diff --git a/.envrc b/.envrc
index 7ae2fb3..a475a37 100644
--- a/.envrc
+++ b/.envrc
@@ -1,3 +1,2 @@
 source $(fetchurl https://gitlab.com/rensa-nix/direnv/-/raw/v0.2.0/direnvrc "sha256-PFFxlZWNz/LLuNHA1Zpu2qdC3MF+oukv/TxFj5Utixk=")
-REN_FLAKE_ATTR=__std
 use ren //repo/devShells/default
diff --git a/.nix/repo/benchmark.nix b/.nix/repo/benchmark.nix
index 3afb05b..b80e1d4 100644
--- a/.nix/repo/benchmark.nix
+++ b/.nix/repo/benchmark.nix
@@ -1,10 +1,9 @@
-{
-  inputs,
-  cell,
-}: {
-  bench = inputs.nixpkgs.writeShellApplication {
+{inputs, ...}: let
+  inherit (inputs) pkgs;
+in {
+  bench = pkgs.writeShellApplication {
     name = "benchmark";
-    runtimeInputs = [inputs.nixpkgs.hyperfine];
+    runtimeInputs = [pkgs.hyperfine];
     text = ''
       echo "Comparison cases first:"
       hyperfine -w 3 \
diff --git a/.nix/repo/devShells.nix b/.nix/repo/devShells.nix
index 2ceb786..e8ce627 100644
--- a/.nix/repo/devShells.nix
+++ b/.nix/repo/devShells.nix
@@ -1,13 +1,10 @@
-{
-  inputs,
-  cell,
-}: let
-  devshell = import "${inputs.self}/lib" {
-    pkgs = inputs.nixpkgs;
-  };
+{inputs, ...}: let
+  inherit (inputs) pkgs devshell;
 in {
   default = devshell.mkShell {
-    packages = [inputs.nixpkgs.alejandra];
+    packages = [
+      pkgs.alejandra
+    ];
     env."HELLO".value = "world!";
     enterShellCommands.test = {
       text = "echo Hello $HELLO";
diff --git a/.nix/repo/flake.nix b/.nix/repo/flake.nix
index ff22c86..6e170ea 100644
--- a/.nix/repo/flake.nix
+++ b/.nix/repo/flake.nix
@@ -2,5 +2,10 @@
   inputs = {
     nixtest-lib.url = "gitlab:TECHNOFAB/nixtest?dir=lib";
   };
-  outputs = i: i;
+  outputs = i:
+    i
+    // {
+      ntlib = i.nixtest-lib.lib {inherit (i.parent) pkgs;};
+      devshell = import "${i.parent.self}/lib" {inherit (i.parent) pkgs;};
+    };
 }
diff --git a/.nix/repo/tests.nix b/.nix/repo/tests.nix
index e1b14b1..7d9bc36 100644
--- a/.nix/repo/tests.nix
+++ b/.nix/repo/tests.nix
@@ -1,10 +1,5 @@
-{
-  inputs,
-  cell,
-}: let
-  pkgs = inputs.nixpkgs;
-  ntlib = inputs.nixtest-lib.lib {inherit pkgs;};
-  devshell = import "${inputs.self}/lib" {inherit pkgs;};
+{inputs, ...}: let
+  inherit (inputs) pkgs ntlib devshell;
 in {
   tests = ntlib.mkNixtest {
     modules = ntlib.autodiscover {dir = "${inputs.self}/tests";};
diff --git a/flake.lock b/flake.lock
index 61c301a..54fbce9 100644
--- a/flake.lock
+++ b/flake.lock
@@ -60,11 +60,11 @@
     },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1753694789,
-        "narHash": "sha256-cKgvtz6fKuK1Xr5LQW/zOUiAC0oSQoA9nOISB0pJZqM=",
+        "lastModified": 1754498491,
+        "narHash": "sha256-erbiH2agUTD0Z30xcVSFcDHzkRvkRXOQ3lb887bcVrs=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "dc9637876d0dcc8c9e5e22986b857632effeb727",
+        "rev": "c2ae88e026f9525daf89587f3cbee584b92b6134",
         "type": "github"
       },
       "original": {
@@ -74,6 +74,21 @@
         "type": "github"
       }
     },
+    "nixpkgs-lib": {
+      "locked": {
+        "lastModified": 1754184128,
+        "narHash": "sha256-AjhoyBL4eSyXf01Bmc6DiuaMrJRNdWopmdnMY0Pa/M0=",
+        "owner": "nix-community",
+        "repo": "nixpkgs.lib",
+        "rev": "02e72200e6d56494f4a7c0da8118760736e41b60",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "nixpkgs.lib",
+        "type": "github"
+      }
+    },
     "nosys": {
       "locked": {
         "lastModified": 1668010795,
@@ -117,9 +132,30 @@
         "type": "github"
       }
     },
+    "ren": {
+      "inputs": {
+        "nixpkgs-lib": "nixpkgs-lib"
+      },
+      "locked": {
+        "dir": "lib",
+        "lastModified": 1755264589,
+        "narHash": "sha256-g8KjU4D/nxpMjCLQNP90VAAWUH89yvONRfChyhhzq4c=",
+        "owner": "rensa-nix",
+        "repo": "core",
+        "rev": "9f20f8c94b09a1c85356f8340ebe0a339b0d32e6",
+        "type": "gitlab"
+      },
+      "original": {
+        "dir": "lib",
+        "owner": "rensa-nix",
+        "repo": "core",
+        "type": "gitlab"
+      }
+    },
     "root": {
       "inputs": {
         "nixpkgs": "nixpkgs",
+        "ren": "ren",
         "std": "std"
       }
     },
diff --git a/flake.nix b/flake.nix
index 2f9ed7c..b7361ad 100644
--- a/flake.nix
+++ b/flake.nix
@@ -1,6 +1,7 @@
 {
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    ren.url = "gitlab:rensa-nix/core?dir=lib";
     std = {
       url = "github:divnix/std";
       inputs = {
@@ -15,20 +16,25 @@
 
   outputs = {
     self,
-    std,
+    ren,
     ...
   } @ inputs:
-    std.growOn
+    ren.buildWith
     {
       inherit inputs;
       cellsFrom = ./.nix;
-      cellBlocks = with std.blockTypes; [
-        (devshells "devShells")
-        (pkgs "tests")
-        (runnables "benchmark")
+      transformInputs = system: i:
+        i
+        // {
+          pkgs = import i.nixpkgs {inherit system;};
+        };
+      cellBlocks = with ren.blocks; [
+        (simple "devShells")
+        (simple "tests")
+        (simple "benchmark")
       ];
     }
     {
-      packages = std.harvest self [["repo" "tests"] ["repo" "benchmark"]];
+      packages = ren.select self [["repo" "tests"] ["repo" "benchmark"]];
     };
 }