diff --git a/lib/messages/builder.js b/lib/messages/builder.js
index 3b58903..590038c 100644
--- a/lib/messages/builder.js
+++ b/lib/messages/builder.js
@@ -48,7 +48,7 @@ function builder(options) {
       headers: 'Headers',
       notfound: 'NotFound',
       inv: 'Inventory',
-      addr: 'Address',
+      addr: 'Addresses',
       alert: 'Alert',
       reject: 'Reject',
       merkleblock: 'MerkleBlock',
@@ -68,17 +68,7 @@ function builder(options) {
     var Command = require('./commands/' + key);
 
     exported.commands[key] = function(obj) {
-      if (!obj) {
-        obj = {};
-      }
-      // pass factory options
-      obj.Block = options.Block;
-      obj.BlockHeader = options.BlockHeader;
-      obj.Transaction = options.Transaction;
-      obj.MerkleBlock = options.MerkleBlock;
-      obj.magicNumber = options.magicNumber;
-      obj.version = options.protocolVersion;
-      return new Command(obj);
+      return new Command(obj, options);
     };
 
     exported.commands[key]._constructor = Command;
diff --git a/lib/messages/commands/addr.js b/lib/messages/commands/addr.js
index 3d1bdcc..ed86b99 100644
--- a/lib/messages/commands/addr.js
+++ b/lib/messages/commands/addr.js
@@ -4,21 +4,31 @@ var Message = require('../message');
 var inherits = require('util').inherits;
 var bitcore = require('bitcore');
 var utils = require('../utils');
+var $ = bitcore.util.preconditions;
+var _ = bitcore.deps._;
 var BufferReader = bitcore.encoding.BufferReader;
 var BufferWriter = bitcore.encoding.BufferWriter;
 
 /**
+ * @param {Array=} arg - An array of addrs
  * @param {Object=} options
- * @param {Array=} options.addresses - An array of addrs
  * @param {Number} options.magicNumber
  * @extends Message
  * @constructor
  */
-function AddrMessage(options) {
+function AddrMessage(arg, options) {
   Message.call(this, options);
   this.command = 'addr';
   this.magicNumber = options.magicNumber;
-  this.addresses = options.addresses;
+  $.checkArgument(
+    _.isUndefined(arg) ||
+      (Array.isArray(arg) &&
+       !_.isUndefined(arg[0].services) &&
+       !_.isUndefined(arg[0].ip) &&
+       !_.isUndefined(arg[0].port)),
+    'First argument is expected to be an array of addrs'
+  );
+  this.addresses = arg;
 }
 inherits(AddrMessage, Message);
 
diff --git a/lib/messages/commands/alert.js b/lib/messages/commands/alert.js
index 064e815..28c12e1 100644
--- a/lib/messages/commands/alert.js
+++ b/lib/messages/commands/alert.js
@@ -8,20 +8,23 @@ var BufferReader = bitcore.encoding.BufferReader;
 var BufferWriter = bitcore.encoding.BufferWriter;
 
 /**
- * @param {Object=} options
- * @param {Buffer=} options.payload
- * @param {Buffer=} options.signature
+ * @param {Object=} arg
+ * @param {Buffer=} arg.payload
+ * @param {Buffer=} arg.signature
+ * @param {Object} options
  * @param {Number} options.magicNumber
  * @extends Message
  * @constructor
  */
-function AlertMessage(options) {
+function AlertMessage(arg, options) {
   Message.call(this, options);
   this.magicNumber = options.magicNumber;
   this.command = 'alert';
-
-  this.payload = options.payload || new Buffer(32);
-  this.signature = options.signature || new Buffer(32);
+  if (!arg) {
+    arg = {};
+  }
+  this.payload = arg.payload || new Buffer(32);
+  this.signature = arg.signature || new Buffer(32);
 }
 inherits(AlertMessage, Message);
 
diff --git a/lib/messages/commands/block.js b/lib/messages/commands/block.js
index 534d347..9bcf9db 100644
--- a/lib/messages/commands/block.js
+++ b/lib/messages/commands/block.js
@@ -2,29 +2,28 @@
 
 var Message = require('../message');
 var inherits = require('util').inherits;
+var bitcore = require('bitcore');
+var $ = bitcore.util.preconditions;
+var _ = bitcore.deps._;
 
