diff --git a/test/python-black-check.sh b/test/python-black-check.sh
index 2861047e..01dcc85d 100755
--- a/test/python-black-check.sh
+++ b/test/python-black-check.sh
@@ -13,4 +13,9 @@ if [ -z "$files" ]; then
 	exit 77
 fi
 
+command -v black >/dev/null 2>&1 || {
+	echo >&2 "black is not installed"
+	exit 77
+}
+
 black --check $files
diff --git a/test/python-ruff-check.sh b/test/python-ruff-check.sh
index fa2f7f2d..e053a0cb 100755
--- a/test/python-ruff-check.sh
+++ b/test/python-ruff-check.sh
@@ -13,4 +13,9 @@ if [ -z "$files" ]; then
 	exit 77
 fi
 
+command -v ruff >/dev/null 2>&1 || {
+	echo >&2 "ruff is not installed"
+	exit 77
+}
+
 ruff check $files
diff --git a/tools/python-black.sh b/tools/python-black.sh
index 748099b8..cd89abe5 100755
--- a/tools/python-black.sh
+++ b/tools/python-black.sh
@@ -13,4 +13,9 @@ if [ -z "$files" ]; then
 	exit 77
 fi
 
+command -v black >/dev/null 2>&1 || {
+	echo >&2 "black is not installed"
+	exit 77
+}
+
 black $files
diff --git a/tools/python-ruff.sh b/tools/python-ruff.sh
index 3bd01da8..1a3443df 100755
--- a/tools/python-ruff.sh
+++ b/tools/python-ruff.sh
@@ -13,4 +13,9 @@ if [ -z "$files" ]; then
 	exit 77
 fi
 
+command -v ruff >/dev/null 2>&1 || {
+	echo >&2 "ruff is not installed"
+	exit 77
+}
+
 ruff check --fix $files