diff --git a/.github/copilot-instructions.md b/.github/copilot-instructions.md
index 018c2d8..af068ee 100644
--- a/.github/copilot-instructions.md
+++ b/.github/copilot-instructions.md
@@ -29,7 +29,7 @@ Default behavior to preserve unless a training scenario says otherwise:
 - Favorite count includes unread favorites.
 - Empty-state copy should mention changing the search term, genre, or reading status.
 
-Use the current Node.js LTS. The app declares `engines.node` as `>=24.0.0`. CI uses Node 24.
+Use the current Node.js LTS. The app declares `engines.node` as `>=24.15.0` because jsdom 30 requires it. CI uses Node 24.
 
 ## Validation
 
diff --git a/samples/book-app-web/package-lock.json b/samples/book-app-web/package-lock.json
index 0c4a6f4..ee093d1 100644
--- a/samples/book-app-web/package-lock.json
+++ b/samples/book-app-web/package-lock.json
@@ -22,7 +22,7 @@
         "vitest": "^5.0.5"
       },
       "engines": {
-        "node": ">=24.0.0"
+        "node": ">=24.15.0"
       }
     },
     "node_modules/@asamuzakjp/css-color": {
diff --git a/samples/book-app-web/package.json b/samples/book-app-web/package.json
index 2d81afd..1280190 100644
--- a/samples/book-app-web/package.json
+++ b/samples/book-app-web/package.json
@@ -4,7 +4,7 @@
   "private": true,
   "type": "module",
   "engines": {
-    "node": ">=24.0.0"
+    "node": ">=24.15.0"
   },
   "scripts": {
     "dev": "vite",