diff --git a/Library/Homebrew/sandbox.rb b/Library/Homebrew/sandbox.rb
index 6b0467f9a1..a21dacadd3 100644
--- a/Library/Homebrew/sandbox.rb
+++ b/Library/Homebrew/sandbox.rb
@@ -7,6 +7,7 @@ class Sandbox
     homebrew/core
     homebrew/dupes
     homebrew/fuse
+    homebrew/devel-only
   ].freeze
 
   def self.available?