diff --git a/.claude/rules/testing.md b/.claude/rules/testing.md
index f5d2897..734eaba 100644
--- a/.claude/rules/testing.md
+++ b/.claude/rules/testing.md
@@ -17,7 +17,7 @@ in-memory registry, and the generators — cheapest first:
 |-------|------|-------|---------|
 | Unit | `spec/docs_kit/**` | nothing | `DocsKit::Registry`, `DocsKit::NavItem`, `Configuration` |
 | Component | `spec/docs_ui/**` | Phlex render (no Rails request) | that a component renders the expected HTML/daisyUI classes given props |
-| Generator | `spec/generators/**` (if present) | generator harness | `docs_kit:install` writes the right files |
+| Generator | `spec/generators/install_generator_spec.rb` | plain Thor against a tmp app skeleton (no Rails boot) | `docs_kit:install` writes the right files/manifest + key contents |
 
 A component spec renders the Phlex class and asserts on the produced markup —
 the daisyUI classes emitted, the config-driven values, the active-link state.
@@ -26,7 +26,9 @@ present) over brittle full-HTML snapshots.
 
 ## Coverage Expectations
 
-- **80% minimum** for all code
+- **80% minimum** for all code — enforced by SimpleCov (`minimum_coverage 80` in
+  `spec/spec_helper.rb`); `bundle exec rspec` / `rake` fails below it, locally and
+  in CI.
 - **100%** for the config surface (`DocsKit::Configuration`) and the registry
   mixin (`DocsKit::Registry`) — the public API sites depend on.
 
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..3f06fec
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,38 @@
+# CI for the docs-kit gem: run the suite + lint on every supported Ruby.
+#
+# `bundle exec rake` is `spec + rubocop` (see Rakefile) — the same command run
+# locally. SimpleCov enforces the 80% coverage floor from within the suite, so a
+# coverage regression fails this job too. The generator specs run in the same job:
+# they invoke the install generator against a tmp skeleton via plain Thor (no Rails
+# boot), so they need no heavier harness than the rest of the suite.
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+# Cancel superseded runs on the same ref (a force-push / new commit to a PR).
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  rake:
+    name: rake (Ruby ${{ matrix.ruby }})
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        ruby: ["3.2", "3.3", "3.4"]
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Ruby ${{ matrix.ruby }}
+        uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ${{ matrix.ruby }}
+          bundler-cache: true
+
+      - name: Run the suite + lint
+        run: bundle exec rake
diff --git a/.gitignore b/.gitignore
index 1729609..d121cea 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,3 +6,5 @@
 Gemfile.lock
 *.gem
 .DS_Store
+# Claude Code agent scratch worktrees.
+/.claude/worktrees/
diff --git a/.rubocop.yml b/.rubocop.yml
index 230fc21..f5efca2 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -7,6 +7,16 @@ AllCops:
   TargetRubyVersion: 3.2
   NewCops: enable
   SuggestExtensions: false
+  Exclude:
+    # SimpleCov's HTML report — generated, not source.
+    - "coverage/**/*"
+    - "tmp/**/*"
+    # The dogfood docs site is a separate consuming app with its own bundle and
+    # .rubocop.yml (it inherits rubocop-rails-omakase, not installed in the gem's
+    # bundle). Linting it from here crashes config loading; it lints itself.
+    - "docs/**/*"
+    # Agent scratch worktrees — never source.
+    - ".claude/**/*"
 
 Style/Documentation:
   Enabled: false
@@ -67,3 +77,9 @@ RSpec/MultipleExpectations:
 
 RSpec/NestedGroups:
   Max: 4
+
+# Generator specs live under spec/generators/ (the conventional Rails location),
+# not a path mirroring the DocsKit::Generators:: namespace.
+RSpec/SpecFilePathFormat:
+  Exclude:
+    - "spec/generators/**/*"
diff --git a/CLAUDE.md b/CLAUDE.md
index ffdbb31..666a5b1 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -101,8 +101,9 @@ session model. See `.claude/rules/agents.md`.
 
