diff --git a/exe/referator b/exe/referator
index 2552cf8..e36e739 100755
--- a/exe/referator
+++ b/exe/referator
@@ -51,16 +51,17 @@ while (line = $stdin.gets)
     ##########
     # Config #
     ##########
+    when 'REGISTER_SCRIPT'
+      data = JSON.parse rest
+      config.scripts.register(**data.transform_keys(&:to_sym))
+      success
     when 'REGISTER_CATEGORY'
       data = JSON.parse rest
       config.categories.register String(data).to_sym
       success
     when 'REGISTER_FORMAT'
       data = JSON.parse rest
-      config.formats.register(
-        String(data['name']).to_sym,
-        **data.except('name').transform_keys(&:to_sym),
-      )
+      config.formats.register(**data.transform_keys(&:to_sym))
       success
     when 'REGISTER_REF'
       data = JSON.parse rest
diff --git a/lib/referator.rb b/lib/referator.rb
index 846611f..360e937 100644
--- a/lib/referator.rb
+++ b/lib/referator.rb
@@ -9,6 +9,7 @@ require_relative 'referator/config'
 require_relative 'referator/config/categories'
 require_relative 'referator/config/formats'
 require_relative 'referator/config/repo'
+require_relative 'referator/config/scripts'
 require_relative 'referator/footnotes'
 require_relative 'referator/note'
 require_relative 'referator/reference'
diff --git a/lib/referator/config.rb b/lib/referator/config.rb
index ef4d4a1..8106c54 100644
--- a/lib/referator/config.rb
+++ b/lib/referator/config.rb
@@ -9,12 +9,17 @@ module Referator
     end
 
     def freeze
+      scripts.freeze
       categories.freeze
       formats.freeze
       repo.freeze
       super
     end
 
+    def scripts
+      @scripts ||= Scripts.new self
+    end
+
     def categories
       @categories ||= Categories.new self
     end
diff --git a/lib/referator/config/formats.rb b/lib/referator/config/formats.rb
index bedb0d1..900c838 100644
--- a/lib/referator/config/formats.rb
+++ b/lib/referator/config/formats.rb
@@ -3,40 +3,40 @@
 module Referator
   class Config
     class Formats
-      attr_reader :config, :names, :scripts
+      attr_reader :config
 
       def initialize(config)
         self.config = config
-        @names = []
         @scripts = {}
       end
 
       def freeze
-        @names.freeze
         @scripts.freeze
         super
       end
 
-      def register(name, **kwargs)
+      def register(name:, script:)
+        name = String(name).to_sym
+        script = String(script).to_sym
         Referator.validate_name! name
-        raise 'Already exists' if names.index(name) || scripts.key?(name)
+        Referator.validate_name! script
+        config.scripts.vars! script, script_vars.keys
+        raise 'Already exists' if @scripts.key? name
 
-        script = Script.new(**kwargs.merge(workdir: config.workdir,
-                                           vars: script_vars.keys))
-
-        names << name
-        scripts[name] = script
+        @scripts[name] = script
         nil
       end
 
       def exists!(name)
-        scripts[name] or raise 'Unknown format'
+        Referator.validate_name! name
+        @scripts[name] or raise 'Unknown format'
         nil
       end
 
       def render(template, name, notes)
         exists! name
-        scripts[name].call(
+        config.scripts.run(
+          @scripts[name],
           **script_vars(
             template:,
             format: name,
diff --git a/lib/referator/config/scripts.rb b/lib/referator/config/scripts.rb
new file mode 100644
index 0000000..6b42ab7
--- /dev/null
+++ b/lib/referator/config/scripts.rb
@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+module Referator
+  class Config
+    class Scripts
+      attr_reader :config
+
+      def initialize(config)
+        self.config = config
+        @scripts = {}
+      end
+
+      def freeze
+        @scripts.freeze
+        super
+      end
+
+      def register(name:, workdir: nil, vars: [], **kwargs)
+        name = String(name).to_sym
+        Referator.validate_name! name
+        raise 'Already exists' if @scripts.key? name
+
+        script = Script.new(
+          **kwargs,
+          workdir: workdir || config.workdir,
+          vars: vars.map { |var| var.instance_of?(String) ? var.to_sym : var },
+        )
+
+        @scripts[name] = script
+        nil
+      end
+
+      def vars!(name, vars)
+        unless vars.instance_of? Array
+          raise TypeError, "Expected #{Array}, got #{vars.class}"
+        end
+
+        Referator.validate_name! name
+        vars.each { |var| Referator.validate_script_var! var }
+
+        script = @scripts[name] or raise 'Invalid script'
+
+        raise 'Invalid vars' unless script.vars.sort == vars.sort
+      end
+
+      def run(name, **vars)
+        vars! name, vars.keys
+        @scripts[name].call(**vars)
+      end
+
+    private
+
+      def config=(config)
+        unless config.instance_of? Config
+          raise TypeError, "Expected #{Config}, got #{config.class}"
+        end
+
+        @config = config
+      end
+    end
+  end
+end
diff --git a/test.rb b/test.rb
index c2f80df..c349de3 100755
--- a/test.rb
+++ b/test.rb
@@ -87,6 +87,20 @@ def cmd(name, data)
   end
 end
 
+###################
+# REGISTER_SCRIPT #
+###################
+
+cmd :REGISTER_SCRIPT,
+    { name: :render,
+      vars: %i[template format notes],
+      args: ['test/render.rb',
+             { template: nil },
+             { format: nil }],
+      stdin: ['{"notes":',
+              { notes: nil },
+              '}'] }
+
 #####################
 # REGISTER_CATEGORY #
 #####################
@@ -98,21 +112,8 @@ cmd :REGISTER_CATEGORY, :link
 # REGISTER_FORMAT #
 ###################
 
-cmd :REGISTER_FORMAT, { name: :html,
-                        args: ['test/render.rb',
-                               { template: nil },
-                               { format: nil }],
-                        stdin: ['{"notes":',
-                                { notes: nil },
-                                '}'] }
-
-cmd :REGISTER_FORMAT, { name: :json,
-                        args: ['test/render.rb',
-                               { template: nil },
-                               { format: nil }],
-                        stdin: ['{"notes":',
-                                { notes: nil },
-                                '}'] }
+cmd :REGISTER_FORMAT, { name: :html, script: :render }
+cmd :REGISTER_FORMAT, { name: :json, script: :render }
 
 ################
 # REGISTER_REF #