diff --git a/.envrc b/.envrc
new file mode 100644
index 0000000..3550a30
--- /dev/null
+++ b/.envrc
@@ -0,0 +1 @@
+use flake
diff --git a/.gitignore b/.gitignore
index c41aa9d..5b12f7f 100755
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 **/result
+.direnv
 
 .pre-commit-config.yaml
diff --git a/flake.nix b/flake.nix
index d67648e..7b3d88e 100755
--- a/flake.nix
+++ b/flake.nix
@@ -254,14 +254,29 @@
         pkgs.writeShellScriptBin "pre-commit-run" script
       );
 
-      checks = forEachSystem (system: {
-        pre-commit-check = inputs.git-hooks.lib.${system}.run {
-          src = ./.;
-          hooks = {
-            nixfmt.enable = true;
+      checks = forEachSystem (
+        system:
+        let
+          pkgs = import nixpkgs { inherit system; };
+        in
+        {
+          pre-commit-check = inputs.git-hooks.lib.${system}.run {
+            src = ./.;
+            hooks = {
+              nixfmt.enable = true;
+
+              check-comment = {
+                enable = true;
+                name = "check comment";
+                entry = "${pkgs.callPackage ./githooks/check-comment.nix { }}";
+                files = "\\.nix$";
+                pass_filenames = false;
+                stages = [ "pre-commit" ];
+              };
+            };
           };
-        };
-      });
+        }
+      );
 
       devShells = forEachSystem (system: {
         default =
diff --git a/githooks/check-comment.nix b/githooks/check-comment.nix
new file mode 100644
index 0000000..d1d44f0
--- /dev/null
+++ b/githooks/check-comment.nix
@@ -0,0 +1,19 @@
+{ pkgs, lib }:
+pkgs.writeShellScript "check-comment" ''
+  FILES=$("${lib.getExe pkgs.git}" diff --cached --name-only --diff-filter=ACM | grep '\.nix$' | grep -v '^githooks/check-comment.nix$')
+
+  TODO_FOUND=0
+
+  for file in $FILES; do
+    if grep -nHE '#\s*(TODO|FIXME|FIX):' "$file"; then
+      TODO_FOUND=1
+    fi
+  done
+
+  if [ $TODO_FOUND -eq 1 ]; then
+    echo "Remove all the '#TODO|FIXME|FIX' before committing"
+    exit 1
+  fi
+
+  exit 0
+''