diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..9dd0150
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,33 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        ruby-version: ["3.2", "3.3", "3.4", "4.0"]
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Ruby ${{ matrix.ruby-version }}
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby-version }}
+          bundler-cache: true
+
+      - name: Install dependencies
+        run: bundle install
+
+      - name: Run RSpec tests
+        run: bundle exec rake spec
+
+      - name: Run RuboCop
+        run: bundle exec rubocop --parallel
+        continue-on-error: true
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
new file mode 100644
index 0000000..d1dcf75
--- /dev/null
+++ b/.github/workflows/release.yml
@@ -0,0 +1,56 @@
+name: release
+
+on:
+  release:
+    types: [published]
+
+jobs:
+  publish-rubygems:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      id-token: write
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Ruby
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: "3.4"
+          bundler-cache: true
+
+      - name: Install dependencies
+        run: bundle install
+
+      - name: Run tests
+        run: bundle exec rake spec
+
+      - name: Build gem
+        run: gem build payjpv2.gemspec
+
+      - name: Get version from release tag
+        id: version
+        run: echo "version=${GITHUB_REF#refs/tags/v}" >> $GITHUB_OUTPUT
+
+      - name: Verify gem version matches tag
+        run: |
+          GEM_VERSION=$(ruby -r ./lib/payjpv2/version -e "puts PAYJPv2::VERSION")
+          TAG_VERSION=${{ steps.version.outputs.version }}
+          if [ "$GEM_VERSION" != "$TAG_VERSION" ]; then
+            echo "Error: Gem version ($GEM_VERSION) does not match tag version ($TAG_VERSION)"
+            exit 1
+          fi
+
+      - name: Configure RubyGems credentials
+        run: |
+          mkdir -p ~/.gem
+          echo -e "---\n:rubygems_api_key: ${{ secrets.RUBYGEMS_API_KEY }}" > ~/.gem/credentials
+          chmod 0600 ~/.gem/credentials
+
+      - name: Publish to RubyGems
+        run: gem push payjpv2-${{ steps.version.outputs.version }}.gem
+
+      - name: Cleanup credentials
+        if: always()
+        run: rm -f ~/.gem/credentials
diff --git a/Gemfile.lock b/Gemfile.lock
index ca4aa59..0d5cae5 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    payjpv2 (0.0.1)
+    payjpv2 (1.0.0)
       typhoeus (~> 1.0, >= 1.0.1)
 
 GEM
diff --git a/README.md b/README.md
index 06c3132..2d270a7 100644
--- a/README.md
+++ b/README.md
@@ -5,7 +5,7 @@ A Ruby client library for the PAY.JP v2 API. This SDK provides a convenient way
 This Ruby gem is automatically generated by the [OpenAPI Generator](https://openapi-generator.tech) project:
 
 - API version: 2.0.0
-- Package version: 0.0.1
+- Package version: 1.0.0
 - Generator version: 7.14.0
 - Build package: org.openapitools.codegen.languages.RubyClientCodegen
 
@@ -26,7 +26,7 @@ gem install payjpv2
 Add this line to your application's Gemfile:
 
 ```ruby
-gem 'payjpv2', '~> 0.0.1'
+gem 'payjpv2', '~> 1.0.0'
 ```
 
 Then execute:
diff --git a/lib/payjpv2/models/tax_rate_create_request.rb b/lib/payjpv2/models/tax_rate_create_request.rb
index a9039e1..02a6856 100644
--- a/lib/payjpv2/models/tax_rate_create_request.rb
+++ b/lib/payjpv2/models/tax_rate_create_request.rb
@@ -182,6 +182,14 @@ def percentage=(percentage)
         raise ArgumentError, 'percentage cannot be nil'
       end
 
+      if percentage > 100.0
+        raise ArgumentError, 'invalid value for "percentage", must be smaller than or equal to 100.0.'
+      end
+
+      if percentage < 0.0
+        raise ArgumentError, 'invalid value for "percentage", must be greater than or equal to 0.0.'
+      end
+
       @percentage = percentage
     end
 
diff --git a/lib/payjpv2/version.rb b/lib/payjpv2/version.rb
index a962abe..ad37a60 100644
--- a/lib/payjpv2/version.rb
+++ b/lib/payjpv2/version.rb
@@ -11,5 +11,5 @@
 =end
 
 module PAYJPv2
-  VERSION = '0.0.1'
+  VERSION = '1.0.0'
 end
diff --git a/payjpv2.gemspec b/payjpv2.gemspec
index 30caa90..be497da 100644
--- a/payjpv2.gemspec
+++ b/payjpv2.gemspec
@@ -26,7 +26,13 @@ Gem::Specification.new do |s|
   s.description = "A Ruby client library for the PAY.JP v2 API"
   s.license     = "MIT"
   s.required_ruby_version = ">= 3.2"
-  s.metadata    = {}
+  s.metadata    = {
+    "homepage_uri"          => "https://github.com/payjp/payjpv2-ruby",
+    "source_code_uri"       => "https://github.com/payjp/payjpv2-ruby",
+    "changelog_uri"         => "https://github.com/payjp/payjpv2-ruby/releases",
+    "bug_tracker_uri"       => "https://github.com/payjp/payjpv2-ruby/issues",
+    "rubygems_mfa_required" => "true"
+  }
 
   s.add_runtime_dependency 'typhoeus', '~> 1.0', '>= 1.0.1'