diff --git a/src/donations.test.c b/src/donations.test.c
index e61ca2536..a3a428a73 100644
--- a/src/donations.test.c
+++ b/src/donations.test.c
@@ -13,7 +13,7 @@ static void test_add_donation(CuTest *tc) {
     region *r;
 
     test_setup();
-    mt_register(mt_new_va("donation", "from:faction", "to:faction", "amount:int", NULL));
+    mt_register(mt_new_va("donation", "from:faction", "to:faction", "amount:int", MT_NEW_END));
     r = test_create_region(0, 0, NULL);
     f1 = test_create_faction(NULL);
     f2 = test_create_faction(NULL);
diff --git a/src/economy.test.c b/src/economy.test.c
index d4322fef7..943ac2090 100644
--- a/src/economy.test.c
+++ b/src/economy.test.c
@@ -143,10 +143,10 @@ static struct unit *create_recruiter(void) {
 
 static void setup_production(void) {
     init_resources();
-    mt_register(mt_new_va("produce", "unit:unit", "region:region", "amount:int", "wanted:int", "resource:resource", NULL));
-    mt_register(mt_new_va("income", "unit:unit", "region:region", "amount:int", "wanted:int", "mode:int", NULL));
-    mt_register(mt_new_va("buy", "unit:unit", "money:int", NULL));
-    mt_register(mt_new_va("buyamount", "unit:unit", "amount:int", "resource:resource", NULL));
+    mt_register(mt_new_va("produce", "unit:unit", "region:region", "amount:int", "wanted:int", "resource:resource", MT_NEW_END));
+    mt_register(mt_new_va("income", "unit:unit", "region:region", "amount:int", "wanted:int", "mode:int", MT_NEW_END));
+    mt_register(mt_new_va("buy", "unit:unit", "money:int", MT_NEW_END));
+    mt_register(mt_new_va("buyamount", "unit:unit", "amount:int", "resource:resource", MT_NEW_END));
 }
 
 static void test_heroes_dont_recruit(CuTest * tc) {
@@ -377,11 +377,11 @@ static void test_tax_cmd(CuTest *tc) {
 }
 
 static void setup_economy(void) {
-    mt_register(mt_new_va("recruit", "unit:unit", "region:region", "amount:int", "want:int", NULL));
-    mt_register(mt_new_va("maintenance", "unit:unit", "building:building", NULL));
-    mt_register(mt_new_va("maintenancefail", "unit:unit", "building:building", NULL));
-    mt_register(mt_new_va("maintenance_nowork", "building:building", NULL));
-    mt_register(mt_new_va("maintenance_noowner", "building:building", NULL));
+    mt_register(mt_new_va("recruit", "unit:unit", "region:region", "amount:int", "want:int", MT_NEW_END));
+    mt_register(mt_new_va("maintenance", "unit:unit", "building:building", MT_NEW_END));
+    mt_register(mt_new_va("maintenancefail", "unit:unit", "building:building", MT_NEW_END));
+    mt_register(mt_new_va("maintenance_nowork", "building:building", MT_NEW_END));
+    mt_register(mt_new_va("maintenance_noowner", "building:building", MT_NEW_END));
 }
 
 /** 
diff --git a/src/give.test.c b/src/give.test.c
index 1f1985b6a..3e58216c9 100644
--- a/src/give.test.c
+++ b/src/give.test.c
@@ -54,24 +54,24 @@ static void setup_give(struct give *env) {
     }
 