 - Unit specs (`spec/docs_kit/`) cover the config surface and the registry — no Rails boot.
 - Component specs (`spec/docs_ui/`) render a `DocsUI::` component and assert on the produced markup's semantics (an active link, a present theme option, a config-driven value).
-- Generator specs cover `docs_kit:install` output.
-- Coverage: 80% minimum; 100% for `DocsKit::Configuration` and `DocsKit::Registry` (the public API sites depend on).
+- Generator specs (`spec/generators/install_generator_spec.rb`) run `docs_kit:install` against a throwaway destination root (a tmp app skeleton, plain Thor — no Rails boot) and assert the file manifest + key contents.
+- Coverage: SimpleCov enforces `minimum_coverage 80` from within the suite (`bundle exec rspec` / `rake` fails below it); 100% aspired for `DocsKit::Configuration` and `DocsKit::Registry` (the public API sites depend on).
+- CI: `.github/workflows/ci.yml` runs `bundle exec rake` on Ruby 3.2/3.3/3.4 for every push to `main` and every PR.
 - See `.claude/rules/testing.md`.
 
 ## Deploy
diff --git a/Gemfile b/Gemfile
index 51a55ed..15041d4 100644
--- a/Gemfile
+++ b/Gemfile
@@ -4,9 +4,11 @@ source "https://rubygems.org"
 
 gemspec
 
-# The daisyui gem is published on rubygems, but track the local checkout so the
-# kit develops against the same source the docs sites use.
-gem "daisyui", path: "../daisyui"
+# The daisyui gem is published on rubygems. When the sibling checkout exists,
+# track it so the kit develops against the same source the docs sites use;
+# otherwise (CI, a fresh clone) fall back to the published gem via the gemspec's
+# `daisyui >= 1.2` dependency.
+gem "daisyui", path: "../daisyui" if File.directory?(File.expand_path("../daisyui", __dir__))
 
 group :development, :test do
   gem "rake"
@@ -15,4 +17,5 @@ group :development, :test do
   gem "rubocop-performance", require: false
   gem "rubocop-rake", require: false
   gem "rubocop-rspec", require: false
+  gem "simplecov", require: false
 end
diff --git a/README.md b/README.md
index 5506dcc..0f2b96e 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,7 @@
 # docs-kit
 
+[![CI](https://github.com/mhenrixon/docs-kit/actions/workflows/ci.yml/badge.svg)](https://github.com/mhenrixon/docs-kit/actions/workflows/ci.yml)
+
 Shared [Phlex](https://www.phlex.fun) chrome for documentation sites built on
 [daisyUI](https://daisyui.com). Extract the shell, sidebar, code blocks, theme
 switcher, and page kit into one gem so multiple docs sites look identical and are
diff --git a/Rakefile b/Rakefile
index d9b6e5e..24cfc5f 100644
--- a/Rakefile
+++ b/Rakefile
@@ -5,6 +5,14 @@ require "rspec/core/rake_task"
 require "rubocop/rake_task"
 
 RSpec::Core::RakeTask.new(:spec)
-RuboCop::RakeTask.new
+
+# Lint only the gem's own source — NOT the dogfood docs/ site. docs/ is a separate
+# consuming app with its own bundle and .rubocop.yml (it `inherit_gem`s
+# rubocop-rails-omakase, absent from the gem's bundle). Passing explicit paths
+# stops RuboCop from discovering and loading docs/.rubocop.yml, whose gem
+# inheritance can't resolve here (and crashes CI). docs/ lints itself.
+RuboCop::RakeTask.new do |task|
+  task.patterns = %w[app lib spec Rakefile Gemfile docs-kit.gemspec]
+end
 