 /**
- * @param {Object|Block=} options - If is an instance of Block will use as options.block
- * @param {Block=} options.block - An instance of a Block
+ * @param {Block=} arg - An instance of a Block
+ * @param {Object} options
  * @param {Number} options.magicNumber
  * @param {Function} options.Block - A block constructor
  * @extends Message
  * @constructor
  */
-function BlockMessage(options) {
+function BlockMessage(arg, options) {
   Message.call(this, options);
   this.Block = options.Block;
   this.command = 'block';
   this.magicNumber = options.magicNumber;
-
-  var block;
-  if (options instanceof this.Block) {
-    block = options;
-  } else {
-    block = options.block;
-  }
-
-  this.block = block;
+  $.checkArgument(
+    _.isUndefined(arg) || arg instanceof this.Block,
+    'An instance of Block or undefined is expected'
+  );
+  this.block = arg;
 }
 inherits(BlockMessage, Message);
 
diff --git a/lib/messages/commands/filteradd.js b/lib/messages/commands/filteradd.js
index 235cd0f..7cd82e1 100644
--- a/lib/messages/commands/filteradd.js
+++ b/lib/messages/commands/filteradd.js
@@ -8,20 +8,25 @@ var BufferUtil = bitcore.util.buffer;
 var BufferWriter = bitcore.encoding.BufferWriter;
 var BufferReader = bitcore.encoding.BufferReader;
 var $ = bitcore.util.preconditions;
+var _ = bitcore.deps._;
 
 /**
  * Request peer to add data to a bloom filter already set by 'filterload'
+ * @param {Buffer=} data - Array of bytes representing bloom filter data
  * @param {Object=} options
- * @param {Buffer=} options.data - Array of bytes representing bloom filter data
  * @param {Number} options.magicNumber
  * @extends Message
  * @constructor
  */
-function FilteraddMessage(options) {
+function FilteraddMessage(arg, options) {
   Message.call(this, options);
   this.magicNumber = options.magicNumber;
   this.command = 'filteradd';
-  this.data = options.data || BufferUtil.EMPTY_BUFFER;
+  $.checkArgument(
+    _.isUndefined(arg) || BufferUtil.isBuffer(arg),
+    'First argument is expected to be a Buffer or undefined'
+  );
+  this.data = arg || BufferUtil.EMPTY_BUFFER;
 }
 inherits(FilteraddMessage, Message);
 
diff --git a/lib/messages/commands/filterclear.js b/lib/messages/commands/filterclear.js
index 50dce6b..017ba20 100644
--- a/lib/messages/commands/filterclear.js
+++ b/lib/messages/commands/filterclear.js
@@ -11,7 +11,7 @@ var BufferUtil = bitcore.util.buffer;
  * @param {Number} options.magicNumber
  * @constructor
  */
-function FilterclearMessage(options) {
+function FilterclearMessage(arg, options) {
   Message.call(this, options);
   this.magicNumber = options.magicNumber;
   this.command = 'filterclear';
diff --git a/lib/messages/commands/filterload.js b/lib/messages/commands/filterload.js
index 6804347..63465e9 100644
--- a/lib/messages/commands/filterload.js
+++ b/lib/messages/commands/filterload.js
@@ -10,20 +10,21 @@ var _ = bitcore.deps._;
 
 /**
  * Request peer to send inv messages based on a bloom filter
- * @param {BloomFilter=} options.filter - An instance of BloomFilter
+ * @param {BloomFilter=} arg - An instance of BloomFilter
+ * @param {Object} options
  * @param {Number} options.magicNumber
  * @extends Message
  * @constructor
  */
-function FilterloadMessage(options) {
+function FilterloadMessage(arg, options) {
   Message.call(this, options);
   this.magicNumber = options.magicNumber;
   this.command = 'filterload';
   $.checkArgument(
-    _.isUndefined(options.filter) || options.filter instanceof BloomFilter,
+    _.isUndefined(arg) || arg instanceof BloomFilter,
     'An instance of BloomFilter or undefined is expected'
   );
-  this.filter = options.filter;
+  this.filter = arg;
 }
 inherits(FilterloadMessage, Message);
 
