diff --git a/tools/fleet/fleet-bg.sh b/tools/fleet/fleet-bg.sh
index d38393ea8..bdf0409c4 100755
--- a/tools/fleet/fleet-bg.sh
+++ b/tools/fleet/fleet-bg.sh
@@ -4,10 +4,11 @@
 #   tools/fleet/fleet-bg.sh start <name> <command...>   runs the command detached, stdout+stderr to ~/Desktop/fleet/<name>.log, pid to ~/Desktop/fleet/pids/<name>.pid
 #   tools/fleet/fleet-bg.sh stop <name>                  kills that pid (and its process group) if it is alive, removes the pid file
 #   tools/fleet/fleet-bg.sh list                          every job and whether its pid is alive
+# macOS has no setsid, so the job runs under nohup alone there (a comment at the end of a case line swallows its ;; : none here).
 set -u; P="$HOME/Desktop/fleet/pids"; L="$HOME/Desktop/fleet"; mkdir -p "$P"
 case "${1:-}" in
   start) n="$2"; shift 2; [ -f "$P/$n.pid" ] && kill -0 "$(cat "$P/$n.pid")" 2>/dev/null && { echo "$n already running (pid $(cat "$P/$n.pid"))"; exit 1; }
-         if command -v setsid >/dev/null; then nohup setsid "$@" > "$L/$n.log" 2>&1 < /dev/null & else nohup "$@" > "$L/$n.log" 2>&1 < /dev/null & fi; echo $! > "$P/$n.pid"   # macOS has no setsid; echo "$n started pid $(cat "$P/$n.pid") log $L/$n.log" ;;
+         if command -v setsid >/dev/null; then nohup setsid "$@" > "$L/$n.log" 2>&1 < /dev/null & else nohup "$@" > "$L/$n.log" 2>&1 < /dev/null & fi; echo $! > "$P/$n.pid"; echo "$n started pid $(cat "$P/$n.pid") log $L/$n.log" ;;
   stop)  n="$2"; [ -f "$P/$n.pid" ] || { echo "$n: no pid file"; exit 1; }; pid=$(cat "$P/$n.pid")
          if kill -0 "$pid" 2>/dev/null; then kill -TERM -- "-$pid" 2>/dev/null || kill -TERM "$pid"; sleep 2; kill -0 "$pid" 2>/dev/null && kill -KILL -- "-$pid" 2>/dev/null; echo "$n stopped (pid $pid)"; else echo "$n not running (pid $pid gone)"; fi; rm -f "$P/$n.pid" ;;
   list)  for f in "$P"/*.pid; do [ -f "$f" ] || continue; n=$(basename "$f" .pid); pid=$(cat "$f"); kill -0 "$pid" 2>/dev/null && echo "$n pid $pid alive" || echo "$n pid $pid gone"; done ;;