diff --git a/docs/plans/state.json b/docs/plans/state.json
index 535d01e..b42f976 100644
--- a/docs/plans/state.json
+++ b/docs/plans/state.json
@@ -60,7 +60,7 @@
       "status": "completed",
       "date": "2026-02-16",
       "updated": "2026-02-16",
-      "summary": "Added a Nix flake/package that builds dist/ (including dist/gateway/ui adjacency) and an optional NixOS module (services.flynn) for systemd deployment. Follow-up fixes switched package build from unavailable buildPnpmPackage to fetchPnpmDeps + stdenv.mkDerivation, migrated to pnpmConfigHook for current nixpkgs, and added flake.lock.",
+      "summary": "Added a Nix flake/package that builds dist/ (including dist/gateway/ui adjacency) and an optional NixOS module (services.flynn) for systemd deployment. Follow-up fixes switched package build from unavailable buildPnpmPackage to fetchPnpmDeps + stdenv.mkDerivation, migrated to pnpmConfigHook for current nixpkgs, added flake.lock, pinned dependency hash, and ensured pnpm is in nativeBuildInputs for hook execution.",
       "files_created": [
         "flake.nix",
         "nix/package.nix",
diff --git a/nix/package.nix b/nix/package.nix
index 31e5c1a..ef91323 100644
--- a/nix/package.nix
+++ b/nix/package.nix
@@ -34,6 +34,7 @@ pkgs.stdenv.mkDerivation rec {
 
   nativeBuildInputs = [
     pkgs.nodejs_22
+    pkgs.pnpm
     pkgs.pnpmConfigHook
     pkgs.makeWrapper
     pkgs.python3