     /* success messages: */
-    mt_register(mt_new_va("receive_person", "unit:unit", "target:unit", "amount:int", NULL));
-    mt_register(mt_new_va("give_person", "unit:unit", "target:unit", "amount:int", NULL));
-    mt_register(mt_new_va("give_person_peasants", "unit:unit", "amount:int", NULL));
-    mt_register(mt_new_va("give_person_ocean", "unit:unit", "amount:int", NULL));
-    mt_register(mt_new_va("receive", "unit:unit", "target:unit", "resource:resource", "amount:int", NULL));
-    mt_register(mt_new_va("give", "unit:unit", "target:unit", "resource:resource", "amount:int", NULL));
-    mt_register(mt_new_va("give_peasants", "unit:unit", "resource:resource", "amount:int", NULL));
+    mt_register(mt_new_va("receive_person", "unit:unit", "target:unit", "amount:int", MT_NEW_END));
+    mt_register(mt_new_va("give_person", "unit:unit", "target:unit", "amount:int", MT_NEW_END));
+    mt_register(mt_new_va("give_person_peasants", "unit:unit", "amount:int", MT_NEW_END));
+    mt_register(mt_new_va("give_person_ocean", "unit:unit", "amount:int", MT_NEW_END));
+    mt_register(mt_new_va("receive", "unit:unit", "target:unit", "resource:resource", "amount:int", MT_NEW_END));
+    mt_register(mt_new_va("give", "unit:unit", "target:unit", "resource:resource", "amount:int", MT_NEW_END));
+    mt_register(mt_new_va("give_peasants", "unit:unit", "resource:resource", "amount:int", MT_NEW_END));
     /* error messages: */
-    mt_register(mt_new_va("too_many_units_in_faction", "unit:unit", "region:region", "command:order", "allowed:int", NULL));
-    mt_register(mt_new_va("too_many_units_in_alliance", "unit:unit", "region:region", "command:order", "allowed:int", NULL));
-    mt_register(mt_new_va("feedback_no_contact", "unit:unit", "region:region", "command:order", "target:unit", NULL));
-    mt_register(mt_new_va("feedback_give_forbidden", "unit:unit", "region:region", "command:order", NULL));
-    mt_register(mt_new_va("peasants_give_invalid", "unit:unit", "region:region", "command:order", NULL));
-    mt_register(mt_new_va("giverestriction", "unit:unit", "region:region", "command:order", "turns:int", NULL));
-    mt_register(mt_new_va("error_unit_size", "unit:unit", "region:region", "command:order", "maxsize:int", NULL));
-    mt_register(mt_new_va("nogive_reserved", "unit:unit", "region:region", "command:order", "resource:resource", "reservation:int", NULL));
-    mt_register(mt_new_va("race_notake", "unit:unit", "region:region", "command:order", "race:race", NULL));
-    mt_register(mt_new_va("race_noregroup", "unit:unit", "region:region", "command:order", "race:race", NULL));
+    mt_register(mt_new_va("too_many_units_in_faction", "unit:unit", "region:region", "command:order", "allowed:int", MT_NEW_END));
+    mt_register(mt_new_va("too_many_units_in_alliance", "unit:unit", "region:region", "command:order", "allowed:int", MT_NEW_END));
+    mt_register(mt_new_va("feedback_no_contact", "unit:unit", "region:region", "command:order", "target:unit", MT_NEW_END));
+    mt_register(mt_new_va("feedback_give_forbidden", "unit:unit", "region:region", "command:order", MT_NEW_END));
+    mt_register(mt_new_va("peasants_give_invalid", "unit:unit", "region:region", "command:order", MT_NEW_END));
+    mt_register(mt_new_va("giverestriction", "unit:unit", "region:region", "command:order", "turns:int", MT_NEW_END));
+    mt_register(mt_new_va("error_unit_size", "unit:unit", "region:region", "command:order", "maxsize:int", MT_NEW_END));
+    mt_register(mt_new_va("nogive_reserved", "unit:unit", "region:region", "command:order", "resource:resource", "reservation:int", MT_NEW_END));
+    mt_register(mt_new_va("race_notake", "unit:unit", "region:region", "command:order", "race:race", MT_NEW_END));
+    mt_register(mt_new_va("race_noregroup", "unit:unit", "region:region", "command:order", "race:race", MT_NEW_END));
 }
 
 static void test_give_unit(CuTest * tc) {
diff --git a/src/kernel/build.test.c b/src/kernel/build.test.c
index ece28f4eb..d7a12325d 100644
--- a/src/kernel/build.test.c
+++ b/src/kernel/build.test.c
@@ -256,7 +256,7 @@ static void test_build_destroy_road(CuTest *tc)
     message *m;
 
     test_setup();
-    mt_register(mt_new_va("destroy_road", "unit:unit", "from:region", "to:region", NULL));
+    mt_register(mt_new_va("destroy_road", "unit:unit", "from:region", "to:region", MT_NEW_END));
     r2 = test_create_region(1, 0, 0);
     r = test_create_region(0, 0, NULL);
     rsetroad(r, D_EAST, 100);
diff --git a/src/kernel/messages.c b/src/kernel/messages.c
index 03883f127..d14ad4740 100644
--- a/src/kernel/messages.c
+++ b/src/kernel/messages.c
@@ -162,7 +162,7 @@ static message *missing_message(const char *name) {
         log_warning("trying to create undefined message of type \"%s\"\n", name);
         if (strcmp(name, "missing_message") != 0) {
             if (!mt_find("missing_message")) {
-                mt_register(mt_new_va("missing_message", "name:string", NULL));
+                mt_register(mt_new_va("missing_message", "name:string", MT_NEW_END));
             }
             return msg_message("missing_message", "name", name);
         }
diff --git a/src/laws.test.c b/src/laws.test.c
index 5edde187d..17de35fa1 100644
--- a/src/laws.test.c
+++ b/src/laws.test.c
@@ -257,7 +257,7 @@ static void test_force_leave_buildings(CuTest *tc) {
     building * b;
 
