diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index d6f5e78..1139098 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -135,4 +135,9 @@ jobs:
         if: github.ref == 'refs/heads/main'
         run: ./cc-test-reporter upload-coverage
         env:
-          CC_TEST_REPORTER_ID: ${{ secrets.CC_TEST_REPORTER_ID }}
\ No newline at end of file
+          CC_TEST_REPORTER_ID: ${{ secrets.CC_TEST_REPORTER_ID }}
+
+      - name: Check code changes coverage
+        run: |
+          git fetch --update-head-ok origin main:main
+          ./bin/undercover -c main
diff --git a/.simplecov b/.simplecov
new file mode 100644
index 0000000..e971a9c
--- /dev/null
+++ b/.simplecov
@@ -0,0 +1,20 @@
+require "simplecov-lcov"
+require "undercover"
+require "simplecov_json_formatter"
+
+SimpleCov::Formatter::LcovFormatter.config.report_with_single_file = true
+
+SimpleCov.start do
+  add_filter "/spec/"
+  add_filter "/features/"
+
+  formatter(
+    SimpleCov::Formatter::MultiFormatter.new(
+      [
+        SimpleCov::Formatter::HTMLFormatter,
+        SimpleCov::Formatter::JSONFormatter,
+        SimpleCov::Formatter::LcovFormatter
+      ]
+    )
+  )
+end
diff --git a/Gemfile b/Gemfile
index 6154a28..e4eb91f 100644
--- a/Gemfile
+++ b/Gemfile
@@ -78,5 +78,7 @@ group :test do
   gem "selenium-webdriver"
   gem "simplecov", "~> 0.21", require: false
   gem "simplecov-json", require: false
+  gem "simplecov-lcov", "~> 0.8", require: false
   gem "shoulda-matchers", "~> 6.2"
+  gem "undercover", "~> 0.5"
 end
diff --git a/Gemfile.lock b/Gemfile.lock
index e2b153b..f6ba599 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -152,6 +152,8 @@ GEM
     image_processing (1.12.2)
       mini_magick (>= 4.9.5, < 5)
       ruby-vips (>= 2.0.17, < 3)
+    imagen (0.1.8)
+      parser (>= 2.5, != 2.5.1.1)
     importmap-rails (2.0.1)
       actionpack (>= 6.0.0)
       activesupport (>= 6.0.0)
@@ -313,6 +315,7 @@ GEM
     ruby-vips (2.1.4)
       ffi (~> 1.12)
     rubyzip (2.3.2)
+    rugged (1.7.2)
     selenium-webdriver (4.21.1)
       base64 (~> 0.2)
       rexml (~> 3.2, >= 3.2.5)
@@ -328,6 +331,7 @@ GEM
     simplecov-json (0.2.3)
       json
       simplecov
+    simplecov-lcov (0.8.0)
     simplecov_json_formatter (0.1.4)
     sprockets (4.2.1)
       concurrent-ruby (~> 1.0)
@@ -350,6 +354,11 @@ GEM
       railties (>= 6.0.0)
     tzinfo (2.0.6)
       concurrent-ruby (~> 1.0)
+    undercover (0.5.0)
+      bigdecimal
+      imagen (>= 0.1.8)
+      rainbow (>= 2.1, < 4.0)
+      rugged (>= 0.27, < 1.8)
     unicode-display_width (2.5.0)
     web-console (4.2.1)
       actionview (>= 6.0.0)
@@ -394,10 +403,12 @@ DEPENDENCIES
   shoulda-matchers (~> 6.2)
   simplecov (~> 0.21)
   simplecov-json
+  simplecov-lcov (~> 0.8)
   sprockets-rails
   stimulus-rails
   turbo-rails
   tzinfo-data
+  undercover (~> 0.5)
   web-console
 
 RUBY VERSION
diff --git a/app/controllers/stories_controller.rb b/app/controllers/stories_controller.rb
index db96063..a2cc22a 100644
--- a/app/controllers/stories_controller.rb
+++ b/app/controllers/stories_controller.rb
@@ -1,6 +1,13 @@
 class StoriesController < ApplicationController
   before_action :set_story, only: %i[ show edit update destroy ]
 
+  def new_test_endpoint
+    random_number = rand(100)
+    sleep(2)
+
+    Array.new(20) { random_number + rand(3) }
+  end
+
   # GET /stories or /stories.json
   def index
     @stories = Story.all
diff --git a/bin/undercover b/bin/undercover
new file mode 100755
index 0000000..1d08481
--- /dev/null
+++ b/bin/undercover
@@ -0,0 +1,6 @@
+#!/usr/bin/env ruby
+
+require "rubygems"
+require "bundler/setup"
+
+load Gem.bin_path("undercover", "undercover")
diff --git a/features/support/env.rb b/features/support/env.rb
index 2bd02fd..3c8e937 100644
--- a/features/support/env.rb
+++ b/features/support/env.rb
@@ -5,8 +5,6 @@
 # files.
 
 require 'simplecov'
-SimpleCov.start
-
 require 'cucumber/rails'
 
 # By default, any exception happening in your Rails application will bubble up
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 8b551b7..829f410 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -1,15 +1,5 @@
 require 'pathname'
 require 'simplecov'
-require "simplecov_json_formatter"
-
-SimpleCov.formatter = SimpleCov::Formatter::MultiFormatter.new([
-  SimpleCov::Formatter::HTMLFormatter,
-  SimpleCov::Formatter::JSONFormatter
-  ])
-
-SimpleCov.start do
-  add_filter '/spec/'
-end
 
 class RootPath
   def pathname