diff --git a/.github/workflows/danger.yml b/.github/workflows/danger.yml
new file mode 100644
index 000000000..d2e59dbb0
--- /dev/null
+++ b/.github/workflows/danger.yml
@@ -0,0 +1,23 @@
+name: Danger
+on:
+  pull_request:
+    types: [opened, synchronize, reopened]
+jobs:
+  danger:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: '3.2.7'
+
+      - name: Install dependencies
+        run: bundle install
+
+      - name: Run Danger
+        env:
+          DANGER_GITHUB_API_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: bundle exec danger --verbose
\ No newline at end of file
diff --git a/.github/workflows/danger_target.yml b/.github/workflows/danger_target.yml
new file mode 100644
index 000000000..00da8ffb8
--- /dev/null
+++ b/.github/workflows/danger_target.yml
@@ -0,0 +1,29 @@
+name: Danger
+on:
+  pull_request_target:
+    types: [opened, synchronize, reopened]
+jobs:
+  danger:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+        with:
+          ref: ${{ github.event.pull_request.head.ref }}
+          repository: ${{ github.event.pull_request.head.repo.full_name }}
+          token: ${{ secrets.GITHUB_TOKEN }}
+          fetch-depth: 0
+
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: '3.2.7'
+
+      - name: Install dependencies
+        run: bundle install
+
+
+      - name: Run Danger
+        env:
+          DANGER_GITHUB_API_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: bundle exec danger --verbose
\ No newline at end of file
diff --git a/Dangerfile b/Dangerfile
new file mode 100644
index 000000000..5179b84e9
--- /dev/null
+++ b/Dangerfile
@@ -0,0 +1,59 @@
+# Dangerfile
+
+# --- PR Size Checks ---
+warn("Pull request is too big (more than 500 LoC).") if git.lines_of_code > 500
+warn("Pull request is too small (less than 50 LoC).") if git.lines_of_code < 50
+
+# --- File Change Checks ---
+warn("Pull request touches too many files (more than 30 files).") if git.modified_files.count > 30
+
+# --- Commit Message Checks ---
+commit_messages = git.commits.map(&:message)
+duplicated_commits = commit_messages.group_by(&:itself).select { |_, v| v.size > 1 }
+warn("Pull request has duplicated commit messages.") if duplicated_commits.any?
+
+# --- TODO/FIXME Checks ---
+todo_fixme = (git.modified_files + git.added_files).any? do |file|
+  File.read(file).match?(/\b(TODO|FIXME)\b/i)
+end
+warn("Pull request contains TODO or FIXME comments.") if todo_fixme
+
+# --- Temp File Checks ---
+temp_files = git.added_files.any? { |file| file.match?(/(tmp|temp|cache)/i) }
+warn("Pull request includes temp, tmp, or cache files.") if temp_files
+
+# --- Missing Test Checks ---
+warn("There are no test changes in this PR.") if (git.modified_files + git.added_files).none? { |f| f.include?('spec/') || f.include?('test/') }
+
+
+# --- .md File Changes ---
+md_changes = git.modified_files.any? { |file| file.end_with?('.md') }
+warn("Pull request modifies markdown files (*.md). Make sure you have a good reason.") if md_changes
+
+# --- DB Schema Changes ---
+schema_changes = git.modified_files.any? { |file| file.match?(/db\/schema\.rb$/) }
+unless git.modified_files.any? { |file| file.match?(/db\/migrate\//) }
+  warn("Schema changes detected without a corresponding DB migration.") if schema_changes
+end
+
+# --- Config/Setup File Changes (selected ones not excluded) ---
+config_files = %w[
+  config/database.yml
+  config/secrets.yml
+  config/secrets.yml.example
+  config/settings.yml
+  config/settings.yml.example
+  setup.sh
+  config.ru
+]
+changed_config_files = git.modified_files.select { |file| config_files.include?(file) }
+warn("Pull request modifies config or setup files: #{changed_config_files.join(', ')}.") if changed_config_files.any?