     test_setup();
-    mt_register(mt_new_va("force_leave_building", "unit:unit", "owner:unit", "building:building", NULL));
+    mt_register(mt_new_va("force_leave_building", "unit:unit", "owner:unit", "building:building", MT_NEW_END));
     r = test_create_region(0, 0, test_create_terrain("plain", LAND_REGION));
     u1 = test_create_unit(test_create_faction(NULL), r);
     u2 = test_create_unit(u1->faction, r);
@@ -287,7 +287,7 @@ static void test_force_leave_ships(CuTest *tc) {
     ship *sh;
 
     test_setup();
-    mt_register(mt_new_va("force_leave_ship", "unit:unit", "owner:unit", "ship:ship", NULL));
+    mt_register(mt_new_va("force_leave_ship", "unit:unit", "owner:unit", "ship:ship", MT_NEW_END));
     r = test_create_region(0, 0, test_create_terrain("plain", LAND_REGION));
     u1 = test_create_unit(test_create_faction(NULL), r);
     u2 = test_create_unit(test_create_faction(NULL), r);
@@ -875,7 +875,7 @@ static void test_luck_message(CuTest *tc) {
     attrib *a;
 
     test_setup();
-    mt_register(mt_new_va("peasantluck_success", "births:int", NULL));
+    mt_register(mt_new_va("peasantluck_success", "births:int", MT_NEW_END));
     setup_terrains(tc);
     r = test_create_region(0, 0, NULL);
     rsetpeasants(r, 1);
@@ -900,8 +900,8 @@ static unit * setup_name_cmd(void) {
     faction *f;
 
     test_setup();
-    mt_register(mt_new_va("renamed_building_seen", "renamer:unit", "region:region", "building:building", NULL));
-    mt_register(mt_new_va("renamed_building_notseen", "region:region", "building:building", NULL));
+    mt_register(mt_new_va("renamed_building_seen", "renamer:unit", "region:region", "building:building", MT_NEW_END));
+    mt_register(mt_new_va("renamed_building_notseen", "region:region", "building:building", MT_NEW_END));
     f = test_create_faction(NULL);
     return test_create_unit(f, test_create_region(0, 0, NULL));
 }
@@ -1300,9 +1300,9 @@ static void test_ally_cmd(CuTest *tc) {
 static void test_nmr_warnings(CuTest *tc) {
     faction *f1, *f2;
     test_setup();
-    mt_register(mt_new_va("nmr_warning", NULL));
-    mt_register(mt_new_va("nmr_warning_final", NULL));
-    mt_register(mt_new_va("warn_dropout", "faction:faction", "turn:int", NULL));
+    mt_register(mt_new_va("nmr_warning", MT_NEW_END));
+    mt_register(mt_new_va("nmr_warning_final", MT_NEW_END));
+    mt_register(mt_new_va("warn_dropout", "faction:faction", "turn:int", MT_NEW_END));
     config_set("nmr.timeout", "3");
     f1 = test_create_faction(NULL);
     f2 = test_create_faction(NULL);
@@ -1324,9 +1324,9 @@ static unit * setup_mail_cmd(void) {
     faction *f;
     
     test_setup();
-    mt_register(mt_new_va("regionmessage", "region:region", "sender:unit", "string:string", NULL));
-    mt_register(mt_new_va("unitmessage", "region:region", "sender:unit", "string:string", "unit:unit", NULL));
-    mt_register(mt_new_va("mail_result", "message:string", "unit:unit", NULL));
+    mt_register(mt_new_va("regionmessage", "region:region", "sender:unit", "string:string", MT_NEW_END));
+    mt_register(mt_new_va("unitmessage", "region:region", "sender:unit", "string:string", "unit:unit", MT_NEW_END));
+    mt_register(mt_new_va("mail_result", "message:string", "unit:unit", MT_NEW_END));
     f = test_create_faction(NULL);
     return test_create_unit(f, test_create_region(0, 0, NULL));
 }
@@ -1443,7 +1443,7 @@ static void test_show_without_item(CuTest *tc)
     struct locale *loc;
 
     test_setup();
-    mt_register(mt_new_va("displayitem", "weight:int", "item:resource", "description:string", NULL));
+    mt_register(mt_new_va("displayitem", "weight:int", "item:resource", "description:string", MT_NEW_END));
 
     loc = get_or_create_locale("de");
     locale_setstring(loc, parameters[P_ANY], "ALLE");
@@ -1488,7 +1488,7 @@ static void test_show_race(CuTest *tc) {
 
     test_setup();
 
