diff --git a/include/modules/custom.hpp b/include/modules/custom.hpp
index a00faaa5..40406e96 100644
--- a/include/modules/custom.hpp
+++ b/include/modules/custom.hpp
@@ -42,7 +42,7 @@ class Custom : public ALabel {
   int pid_;
   util::command::res output_;
   util::JsonParser parser_;
-  int signal_;  // Cached signal value to avoid JSON access in signal handler
+  int signal_;  // Cached signal value (-1 = disabled) to avoid JSON access in signal handler
 
   util::SleeperThread thread_;
 };
diff --git a/include/modules/image.hpp b/include/modules/image.hpp
index e31de0fc..40be856a 100644
--- a/include/modules/image.hpp
+++ b/include/modules/image.hpp
@@ -33,7 +33,7 @@ class Image : public AModule {
   int size_;
   std::chrono::milliseconds interval_;
   util::command::res output_;
-  int signal_;  // Cached signal value to avoid JSON access in signal handler
+  int signal_;  // Cached signal value (-1 = disabled) to avoid JSON access in signal handler
 
   util::SleeperThread thread_;
 };