diff --git a/contrib/dump-asy.pl b/contrib/dump-asy.pl
index 4fcf9b77..9bb2db3a 100755
--- a/contrib/dump-asy.pl
+++ b/contrib/dump-asy.pl
@@ -15,6 +15,12 @@ use AnyEvent::I3;
 use File::Temp;
 use File::Basename;
 use v5.10;
+use IPC::Cmd qw[can_run];
+
+# prerequisites check so we can be specific about failures caused
+# by not having these tools in the path
+can_run('asy') or die 'Please install asymptote';
+can_run('gv') or die 'Please install gv';
 
 my $i3 = i3();
 
@@ -31,7 +37,7 @@ sub dump_node {
 
     my $o = ($n->{orientation} eq 'none' ? "u" : ($n->{orientation} eq 'horizontal' ? "h" : "v"));
     my $w = (defined($n->{window}) ? $n->{window} : "N");
-    my $na = $n->{name};
+    my $na = ($n->{name} or "[Empty]");
     $na =~ s/#/\\#/g;
     $na =~ s/\$/\\\$/g;
     $na =~ s/&/\\&/g;