-    mt_register(mt_new_va("msg_event", "string:string", NULL));
+    mt_register(mt_new_va("msg_event", "string:string", MT_NEW_END));
     test_create_race("human");
     rc = test_create_race("elf");
 
@@ -1528,8 +1528,8 @@ static void test_show_both(CuTest *tc) {
     message * msg;
 
     test_setup();
-    mt_register(mt_new_va("msg_event", "string:string", NULL));
-    mt_register(mt_new_va("displayitem", "weight:int", "item:resource", "description:string", NULL));
+    mt_register(mt_new_va("msg_event", "string:string", MT_NEW_END));
+    mt_register(mt_new_va("displayitem", "weight:int", "item:resource", "description:string", MT_NEW_END));
     rc = test_create_race("elf");
     test_create_itemtype("elvenhorse");
 
diff --git a/src/market.test.c b/src/market.test.c
index 1fc8307fa..452f75091 100644
--- a/src/market.test.c
+++ b/src/market.test.c
@@ -33,7 +33,7 @@ static void test_market_curse(CuTest * tc)
     building_type *btype;
 
     test_setup();
-    mt_register(mt_new_va("buyamount", "unit:unit", "amount:int", "resource:resource", NULL));
+    mt_register(mt_new_va("buyamount", "unit:unit", "amount:int", "resource:resource", MT_NEW_END));
 
     htype = test_create_itemtype("herb");
     htype->flags |= ITF_HERB;
diff --git a/src/monsters.test.c b/src/monsters.test.c
index 32efc6a4c..47ae526f4 100644
--- a/src/monsters.test.c
+++ b/src/monsters.test.c
@@ -48,7 +48,7 @@ static void create_monsters(unit **up, unit **um) {
     region *r;
     faction *fp, *fm;
 
-    mt_register(mt_new_va("dragon_growl", "dragon:unit", "number:int", "target:region", "growl:string", NULL));
+    mt_register(mt_new_va("dragon_growl", "dragon:unit", "number:int", "target:region", "growl:string", MT_NEW_END));
     test_create_horse();
     default_locale = test_create_locale();
     fp = test_create_faction(NULL);
@@ -216,7 +216,7 @@ static void test_dragon_moves(CuTest * tc)
     plan_monsters(m->faction);
     CuAssertPtrNotNull(tc, find_order("move east", m));
 
-    mt_register(mt_new_va("dragon_growl", "dragon:unit", "number:int", "target:region", "growl:string", NULL));
+    mt_register(mt_new_va("dragon_growl", "dragon:unit", "number:int", "target:region", "growl:string", MT_NEW_END));
 
     random_growl(m, findregion(1, 0), 3);
 
diff --git a/src/move.test.c b/src/move.test.c
index 3aca0c2ab..3c8dccf32 100644
--- a/src/move.test.c
+++ b/src/move.test.c
@@ -28,8 +28,8 @@
 #include <assert.h>
 
 static void setup_move(void) {
-    mt_register(mt_new_va("travel", "unit:unit", "start:region", "end:region", "mode:int", "regions:regions", NULL));
-    mt_register(mt_new_va("moveblocked", "unit:unit", "direction:int", NULL));
+    mt_register(mt_new_va("travel", "unit:unit", "start:region", "end:region", "mode:int", "regions:regions", MT_NEW_END));
+    mt_register(mt_new_va("moveblocked", "unit:unit", "direction:int", MT_NEW_END));
 }
 
 static void test_ship_not_allowed_in_coast(CuTest * tc)
@@ -285,9 +285,9 @@ void setup_drift (struct drift_fixture *fix) {
     u_set_ship(fix->u, fix->sh = test_create_ship(fix->u->region, fix->st_boat));
     assert(fix->sh);
 