diff --git a/lib/messages/commands/getaddr.js b/lib/messages/commands/getaddr.js
index 9739075..2beca5d 100644
--- a/lib/messages/commands/getaddr.js
+++ b/lib/messages/commands/getaddr.js
@@ -8,10 +8,11 @@ var BufferUtil = bitcore.util.buffer;
 /**
  * Request information about active peers
  * @extends Message
+ * @param {Object} options
  * @param {Number} options.magicNumber
  * @constructor
  */
-function GetaddrMessage(options) {
+function GetaddrMessage(arg, options) {
   Message.call(this, options);
   this.magicNumber = options.magicNumber;
   this.command = 'getaddr';
diff --git a/lib/messages/commands/getblocks.js b/lib/messages/commands/getblocks.js
index e674710..771c5b2 100644
--- a/lib/messages/commands/getblocks.js
+++ b/lib/messages/commands/getblocks.js
@@ -12,22 +12,25 @@ var $ = bitcore.util.preconditions;
  * Query another peer about blocks. It can query for multiple block hashes,
  * and the response will contain all the chains of blocks starting from those
  * hashes.
- * @param {Object=} options
- * @param {Array=} options.starts - Array of buffers or strings with the starting block hashes
- * @param {Buffer=} options.stop - Hash of the last block
+ * @param {Object=} arg
+ * @param {Array=} arg.starts - Array of buffers or strings with the starting block hashes
+ * @param {Buffer=} arg.stop - Hash of the last block
+ * @param {Object} options
  * @param {Number} options.magicNumber
  * @extends Message
  * @constructor
  */
-function GetblocksMessage(options) {
+function GetblocksMessage(arg, options) {
   Message.call(this, options);
   this.command = 'getblocks';
-  this.version = options.version;
+  this.version = options.protocolVersion;
   this.magicNumber = options.magicNumber;
-
-  options = utils.sanitizeStartStop(options);
-  this.starts = options.starts;
-  this.stop = options.stop;
+  if (!arg) {
+    arg = {};
+  }
+  arg = utils.sanitizeStartStop(arg);
+  this.starts = arg.starts;
+  this.stop = arg.stop;
 }
 inherits(GetblocksMessage, Message);
 
diff --git a/lib/messages/commands/getdata.js b/lib/messages/commands/getdata.js
index 04ef7d2..cd9b7ef 100644
--- a/lib/messages/commands/getdata.js
+++ b/lib/messages/commands/getdata.js
@@ -15,20 +15,12 @@ var _ = bitcore.deps._;
  * @extends Message
  * @constructor
  */
-function GetdataMessage(options) {
+function GetdataMessage(arg, options) {
   Message.call(this, options);
   this.command = 'getdata';
   this.magicNumber = options.magicNumber;
-
-  var inventory;
-  if (_.isArray(options)) {
-    inventory = options;
-  } else {
-    inventory = options.inventory;
-  }
-
-  utils.checkInventory(inventory);
-  this.inventory = inventory;
+  utils.checkInventory(arg);
+  this.inventory = arg;
 }
 inherits(GetdataMessage, Message);
 
diff --git a/lib/messages/commands/getheaders.js b/lib/messages/commands/getheaders.js
index f0af1e5..19b96bd 100644
--- a/lib/messages/commands/getheaders.js
+++ b/lib/messages/commands/getheaders.js
@@ -19,15 +19,17 @@ var $ = bitcore.util.preconditions;
  * @extends Message
  * @constructor
  */
-function GetheadersMessage(options) {
+function GetheadersMessage(arg, options) {
   Message.call(this, options);
   this.command = 'getheaders';
-  this.version = options.version;
+  this.version = options.protocolVersion;
   this.magicNumber = options.magicNumber;
-
-  options = utils.sanitizeStartStop(options);
-  this.starts = options.starts;
-  this.stop = options.stop;
+  if (!arg) {
+    arg = {};
+  }
+  arg = utils.sanitizeStartStop(arg);
+  this.starts = arg.starts;
+  this.stop = arg.stop;
 }
 inherits(GetheadersMessage, Message);
 
diff --git a/lib/messages/commands/headers.js b/lib/messages/commands/headers.js
index d937609..4fd1688 100644
--- a/lib/messages/commands/headers.js
+++ b/lib/messages/commands/headers.js
@@ -6,11 +6,13 @@ var bitcore = require('bitcore');
 var utils = require('../utils');
 var BufferReader = bitcore.encoding.BufferReader;
 var BufferWriter = bitcore.encoding.BufferWriter;
+var _ = bitcore.deps._;
 var $ = bitcore.util.preconditions;
 