 task default: %i[spec rubocop]
diff --git a/spec/generators/install_generator_spec.rb b/spec/generators/install_generator_spec.rb
new file mode 100644
index 0000000..e7d1fda
--- /dev/null
+++ b/spec/generators/install_generator_spec.rb
@@ -0,0 +1,216 @@
+# frozen_string_literal: true
+
+require "fileutils"
+require "tmpdir"
+require "rails/generators"
+require "generators/docs_kit/install/install_generator"
+
+# The install generator never touches a booted Rails app — it only reads/writes
+# files under destination_root via Thor. So we exercise it against a throwaway
+# destination root: a minimal fake app skeleton (routes.rb, application_controller,
+# controllers/index.js, assets.rb) built per-example, run the generator, and assert
+# the produced file manifest + key contents.
+#
+# These specs assert CURRENT behavior. Most steps guard against re-runs (Thor's
+# `route`/`inject_into_file` skip a line that's already present; several methods
+# `say_status(:skip)` when a target exists), so the generator is largely
+# idempotent; `create_initializer` is the exception (it re-renders the template
+# on every run). If a later change tightens idempotency, update these assertions.
+RSpec.describe DocsKit::Generators::InstallGenerator do
+  # A named destination dir so app_brand humanizes deterministically
+  # ("my_app_docs" → "My app docs"). Rails isn't booted, so app_brand falls back
+  # to the basename of destination_root.
+  let(:app_name) { "my_app_docs" }
+  let(:destination) { File.join(Dir.tmpdir, "docs-kit-gen-spec", app_name) }
+
+  # A stock Stimulus controllers/index.js: only the eager-load line the generator
+  # injects the docs_kit path after.
+  def stimulus_index_source
+    <<~JS
+      import { application } from "controllers/application"
+      eagerLoadControllersFrom("controllers", application)
+    JS
+  end
+
+  # Build a minimal Rails-ish skeleton the generator's injections expect to find.
+  def build_skeleton(routes: true, app_controller: true, stimulus_index: true, package_json: nil)
+    FileUtils.mkdir_p(File.join(destination, "config/initializers"))
+    FileUtils.mkdir_p(File.join(destination, "app/controllers"))
+    FileUtils.mkdir_p(File.join(destination, "app/javascript/controllers"))
+
+    write("config/initializers/assets.rb", %(Rails.application.config.assets.version = "1.0"\n))
+    write("config/routes.rb", "Rails.application.routes.draw do\nend\n") if routes
+    if app_controller
+      write("app/controllers/application_controller.rb",
+            "class ApplicationController < ActionController::Base\nend\n")
+    end
+    write("app/javascript/controllers/index.js", stimulus_index_source) if stimulus_index
+    write("package.json", package_json) if package_json
+  end
+
+  def write(rel, content)
+    path = File.join(destination, rel)
+    FileUtils.mkdir_p(File.dirname(path))
+    File.write(path, content)
+  end
+
+  def read(rel) = File.read(File.join(destination, rel))
+  def exist?(rel) = File.exist?(File.join(destination, rel))
+
+  # Run the generator quietly against the skeleton.
+  def run_generator
+    generator = described_class.new([], {}, destination_root: destination)
+    silence_stream { generator.invoke_all }
+  end
+
+  # Thor writes progress to $stdout; keep the suite output clean.
+  def silence_stream
+    original = $stdout
+    $stdout = File.open(File::NULL, "w")
+    yield
+  ensure
+    $stdout.close
+    $stdout = original
+  end
+
+  before { FileUtils.rm_rf(destination) }
+  after  { FileUtils.rm_rf(destination) }
+
+  describe "the file manifest" do
+    before do
+      build_skeleton
+      run_generator
+    end
+
+    it "creates the config initializers" do
+      expect(exist?("config/initializers/docs_kit.rb")).to be(true)
+      expect(exist?("config/initializers/phlex.rb")).to be(true)
+      expect(exist?("config/initializers/rails_icons.rb")).to be(true)
+    end
+
+    it "creates the registry model + controllers + pages" do
+      expect(exist?("app/models/doc.rb")).to be(true)
+      expect(exist?("app/controllers/docs_controller.rb")).to be(true)
+      expect(exist?("app/controllers/landings_controller.rb")).to be(true)
+      expect(exist?("app/views/docs/pages/installation.rb")).to be(true)
+      expect(exist?("app/views/landings/show.rb")).to be(true)
+    end
+
+    it "creates the CSS build files + keeps" do
+      expect(exist?("app/assets/stylesheets/application.tailwind.css")).to be(true)
+      expect(exist?("bin/build-css")).to be(true)
+      expect(exist?("lib/tasks/build_css.rake")).to be(true)
+      expect(exist?("app/assets/builds/.keep")).to be(true)
+      expect(exist?("app/components/.keep")).to be(true)
+    end
+  end
+
+  describe "config/initializers/docs_kit.rb" do
+    before do
+      build_skeleton
+      run_generator
+    end
+
+    it "substitutes the humanized app name as the brand" do
+      initializer = read("config/initializers/docs_kit.rb")
+
+      expect(initializer).to include(%(c.brand        = "My app docs"))
+      expect(initializer).to include(%(c.title_suffix = "My app docs"))
+    end
+
+    it "ships the theme list that matches the Tailwind @plugin block" do
+      css = read("app/assets/stylesheets/application.tailwind.css")
+      initializer = read("config/initializers/docs_kit.rb")
+
+      %w[dark light synthwave retro cyberpunk dracula night nord sunset].each do |theme|
+        expect(initializer).to include(theme)
+        expect(css).to include(theme)
+      end
+    end
+  end
+
+  describe "route injection (add_routes)" do
+    before do
+      build_skeleton
+      run_generator
+    end
+
+    it "adds the docs and root routes" do
+      routes = read("config/routes.rb")
+
+      expect(routes).to include(%(get "docs/:doc" => "docs#show", as: :doc))
+      expect(routes).to include(%(root "landings#show"))
+    end
+  end
+
+  describe "controller injection (include_controller_helper)" do
+    it "injects include DocsKit::Controller into ApplicationController" do
+      build_skeleton
+      run_generator
+
+      expect(read("app/controllers/application_controller.rb"))
+        .to include("include DocsKit::Controller")
+    end
+
+    it "skips injection when ApplicationController is absent" do
+      build_skeleton(app_controller: false)
+      run_generator
+
+      expect(exist?("app/controllers/application_controller.rb")).to be(false)
+    end
+  end
+
+  describe "asset paths + package.json (wire_assets_and_package_json)" do
+    it "appends the builds path to config/initializers/assets.rb" do
+      build_skeleton
+      run_generator
+
+      expect(read("config/initializers/assets.rb"))
+        .to include(%(Rails.application.config.assets.paths << Rails.root.join("app", "assets", "builds")))
+    end
+
+    it "creates a package.json stub with the build:css scripts when none exists" do
+      build_skeleton
+      run_generator
+
+      package = read("package.json")
+      expect(package).to include(%("build:css": "bin/build-css --minify"))
+      expect(package).to include(%("watch:css": "bin/build-css --watch"))
+    end
+
+    it "does not overwrite an existing package.json that already has build:css" do
+      existing = %({\n  "scripts": { "build:css": "custom" }\n}\n)
+      build_skeleton(package_json: existing)
+      run_generator
+
+      expect(read("package.json")).to eq(existing)
+    end
+  end
+
+  describe "Stimulus registration (register_stimulus_controller)" do
+    it "registers the docs_kit controllers path in controllers/index.js" do
+      build_skeleton
+      run_generator
+
+      expect(read("app/javascript/controllers/index.js"))
+        .to include(%(eagerLoadControllersFrom("docs_kit/controllers", application)))
+    end
+
+    it "skips registration when there is no controllers/index.js" do
+      build_skeleton(stimulus_index: false)
+      run_generator
+
+      expect(exist?("app/javascript/controllers/index.js")).to be(false)
+    end
+  end
+
+  describe "bin/build-css" do
+    it "is created executable (chmod 0755)" do
+      build_skeleton
+      run_generator
+
+      mode = File.stat(File.join(destination, "bin/build-css")).mode & 0o777
+      expect(mode).to eq(0o755)
+    end
+  end
+end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 41075db..60687c4 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -1,5 +1,20 @@
 # frozen_string_literal: true
 