-    mt_register(mt_new_va("ship_drift", "ship:ship", "dir:int", NULL));
-    mt_register(mt_new_va("shipsink", "ship:ship", NULL));
-    mt_register(mt_new_va("massive_overload", "ship:ship", NULL));
+    mt_register(mt_new_va("ship_drift", "ship:ship", "dir:int", MT_NEW_END));
+    mt_register(mt_new_va("shipsink", "ship:ship", MT_NEW_END));
+    mt_register(mt_new_va("massive_overload", "ship:ship", MT_NEW_END));
 }
 
 static void test_ship_no_overload(CuTest *tc) {
@@ -482,7 +482,7 @@ static void test_follow_ship_msg(CuTest * tc) {
     td->dir = D_NORTHWEST;
     td->age = 2;
 
-    mt_register(mt_new_va("error18", "unit:unit", "region:region", "command:order", NULL));
+    mt_register(mt_new_va("error18", "unit:unit", "region:region", "command:order", MT_NEW_END));
 
     init_order_depr(ord);
     getstrtoken();
diff --git a/src/orderfile.test.c b/src/orderfile.test.c
index 500c68fdf..904814856 100644
--- a/src/orderfile.test.c
+++ b/src/orderfile.test.c
@@ -63,7 +63,7 @@ static void test_faction_password_bad(CuTest *tc) {
     const char *orders[] = { "ERESSEA 1 password", NULL };
 
     test_setup();
-    mt_register(mt_new_va("wrongpasswd", "password:string", NULL));
+    mt_register(mt_new_va("wrongpasswd", "password:string", MT_NEW_END));
 
     f = test_create_faction(NULL);
     renumber_faction(f, 1);
diff --git a/src/piracy.test.c b/src/piracy.test.c
index 22f5ccc5a..110dc3dcf 100644
--- a/src/piracy.test.c
+++ b/src/piracy.test.c
@@ -30,12 +30,12 @@ static void setup_piracy(void) {
     st_boat = test_create_shiptype("boat");
     st_boat->cargo = 1000;
 
-    mt_register(mt_new_va("piratenovictim", "ship:ship", "unit:unit", "region:region", NULL));
-    mt_register(mt_new_va("piratesawvictim", "ship:ship", "unit:unit", "region:region", "dir:int", NULL));
-    mt_register(mt_new_va("shipsail", "ship:ship", "from:region", "to:region", NULL));
-    mt_register(mt_new_va("shipfly", "ship:ship", "from:region", "to:region", NULL));
-    mt_register(mt_new_va("shipnoshore", "ship:ship", "region:region", NULL));
-    mt_register(mt_new_va("travel", "unit:unit", "start:region", "end:region", "mode:int", "regions:regions", NULL));
+    mt_register(mt_new_va("piratenovictim", "ship:ship", "unit:unit", "region:region", MT_NEW_END));
+    mt_register(mt_new_va("piratesawvictim", "ship:ship", "unit:unit", "region:region", "dir:int", MT_NEW_END));
+    mt_register(mt_new_va("shipsail", "ship:ship", "from:region", "to:region", MT_NEW_END));
+    mt_register(mt_new_va("shipfly", "ship:ship", "from:region", "to:region", MT_NEW_END));
+    mt_register(mt_new_va("shipnoshore", "ship:ship", "region:region", MT_NEW_END));
+    mt_register(mt_new_va("travel", "unit:unit", "start:region", "end:region", "mode:int", "regions:regions", MT_NEW_END));
 }
 
 static void setup_pirate(unit **pirate, int p_r_flags, int p_rc_flags, const char *p_shiptype,
diff --git a/src/renumber.test.c b/src/renumber.test.c
index 0c2030379..f176cc3d2 100644
--- a/src/renumber.test.c
+++ b/src/renumber.test.c
@@ -38,7 +38,7 @@ static void test_renumber_faction_duplicate(CuTest *tc) {
     const struct locale *lang;
 
     test_setup_ex(tc);
-    mt_register(mt_new_va("renumber_inuse", "id:int", NULL));
+    mt_register(mt_new_va("renumber_inuse", "id:int", MT_NEW_END));
     f2 = test_create_faction(NULL);
     u = test_create_unit(f = test_create_faction(NULL), test_create_region(0, 0, NULL));
     no = f->no;
diff --git a/src/spells.test.c b/src/spells.test.c
index e151e7680..dc0644ecc 100644
--- a/src/spells.test.c
+++ b/src/spells.test.c
@@ -130,8 +130,8 @@ static void test_view_reality(CuTest *tc) {
 