 /**
  * Sent in response to a `getheaders` message. It contains information about
  * block headers.
+ * @param {Array} arg - An array of BlockHeader instances
  * @param {Object=} options
  * @param {Array=} options.headers - array of block headers
  * @param {Number} options.magicNumber
@@ -18,12 +20,16 @@ var $ = bitcore.util.preconditions;
  * @extends Message
  * @constructor
  */
-function HeadersMessage(options) {
+function HeadersMessage(arg, options) {
   Message.call(this, options);
   this.BlockHeader = options.BlockHeader;
   this.magicNumber = options.magicNumber;
   this.command = 'headers';
-  this.headers = options.headers;
+  $.checkArgument(
+    _.isUndefined(arg) || (Array.isArray(arg) && arg[0] instanceof this.BlockHeader),
+    'First argument is expected to be an array of BlockHeader instances'
+  );
+  this.headers = arg;
 }
 inherits(HeadersMessage, Message);
 
diff --git a/lib/messages/commands/inv.js b/lib/messages/commands/inv.js
index 370c0a9..073354b 100644
--- a/lib/messages/commands/inv.js
+++ b/lib/messages/commands/inv.js
@@ -9,25 +9,19 @@ var BufferWriter = bitcore.encoding.BufferWriter;
 var _ = bitcore.deps._;
 
 /**
- * @param {Object|Array=} - options - If options is an array will use as "inventory"
+ * @param {Array=} arg - An array of inventory
+ * @param {Object} options
  * @param {Array=} options.inventory - An array of inventory items
  * @param {Number} options.magicNumber
  * @extends Message
  * @constructor
  */
-function InvMessage(options) {
+function InvMessage(arg, options) {
   Message.call(this, options);
   this.command = 'inv';
   this.magicNumber = options.magicNumber;
-
-  var inventory;
-  if (_.isArray(options)) {
-    inventory = options;
-  } else {
-    inventory = options.inventory;
-  }
-  utils.checkInventory(inventory);
-  this.inventory = inventory;
+  utils.checkInventory(arg);
+  this.inventory = arg;
 }
 inherits(InvMessage, Message);
 
diff --git a/lib/messages/commands/mempool.js b/lib/messages/commands/mempool.js
index 2b3788f..00fad39 100644
--- a/lib/messages/commands/mempool.js
+++ b/lib/messages/commands/mempool.js
@@ -9,11 +9,12 @@ var BufferUtil = bitcore.util.buffer;
  * The mempool message sends a request to a node asking for information about
  * transactions it has verified but which have not yet confirmed.
  * @see https://en.bitcoin.it/wiki/Protocol_documentation#mempool
+ * @param {Object} options
  * @param {Number} options.magicNumber
  * @extends Message
  * @constructor
  */
-function MempoolMessage(options) {
+function MempoolMessage(arg, options) {
   Message.call(this, options);
   this.magicNumber = options.magicNumber;
   this.command = 'mempool';
diff --git a/lib/messages/commands/merkleblock.js b/lib/messages/commands/merkleblock.js
index 3285048..e26f405 100644
--- a/lib/messages/commands/merkleblock.js
+++ b/lib/messages/commands/merkleblock.js
@@ -10,23 +10,23 @@ var _ = bitcore.deps._;
 /**
  * Contains information about a MerkleBlock
  * @see https://en.bitcoin.it/wiki/Protocol_documentation
+ * @param {MerkleBlock} arg - An instance of MerkleBlock
  * @param {Object=} options
- * @param {MerkleBlock=} options.merkleBlock
  * @param {Number} options.magicNumber
  * @param {Function} options.MerkleBlock - a MerkleBlock constructor
  * @extends Message
  * @constructor
  */
-function MerkleblockMessage(options) {
+function MerkleblockMessage(arg, options) {
   Message.call(this, options);
   this.MerkleBlock = options.MerkleBlock; // constructor
   this.magicNumber = options.magicNumber;
   this.command = 'merkleblock';
   $.checkArgument(
-    _.isUndefined(options.merkleBlock) || options.merkleBlock instanceof this.MerkleBlock,
+    _.isUndefined(arg) || arg instanceof this.MerkleBlock,
     'An instance of MerkleBlock or undefined is expected'
   );
-  this.merkleBlock = options.merkleBlock;
+  this.merkleBlock = arg;
 }
 inherits(MerkleblockMessage, Message);
 
