diff --git a/nix/devshell.nix b/nix/devshell.nix
index 5935bc71..a42a5138 100644
--- a/nix/devshell.nix
+++ b/nix/devshell.nix
@@ -5,6 +5,7 @@
   perSystem = {pkgs, ...}: {
     devShells.default = pkgs.mkShell {
       packages = with pkgs; [
+        alejandra
         azure-cli
         git
         nix
diff --git a/tasks.py b/tasks.py
index 364a420a..9f30b90e 100644
--- a/tasks.py
+++ b/tasks.py
@@ -495,9 +495,10 @@ def pre_push(c: Any) -> None:
     if not ret:
         LOG.warning("Run `terraform fmt -recursive` locally to fix formatting")
         sys.exit(1)
-    cmd = "nix fmt"
+    cmd = "alejandra --check ."
     ret = exec_cmd(cmd, raise_on_error=False)
     if not ret:
+        LOG.warning("Run `nix fmt` locally to fix formatting")
         sys.exit(1)
     cmd = "nix flake check -v"
     ret = exec_cmd(cmd, raise_on_error=False)