diff --git a/Justfile b/Justfile
new file mode 100644
index 0000000..2e3573c
--- /dev/null
+++ b/Justfile
@@ -0,0 +1,15 @@
+system := `nix-instantiate --eval --raw -E builtins.currentSystem`
+
+help:
+  just -l
+
+ci:
+  just fmt -- --ci --no-cache
+  just test
+
+fmt *args:
+  nix run github:denful/checkmate#fmt --override-input target path:. {{args}}
+
+test *args:
+  nix flake check github:denful/checkmate --override-input target . {{args}}
+
diff --git a/checkmate/modules/formatter.nix b/checkmate/modules/formatter.nix
index 976cdf9..41301a2 100644
--- a/checkmate/modules/formatter.nix
+++ b/checkmate/modules/formatter.nix
@@ -2,5 +2,6 @@
   perSystem.treefmt.settings.global.excludes = [
     "checkmate/tree/*"
     "docs/*"
+    "Justfile"
   ];
 }
diff --git a/checkmate/modules/tests.nix b/checkmate/modules/tests.nix
index 7b15815..09aee13 100644
--- a/checkmate/modules/tests.nix
+++ b/checkmate/modules/tests.nix
@@ -260,6 +260,16 @@ in
           expr = lit.leafs ../tree/a/b/_c;
           expected = [ ../tree/a/b/_c/d/e.nix ];
         };
+
+        scoped."test adds attrs via scopedImport" = {
+          expr =
+            (lib.evalModules {
+              modules = [
+                ((lit.addScoped { foo = 22; }) ../tree/_scoped)
+              ];
+            }).config.foo;
+          expected = 22;
+        };
       };
 
     }
diff --git a/checkmate/tree/_scoped/foo.nix b/checkmate/tree/_scoped/foo.nix
new file mode 100644
index 0000000..8badecc
--- /dev/null
+++ b/checkmate/tree/_scoped/foo.nix
@@ -0,0 +1,4 @@
+{ lib, ... }:
+{
+  options.foo = lib.mkOption { default = foo; };
+}
diff --git a/default.nix b/default.nix
index d4f23a2..05adaf7 100644
--- a/default.nix
+++ b/default.nix
@@ -7,6 +7,7 @@ let
       filterf,
       mapf,
       paths,
+      scoped,
       ...
     }:
     path:
@@ -23,9 +24,19 @@ let
       module =
         { lib, ... }:
         {
-          imports = leafs lib path;
+          imports = (if scoped == { } then leafs else scoped-leafs) lib path;
         };
 
+      scoped-leafs =
+        lib: root:
+        map (builtins.scopedImport (
+          {
+            inherit builtins;
+            __nixPath = [ ];
+          }
+          // scoped
+        )) (leafs lib root);
+
       leafs =
         lib:
         let
@@ -144,6 +155,7 @@ let
         mapf = (i: i);
         filterf = _: true;
         paths = [ ];
+        scoped = { };
 
         # config is our state (initial at first). this functor allows it
         # to work as if it was a function, taking an update function
@@ -175,6 +187,7 @@ let
             match = regex: accAttr "filterf" (and (matchesRegex regex));
             matchNot = regex: accAttr "filterf" (andNot (matchesRegex regex));
             map = mapf: accAttr "mapf" (compose mapf);
+            addScoped = attrs: accAttr "scoped" (s: s // attrs);
             addPath = path: accAttr "paths" (p: p ++ [ path ]);
             addAPI = api: accAttr "api" (a: a // api);