diff --git a/mpcdf_setup_home_project.py b/mpcdf_setup_home_project.py
index 23313a3478fd8933103aba87d233babf0ffb1b99..2644b3d8bdaaf4489fc5bc419f481a9d60f702cc 100644
--- a/mpcdf_setup_home_project.py
+++ b/mpcdf_setup_home_project.py
@@ -13,8 +13,9 @@ import osc.cmdln
                   help="Do not actually run anything but output the resulting XML configuration")
 @osc.cmdln.option('--remove-old', action="store_true", default=False,
                   help="Remove all obsolete repositories instead of only disabling builds for packages there")
-@osc.cmdln.option('--distribution',
-                  help="Base distribution, necessary argument unless set previously for this project")
+@osc.cmdln.option('--distribution', metavar="DIST", nargs=1,
+                  help="Base distribution, necessary argument unless set previously for this project. "
+                       "Valid arguments are the names of any repository in the 'software' project.")
 @osc.cmdln.option('--microarchitecture', metavar="ARCH", nargs=1,
                   help="Configure project to use ARCH as microarchitecture, "
                        "defaults to 'sandybridge' or what has been set before in the "