diff --git a/cmds/liter-server/globals.go b/cmds/liter-server/globals.go
index 9f718b0..76e508a 100644
--- a/cmds/liter-server/globals.go
+++ b/cmds/liter-server/globals.go
@@ -543,11 +543,11 @@ type ServerIns struct {
 	Target      string   `json:"target" yaml:"target"`
 	ServerNames []string `json:"names" yaml:"names"`
 	// HandlePing is useful if you want to hide online players from others who won't join the server
-	HandlePing  bool     `json:"handle-ping" yaml:"handle-ping"`
+	HandlePing  bool     `json:"handlePing" yaml:"handle-ping"`
 	// Motd only use when HandlePing is true
 	Motd        string   `json:"motd" yaml:"motd"`
 	// MotdFailed will be send back when the ping connection failed on the server
-	MotdFailed  string   `json:"motd-failed" yaml:"motd-failed"`
+	MotdFailed  string   `json:"motdFailed" yaml:"motd-failed"`
 }
 
 func getServers()(servers []*ServerIns, listHash string){
diff --git a/cmds/liter-server/handler.go b/cmds/liter-server/handler.go
index 2bf571d..9a024ed 100644
--- a/cmds/liter-server/handler.go
+++ b/cmds/liter-server/handler.go
@@ -65,7 +65,7 @@ func (s *Server)handle(c *liter.Conn, cfg *Config){
 	noforward := <-s.scripts.Emit(script.NewEvent("handshake", Map{
 		"client": wc.Exports(),
 		"handshake": hp,
-		"target": &svr, // to allow changes to the target
+		"target": *svr, // do not allow changes
 	}))
 	if wc.Closed() {
 		return
diff --git a/script/types/lib/index.d.ts b/script/types/lib/index.d.ts
index 75733b8..0f9ccb7 100644
--- a/script/types/lib/index.d.ts
+++ b/script/types/lib/index.d.ts
@@ -32,12 +32,12 @@ declare global {
 		error(...args: any[]): void
 	}
 
-	function setInterval(handler: Function, timeout?: number, ...arguments: any[]): Object
-	function setTimeout(handler: Function, timeout?: number, ...arguments: any[]): Object
-	function setImmediate(handler: Function, ...arguments: any[]): Object
-	function clearInterval(id: Object | undefined): void
-	function clearTimeout(id: Object | undefined): void
-	function clearImmediate(id: Object | undefined): void
+	function setInterval(handler: Function, timeout?: number, ...arguments: any[]): Readonly<Object>
+	function setTimeout(handler: Function, timeout?: number, ...arguments: any[]): Readonly<Object>
+	function setImmediate(handler: Function, ...arguments: any[]): Readonly<Object>
+	function clearInterval(id: Readonly<Object> | undefined): void
+	function clearTimeout(id: Readonly<Object> | undefined): void
+	function clearImmediate(id: Readonly<Object> | undefined): void
 
 	type Event<T extends obj = Object> = _Event<T> & T
 
@@ -105,17 +105,34 @@ declare global {
 		json<T>(): T
 	}
 
+	interface HandshakePkt {
+		protocol: number
+		addr: string
+		addition: string
+		port: number
+		nextState: number
+	}
+
+	interface ServerIns {
+		id: string
+		target: string
+		serverNames: string[]
+		handlePing: boolean
+		motd: string
+		motdFailed: string
+	}
+
+	type HandshakeEvent = Event<{
+		client: Conn
+		handshake: Readonly<HandshakePkt>
+		target: Readonly<ServerIns>
+	}>
+
 	type ServeEvent = Event<{
-		player?: PlayerInfo
+		player?: PlayerInfo // undefined means serve for ping connection
 		client: Conn
 		server: Conn
-		handshake: {
-			protocol: number
-			addr: string
-			addition: string
-			port: number
-			nextState: number
-		}
+		handshake: Readonly<HandshakePkt>
 	}>
 
 	type PacketEvent = Event<{
diff --git a/script/types/package.json b/script/types/package.json
index 3ef996a..51b7ab0 100644
--- a/script/types/package.json
+++ b/script/types/package.json
@@ -1,6 +1,6 @@
 {
   "name": "go-liter-plugin",
-  "version": "1.0.2",
+  "version": "1.0.3",
   "description": "Typescript definitions for Go Liter script",
   "types": "./lib/index.d.ts",
   "scripts": {