     test_setup();
     setup_spells();
-    mt_register(mt_new_va("spell_astral_only", "unit:unit", "region:region", "command:order", NULL));
-    mt_register(mt_new_va("viewreality_effect", "unit:unit", NULL));
+    mt_register(mt_new_va("spell_astral_only", "unit:unit", "region:region", "command:order", MT_NEW_END));
+    mt_register(mt_new_va("viewreality_effect", "unit:unit", MT_NEW_END));
     r = test_create_region(0, 0, NULL);
     ra = test_create_region(real2tp(r->x), real2tp(r->y), NULL);
     ra->_plane = get_astralplane();
diff --git a/src/spells/flyingship.test.c b/src/spells/flyingship.test.c
index 3459adcd3..4440c5fdf 100644
--- a/src/spells/flyingship.test.c
+++ b/src/spells/flyingship.test.c
@@ -29,7 +29,7 @@ static void test_flyingship(CuTest * tc)
     ship *sh1, *sh2;
 
     test_setup();
-    mt_register(mt_new_va("flying_ship_result", "mage:unit", "ship:ship", NULL));
+    mt_register(mt_new_va("flying_ship_result", "mage:unit", "ship:ship", MT_NEW_END));
 
     par.param = &par_data_ptr;
     par_data.typ = SPP_SHIP;
diff --git a/src/spells/magicresistance.test.c b/src/spells/magicresistance.test.c
index ccce0216c..86a66bc0e 100644
--- a/src/spells/magicresistance.test.c
+++ b/src/spells/magicresistance.test.c
@@ -29,7 +29,7 @@ static void test_magicresistance_unit(CuTest *tc) {
     curse *c;
 
     test_setup();
-    mt_register(mt_new_va("magicresistance_unit", "unit:unit", "id:int", NULL));
+    mt_register(mt_new_va("magicresistance_unit", "unit:unit", "id:int", MT_NEW_END));
     r = test_create_plain(0, 0);
     f1 = test_create_faction(NULL);
     u1 = test_create_unit(f1, r);
@@ -57,7 +57,7 @@ static void test_magicresistance_building(CuTest *tc) {
     curse *c;
 
     test_setup();
-    mt_register(mt_new_va("magicresistance_building", "building:building", "id:int", NULL));
+    mt_register(mt_new_va("magicresistance_building", "building:building", "id:int", MT_NEW_END));
     r = test_create_plain(0, 0);
     f1 = test_create_faction(NULL);
     u1 = test_create_unit(f1, r);
diff --git a/src/spy.test.c b/src/spy.test.c
index 79108f03b..c6a74822c 100644
--- a/src/spy.test.c
+++ b/src/spy.test.c
@@ -33,19 +33,19 @@ typedef struct {
 } spy_fixture;
 
 static void setup_spy(spy_fixture *fix) {
-    mt_register(mt_new_va("spyreport", "spy:unit", "target:unit", "status:int", NULL));
-    mt_register(mt_new_va("spyreport_mage", "spy:unit", "target:unit", "type:int", NULL));
-    mt_register(mt_new_va("spyreport_faction", "spy:unit", "target:unit", "faction:faction", NULL));
-    mt_register(mt_new_va("spyreport_skills", "spy:unit", "target:unit", "skills:string", NULL));
-    mt_register(mt_new_va("spyreport_items", "spy:unit", "target:unit", "items:items", NULL));
-    mt_register(mt_new_va("destroy_ship_0", "unit:unit", "ship:ship", NULL));
-    mt_register(mt_new_va("destroy_ship_1", "unit:unit", "ship:ship", NULL));
-    mt_register(mt_new_va("destroy_ship_2", "unit:unit", "ship:ship", NULL));
-    mt_register(mt_new_va("destroy_ship_3", "ship:ship", NULL));
-    mt_register(mt_new_va("destroy_ship_4", "ship:ship", NULL));
-    mt_register(mt_new_va("sink_msg", "ship:ship", "region:region", NULL));
-    mt_register(mt_new_va("sink_lost_msg", "unit:unit", "region:region", "dead:int", NULL));
-    mt_register(mt_new_va("sink_saved_msg", "unit:unit", "region:region", NULL));
+    mt_register(mt_new_va("spyreport", "spy:unit", "target:unit", "status:int", MT_NEW_END));
+    mt_register(mt_new_va("spyreport_mage", "spy:unit", "target:unit", "type:int", MT_NEW_END));
+    mt_register(mt_new_va("spyreport_faction", "spy:unit", "target:unit", "faction:faction", MT_NEW_END));
+    mt_register(mt_new_va("spyreport_skills", "spy:unit", "target:unit", "skills:string", MT_NEW_END));
+    mt_register(mt_new_va("spyreport_items", "spy:unit", "target:unit", "items:items", MT_NEW_END));
+    mt_register(mt_new_va("destroy_ship_0", "unit:unit", "ship:ship", MT_NEW_END));
+    mt_register(mt_new_va("destroy_ship_1", "unit:unit", "ship:ship", MT_NEW_END));
+    mt_register(mt_new_va("destroy_ship_2", "unit:unit", "ship:ship", MT_NEW_END));
+    mt_register(mt_new_va("destroy_ship_3", "ship:ship", MT_NEW_END));
+    mt_register(mt_new_va("destroy_ship_4", "ship:ship", MT_NEW_END));
+    mt_register(mt_new_va("sink_msg", "ship:ship", "region:region", MT_NEW_END));
+    mt_register(mt_new_va("sink_lost_msg", "unit:unit", "region:region", "dead:int", MT_NEW_END));
+    mt_register(mt_new_va("sink_saved_msg", "unit:unit", "region:region", MT_NEW_END));
 
