diff --git a/nixos/tests/radicale.nix b/nixos/tests/radicale.nix
index 66650dce4a00..868b28085a67 100644
--- a/nixos/tests/radicale.nix
+++ b/nixos/tests/radicale.nix
@@ -6,7 +6,7 @@ let
   port = "5232";
   filesystem_folder = "/data/radicale";
 
-  cli = "${pkgs.calendar-cli}/bin/calendar-cli --caldav-user ${user} --caldav-pass ${password}";
+  cli = "${lib.getExe pkgs.calendar-cli} --caldav-user ${user} --caldav-pass ${password}";
 in {
   name = "radicale3";
   meta.maintainers = with lib.maintainers; [ dotlambda ];
diff --git a/pkgs/tools/networking/calendar-cli/default.nix b/pkgs/tools/networking/calendar-cli/default.nix
index 45b3afbf895e..1aae34bf8989 100644
--- a/pkgs/tools/networking/calendar-cli/default.nix
+++ b/pkgs/tools/networking/calendar-cli/default.nix
@@ -36,6 +36,7 @@ python3.pkgs.buildPythonApplication rec {
     description = "Simple command-line CalDav client";
     homepage = "https://github.com/tobixen/calendar-cli";
     license = licenses.gpl3Plus;
+    mainProgram = "calendar-cli";
     maintainers = with maintainers; [ dotlambda ];
   };
 }