diff --git a/default.nix b/default.nix
new file mode 100644
index 00000000..52387226
--- /dev/null
+++ b/default.nix
@@ -0,0 +1,19 @@
+{
+  pkgs ? import <nixpkgs> { },
+}:
+
+with pkgs;
+pkgs.mkShell {
+  name = "stoatEnv";
+
+  buildInputs = [
+    # Tools
+    git
+    gh
+    deno
+
+    # Node
+    nodejs
+    nodejs.pkgs.pnpm
+  ];
+}
diff --git a/src/events/v1.ts b/src/events/v1.ts
index 32821dd3..9a23a75b 100644
--- a/src/events/v1.ts
+++ b/src/events/v1.ts
@@ -322,7 +322,7 @@ export async function handleEvent(
       setReady(true);
       client.emit("ready");
 
-      if (event.policy_changes.length) {
+      if (event.policy_changes?.length) {
         client.emit("policyChanges", event.policy_changes, async () =>
           client.api.post("/policy/acknowledge"),
         );