     if (fix) {
         fix->r = test_create_region(0, 0, NULL);
diff --git a/src/study.test.c b/src/study.test.c
index b89d0ed07..46722c0f6 100644
--- a/src/study.test.c
+++ b/src/study.test.c
@@ -58,9 +58,9 @@ typedef struct {
 } study_fixture;
 
 static void setup_study(void) {
-    mt_register(mt_new_va("studycost", "unit:unit", "region:region", "cost:int", "skill:int", NULL));
-    mt_register(mt_new_va("teach_teacher", "teacher:unit", "student:unit", "skill:int", "level:int", NULL));
-    mt_register(mt_new_va("teach_student", "teacher:unit", "student:unit", "skill:int", NULL));
+    mt_register(mt_new_va("studycost", "unit:unit", "region:region", "cost:int", "skill:int", MT_NEW_END));
+    mt_register(mt_new_va("teach_teacher", "teacher:unit", "student:unit", "skill:int", "level:int", MT_NEW_END));
+    mt_register(mt_new_va("teach_student", "teacher:unit", "student:unit", "skill:int", MT_NEW_END));
 }
 
 static void setup_locale(struct locale *lang) {
@@ -218,7 +218,7 @@ static void test_academy_building(CuTest *tc) {
     message * msg;
 
     test_setup();
-    mt_register(mt_new_va("teach_asgood", "unit:unit", "region:region", "command:order", "student:unit", NULL));
+    mt_register(mt_new_va("teach_asgood", "unit:unit", "region:region", "command:order", "student:unit", MT_NEW_END));
 
     random_source_inject_constant(0.0);
     init_resources();
@@ -636,8 +636,8 @@ static void test_teach_message(CuTest *tc) {
     teaching_info *teach;
 
     test_setup();
-    mt_register(mt_new_va("teach_teacher", "teacher:unit", "student:unit", "skill:int", "level:int", NULL));
-    mt_register(mt_new_va("teach_student", "teacher:unit", "student:unit", "skill:int", NULL));
+    mt_register(mt_new_va("teach_teacher", "teacher:unit", "student:unit", "skill:int", "level:int", MT_NEW_END));
+    mt_register(mt_new_va("teach_student", "teacher:unit", "student:unit", "skill:int", MT_NEW_END));
     init_resources();
     u = test_create_unit(test_create_faction(NULL), test_create_region(0, 0, NULL));
     scale_number(u, 20);
diff --git a/src/tests.c b/src/tests.c
index 18ecdef34..282814148 100644
--- a/src/tests.c
+++ b/src/tests.c
@@ -231,9 +231,9 @@ static void test_reset(void) {
     }
     random_source_reset();
 
-    mt_register(mt_new_va("changepasswd", "value:string", NULL));
-    mt_register(mt_new_va("starvation", "unit:unit", "region:region", "dead:int", "live:int", NULL));
-    mt_register(mt_new_va("malnourish", "unit:unit", "region:region", NULL));
+    mt_register(mt_new_va("changepasswd", "value:string", MT_NEW_END));
+    mt_register(mt_new_va("starvation", "unit:unit", "region:region", "dead:int", "live:int", MT_NEW_END));
+    mt_register(mt_new_va("malnourish", "unit:unit", "region:region", MT_NEW_END));
 
     if (errno) {
         int error = errno;
diff --git a/src/triggers/shock.test.c b/src/triggers/shock.test.c
index 314c877df..dad675e64 100644
--- a/src/triggers/shock.test.c
+++ b/src/triggers/shock.test.c
@@ -12,7 +12,7 @@
 #include <CuTest.h>
 