+# Coverage. Start SimpleCov BEFORE requiring docs_kit so every lib/ file loaded
+# below is tracked. CLAUDE.md sets the 80% floor; enforce it here so `rake` fails
+# locally and in CI when coverage regresses. The generators/ tree is the install
+# generator, exercised by spec/generators/**.
+require "simplecov"
+SimpleCov.start do
+  enable_coverage :branch
+  add_filter "/spec/"
+  add_group "Config", "lib/docs_kit/configuration.rb"
+  add_group "Registry", "lib/docs_kit/registry.rb"
+  add_group "Components", "app/components"
+  add_group "Generators", "lib/generators"
+  minimum_coverage 80
+end
+
 # Component specs render DocsUI:: Phlex components in isolation (no Rails
 # request). Shell and Code compose phlex-rails value helpers (e.g.
 # content_security_policy_nonce), so load phlex-rails here — plus the two
@@ -10,6 +25,13 @@
 require "active_support/json"
 require "phlex/rails"
 
+# DocsUI::Shell / Sidebar `include DaisyUI` (the daisyUI Phlex kit). The gem name
+# is `daisyui`; the require path is `daisy_ui` — a consuming site loads it via
+# `gem "daisyui", require: "daisy_ui"`. docs_kit itself never requires it (the
+# host app does), so the standalone suite must load it here or the constant is
+# undefined when a component is rendered.
+require "daisy_ui"
+
 require "docs_kit"
 
 RSpec.configure do |config|