diff --git a/README.md b/README.md
index eb4cfe4..4a5122b 100644
--- a/README.md
+++ b/README.md
@@ -105,3 +105,4 @@ What is not verified here: clicking through the actual browser UI. `devbox run s
 - Rotation is not revocation (§7): a stolen key can rotate onward and the chain validates. The UI surfaces rotations instead of applying them invisibly; out-of-band re-verification is the only defence.
 - The requests tier is a quota boundary the server enforces, not a filter: it does not refuse anyone's mail outright, which stays the reader's decision after decryption (§5.8).
 - The bridge binds to 127.0.0.1 by default and has no TLS of its own. Serving it beyond localhost directly is possible but unadvised: the relay is plaintext-agnostic (the traffic is already end-to-end encrypted, but the bridge would relay anyone's bytes to allowlisted ports). The NixOS module's `nginx.enable` puts a TLS-terminating reverse proxy in front instead, which is the deployment path "Deploy" above documents.
+- The relay is a proxy and is bounded as one, per the smolmail WebSocket annex: it relays only to allowlisted ports (`--allow-port`, checked per request) and refuses a WebSocket upgrade with a foreign `Origin`, so a page the user happens to visit cannot drive it. The annex's third bound is not implemented: `/tcp/{host}/{port}` dials any host the path names, including the loopback, private and link-local addresses of the machine the bridge runs on, which turns a public deployment into a door into the operator's own network. When implemented, the check belongs on the address the name resolved to, not on the name.
diff --git a/flake.nix b/flake.nix
index 70e9195..7b4e79b 100644
--- a/flake.nix
+++ b/flake.nix
@@ -16,7 +16,7 @@
       apps = forEachSystem (pkgs: {
         default = {
           type = "app";
-          program = pkgs.lib.getExe self.packages.${pkgs.system}.default;
+          program = pkgs.lib.getExe self.packages.${pkgs.stdenv.hostPlatform.system}.default;
         };
       });
 
diff --git a/nix/module.nix b/nix/module.nix
index f8d0f74..6fc01bc 100644
--- a/nix/module.nix
+++ b/nix/module.nix
@@ -15,8 +15,8 @@ in
       type = lib.types.package;
       default =
         if cfg.presetServer == null
-        then self.packages.${pkgs.system}.default
-        else self.packages.${pkgs.system}.default.override {
+        then self.packages.${pkgs.stdenv.hostPlatform.system}.default
+        else self.packages.${pkgs.stdenv.hostPlatform.system}.default.override {
           serverHost = cfg.presetServer.host;
           serverPublicKey = cfg.presetServer.publicKey;
         };