diff --git a/lib/messages/commands/notfound.js b/lib/messages/commands/notfound.js
index 00a99ad..a8c9f03 100644
--- a/lib/messages/commands/notfound.js
+++ b/lib/messages/commands/notfound.js
@@ -9,25 +9,19 @@ var BufferWriter = bitcore.encoding.BufferWriter;
 var _ = bitcore.deps._;
 
 /**
- * @param {Object|Array=} options - If options is an array will use as "inventory"
+ * @param {Array} arg - An array of inventory
+ * @param {Object} options
  * @param {Array=} options.inventory - An array of inventory items
  * @param {Number} options.magicNumber
  * @extends Message
  * @constructor
  */
-function NotfoundMessage(options) {
+function NotfoundMessage(arg, options) {
   Message.call(this, options);
   this.command = 'notfound';
   this.magicNumber = options.magicNumber;
-
-  var inventory;
-  if (_.isArray(options)) {
-    inventory = options;
-  } else {
-    inventory = options.inventory;
-  }
-  utils.checkInventory(inventory);
-  this.inventory = inventory;
+  utils.checkInventory(arg);
+  this.inventory = arg;
 }
 inherits(NotfoundMessage, Message);
 
diff --git a/lib/messages/commands/ping.js b/lib/messages/commands/ping.js
index 3f356c5..92ba3f3 100644
--- a/lib/messages/commands/ping.js
+++ b/lib/messages/commands/ping.js
@@ -4,21 +4,28 @@ var Message = require('../message');
 var inherits = require('util').inherits;
 var bitcore = require('bitcore');
 var utils = require('../utils');
+var $ = bitcore.util.preconditions;
+var _ = bitcore.deps._;
+var BufferUtil = bitcore.util.buffer;
 var BufferReader = bitcore.encoding.BufferReader;
 
 /**
  * A message to confirm that a connection is still valid.
+ * @param {Number} arg - A nonce for the Ping message
  * @param {Object=} options
- * @param {Buffer=} options.nonce
  * @param {Number} options.magicNumber
  * @extends Message
  * @constructor
  */
-function PingMessage(options) {
+function PingMessage(arg, options) {
   Message.call(this, options);
   this.command = 'ping';
   this.magicNumber = options.magicNumber;
-  this.nonce = options.nonce || utils.getNonce();
+  $.checkArgument(
+    _.isUndefined(arg) || (BufferUtil.isBuffer(arg) && arg.length === 8),
+    'First argument is expected to be an 8 byte buffer'
+  );
+  this.nonce = arg || utils.getNonce();
 }
 inherits(PingMessage, Message);
 
diff --git a/lib/messages/commands/pong.js b/lib/messages/commands/pong.js
index 40c7329..111c4cc 100644
--- a/lib/messages/commands/pong.js
+++ b/lib/messages/commands/pong.js
@@ -4,21 +4,28 @@ var Message = require('../message');
 var inherits = require('util').inherits;
 var bitcore = require('bitcore');
 var utils = require('../utils');
+var $ = bitcore.util.preconditions;
+var _ = bitcore.deps._;
+var BufferUtil = bitcore.util.buffer;
 var BufferReader = bitcore.encoding.BufferReader;
 
