diff --git a/README.md b/README.md
index 1b638514..4a0a708e 100644
--- a/README.md
+++ b/README.md
@@ -116,6 +116,14 @@ lives at `/var/lib/nixos-containers/hive-matrix/`. Federation is
 enabled with an empty `trusted_servers` list; e2ee is deferred to
 a follow-up (#551).
 
+Optional: set `services.hyperhive.matrix.gui.enable = true;` to serve a
+[fluffychat-web](https://fluffychat.im) matrix client at `/matrix/`
+via the hive-gateway nginx container (see gateway option above). Disabled by default. The `◆ M4TR1X ◆ →`
+tab appears in the dashboard chrome when enabled. The web client can
+connect to any Matrix homeserver; enter the URL at first visit (e.g.
+the local tuwunel instance if `services.hyperhive.matrix.enable = true`, or
+any external homeserver).
+
 ## Agent configuration
 
 Per-agent settings live in each agent's `agent.nix` and are synced to