diff --git a/scripts/run-jepsen-m5-local.sh b/scripts/run-jepsen-m5-local.sh
index 4afd2653..c47f5835 100755
--- a/scripts/run-jepsen-m5-local.sh
+++ b/scripts/run-jepsen-m5-local.sh
@@ -98,11 +98,18 @@ for bin in "$ROUTE_KEY_BIN" "$LIST_ROUTES_BIN" "$BINARY"; do
 done
 T1_KEY="$("$ROUTE_KEY_BIN" jepsen_append_t1)"
 T3_KEY="$("$ROUTE_KEY_BIN" jepsen_append_t3)"
-# Group 1: [T1_KEY, T3_KEY) — tables 1, 2
-# Group 2: [T3_KEY, +inf)   — tables 3, 4
-# Keys outside [T1_KEY, +inf) fall through to the default group; this
-# workload only writes table-route keys so that range is unused.
-SHARD_RANGES="${T1_KEY}:${T3_KEY}=1,${T3_KEY}:=2"
+# Issue #930 fix: --shardRanges must cover every routing key.  Without
+# a [<empty>, T1_KEY) range, any table whose base64-encoded name sorts
+# before "amVwc2VuX2FwcGVuZF90MQ" (= base64("jepsen_append_t1"))
+# returns "no route for key" from ShardedCoordinator.dispatchTxn, and
+# createTableWithRetry silently swallows that as ACTIVE.
+#
+# Group 1: [<empty>, T3_KEY)   — default + tables 1, 2
+# Group 2: [T3_KEY, +inf)      — tables 3, 4
+#
+# Note: assigning the default range to group 1 (not a third group) keeps
+# the topology consistent with the 1-process-2-groups launch.
+SHARD_RANGES=":${T3_KEY}=1,${T3_KEY}:=2"
 echo "[shard-ranges] $SHARD_RANGES"
 
 # ---- stop any previously managed cluster ----
@@ -206,10 +213,19 @@ HOME="$(pwd)/tmp-home" LEIN_HOME="$(pwd)/.lein" \
     --local \
     --time-limit 30 \
     --rate 5 \
+    --host 127.0.0.1 \
     --dynamo-port 63801 \
     --list-routes-bin "$LIST_ROUTES_BIN" \
     --grpc-host-port  "$PROC_ADDR" \
   || EXIT_CODE=$?
+# --host 127.0.0.1 — without this the workload's open! resolves the
+# DynamoDB client hostname from (name node) where node is one of
+# default-nodes ["n1" "n2" "n3" "n4" "n5"]; these are virtual labels,
+# not real hostnames, and DNS resolution fails with 'nodename nor
+# servname provided'.  --host overrides via cli/common-cli-opts'
+# --host -> :host -> :dynamo-host -> make-ddb-client wiring.  Required
+# for the single-process two-group topology this script launches —
+# every "node" client talks to the same loopback DynamoDB endpoint.
 
 EXIT_CODE=${EXIT_CODE:-0}