diff --git a/tracetools_launch/tracetools_launch/actions/ld_preload.py b/tracetools_launch/tracetools_launch/actions/ld_preload.py
index 1aa4d77..b1f19da 100644
--- a/tracetools_launch/tracetools_launch/actions/ld_preload.py
+++ b/tracetools_launch/tracetools_launch/actions/ld_preload.py
@@ -39,7 +39,7 @@ class LdPreload(Action):
         """
         Create an LdPreload action.
 
-        :param lib_name: the name of the library
+        :param lib_name: the name of the library (e.g. 'lib.so')
         """
         super().__init__(**kwargs)
         self.__lib_name = lib_name