diff --git a/include/ircd/m/filter.h b/include/ircd/m/filter.h
index ab545ea45..577265996 100644
--- a/include/ircd/m/filter.h
+++ b/include/ircd/m/filter.h
@@ -36,6 +36,8 @@ struct ircd::m::event_filter
 >
 {
 	using super_type::tuple;
+	event_filter(const mutable_buffer &, const json::members &);
+	event_filter() = default;
 	using super_type::operator=;
 };
 
diff --git a/ircd/m/filter.cc b/ircd/m/filter.cc
index d13ce3529..facee35fd 100644
--- a/ircd/m/filter.cc
+++ b/ircd/m/filter.cc
@@ -156,3 +156,12 @@ ircd::m::filter::get(std::nothrow_t,
 		closure(content);
 	});
 }
+
+ircd::m::event_filter::event_filter(const mutable_buffer &buf,
+                                    const json::members &members)
+:super_type::tuple
+{
+	json::stringify(mutable_buffer{buf}, members)
+}
+{
+}