diff --git a/work/scripts/check-commit-message-rules.sh b/work/scripts/check-commit-message-rules.sh
index f95abbe3..7be904db 100755
--- a/work/scripts/check-commit-message-rules.sh
+++ b/work/scripts/check-commit-message-rules.sh
@@ -112,6 +112,18 @@ if [ -n "$body" ] && printf '%s\n' "$body" | grep -Eq '^Refs:'; then
     fi
 fi
 
+if [ -n "$body" ]; then
+    if printf '%s\n' "$body" | grep -Fq 'Ultraworked with [Sisyphus]'; then
+        echo "[FAIL] Sisyphus attribution footer must not be included"
+        exit_code=1
+    fi
+
+    if printf '%s\n' "$body" | grep -Ei '^Co-authored-by:[[:space:]]*Sisyphus[[:space:]]*<clio-agent@sisyphuslabs\.ai>$' >/dev/null; then
+        echo "[FAIL] Automatic Sisyphus co-author footer must not be included"
+        exit_code=1
+    fi
+fi
+
 if [ $exit_code -eq 0 ]; then
     echo "[PASS] Commit message follows AGENTS.md rules"
 else