 /**
  * A message in response to a ping message.
+ * @param {Number} arg - A nonce for the Pong message
  * @param {Object=} options
- * @param {Buffer=} options.nonce
  * @param {Number} options.magicNumber
  * @extends Message
  * @constructor
  */
-function PongMessage(options) {
+function PongMessage(arg, options) {
   Message.call(this, options);
   this.command = 'pong';
   this.magicNumber = options.magicNumber;
-  this.nonce = options.nonce;
+  $.checkArgument(
+    _.isUndefined(arg) || (BufferUtil.isBuffer(arg) && arg.length === 8),
+    'First argument is expected to be an 8 byte buffer'
+  );
+  this.nonce = arg || utils.getNonce();
 }
 inherits(PongMessage, Message);
 
diff --git a/lib/messages/commands/reject.js b/lib/messages/commands/reject.js
index 0fcfc43..ab73e36 100644
--- a/lib/messages/commands/reject.js
+++ b/lib/messages/commands/reject.js
@@ -6,7 +6,7 @@ var bitcore = require('bitcore');
 var BufferUtil = bitcore.util.buffer;
 
 // todo: add payload: https://en.bitcoin.it/wiki/Protocol_documentation#reject
-function RejectMessage(options) {
+function RejectMessage(arg, options) {
   Message.call(this, options);
   this.magicNumber = options.magicNumber;
   this.command = 'reject';
diff --git a/lib/messages/commands/tx.js b/lib/messages/commands/tx.js
index 883e69b..614c42b 100644
--- a/lib/messages/commands/tx.js
+++ b/lib/messages/commands/tx.js
@@ -2,28 +2,30 @@
 
 var Message = require('../message');
 var inherits = require('util').inherits;
+var bitcore = require('bitcore');
+var $ = bitcore.util.preconditions;
+var _ = bitcore.deps._;
 
 /**
- * @param {Object|Transaction=} options - If is an instance of Transaction will use as options.transaction
- * @param {Transaction=} options.transaction - An instance of a Transaction
+ * @param {Transaction=} arg - An instance of Transaction
+ * @param {Object} options
  * @param {Number} options.magicNumber
  * @extends Message
  * @constructor
  */
-function TransactionMessage(options) {
+function TransactionMessage(arg, options) {
   Message.call(this, options);
   this.command = 'tx';
   this.magicNumber = options.magicNumber;
   this.Transaction = options.Transaction;
-
-  var transaction;
-  if(options instanceof this.Transaction) {
-    transaction = options;
-  } else {
-    transaction = options.transaction;
+  $.checkArgument(
+    _.isUndefined(arg) || arg instanceof this.Transaction,
+    'An instance of Transaction or undefined is expected'
+  );
+  this.transaction = arg;
+  if (!this.transaction) {
+    this.transaction = new this.Transaction();
   }
-
-  this.transaction = transaction;
 }
 inherits(TransactionMessage, Message);
 
diff --git a/lib/messages/commands/verack.js b/lib/messages/commands/verack.js
index 55c847a..5c19751 100644
--- a/lib/messages/commands/verack.js
+++ b/lib/messages/commands/verack.js
@@ -11,7 +11,7 @@ var BufferUtil = bitcore.util.buffer;
  * @extends Message
  * @constructor
  */
-function VerackMessage(options) {
+function VerackMessage(arg, options) {
   Message.call(this, options);
   this.magicNumber = options.magicNumber;
   this.command = 'verack';
diff --git a/lib/messages/commands/version.js b/lib/messages/commands/version.js
index 6d18c62..11dc5ad 100644
--- a/lib/messages/commands/version.js
+++ b/lib/messages/commands/version.js
@@ -5,7 +5,6 @@ var inherits = require('util').inherits;
 var bitcore = require('bitcore');
 var BufferWriter = bitcore.encoding.BufferWriter;
 var BufferReader = bitcore.encoding.BufferReader;
-var _ = bitcore.deps._;
 var BN = bitcore.crypto.BN;
 
