diff --git a/include/ircd/m/room.h b/include/ircd/m/room.h
index 0a5277dbf..30286cc4c 100644
--- a/include/ircd/m/room.h
+++ b/include/ircd/m/room.h
@@ -360,6 +360,7 @@ struct ircd::m::room::head
 
 	bool for_each(const closure_bool &) const;
 	void for_each(const closure &) const;
+	bool has(const event::id &) const;
 	size_t count() const;
 
 	head(const m::room &room)
diff --git a/ircd/m/room.cc b/ircd/m/room.cc
index 95cfb7102..6ecc5d5f7 100644
--- a/ircd/m/room.cc
+++ b/ircd/m/room.cc
@@ -1510,6 +1510,21 @@ const
 	return ret;
 }
 
+bool
+ircd::m::room::head::has(const event::id &event_id)
+const
+{
+	bool ret{false};
+	for_each(closure_bool{[&ret, &event_id]
+	(const event::idx &event_idx, const event::id &event_id_)
+	{
+		ret = event_id_ == event_id;
+		return !ret; // for_each protocol: false to break
+	}});
+
+	return ret;
+}
+
 void
 ircd::m::room::head::for_each(const closure &closure)
 const