diff --git a/luna/include/luna/Check.h b/luna/include/luna/Check.h
index 897c4486..9fb7a495 100644
--- a/luna/include/luna/Check.h
+++ b/luna/include/luna/Check.h
@@ -7,6 +7,7 @@
 #define STRINGIZE_VALUE_OF(x) STRINGIZE(x)
 #endif
 
+// Like check(), but with a custom error message.
 #define expect(expr, message)                                                                                          \
     do {                                                                                                               \
         if (!(expr)) [[unlikely]]                                                                                      \
@@ -15,6 +16,7 @@
         }                                                                                                              \
     } while (0)
 
+// Like assert(), but always enabled.
 #define check(expr)                                                                                                    \
     do {                                                                                                               \
         if (!(expr)) [[unlikely]]                                                                                      \