diff --git a/packages/synthetic-chain/public/upgrade-test-scripts/env_setup.sh b/packages/synthetic-chain/public/upgrade-test-scripts/env_setup.sh
index 25f74614..98f2cd93 100755
--- a/packages/synthetic-chain/public/upgrade-test-scripts/env_setup.sh
+++ b/packages/synthetic-chain/public/upgrade-test-scripts/env_setup.sh
@@ -63,9 +63,11 @@ fi
 startAgd() {
   echo "startAgd()"
 
-  # XXX debugging https://github.com/Agoric/agoric-3-proposals/issues/93
-  apt install net-tools
-  netstat
+  # precondition check
+  if agd status >/dev/null 2>&1; then
+    echo "Cannot start agd because it's already running"
+    exit 1
+  fi
 
   agd start --log_level warn "$@" &
   AGD_PID=$!
diff --git a/packages/synthetic-chain/public/upgrade-test-scripts/run_prepare_zero.sh b/packages/synthetic-chain/public/upgrade-test-scripts/run_prepare_zero.sh
index 72403797..c21d1015 100755
--- a/packages/synthetic-chain/public/upgrade-test-scripts/run_prepare_zero.sh
+++ b/packages/synthetic-chain/public/upgrade-test-scripts/run_prepare_zero.sh
@@ -59,6 +59,15 @@ agd add-genesis-account "$GENACCT" "$coins"
 
 agd gentx validator 5000000000ubld --keyring-backend="test" --chain-id "$CHAINID"
 agd collect-gentxs
+
+# XXX why is it sometimes already running?
+if agd status >/dev/null 2>&1; then
+  echo "agd already running; attempting to kill"
+  ps -aux
+  pgrep ag0 >$HOME/.agoric/agd.pid
+  killAgd
+fi
+
 startAgd
 
 voting_period_s=10