diff --git a/include/ircd/m/vm.h b/include/ircd/m/vm.h
index bb89f4aee..4eebf6b72 100644
--- a/include/ircd/m/vm.h
+++ b/include/ircd/m/vm.h
@@ -119,6 +119,17 @@ struct ircd::m::vm::opts
 	/// update the optimized present state table of the room if it is proper.
 	bool present {true};
 
+	/// Toggles whether event may be added to the room head table which means
+	/// it is considered unreferenced by any other event at this time. It is
+	/// safe for this to always be true if events are evaluated in order. If
+	/// `present` is false this should be set to false but they are not tied.
+	bool head {true};
+
+	/// Toggles whether the prev_events of this event are removed from the
+	/// room head table, now that this event has referenced them. It is safe
+	/// for this to always be true.
+	bool refs {true};
+
 	/// Toggles whether the state btree is updated; this should be consistently
 	/// true or false for all events in a room.
 	bool history {true};
diff --git a/ircd/m/vm.cc b/ircd/m/vm.cc
index 3b25aa09c..ecec6e7a7 100644
--- a/ircd/m/vm.cc
+++ b/ircd/m/vm.cc
@@ -444,6 +444,8 @@ ircd::m::vm::_eval_pdu(eval &eval,
 	m::dbs::write_opts wopts;
 	wopts.present = opts.present;
 	wopts.history = opts.history;
+	wopts.head = opts.head;
+	wopts.refs = opts.refs;
 	wopts.idx = eval.sequence;
 
 	eval_hook(event);