hyphen_values(true));
     }
 
+    // both command and error are returned because an invalid usage string doesn't prevent the
+    // command from being invoked, but it should be reported to the user
     return Usage::new(command, error);
 }