diff --git a/add-external-repos.sh b/add-external-repos.sh
index d8e8318..6ab0c73 100755
--- a/add-external-repos.sh
+++ b/add-external-repos.sh
@@ -4,6 +4,16 @@
 set -e  # Exit immediately if any command fails
 umask 022  # Set default file permissions (files=644, dirs=755)
 
+# --- Check if inside OpenWRT source directory ---
+# Every path below is relative to the current directory, so running this from
+# the helper checkout would clone into helper/package/ instead of the real
+# OpenWRT package/ directory.
+if [ ! -f "feeds.conf.default" ] || [ ! -d "package" ]; then
+    echo "[ERROR] Must run inside OpenWRT root directory."
+    echo "[ERROR] From the OpenWrt root, run it as: ./helper/add-external-repos.sh"
+    exit 1
+fi
+
 # Define repositories in the format: "git_url branch local_dir"
 REPOS=(
   "https://github.com/muink/luci-app-netspeedtest.git master package/luci-app-netspeedtest"