diff --git a/run.sh b/run.sh
index f806d02..ad7e5e4 100755
--- a/run.sh
+++ b/run.sh
@@ -6,6 +6,10 @@ OAUTH_ENABLED=""
 while [[ $# -gt 0 ]]; do
     case "$1" in
         --oauth)
+            if [[ -n "$OAUTH_ENABLED" ]]; then
+                echo "Error: --oauth flag specified multiple times." >&2
+                exit 1
+            fi
             OAUTH_ENABLED=true
             EXPOSED_PORTS=("-p" "443:10000" "-p" "10001:10001" "-p" "10002:10002")
             shift