 var utils = require('../utils');
@@ -17,29 +16,32 @@ var packageInfo = require('../../../package.json');
  * communication is possible until both peers have exchanged their versions.
  *
  * @see https://en.bitcoin.it/wiki/Protocol_documentation#version
- * @param {Object=} obj - properties for the version
- * @param {Buffer=} obj.nonce - a random 8 byte buffer
- * @param {String=} obj.subversion - version of the client
- * @param {BN=} obj.services
- * @param {Date=} obj.timestamp
- * @param {Number=} obj.startHeight
- * @param {Number} obj.magicNumber
+ * @param {Object=} arg - properties for the version message
+ * @param {Buffer=} arg.nonce - a random 8 byte buffer
+ * @param {String=} arg.subversion - version of the client
+ * @param {BN=} arg.services
+ * @param {Date=} arg.timestamp
+ * @param {Number=} arg.startHeight
+ * @param {Object} options
+ * @param {Number} options.magicNumber
  * @extends Message
  * @constructor
  */
-function VersionMessage(obj) {
+function VersionMessage(arg, options) {
   /* jshint maxcomplexity: 10 */
-  Message.call(this, obj);
+  if (!arg) {
+    arg = {};
+  }
+  Message.call(this, options);
   this.command = 'version';
-  _.assign(this, obj);
-  this.magicNumber = obj.magicNumber;
-  this.version = obj.version;
-  this.nonce = this.nonce || utils.getNonce();
-  this.services = this.services || new BN(1, 10);
-  this.timestamp = this.timestamp || new Date();
-  this.subversion = this.subversion || '/bitcore:' + packageInfo.version + '/';
-  this.startHeight = this.startHeight || 0;
-  this.relay = this.relay === false ? false : true;
+  this.magicNumber = options.magicNumber;
+  this.version = arg.version || options.protocolVersion;
+  this.nonce = arg.nonce || utils.getNonce();
+  this.services = arg.services || new BN(1, 10);
+  this.timestamp = arg.timestamp || new Date();
+  this.subversion = arg.subversion || '/bitcore:' + packageInfo.version + '/';
+  this.startHeight = arg.startHeight || 0;
+  this.relay = arg.relay === false ? false : true;
 }
 inherits(VersionMessage, Message);
 
diff --git a/lib/messages/utils.js b/lib/messages/utils.js
index d1bd29e..eb3a975 100644
--- a/lib/messages/utils.js
+++ b/lib/messages/utils.js
@@ -7,12 +7,12 @@ var _ = bitcore.deps._;
 var utils;
 
 module.exports = utils = {
-  checkInventory: function(inventory) {
+  checkInventory: function(arg) {
     $.checkArgument(
-      _.isUndefined(inventory) ||
-        inventory.length === 0 ||
-        (!_.isUndefined(inventory[0].type) && !_.isUndefined(inventory[0].hash)),
-      'Inventory must be an array of inventory objects'
+      _.isUndefined(arg) ||
+        (Array.isArray(arg) && arg.length === 0) ||
+        (Array.isArray(arg) && !_.isUndefined(arg[0].type) && !_.isUndefined(arg[0].hash)),
+      'Argument is expected to be an array of inventory objects'
     );
   },
   checkFinished: function checkFinished(parser) {
diff --git a/lib/peer.js b/lib/peer.js
index 716a1ce..f81b510 100644
--- a/lib/peer.js
+++ b/lib/peer.js
@@ -208,7 +208,7 @@ Peer.prototype._sendVersion = function() {
  * Send a PONG message to the remote peer.
  */
 Peer.prototype._sendPong = function(nonce) {
-  var message = this.messages.Pong({nonce: nonce});
+  var message = this.messages.Pong(nonce);
   this.sendMessage(message);
 };
 
diff --git a/test/messages/commands/index.js b/test/messages/commands/index.js
index 73b812d..741f368 100644
--- a/test/messages/commands/index.js
+++ b/test/messages/commands/index.js
@@ -10,6 +10,38 @@ describe('Command Messages', function() {
 
   var messages = new Messages();
 
+  describe('Addr', function() {
+
+    it('should error if arg is not an array of addrs', function() {
+      (function() {
+        var message = messages.Addresses(['not an addr']);
+      }).should.throw('First argument is expected to be an array of addrs');
+    });
+
+    it('should instantiate with an array of addrs', function() {
+      var message = messages.Addresses([{
+        ip: {
+          v4: 'localhost'
+        },
+        services: 1,
+        port: 1234
+      }]);
+    });
+  });
+
+  describe('Alert', function() {
+
+    it('should accept a transaction instance as an argument', function() {
+      var message = messages.Alert({
+        payload: new Buffer('abcdef', 'hex'),
+        signature: new Buffer('123456', 'hex')
+      });
+      message.payload.should.deep.equal(new Buffer('abcdef', 'hex'));
+      message.signature.should.deep.equal(new Buffer('123456', 'hex'));
+    });
+
+  });
+
   describe('Transaction', function() {
 
     it('should accept a transaction instance as an argument', function() {
@@ -18,6 +50,18 @@ describe('Command Messages', function() {
       message.transaction.should.be.instanceof(bitcore.Transaction);
     });
 
