diff --git a/flake.nix b/flake.nix
index a1d8017..4b64464 100644
--- a/flake.nix
+++ b/flake.nix
@@ -29,6 +29,11 @@
         "aarch64-linux"
         "aarch64-darwin"
       ];
+
+      # Add overlay for custom packages
+      overlay = final: prev: {
+        hammerspoon = final.callPackage ./modules/hammerspoon.nix { };
+      };
     in
     {
       lib = {
@@ -85,6 +90,13 @@
             self = self;
           };
           modules = [
+            # Add our overlay to the system configuration
+            (
+              { pkgs, ... }:
+              {
+                nixpkgs.overlays = [ overlay ];
+              }
+            )
             mac-app-util.darwinModules.default
             ./darwin/common.nix
             ./darwin/lcech-mac-veracode.nix
diff --git a/home-manager/lcech-mac-veracode.nix b/home-manager/lcech-mac-veracode.nix
index 66a08d6..2783ce6 100644
--- a/home-manager/lcech-mac-veracode.nix
+++ b/home-manager/lcech-mac-veracode.nix
@@ -18,6 +18,7 @@ in
 
   home.packages = with pkgs; [
     awscli2
+    hammerspoon
     k9s
     kubectl
     nixd
@@ -35,6 +36,11 @@ in
         window-height = 9999
       '';
     };
+    "${homedir}/.hammerspoon/init.lua" = {
+      text = ''
+
+      '';
+    };
   };
 
   programs.direnv = {
diff --git a/modules/hammerspoon.nix b/modules/hammerspoon.nix
new file mode 100644
index 0000000..0fc6d6b
--- /dev/null
+++ b/modules/hammerspoon.nix
@@ -0,0 +1,41 @@
+{
+  lib,
+  stdenvNoCC,
+  fetchurl,
+  unzip,
+}:
+# This cannot be built from source since Hammerspoon requires entitlements to work,
+# and codesigning entitlements is unfortunately incompatible with immutability.
+stdenvNoCC.mkDerivation (self: {
+  pname = "hammerspoon";
+  version = "1.0.0";
+
+  # We don't use fetchzip because that seems to unpack the .app as well.
+  src = fetchurl {
+    name = "${self.pname}-${self.version}-source.zip";
+    url = "https://github.com/Hammerspoon/hammerspoon/releases/download/${self.version}/Hammerspoon-${self.version}.zip";
+    sha256 = "sha256-XbcCtV2kfcMG6PWUjZHvhb69MV3fopQoMioK9+1+an4=";
+  };
+
+  nativeBuildInputs = [
+    # Adds unpack hook.
+    unzip
+  ];
+
+  installPhase = ''
+    runHook preInstall
+    mkdir -p $out/Applications
+    cp -r ../Hammerspoon.app $out/Applications/
+    runHook postInstall
+  '';
+
+  meta = {
+    homepage = "https://www.hammerspoon.org";
+    description = "Staggeringly powerful macOS desktop automation with Lua";
+    license = lib.licenses.mit;
+    platforms = [
+      "x86_64-darwin"
+      "aarch64-darwin"
+    ];
+  };
+})