diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ba9c93e99..cb634280d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -47,6 +47,26 @@ jobs:
           signingKey: "VhaWuN3IyJVpWg+aZvTocVB+W8ziZKKRGLKR53Pkld3YRZxYOUfXZf0fvqF+LkqVW0eA60trVd5vsqNONpX9Hw=="
       - run: nix build -L ".#${{ matrix.attr }}" --keep-going
 
+  nix-build-shell:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os:
+          - ubuntu-latest
+          - macos-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: cachix/install-nix-action@v23
+      - uses: cachix/cachix-action@v12
+        with:
+          name: poetry2nix
+          signingKey: "VhaWuN3IyJVpWg+aZvTocVB+W8ziZKKRGLKR53Pkld3YRZxYOUfXZf0fvqF+LkqVW0eA60trVd5vsqNONpX9Hw=="
+      - name: compute system from nixpkgs
+        run: |
+          echo "NIXPKGS_SYSTEM=$(nix eval --raw 'nixpkgs#system')" >> "$GITHUB_ENV"
+      - run: nix build -L ".#devShells.${NIXPKGS_SYSTEM}.default" --keep-going
+
   test-template:
     runs-on: ${{ matrix.os }}
     strategy:
diff --git a/flake.nix b/flake.nix
index 94d580346..ce7e368d0 100644
--- a/flake.nix
+++ b/flake.nix
@@ -76,7 +76,7 @@
         };
 
         poetry2nix = import ./default.nix { inherit pkgs; };
-        p2nix-tools = pkgs.callPackage ./tools { };
+        p2nix-tools = pkgs.callPackage ./tools { inherit poetry2nix; };
       in
       rec {
         formatter = treefmtEval.${system}.config.build.wrapper;
diff --git a/tools/default.nix b/tools/default.nix
index 8e675b819..2759874d3 100644
--- a/tools/default.nix
+++ b/tools/default.nix
@@ -1,9 +1,4 @@
-{ pkgs ? import <nixpkgs> {
-    overlays = [
-      (import ../overlay.nix)
-    ];
-  }
-}:
+{ pkgs, poetry2nix }:
 let
   inherit (pkgs) lib;
 
@@ -36,7 +31,7 @@ in
       flamegraph.pl $workdir/traceFile.folded > poetry2nix-flamegraph.svg
     '';
 
-  env = pkgs.poetry2nix.mkPoetryEnv {
+  env = poetry2nix.mkPoetryEnv {
     projectDir = ./.;
   };