diff --git a/spec/shared_contexts/forgery_protection_spec.rb b/spec/shared_contexts/forgery_protection_spec.rb
new file mode 100644
index 000000000..0f9380c9a
--- /dev/null
+++ b/spec/shared_contexts/forgery_protection_spec.rb
@@ -0,0 +1,15 @@
+require 'rails_helper'
+
+# Canary for the 'with forgery protection enforced' shared context. All
+# no-CSRF regression specs depend on its before hook actually enabling
+# protection; if that hook stops applying, they pass vacuously. This
+# example fails loudly if the toggle breaks.
+# rubocop:disable RSpec/DescribeClass -- the subject is a shared context, not a class
+RSpec.describe 'with forgery protection enforced' do
+  include_context 'with forgery protection enforced'
+
+  it 'enables forgery protection for examples that include it' do
+    expect(ActionController::Base.allow_forgery_protection).to be true
+  end
+end
+# rubocop:enable RSpec/DescribeClass