diff --git a/luprex/cpp/core/luastack.cpp b/luprex/cpp/core/luastack.cpp
index 3b6615a4..6169dc91 100644
--- a/luprex/cpp/core/luastack.cpp
+++ b/luprex/cpp/core/luastack.cpp
@@ -94,8 +94,8 @@ lua_State *LuaCoreStack::newstate (lua_Alloc allocf) {
     lua_pushstring(L, "tangibles");
     lua_newtable(L);
     lua_rawset(L, LUA_REGISTRYINDEX);
-    lua_pushstring(L, "worldtype");
-    lua_pushnumber(L, WORLD_TYPE_MASTER);
+    lua_pushstring(L, "is_authoritative");
+    lua_pushboolean(L, 1);
     lua_rawset(L, LUA_REGISTRYINDEX);
 
     return L;
@@ -687,24 +687,19 @@ void LuaCoreStack::setvisited(LuaSlot tab, bool visited) const {
     lua_modflagbits(L_, tab.index(), 0x0010, visited ? 0x0010 : 0);
 }
 
-WorldType LuaCoreStack::get_world_type() const {
-    lua_pushstring(L_, "worldtype");
-    lua_rawget(L_, LUA_REGISTRYINDEX);
-    lua_Integer n = lua_tointeger(L_, -1);
-    lua_pop(L_, 1);
-    assert(n != 0);
-    return (WorldType)n;
-}
-
-void LuaCoreStack::set_world_type(WorldType t) const {
-    lua_pushstring(L_, "worldtype");
-    lua_pushnumber(L_, (int)t);
+void LuaCoreStack::set_authoritative(bool auth) const {
+    lua_pushstring(L_, "is_authoritative");
+    lua_pushboolean(L_, auth ? 1 : 0);
     lua_rawset(L_, LUA_REGISTRYINDEX);
 }
 
 void LuaCoreStack::guard_nopredict(const char *fn) {
     if (lua_isyieldable(L_)) {
-        if (!is_authoritative()) {
+        lua_pushstring(L_, "is_authoritative");
+        lua_rawget(L_, LUA_REGISTRYINDEX);
+        bool auth = lua_toboolean(L_, -1);
+        lua_pop(L_, 1);
+        if (!auth) {
             lua_yield(L_, 0);
             luaL_error(L_, "unexplained nopredict failure in %s", fn);
         }
diff --git a/luprex/cpp/core/luastack.hpp b/luprex/cpp/core/luastack.hpp
index 5910d640..eb163f19 100644
--- a/luprex/cpp/core/luastack.hpp
+++ b/luprex/cpp/core/luastack.hpp
@@ -989,25 +989,11 @@ public:
     //
     void setvisited(LuaSlot tab, bool visited) const;
 
-    // Store the world type in the registry.
+    // Store whether the world is authoritative in the 
+    // registry.  This is used to implement guard_nopredict.
     //
-    // This just stores the enum value in the registry key "worldtype".
-    //
-    void set_world_type(WorldType t) const;
+    void set_authoritative(bool auth) const;
 
-    // Return the world type from the registry.
-    //
-    // This just fetches the enum value from the registry key "worldtype".
-    //
-    WorldType get_world_type() const;
-
-    // Return true if this world is authoritative.
-    //
-    // This fetches the enum value from the registry key "worldtype",
-    // then it checks if the world type is authoritative.
-    //
-    bool is_authoritative() { return util::is_authoritative(get_world_type()); }
-    
     // Yield this thread with zero if in a nonauth model, and not a probe.
     //
     // The function name is just used for generating better error messages.
diff --git a/luprex/cpp/core/util.hpp b/luprex/cpp/core/util.hpp
index e70629b7..3935a1a4 100644
--- a/luprex/cpp/core/util.hpp
+++ b/luprex/cpp/core/util.hpp
@@ -33,11 +33,6 @@
 #include "spookyv2.hpp"
 
 
-enum WorldType {
-    WORLD_TYPE_MASTER = 1,
-    WORLD_TYPE_PREDICTIVE = 2,
-};
-
 
 namespace sv {
 
@@ -355,9 +350,6 @@ double distance_squared(double x1, double y1, double x2, double y2);
 // Make a LuaSourceVec with one element, for unit testing.
 LuaSourcePtr make_lua_source(const eng::string &code);
 
-// Return true if the worldtype is authoritative.
-inline bool is_authoritative(WorldType t) { return (t == WORLD_TYPE_MASTER); }
-
 // Remove items from a vector that are nullptr.
 template<class T>
 void remove_nullptrs(T &vec) {
diff --git a/luprex/cpp/core/world-core.cpp b/luprex/cpp/core/world-core.cpp
index 1a03231e..7ae96a43 100644
--- a/luprex/cpp/core/world-core.cpp
+++ b/luprex/cpp/core/world-core.cpp
@@ -131,8 +131,8 @@ World::World(WorldType wt) {
     LS.getglobaltable(globtab);
     LS.settabletype(globtab, LUA_TT_GLOBALENV);
 
-    // Store the world type in the registry.
-    LS.set_world_type(wt);
+    // Store whether the world is authoritative in the registry.
+    LS.set_authoritative(wt == WORLD_TYPE_MASTER);
         
     // Create the globaldb in the registry.
     LS.rawset(LuaRegistry, "globaldb", LuaNewTable);
diff --git a/luprex/cpp/core/world.hpp b/luprex/cpp/core/world.hpp
index b5094f9d..5cfe819e 100644
--- a/luprex/cpp/core/world.hpp
+++ b/luprex/cpp/core/world.hpp
@@ -22,6 +22,11 @@
 #include "source.hpp"
 #include "luasnap.hpp"
 
+enum WorldType {
+    WORLD_TYPE_MASTER = 1,
+    WORLD_TYPE_PREDICTIVE = 2,
+};
+
 class World;
 
 class Tangible : public eng::opnew {
@@ -313,7 +318,7 @@ public:
 
     // Check if the world is authoritative.
     //
-    bool is_authoritative() const { return util::is_authoritative(world_type_); }
+    bool is_authoritative() const { return world_type_ == WORLD_TYPE_MASTER; }
     
     // Get a table showing all outstanding HTTP requests.
     //