diff --git a/NucleicRemote/NucleicRemote/Models/HostConnection.swift b/NucleicRemote/NucleicRemote/Models/HostConnection.swift
index 8c482e3..cfe8b0b 100644
--- a/NucleicRemote/NucleicRemote/Models/HostConnection.swift
+++ b/NucleicRemote/NucleicRemote/Models/HostConnection.swift
@@ -60,6 +60,9 @@ final class HostConnection {
         var wireError: (WireError) -> Void = { _ in }
         /// A pairing handshake succeeded — persist the pinned host record.
         var didPair: (PairedHost) -> Void = { _ in }
+        /// The mesh roster changed (mesh "join"): a Mac was learned or revoked via gossip — the
+        /// registry was updated, so (re)connect to every paired Mac and drop any that left.
+        var meshRosterChanged: () -> Void = {}
         /// The embedded Tailscale node's status changed (for Settings).
         var tailnetStatus: (String?, URL?) -> Void = { _, _ in }
     }