diff --git a/.changeset/registry-cloud-transports.md b/.changeset/registry-cloud-transports.md
new file mode 100644
index 0000000..016ff47
--- /dev/null
+++ b/.changeset/registry-cloud-transports.md
@@ -0,0 +1,5 @@
+---
+"ftw-webapp": patch
+---
+
+Name how a session with FTW Cloud travels in the shared registry: `cloud_transports`, `quic` or `websocket`. The web app uses neither yet.
diff --git a/contract/registry.yaml b/contract/registry.yaml
index 10941ba..ca5bdb6 100644
--- a/contract/registry.yaml
+++ b/contract/registry.yaml
@@ -363,6 +363,11 @@ source_states: [live, lagging, stale, down, never]
 # tunnel is the box's own session carried by FTW Cloud, which cannot read it.
 # cloud is the box-signed copy FTW Cloud holds and can read.
 carrier_states: [webrtc, relay, tunnel, cloud, cache, none]
+# How a session with FTW Cloud travels, under the tunnel and cloud carriers:
+# QUIC on UDP 443, or the WebSocket on TCP 443 that a client falls back to
+# (srcfl/ftw docs/protocol-cloud.md, "QUIC"). It says nothing about
+# freshness, which stays carrier and source state.
+cloud_transports: [quic, websocket]
 
 # ---------------------------------------------------------------------------
 # History resolutions backed by what the box actually stores.