diff --git a/backend/src/main/java/org/raddatz/familienarchiv/user/UserService.java b/backend/src/main/java/org/raddatz/familienarchiv/user/UserService.java
index 96cb98df..897e67c9 100644
--- a/backend/src/main/java/org/raddatz/familienarchiv/user/UserService.java
+++ b/backend/src/main/java/org/raddatz/familienarchiv/user/UserService.java
@@ -37,6 +37,8 @@ public class UserService {
 
     private final AppUserRepository userRepository;
     private final UserGroupRepository groupRepository;
+    // Injected directly (not via InviteService) to avoid a constructor injection cycle:
+    // InviteService → UserService → InviteService. Spring Framework 7 forbids such cycles.
     private final InviteTokenRepository inviteTokenRepository;
     private final PasswordEncoder passwordEncoder;
     private final AuditService auditService;