diff --git a/stylix/cursor.nix b/stylix/cursor.nix
index 2e6b371d..a892e449 100644
--- a/stylix/cursor.nix
+++ b/stylix/cursor.nix
@@ -1,26 +1,47 @@
-{ lib, ... }:
+{ lib, config, ... }:
 
 {
   options.stylix.cursor = lib.mkOption {
-    description = "Attributes defining the systemwide cursor.";
+    description = ''
+      Attributes defining the systemwide cursor. Set either all or none of
+      these attributes.
+    '';
     type = lib.types.nullOr (
       lib.types.submodule {
         options = {
           name = lib.mkOption {
             description = "The cursor name within the package.";
-            type = lib.types.str;
+            type = lib.types.nullOr lib.types.str;
+            default = null;
           };
           package = lib.mkOption {
             description = "Package providing the cursor theme.";
-            type = lib.types.package;
+            type = lib.types.nullOr lib.types.package;
+            default = null;
           };
           size = lib.mkOption {
             description = "The cursor size.";
-            type = lib.types.int;
+            type = lib.types.nullOr lib.types.int;
+            default = null;
           };
         };
       }
     );
     default = null;
   };
+  config.assertions =
+    let
+      inherit (config.stylix) cursor;
+    in
+    [
+      {
+        assertion =
+          cursor == null
+          || cursor.name != null && cursor.package != null && cursor.size != null;
+        message = ''
+          stylix: `stylix.cursor` is only partially defined. Set either none or
+          all of the `stylix.cursor` options.
+        '';
+      }
+    ];
 }