 static void shock_setup(void) {
-    mt_register(mt_new_va("shock", "mage:unit", "reason:string", NULL));
+    mt_register(mt_new_va("shock", "mage:unit", "reason:string", MT_NEW_END));
 }
 
 static void test_shock(CuTest *tc) {
diff --git a/src/util/message.h b/src/util/message.h
index 5937fb83e..7521b8e24 100644
--- a/src/util/message.h
+++ b/src/util/message.h
@@ -45,8 +45,9 @@ extern "C" {
     void mt_clear(void);
     struct message_type *mt_new(const char *name, const char *args[]);
     struct message_type *mt_new_va(const char *name, ...);
+#define MT_NEW_END ((const char *)0)
     /* mt_new("simple_sentence", "subject:string", "predicate:string",
-     *        "object:string", "lang:locale", NULL); */
+     *        "object:string", "lang:locale", MT_NEW_END); */
 
     struct message *msg_create(const struct message_type *type,
         variant args[]);
diff --git a/src/util/message.test.c b/src/util/message.test.c
index e86b3aa38..4b00b4006 100644
--- a/src/util/message.test.c
+++ b/src/util/message.test.c
@@ -8,7 +8,7 @@ static void test_mt_new(CuTest *tc)
 {
     message_type *mt;
     test_setup();
-    mt = mt_new_va("test", "name:string", "number:int", NULL);
+    mt = mt_new_va("test", "name:string", "number:int", MT_NEW_END);
     mt_register(mt);
     CuAssertPtrNotNull(tc, mt);
     CuAssertStrEquals(tc, "test", mt->name);
diff --git a/src/volcano.test.c b/src/volcano.test.c
index bc2aa2165..8a8358c1c 100644
--- a/src/volcano.test.c
+++ b/src/volcano.test.c
@@ -20,7 +20,7 @@ static void test_volcano_update(CuTest *tc) {
     const struct terrain_type *t_volcano, *t_active;
     
     test_setup();
-    mt_register(mt_new_va("volcanostopsmoke", "region:region", NULL));
+    mt_register(mt_new_va("volcanostopsmoke", "region:region", MT_NEW_END));
     t_volcano = test_create_terrain("volcano", LAND_REGION);
     t_active = test_create_terrain("activevolcano", LAND_REGION);
     r = test_create_region(0, 0, t_active);
@@ -42,9 +42,9 @@ static void test_volcano_outbreak(CuTest *tc) {
     const struct terrain_type *t_volcano, *t_active;
     
     test_setup();
-    mt_register(mt_new_va("volcanooutbreak", "regionv:region", "regionn:region", NULL));
-    mt_register(mt_new_va("volcanooutbreaknn", "region:region", NULL));
-    mt_register(mt_new_va("volcano_dead", "unit:unit", "region:region", "dead:int", NULL));
+    mt_register(mt_new_va("volcanooutbreak", "regionv:region", "regionn:region", MT_NEW_END));
+    mt_register(mt_new_va("volcanooutbreaknn", "region:region", MT_NEW_END));
+    mt_register(mt_new_va("volcano_dead", "unit:unit", "region:region", "dead:int", MT_NEW_END));
     t_volcano = test_create_terrain("volcano", LAND_REGION);
     t_active = test_create_terrain("activevolcano", LAND_REGION);
     r = test_create_region(0, 0, t_active);
diff --git a/src/wormhole.test.c b/src/wormhole.test.c
index eafa86572..e275d4d67 100644
--- a/src/wormhole.test.c
+++ b/src/wormhole.test.c
@@ -19,10 +19,10 @@ void sort_wormhole_regions(selist *rlist, region **match, int count);
 void make_wormholes(region **match, int count, const building_type *bt_wormhole);
 
 static void setup_wormholes(void) {
-    mt_register(mt_new_va("wormhole_appear", "region:region", NULL));
-    mt_register(mt_new_va("wormhole_dissolve", "region:region", NULL));
-    mt_register(mt_new_va("wormhole_exit", "unit:unit", "region:region", NULL));
-    mt_register(mt_new_va("wormhole_requirements", "unit:unit", "region:region", NULL));
+    mt_register(mt_new_va("wormhole_appear", "region:region", MT_NEW_END));
+    mt_register(mt_new_va("wormhole_dissolve", "region:region", MT_NEW_END));
+    mt_register(mt_new_va("wormhole_exit", "unit:unit", "region:region", MT_NEW_END));
+    mt_register(mt_new_va("wormhole_requirements", "unit:unit", "region:region", MT_NEW_END));
 }
 
 static void test_make_wormholes(CuTest *tc) {