diff --git a/scripts/setup/machine-setup/lib/packages.sh b/scripts/setup/machine-setup/lib/packages.sh
index 277a3dee..edd3f41b 100644
--- a/scripts/setup/machine-setup/lib/packages.sh
+++ b/scripts/setup/machine-setup/lib/packages.sh
@@ -81,6 +81,12 @@ LAST_SKIPPED=()
 # distribution's default alongside it. It stays in core because anything that
 # compiles a native module needs it, but it is the one to move out first if that
 # ever bites.
+#
+# inotify-tools is `inotifywait`, and it is what lets a COMMANDER react the
+# moment a file lands instead of polling for it. Without it a watcher can only
+# ask "is there anything new?" on a timer, which is both slower and more work —
+# and the commander has no way to know the tool is missing until it tries. macOS
+# has no equivalent in the package sets here; a commander there polls.
 pkgs_core() {
   case "$PM" in
     apt)
@@ -103,17 +109,17 @@ pkgs_core() {
       echo curl ca-certificates gnupg git jq unzip \
         apt-transport-https lsb-release software-properties-common \
         wget zip brotli build-essential python3 btop htop tree tmux ripgrep fd-find net-tools eza \
-        poppler-utils radicale fail2ban unattended-upgrades
+        inotify-tools poppler-utils radicale fail2ban unattended-upgrades
       ;;
     pacman)
       echo curl ca-certificates gnupg git jq unzip \
         wget zip brotli base-devel python btop htop tree tmux ripgrep fd net-tools eza \
-        poppler radicale fail2ban
+        inotify-tools poppler radicale fail2ban
       ;;
     dnf)
       echo curl ca-certificates gnupg2 git jq unzip \
         wget zip brotli python3 btop htop tree tmux ripgrep fd-find net-tools eza \
-        poppler-utils radicale fail2ban
+        inotify-tools poppler-utils radicale fail2ban
       ;;
     brew)
       # curl, unzip and the TLS roots ship with macOS; the compilers come from