diff --git a/csst_common/_crds_api.py b/csst_common/_crds_api.py
new file mode 100644
index 0000000000000000000000000000000000000000..5189ee5637f2e49d4a9eb4a1b48bfbc6c70fe430
--- /dev/null
+++ b/csst_common/_crds_api.py
@@ -0,0 +1,3 @@
+def get_slsconf(dir_save=".", **kwargs):
+    """ save SLS conf files to `dir_save` """
+    pass