diff --git a/examples/demo/app.rb b/examples/demo/app.rb
index 0d64866..966efe9 100644
--- a/examples/demo/app.rb
+++ b/examples/demo/app.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'prubot'
 
 on 'test-event', 'say howdy' do
diff --git a/examples/register/app.rb b/examples/register/app.rb
index 0d64866..966efe9 100644
--- a/examples/register/app.rb
+++ b/examples/register/app.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'prubot'
 
 on 'test-event', 'say howdy' do
diff --git a/lib/prubot.rb b/lib/prubot.rb
index 1d15b0f..ed2c3a7 100644
--- a/lib/prubot.rb
+++ b/lib/prubot.rb
@@ -37,7 +37,7 @@ def run!
     end
 
     def run?
-      $0 == 'app.rb' # HACK HACK HACK need to decide how we want to handle this.
+      $PROGRAM_NAME == 'app.rb' # HACK: HACK HACK need to decide how we want to handle this.
     end
 
     def register_event(name, event, action = nil, &block)
@@ -56,8 +56,10 @@ def setup_routing
     end
   end
 
+  ##
+  # Prubot DSL
   module DSL
-    @@app = Prubot::Application.new
+    @@app = Prubot::Application.new # rubocop:disable Style/ClassVars
 
     ##
     # Supports both +on 'event' 'description' do...+ and +on 'action', 'event', 'description' do...+
@@ -70,7 +72,8 @@ def on(*args, &block)
       when 3
         @@app.register_event(args[2], args[1], args[0], &block)
       else
-        raise Prubot::Error 'on supports either "on <event> <description> do..." or "on <action> <event> <description> do..."'
+        raise Prubot::Error 'on supports either "on <event> <description> do..." or '\
+        '"on <action> <event> <description> do..."'
       end
     end
 
@@ -78,4 +81,4 @@ def on(*args, &block)
   end
 end
 
-extend Prubot::DSL
+extend Prubot::DSL # rubocop:disable Style/MixinUsage
diff --git a/lib/prubot/dispatcher.rb b/lib/prubot/dispatcher.rb
index f1f9100..fb28532 100644
--- a/lib/prubot/dispatcher.rb
+++ b/lib/prubot/dispatcher.rb
@@ -23,7 +23,7 @@ def call(env)
 
     private
 
-    def register_app(request)
+    def register_app(_request)
       [200, { 'Content-Type' => 'text/html' }, ['howdy']]
     end
 
@@ -35,7 +35,6 @@ def handle_event(request)
       generate_response event, action, result
     end
 
-
     def skip_verify?
       @config.secret == false
     end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 690cd4a..5eb9267 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -4,7 +4,7 @@
 require 'prubot'
 
 RSpec.configure do |config|
-  # HACK HACK HACK clean up environment after every test (sigh)
+  # HACK: HACK HACK clean up environment after every test (sigh)
   config.after  { ENV.delete_if { |k, _v| k.start_with?('PRUBOT') } }
   # Enable flags like --only-failures and --next-failure
   config.example_status_persistence_file_path = '.rspec_status'