diff --git a/Library/.rubocop.yml b/Library/.rubocop.yml
index 568235043a..843d583369 100644
--- a/Library/.rubocop.yml
+++ b/Library/.rubocop.yml
@@ -55,16 +55,14 @@ FormulaAudit:
 FormulaAuditStrict:
   Enabled: true
 
-Homebrew/MoveToExtendOS:
-  Exclude:
-    - "Homebrew/{extend,test,requirements}/**/*"
-    - "Taps/**/*"
-    - "Homebrew/os.rb"
-
 # enable all Homebrew custom cops
 Homebrew:
   Enabled: true
 
+# only used internally
+Homebrew/MoveToExtendOS:
+  Enabled: false
+
 # makes DSL usage ugly.
 Layout/SpaceBeforeBrackets:
   Exclude:
diff --git a/Library/Homebrew/.rubocop.yml b/Library/Homebrew/.rubocop.yml
index b5ba4ec572..5897f0a641 100644
--- a/Library/Homebrew/.rubocop.yml
+++ b/Library/Homebrew/.rubocop.yml
@@ -2,6 +2,12 @@ inherit_from:
   - ../.rubocop_rspec.yml
   - .rubocop_todo.yml
 
+Homebrew/MoveToExtendOS:
+  Enabled: true
+  Exclude:
+    - "{extend,test,requirements}/**/*"
+    - "os.rb"
+
 # make rspec formatting more flexible
 Layout/MultilineMethodCallIndentation:
   Exclude: