diff --git a/lib/system.js b/lib/system.js
index 3d5e678..f4119c0 100644
--- a/lib/system.js
+++ b/lib/system.js
@@ -1,10 +1,9 @@
-const { system } = lo.load('system')
+// const { system } = lo.load('system')
 
 const { cstr, ptr } = lo
-const { sysconf, _SC_CLK_TCK } = system
-
-//const { wrap } = lo
+// const { sysconf, _SC_CLK_TCK } = system
 
+/** @param {string[]} args */
 function make_args (args) {
   const argb = new Array(args.length)
   if (!args.length) return { args: new Uint8Array(0) }
@@ -22,6 +21,7 @@ function make_args (args) {
 
 function wrapStrError () {
   const eb = new Uint8Array(1024)
+  const decoder = new TextDecoder()
   const { strerror_r } = system
   system.strerror = (errnum = lo.errno) => {
     const rc = strerror_r(errnum, eb, 1024)
@@ -39,6 +39,7 @@ function wrapCPUTime () {
 }
 
 class SystemError extends Error {
+  /** @param {string} name */
   constructor (name) {
     const { errno } = lo
     super(`${name} ${system.strerror(errno)}`)
@@ -49,13 +50,25 @@ class SystemError extends Error {
 
 /*
 const sys_assert = (...args) => {
-  return lo.assert(...[...args, err => console.log(`errno ${lo.errno}\n${strerror()}\n${err.stack}`)]) 
+  return lo.assert(...[...args, err => console.log(`errno ${lo.errno}\n${strerror()}\n${err.stack}`)])
 }
 */
 
-system.clock_ticks_per_second = sysconf(_SC_CLK_TCK)
-const decoder = new TextDecoder()
-system.SystemError = SystemError
+const system = (() => {
+  const strerror = (_ = 0) => _ == 0 ? void 0 : `${_}: ${''}`
+  const cputime = () => new Uint32Array(0)
+  const system = lo.load('system').system
+  const clock_ticks_per_second = system.sysconf(system._SC_CLK_TCK)
+
+  return Object.assign({}, system, {
+    clock_ticks_per_second,
+    SystemError,
+    // type placeholders
+    strerror,
+    cputime
+  })
+})()
+
 wrapStrError()
 wrapCPUTime()
 
diff --git a/lib/udp.js b/lib/udp.js
index 594607e..7df4cb2 100644
--- a/lib/udp.js
+++ b/lib/udp.js
@@ -3,9 +3,9 @@ import { net } from 'lib/net.js'
 
 //const { strerror } = system
 const { assert, ptr, core } = lo
-const { 
+const {
   sendmsg, recvmsg, connect, listen,
-  AF_INET, SOCK_DGRAM, SOCK_NONBLOCK, SOCKADDR_LEN, EINPROGRESS
+  AF_INET, SOCK_DGRAM, SOCK_NONBLOCK, SOCKADDR_LEN
 } = net
 const { socket, bind, close } = net
 const { sockaddr_in } = net.types
@@ -19,13 +19,18 @@ class IoVec {
     this.view = new DataView(this.raw.buffer)
   }
 
-  set payload (u8) {
-    if (u8 === this.u8) return
+  /** @param {Uint8Array & Partial<Ptr<Uint8Array>>} _u8 */
+  set payload (_u8) {
+    if (_u8 === this.u8) return
+    const u8 = /**@type {Ptr<Uint8Array>}*/(
+      _u8.ptr ? _u8 : ptr(_u8)
+    )
     this.u8 = u8.ptr ? u8 : ptr(u8)
     this.view.setBigUint64(0, BigInt(u8.ptr), true)
     this.view.setUint32(8, u8.length, true)
   }
 
+  /** @param {number} len */
   set length (len) {
     this.view.setUint32(8, len, true)
   }
@@ -38,13 +43,18 @@ class MsgHdr {
     this.view = new DataView(this.raw.buffer)
   }
 
-  set address (sockaddr) {
-    if (sockaddr === this.sockaddr) return
-    this.sockaddr = sockaddr.ptr ? sockaddr : ptr(sockaddr)
+  /** @param {Uint8Array & Partial<Ptr<Uint8Array>>} _sockaddr */
+  set address (_sockaddr) {
+    if (_sockaddr === this.sockaddr) return
+    const sockaddr = /**@type {Ptr<Uint8Array>}*/(
+      _sockaddr.ptr ? _sockaddr : ptr(_sockaddr)
+    )
+    this.sockaddr = sockaddr
     this.view.setBigUint64(0, BigInt(sockaddr.ptr), true)
     this.view.setUint32(8, sockaddr.length, true)
   }
 
+  /** @param {IoVec} iov */
   set payload (iov) {
     if (iov === this.iov) return
     this.iov = iov
@@ -57,24 +67,34 @@ class MsgHdr {
     this.view.setUint32(40, u8.length, true)
   }
 */
+  /** @param {number} flags */
   set flags (flags) {
     this.view.setUint32(48, flags, true)
   }
 }
 
 class Node {
+  /** @type {import('lib/loop.d.ts').bindings['Loop'] | undefined} */
   loop = undefined
   fd = -1
   msghdr = new MsgHdr()
   iov = new IoVec()
   #port = 0
   address = '127.0.0.1'
+  /** @type {ReturnType<typeof sockaddr_in> | undefined} */
   peer_address = undefined
 
+  /**
+   * @param {Node['loop']} loop
+   */
   constructor (loop) {
     if (loop) this.loop = loop
   }
 
+  /**
+   * @param {string} address
+   * @param {(fd: number, events: number) => void} on_readable
+   */
   bind (address, on_readable, port = 0, on_error = noop) {
     assert(this.fd === -1)
     const { loop } = this
@@ -93,6 +113,10 @@ class Node {
     if (!loop) lo.nextTick(on_readable)
   }
 
+  /**
+   * @param {string} address
+   * @param {number} port
+   */
   connect (address, port) {
     return connect(this.fd, sockaddr_in(address, port), SOCKADDR_LEN)
   }
@@ -101,21 +125,31 @@ class Node {
     assert(listen(this.fd, 128) === 0)
   }
 
+  /**
+   * @param {IoVec['payload']} u8
+   */
   recv (u8, flags = 0) {
     this.iov.payload = u8
     this.iov.length = u8.length
     return recvmsg(this.fd, this.msghdr.raw, flags)
   }
 
+  /**
+   * @param {IoVec['payload']} u8
+   */
   send (u8, size = u8.length, flags = 0) {
     this.iov.payload = u8
     this.iov.length = size
     return sendmsg(this.fd, this.msghdr.raw, flags)
   }
 
+  /**
+   * @param {string} address
+   * @param {number} port
+   */
   peer (address, port) {
     this.peer_address = sockaddr_in(address, port)
-    this.msghdr.address = this.peer_address
+    this.msghdr.address = /**@type {MsgHdr['address']}*/(this.peer_address)
   }
 
   close () {
@@ -129,7 +163,7 @@ class Node {
     const src = sockaddr_in(this.address, this.#port)
     net.get_sockname(this.fd, src)
     this.#port = (new DataView(src.buffer)).getUint16(2, true)
-    return this.#port    
+    return this.#port
   }
 }