diff --git a/scripts/super-board-card.sh b/scripts/super-board-card.sh
index f11ea170..f3abf4cc 100755
--- a/scripts/super-board-card.sh
+++ b/scripts/super-board-card.sh
@@ -201,10 +201,18 @@ items() {  # whole board, gh item-list shape, ~1 point per 100 cards
     || { echo "board read incomplete" >&2; return 69; }
 }
 
+# The reads above run strict, so anything GitHub rejects halts the whole run.
+# A malformed issue is the caller's mistake, not GitHub's: refuse it here (64).
+# zsh does not word-split `set -- $pair`, which once passed "26 53" as one issue.
+issue_arg() {  # $1 = issue
+  [[ "$1" =~ ^[1-9][0-9]*$ ]] && return 0
+  echo "invalid issue: '$1' — pass one issue number per call" >&2; exit 64
+}
+
 case "$VERB" in
-  move)    [ $# -eq 2 ] || { echo "usage: move <issue> <Status>" >&2; exit 64; }; move "$1" "$2" ;;
-  status)  [ $# -eq 1 ] || { echo "usage: status <issue>" >&2; exit 64; }; read_card "$1"; echo "$STATUS_NAME" ;;
-  item-id) [ $# -eq 1 ] || { echo "usage: item-id <issue>" >&2; exit 64; }; item_id "$1"; echo "$ITEM_ID" ;;
+  move)    [ $# -eq 2 ] || { echo "usage: move <issue> <Status>" >&2; exit 64; }; issue_arg "$1"; move "$1" "$2" ;;
+  status)  [ $# -eq 1 ] || { echo "usage: status <issue>" >&2; exit 64; }; issue_arg "$1"; read_card "$1"; echo "$STATUS_NAME" ;;
+  item-id) [ $# -eq 1 ] || { echo "usage: item-id <issue>" >&2; exit 64; }; issue_arg "$1"; item_id "$1"; echo "$ITEM_ID" ;;
   ids)     load_ids; jq -n --arg p "$PROJECT_ID" --arg f "$FIELD_ID" --argjson o "$OPTIONS_JSON" '{projectId:$p, fieldId:$f, options:$o}' ;;
   items)   items ;;
   *) echo "unknown verb: $VERB" >&2; exit 64 ;;
diff --git a/tests/test-card.sh b/tests/test-card.sh
index 17e5340e..0ff586bc 100644
--- a/tests/test-card.sh
+++ b/tests/test-card.sh
@@ -112,4 +112,19 @@ RC=0; card items >/dev/null 2>&1 || RC=$?
 [ "$RC" != 0 ] || fail "incomplete board read must fail"
 ok "incomplete board read refused"
 
+# 10 — a card number that is not one positive integer is a usage error (64):
+# no GitHub call, no halt file. zsh does not word-split `$pair`, so
+# `set -- $pair` once passed "26 53" here and halted a whole run (3 retries).
+for bad in "26 53" "#26" "abc" "0" ""; do
+  for verb in status item-id; do
+    reset_log; rm -f "$TMP/halt.json"; RC=0; card $verb "$bad" >/dev/null 2>&1 || RC=$?
+    [ "$RC" = 64 ] || fail "$verb '$bad' should exit 64 (rc=$RC)"
+    [ ! -s "$FAKE_LOG" ] || fail "$verb '$bad' must not call gh: $(cat "$FAKE_LOG")"
+    [ ! -e "$TMP/halt.json" ] || fail "$verb '$bad' must not write a halt file"
+  done
+  reset_log; RC=0; card move "$bad" QA >/dev/null 2>&1 || RC=$?
+  [ "$RC" = 64 ] && [ ! -s "$FAKE_LOG" ] || fail "move '$bad' should exit 64 with no gh call (rc=$RC)"
+done
+ok "bad card number → 64, no GitHub call, no halt"
+
 echo "PASS: $pass card-helper checks"