diff --git a/client/internal/peer/handshaker.go b/client/internal/peer/handshaker.go
index fe8d1d0ec..e81fc4cf5 100644
--- a/client/internal/peer/handshaker.go
+++ b/client/internal/peer/handshaker.go
@@ -45,8 +45,10 @@ type OfferAnswer struct {
 	// when the peer does not run the ML-KEM PQ exchange.
 	MlkemPayload []byte
 
-	// MlkemPort is the peer's ML-KEM PQ service UDP port (bound on its WG overlay
-	// IP) where data-path rekey messages are sent. Zero when not running the exchange.
+	// MlkemPort is the peer's ML-KEM PQ service UDP port (bound on its WG overlay IP)
+	// where data-path rekey messages are sent. Zero means "not explicitly advertised,
+	// assume DefaultPort" — it does NOT indicate whether the peer runs the exchange;
+	// that is told by the presence of MlkemPayload / the manager's capability state.
 	MlkemPort uint16
 
 	// relay server address