diff --git a/capa/features/common.py b/capa/features/common.py
index 8318dee5..4084994d 100644
--- a/capa/features/common.py
+++ b/capa/features/common.py
@@ -273,40 +273,15 @@ class _MatchedSubstring(Substring):
 
 
 class Registry(String):
-    # todo: add a way to tell whether this registry key was created, accessed, or deleted.
-    def __init__(self, value: str, description=None):
-        super().__init__(value, description)
-
-    def __eq__(self, other):
-        # Registry instance is in a ruleset
-        if isinstance(other, Registry):
-            return super().__eq__(other)
-        return False
+    pass
 
 
 class Filename(String):
-    # todo: add a way to tell whether this file was created, accessed, or deleted.
-    def __init__(self, value: str, description=None):
-        super().__init__(value, description)
-
-    def __eq__(self, other):
-        # Mutex instance is in a ruleset
-        if isinstance(other, Filename):
-            return super().__eq__(other)
-        return False
+    pass
 
 
 class Mutex(String):
-    # todo: add a way to tell whether this mutex was created or used
-    def __init__(self, value: str, description=None):
-        super().__init__(value, description)
-
-    def __eq__(self, other):
-        # Mutex instance is in a ruleset
-        if isinstance(other, Mutex):
-            return super().__eq__(other)
-        return False
-
+    pass
 
 class Regex(String):
     def __init__(self, value: str, description=None):