diff --git a/middleman-core/lib/middleman-core/config_context.rb b/middleman-core/lib/middleman-core/config_context.rb
index d140e8ea..ebf0d67c 100644
--- a/middleman-core/lib/middleman-core/config_context.rb
+++ b/middleman-core/lib/middleman-core/config_context.rb
@@ -8,7 +8,7 @@ module Middleman
     attr_reader :app
 
     # Whitelist methods that can reach out.
-    def_delegators :@app, :config, :logger, :use, :map, :mime_type, :files, :root, :build?, :server?, :environment?
+    def_delegators :@app, :config, :logger, :use, :map, :mime_type, :files, :root, :build?, :server?, :environment?, :extensions
     def_delegator :"@app.extensions", :activate
 
     def initialize(app, template_context_class)