diff --git a/.github/workflows/api-http.yml b/.github/workflows/api-http.yml
index 77d3445..c200fa0 100644
--- a/.github/workflows/api-http.yml
+++ b/.github/workflows/api-http.yml
@@ -12,4 +12,5 @@ jobs:
           ruby-version: '3.3'
       - run: gem install webrick --no-document
       - run: ruby -c services/api/simple_server.rb
+      - run: ruby scripts/check_gem_package.rb
       - run: python3 scripts/check_api_http.py
diff --git a/cli/gemhub.gemspec b/cli/gemhub.gemspec
index 07f9b84..cbc1a89 100644
--- a/cli/gemhub.gemspec
+++ b/cli/gemhub.gemspec
@@ -19,13 +19,12 @@ Gem::Specification.new do |spec|
   spec.metadata["source_code_uri"] = "https://github.com/your-org/gemhub"
   spec.metadata["changelog_uri"] = "https://github.com/your-org/gemhub/blob/main/CHANGELOG.md"
 
-  # Specify which files should be added to the gem when it is released.
-  # The `git ls-files -z` loads the files in the RubyGem that have been added into git.
+  # Container/source builds may not contain Git or a .git directory. Enumerate
+  # the package's own source, and include bin/ so gem installation exposes the CLI.
   spec.files = Dir.chdir(__dir__) do
-    `git ls-files -z`.split("\x0").reject do |f|
-      (File.expand_path(f) == __FILE__) ||
-        f.start_with?(*%w[bin/ test/ spec/ features/ .git .circleci appveyor Gemfile])
-    end
+    Dir.glob(["lib/**/*", "bin/*", "README*", "LICENSE*"]).select do |file|
+      File.file?(file)
+    end.sort
   end
   spec.bindir = "bin"
   spec.executables = spec.files.grep(%r{\Abin/}) { |f| File.basename(f) }
diff --git a/scripts/check_gem_package.rb b/scripts/check_gem_package.rb
new file mode 100644
index 0000000..cc01ace
--- /dev/null
+++ b/scripts/check_gem_package.rb
@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+require "fileutils"
+require "tmpdir"
+require "rubygems"
+
+root = File.expand_path("..", __dir__)
+Dir.mktmpdir("gemhub-source-package") do |directory|
+  %w[gemhub.gemspec lib bin].each do |entry|
+    FileUtils.cp_r(File.join(root, "cli", entry), directory)
+  end
+  original_path = ENV["PATH"]
+  begin
+    ENV["PATH"] = directory # No external Git executable and no repository metadata.
+    spec = Gem::Specification.load(File.join(directory, "gemhub.gemspec"))
+    raise "Gemspec cannot load without Git" unless spec
+    raise "Missing CLI executable" unless spec.executables == ["gemhub"]
+    raise "Missing packaged executable" unless spec.files.include?("bin/gemhub")
+    raise "Missing implementation" unless spec.files.include?("lib/gemhub/version.rb")
+    raise "Unexpected repository files" unless spec.files.all? { |file| File.file?(File.join(directory, file)) }
+    puts "PASS: source gemspec loads without Git and packages executable plus implementation"
+  ensure
+    ENV["PATH"] = original_path
+  end
+end