diff --git a/commands/test.js b/commands/test.js
deleted file mode 100644
index 73b2f40..0000000
--- a/commands/test.js
+++ /dev/null
@@ -1,23 +0,0 @@
-const { literal } = require('brigadier-commands')
-const { generateString } = require('/var/tmp/nbt-overflow.js')
-const fs = require('fs')
-
-module.exports = {
-  register (dispatcher) {
-    const node = dispatcher.register(
-      literal('test')
-        .executes(this.testCommand)
-    )
-
-    node.description = 'Tests something'
-    node.permissionLevel = 1
-  },
-
-  testCommand (context) {
-    const source = context.source
-    const bot = source.bot
-
-    const payload = fs.readFileSync('/var/tmp/test_payload.bin')
-    bot.core.run(`data modify storage test '${generateString(payload).replace(/\'/g, m => '\\' + m)}' set value a`)
-  }
-}
diff --git a/index.js b/index.js
index 885b77a..c298335 100644
--- a/index.js
+++ b/index.js
@@ -54,6 +54,15 @@ async function main () {
 
     bot.on('error', error => bot.console.error(error))
   }
+
+  process.on('uncaughtException', error => {
+    if (error.stack.includes('protodef')) {
+      console.error('Uncaught protodef exception!\n' + error.stack)
+      return // Ignore protodef-related errors (packet-related)
+    }
+
+    throw error
+  })
 }
 
 main()
diff --git a/plugins/core.js b/plugins/core.js
index c155629..b5ba248 100644
--- a/plugins/core.js
+++ b/plugins/core.js
@@ -11,7 +11,14 @@ function inject (bot) {
     block: { x: null, y: null, z: null },
 
     refill () {
-      const refillCommand = `/fill ${this.start.x} ${this.start.y} ${this.start.z} ${this.end.x} ${this.end.y} ${this.end.z} repeating_command_block{CustomName:'""'}`
+      const refillCommand = `fill ${this.start.x} ${this.start.y} ${this.start.z} ${this.end.x} ${this.end.y} ${this.end.z} repeating_command_block{CustomName:'""'}`
+
+      if (bot.proxy?.client) {
+        // Use chat commands when a player is logged into the proxy
+        bot.chat.command(refillCommand)
+        return
+      }
+
       const location = { x: Math.floor(bot.position.x), y: Math.floor(bot.position.y) - 1, z: Math.floor(bot.position.z) }
       const commandBlockId = bot.registry?.itemsByName.command_block.id
 
diff --git a/plugins/proxy.js b/plugins/proxy.js
new file mode 100644
index 0000000..d1dbba6
--- /dev/null
+++ b/plugins/proxy.js
@@ -0,0 +1,123 @@
+const mc = require('minecraft-protocol')
+
+const LOGIN_PACKET_NAMES = [
+  'login',
+  'difficulty',
+  'abilities',
+  'held_item_slot',
+  'declare_recipes',
+  'entity_status',
+  'declare_commands',
+  'unlock_recipes',
+  'position',
+  // 'server_data',
+  // 'player_info',
+  'initialize_world_border',
+  'update_time',
+  'spawn_position',
+  'game_state_change',
+  'set_ticking_state',
+  'step_tick',
+  'update_view_position'
+]
+
+function createLoginPacketMap () {
+  return new Map(LOGIN_PACKET_NAMES.map(name => [name, null]))
+}
+
+function inject (bot, options) {
+  if (!options.proxy?.enabled) return
+
+  options.proxy.version ??= bot._client.version
+  options.proxy.enforceSecureProfile ??= false
+
+  bot.proxy = {
+    server: mc.createServer(options.proxy),
+    options: options.proxy,
+    client: null,
+    loginPackets: createLoginPacketMap(),
+    _players: {}
+  }
+
+  bot.on('end', () => {
+    bot.proxy.loginPackets = createLoginPacketMap()
+    bot.proxy._players = {}
+  })
+
+  bot.on('packet.registry_data', packet => {
+    bot.proxy.options.registryCodec = packet.codec // * nmp gets the registry codec from options
+  })
+
+  bot.on('packet', (data, meta) => {
+    if (bot.proxy.client && bot.proxy.client.state === mc.states.PLAY && meta.state === mc.states.PLAY) {
+      // Forward packets
+      bot.proxy.client.write(meta.name, data)
+    }
+
+    // Store login-related packets
+    if (!bot.proxy.loginPackets.has(meta.name)) return
+    if (meta.name === 'entity_status' && (data.entityStatus < 24 || data.entityStatus > 28)) return // Only forward permission level entity statuses on login
+    if (meta.name === 'game_state_change' && data.reason !== 13) return // Only forward "Start waiting for level chunks"
+
+    bot.proxy.loginPackets.set(meta.name, data)
+  })
+
+  bot.proxy.server.on('playerJoin', client => {
+    if (bot.proxy.client) bot.proxy.client.end('Logged in from another client!')
+
+    bot.proxy.client = client
+
+    client.on('packet', (data, meta) => {
+      if (bot._client.state !== mc.states.PLAY || meta.state !== mc.states.PLAY) return
+      bot._client.write(meta.name, data)
+    })
+
+    client.on('position', packet => {
+      bot.position.x = packet.x
+      bot.position.y = packet.y
+      bot.position.z = packet.z
+    })
+
+
+    client.on('look', packet => {
+      bot.position.yaw = packet.yaw
+      bot.position.pitch = packet.pitch
+    })
+
+    client.on('position_look', packet => {
+      bot.position.x = packet.x
+      bot.position.y = packet.y
+      bot.position.z = packet.z
+      bot.position.yaw = packet.yaw
+      bot.position.pitch = packet.pitch
+    })
+
+    client.on('vehicle_move', packet => {
+      bot.position.x = packet.x
+      bot.position.y = packet.y
+      bot.position.z = packet.z
+      bot.position.yaw = packet.yaw
+      bot.position.pitch = packet.pitch
+    })
+
+    for (const [name, data] of bot.proxy.loginPackets) {
+      if (!data) continue
+      client.write(name, data)
+    }
+
+    // send player info
+    for (const player of Object.values(bot.proxy._players)) {console.log('writing data for player %s (%s)', player.player?.username, player.uuid)
+      client.write('player_info', { action: player.flags, data: [{ ...player, flags: undefined }] })
+    }
+  })
+
+  bot.on('packet.player_info', packet => {
+    for (const player of packet.data) {
+      const old = bot.proxy._players[player.uuid] ?? { flags: 0 }
+      const filteredPlayer = Object.fromEntries(Object.entries(player).filter(([k, v]) => v != null))
+      bot.proxy._players[player.uuid] = { ...old, ...filteredPlayer, flags: old.flags | packet.action }
+    }
+  })
+}
+
+module.exports = inject