diff --git a/.ruby-version b/.ruby-version
deleted file mode 120000
index 6502bef..0000000
--- a/.ruby-version
+++ /dev/null
@@ -1 +0,0 @@
-external-content/cookie/.ruby-version
\ No newline at end of file
diff --git a/Makefile b/Makefile
index 1bfc407..4f9a5cd 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-.PHONY: help prepare cookie cookie_ruby_deps cookie_web_prepare external html serve clean
+.PHONY: help prepare cookie external html serve clean
 .DEFAULT_GOAL := help
 
 # Add help text after each target name starting with '\#\#'
@@ -10,17 +10,11 @@ help:   ## show this help
 prepare:
 	git submodule update --init
 
-cookie_ruby_deps:
-	(cd external-content/cookie && \
-	bundle install)
-
-cookie_web_prepare:
-	(cd external-content/cookie && \
-    ./helpers/fetch_repo_review_app.sh)
-
-cookie: cookie_ruby_deps cookie_web_prepare
-	(cd external-content/cookie && \
-	JEKYLL_ENV=production bundle exec jekyll build --destination ../../public/development --baseurl "/development/")
+cookie:
+	(cd external-content/cookie/docs && \
+	BASE_URL=/development/ npx --yes mystmd build --html)
+	mkdir -p public/development
+	cp -r external-content/cookie/docs/_build/html/. public/development/
 
 external: cookie
 
diff --git a/external-content/cookie b/external-content/cookie
index 4d7762b..bbb319a 160000
--- a/external-content/cookie
+++ b/external-content/cookie
@@ -1 +1 @@
-Subproject commit 4d7762bf66f47430a218d824021bca35c1513279
+Subproject commit bbb319ab2eb9f68719a34028e1552a2690685948
diff --git a/netlify.toml b/netlify.toml
index 2eda9d5..ec0951c 100644
--- a/netlify.toml
+++ b/netlify.toml
@@ -1,5 +1,6 @@
 [build.environment]
   PYTHON_VERSION = "3.13"
+  NODE_VERSION = "24"
   HUGO_VERSION = "0.141.0"
   DART_SASS_VERSION = "1.83.4"
   DART_SASS_URL = "https://github.com/sass/dart-sass/releases/download/"
@@ -21,3 +22,9 @@
 
   [plugins.inputs]
   skipPatterns = ['https://fonts.gstatic.com', 'https://fonts.googleapis.com', "https://unpkg.com"]
+  # Tolerate two unavoidable artifacts of link-checking the MyST-built
+  # `/development/` site: hyperlink's parser chokes on MyST's bundled
+  # mermaid chunk (`static {}` class blocks), and it reports valid
+  # in-page fragments as failures when the target passes through MyST's
+  # pretty-URL normalization (e.g. /pages/guides/pytest -> .../index.html).
+  todoPatterns = ['fragment-redirect', 'mermaid.core']