diff --git a/plugins/core.js b/plugins/core.js
index b8ffebe..777c161 100644
--- a/plugins/core.js
+++ b/plugins/core.js
@@ -7,6 +7,8 @@ const relativePosition = new Vec3(0, 0, 0)
 function inject (bot, dcclient, config) {
   const mcData = require('minecraft-data')(bot.version)
   const core = {
+    start: new Vec3(null, null, null),
+    end: new Vec3(null, null, null),
     isCore (position) {
       return position.x >= core.start.x && position.x <= core.end.x && position.y >= core.start.y && position.y <= core.end.y && position.z >= core.start.z && position.z <= core.end.z
     },
@@ -58,7 +60,7 @@ function inject (bot, dcclient, config) {
 
   function placeCore () {
     try {
-      const fillCommand = `/minecraft:fill ${core.start.x} ${core.start.y} ${core.start.z} ${core.end.x} ${core.end.y} ${core.end.z} command_block{CustomName:'${JSON.stringify(config.core.customName)}'}`
+      const fillCommand = `minecraft:fill ${core.start.x} ${core.start.y} ${core.start.z} ${core.end.x} ${core.end.y} ${core.end.z} command_block{CustomName:'${JSON.stringify(config.core.customName)}'}`
       const location = { x: Math.floor(bot.position.x), y: Math.floor(bot.position.y) - 1, z: Math.floor(bot.position.z) }
 
       bot.write('set_creative_slot', {