+    it('should create a transaction instance', function() {
+      var message = messages.Transaction();
+      message.transaction.should.be.instanceof(bitcore.Transaction);
+    });
+
+    it('version should remain the same', function() {
+      var tx = new bitcore.Transaction();
+      var version = Number(tx.version);
+      var message = messages.Transaction(tx);
+      message.transaction.version.should.equal(version);
+    });
+
   });
 
   describe('Block', function() {
@@ -33,6 +77,60 @@ describe('Command Messages', function() {
 
   });
 
+  describe('Pong', function() {
+
+    it('should error if nonce is not a buffer', function() {
+      (function() {
+        var message = messages.Pong('not a buffer');
+      }).should.throw('First argument is expected to be an 8 byte buffer');
+    });
+
+    it('should error if nonce buffer has invalid length', function() {
+      (function() {
+        var message = messages.Pong(new Buffer(Array(9)));
+      }).should.throw('First argument is expected to be an 8 byte buffer');
+    });
+
+    it('should set a nonce if not included', function() {
+      var message = messages.Pong();
+      should.exist(message.nonce);
+      message.nonce.length.should.equal(8);
+    });
+
+  });
+
+  describe('Ping', function() {
+
+    it('should error if nonce is not a buffer', function() {
+      (function() {
+        var message = messages.Ping('not a buffer');
+      }).should.throw('First argument is expected to be an 8 byte buffer');
+    });
+
+    it('should error if nonce buffer has invalid length', function() {
+      (function() {
+        var message = messages.Ping(new Buffer(Array(9)));
+      }).should.throw('First argument is expected to be an 8 byte buffer');
+    });
+
+    it('should set a nonce if not included', function() {
+      var message = messages.Ping();
+      should.exist(message.nonce);
+      message.nonce.length.should.equal(8);
+    });
+
+  });
+
+  describe('FilterAdd', function() {
+
+    it('should error if arg is not a buffer', function() {
+      (function() {
+        var message = messages.FilterAdd('not a buffer');
+      }).should.throw('First argument is expected to be a Buffer or undefined');
+    });
+
+  });
+
   describe('FilterLoad', function() {
 
     it('should return a null payload', function() {
@@ -50,6 +148,22 @@ describe('Command Messages', function() {
 
   });
 
+  describe('Inventory', function() {
+    it('should error if arg is not an array', function() {
+      (function() {
+        var message = messages.Inventory({});
+      }).should.throw('Argument is expected to be an array of inventory objects');
+    });
+    it('should not error if arg is an empty array', function() {
+      var message = messages.Inventory([]);
+    });
+    it('should error if arg is not an array of inventory objects', function() {
+      (function() {
+        var message = messages.Inventory([Number(0)]);
+      }).should.throw('Argument is expected to be an array of inventory objects');
+    });
+  });
+
   describe('Transaction', function() {
 
     it('should be able to pass a custom Transaction', function(done) {
@@ -116,6 +230,24 @@ describe('Command Messages', function() {
 
   });
 
+  describe('Headers', function() {
+    it('should error if arg is not an array', function() {
+      (function() {
+        var message = messages.Headers({});
+      }).should.throw('First argument is expected to be an array');
+    });
+    it('should error if arg is an empty array', function() {
+      (function() {
+        var message = messages.Headers([]);
+      }).should.throw('First argument is expected to be an array');
+    });
+    it('should error if arg is not an array of BlockHeaders', function() {
+      (function() {
+        var message = messages.Headers([Number(0)]);
+      }).should.throw('First argument is expected to be an array');
+    });
+  });
+
   describe('MerkleBlock', function() {
 
     it('should return null buffer for payload', function() {