diff --git a/src/lib/webrtc/broadcaster.ts b/src/lib/webrtc/broadcaster.ts
index fa4b7f6..4a0fb54 100644
--- a/src/lib/webrtc/broadcaster.ts
+++ b/src/lib/webrtc/broadcaster.ts
@@ -12,6 +12,8 @@ export interface BroadcasterHandle {
   code: string;
   stop: () => Promise<void>;
   onViewerCountChange: (cb: (n: number) => void) => () => void;
+  /** Swap the outgoing video track on every active peer (e.g. when the XR mirror canvas becomes available). */
+  replaceVideoTrack: (newStream: MediaStream) => Promise<void>;
 }
 
 const MAX_VIEWERS = 5;