+
+
+# --- Shallow Tests (RSpec) ---
+# (Rules 37-41 — Shallow tests — assuming you want them included)
+shallow_test_files = git.modified_files.select { |file| file.include?('spec/') }
+shallow_test_warning = shallow_test_files.any? do |file|
+  File.read(file).match?(/\bit\b|\bspecify\b/)
+end
+warn("RSpec tests seem shallow (single `it` blocks or no context). Consider improving test structure.") if shallow_test_warning
diff --git a/Gemfile b/Gemfile
index b5f47ee4b..a9e65ec86 100644
--- a/Gemfile
+++ b/Gemfile
@@ -47,6 +47,7 @@ group :development, :test do
   gem 'simplecov', require: false, group: :test
   gem 'coveralls'
   gem 'simplecov_json_formatter'
+  gem 'danger'
 end
 
 group :development do
diff --git a/Gemfile.lock b/Gemfile.lock
index 9cca8ef5d..70f485173 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -82,8 +82,16 @@ GEM
     bootsnap (1.18.4)
       msgpack (~> 1.2)
     builder (3.2.4)
+    claide (1.1.0)
+    claide-plugins (0.9.2)
+      cork
+      nap
+      open4 (~> 1.3)
+    colored2 (3.1.2)
     concurrent-ruby (1.3.5)
     connection_pool (2.5.0)
+    cork (0.3.0)
+      colored2 (~> 3.1)
     coveralls (0.7.1)
       multi_json (~> 1.3)
       rest-client
@@ -91,6 +99,20 @@ GEM
       term-ansicolor
       thor
     crass (1.0.6)
+    danger (9.5.1)
+      base64 (~> 0.2)
+      claide (~> 1.0)
+      claide-plugins (>= 0.9.2)
+      colored2 (~> 3.1)
+      cork (~> 0.1)
+      faraday (>= 0.9.0, < 3.0)
+      faraday-http-cache (~> 2.0)
+      git (~> 1.13)
+      kramdown (~> 2.3)
+      kramdown-parser-gfm (~> 1.0)
+      octokit (>= 4.0)
+      pstore (~> 0.1)
+      terminal-table (>= 1, < 4)
     database_cleaner-active_record (2.2.0)
       activerecord (>= 5.a)
       database_cleaner-core (~> 2.0.0)
@@ -111,8 +133,19 @@ GEM
       railties (>= 5.0.0)
     faker (3.2.0)
       i18n (>= 1.8.11, < 2)
+    faraday (2.13.1)
+      faraday-net_http (>= 2.0, < 3.5)
+      json
+      logger
+    faraday-http-cache (2.5.1)
+      faraday (>= 0.8)
+    faraday-net_http (3.4.0)
+      net-http (>= 0.5.0)
     find_with_order (1.3.1)
       activerecord (>= 3)
+    git (1.19.1)
+      addressable (~> 2.8)
+      rchardet (~> 1.8)
     globalid (1.2.1)
       activesupport (>= 6.1)
     http-accept (1.7.0)
@@ -129,6 +162,10 @@ GEM
     json-schema (3.0.0)
       addressable (>= 2.8)
     jwt (2.7.1)
+    kramdown (2.4.0)
+      rexml
+    kramdown-parser-gfm (1.1.0)
+      kramdown (~> 2.0)
     language_server-protocol (3.17.0.3)
     lingua (0.6.2)
     logger (1.6.6)
@@ -150,6 +187,9 @@ GEM
     msgpack (1.8.0)
     multi_json (1.15.0)
     mysql2 (0.5.5)
+    nap (1.1.0)
+    net-http (0.6.0)
+      uri
     net-imap (0.5.6)
       date
       net-protocol
@@ -169,6 +209,10 @@ GEM
       racc (~> 1.4)
     nokogiri (1.15.2-x86_64-linux)
       racc (~> 1.4)
+    octokit (10.0.0)
+      faraday (>= 1, < 3)
+      sawyer (~> 0.9)
+    open4 (1.3.4)
     parallel (1.23.0)
     parser (3.2.2.3)
       ast (~> 2.4.1)
@@ -176,6 +220,7 @@ GEM
     pp (0.6.2)
       prettyprint
     prettyprint (0.2.0)
+    pstore (0.2.0)
     psych (5.2.3)
       date
       stringio
@@ -224,6 +269,7 @@ GEM
       zeitwerk (~> 2.6)
     rainbow (3.1.1)
     rake (13.0.6)
+    rchardet (1.9.0)
     rdoc (6.12.0)
       psych (>= 4.0.0)
     regexp_parser (2.8.1)
@@ -277,6 +323,9 @@ GEM
     rubocop-ast (1.29.0)
       parser (>= 3.2.1.0)
     ruby-progressbar (1.13.0)
+    sawyer (0.9.2)
+      addressable (>= 2.3.5)
+      faraday (>= 0.17.3, < 3)
     securerandom (0.4.1)
     simplecov (0.22.0)
       docile (~> 1.1)
@@ -289,6 +338,8 @@ GEM
     sync (0.5.0)
     term-ansicolor (1.11.2)
       tins (~> 1.0)
+    terminal-table (3.0.2)
+      unicode-display_width (>= 1.1.1, < 3)
     thor (1.2.2)
     timeout (0.4.3)
     tins (1.38.0)
@@ -319,6 +370,7 @@ DEPENDENCIES
   bcrypt (~> 3.1.7)
   bootsnap (>= 1.18.4)
   coveralls
+  danger
   database_cleaner-active_record
   debug
   factory_bot_rails