diff --git a/protocol/client_codec.go b/protocol/client_codec.go
index 43dfd48..92d9fd1 100644
--- a/protocol/client_codec.go
+++ b/protocol/client_codec.go
@@ -9,7 +9,7 @@ type ClientCodec interface {
 type ClientResponseCodec interface {
 	Notification() (ClientNotificationCodec, error)
 	Result(result interface{}) error
-	Error() error
+	Error() *Error
 	ID() interface{}
 }
 
diff --git a/protocol/error.go b/protocol/error.go
index 25e8197..8ece1da 100644
--- a/protocol/error.go
+++ b/protocol/error.go
@@ -1,5 +1,10 @@
 package protocol
 
+import (
+	"errors"
+	"fmt"
+)
+
 type ErrorCode int
 
 const (
@@ -10,3 +15,21 @@ const (
 	E_INTERNAL    ErrorCode = -32603
 	E_SERVER      ErrorCode = -32000
 )
+
+var ErrNullResult = errors.New("result is null")
+
+type Error struct {
+	// A Number that indicates the error type that occurred.
+	Code ErrorCode `json:"code"` /* required */
+
+	// A String providing a short description of the error.
+	// The message SHOULD be limited to a concise single sentence.
+	Message string `json:"message"` /* required */
+
+	// A Primitive or Structured value that contains additional information about the error.
+	Data interface{} `json:"data"` /* optional */
+}
+
+func (e Error) Error() string {
+	return fmt.Sprintf("Code[%d] Message[%s] Data[%v]", e.Code, e.Message, e.Data)
+}
diff --git a/protocol/json/client_notification.go b/protocol/json/client_notification.go
index 1229427..9d272a1 100644
--- a/protocol/json/client_notification.go
+++ b/protocol/json/client_notification.go
@@ -37,7 +37,7 @@ func (cnc *ClientNotificationCodec) ReadParams(args []interface{}) error {
 		// Note: if scr.request.Params is nil it's not an error, it's an optional member.
 		// JSON params structured object. Unmarshal to the args object.
 		if err := cuej.SetValueWithJSONStringArray(*cnc.noti.Params, args); nil != err {
-			cnc.err = &Error{
+			cnc.err = &crp.Error{
 				Code:    crp.E_INVALID_REQ,
 				Message: err.Error(),
 				Data:    cnc.noti.Params,
@@ -54,7 +54,7 @@ func (cnc *ClientNotificationCodec) Params() ([]string, error) {
 		var values []string
 
 		if err := json.Unmarshal(*cnc.noti.Params, &values); err != nil {
-			cnc.err = &Error{
+			cnc.err = &crp.Error{
 				Code:    crp.E_INVALID_REQ,
 				Message: err.Error(),
 				Data:    cnc.noti.Params,
diff --git a/protocol/json/client_response.go b/protocol/json/client_response.go
index f5423ea..03f5ba4 100644
--- a/protocol/json/client_response.go
+++ b/protocol/json/client_response.go
@@ -15,7 +15,7 @@ import (
 type clientResponse struct {
 	Version string           `json:"jsonrpc"`
 	Result  *json.RawMessage `json:"result,omitempty"`
-	Error   error            `json:"error,omitempty"`
+	Error   *json.RawMessage `json:"error,omitempty"`
 	ID      interface{}      `json:"id,omitempty"`
 }
 
@@ -32,7 +32,7 @@ func (crc *ClientResponseCodec) ID() interface{} {
 func (crc *ClientResponseCodec) Result(result interface{}) error {
 	if nil == crc.err && nil != crc.res.Result {
 		if err := json.Unmarshal(*crc.res.Result, result); nil != err {
-			crc.err = &Error{
+			crc.err = &crp.Error{
 				Code:    crp.E_PARSE,
 				Message: err.Error(),
 				Data:    crc.res.Result,
@@ -43,8 +43,17 @@ func (crc *ClientResponseCodec) Result(result interface{}) error {
 	return crc.err
 }
 
-func (crc *ClientResponseCodec) Error() error {
-	return crc.res.Error
+func (crc *ClientResponseCodec) Error() *crp.Error {
+	protocolError := &crp.Error{}
+	err := json.Unmarshal(*crc.res.Error, protocolError)
+	if nil != err {
+		return &crp.Error{
+			Code:    crp.E_PARSE,
+			Message: err.Error(),
+			Data:    crc.res.Error,
+		}
+	}
+	return protocolError
 }
 
 func (crc *ClientResponseCodec) Notification() (protocol.ClientNotificationCodec, error) {
@@ -68,14 +77,14 @@ func newClientResponseCodec(buf []byte) (protocol.ClientResponseCodec, error) {
 	err := json.Unmarshal(buf, res)
 
 	if err != nil {
-		err = &Error{
+		err = &crp.Error{
 			Code:    crp.E_PARSE,
 			Message: err.Error(),
 			Data:    res,
 		}
 	}
 	if res.Version != Version {
-		err = &Error{
+		err = &crp.Error{
 			Code:    crp.E_INVALID_REQ,
 			Message: "jsonrpc must be " + Version,
 			Data:    res,
diff --git a/protocol/json/error.go b/protocol/json/error.go
deleted file mode 100644
index 8c2353c..0000000
--- a/protocol/json/error.go
+++ /dev/null
@@ -1,25 +0,0 @@
-package json
-
-import (
-	"errors"
-
-	crp "git.loafle.net/commons_go/rpc/protocol"
-)
-
-var ErrNullResult = errors.New("result is null")
-
-type Error struct {
-	// A Number that indicates the error type that occurred.
-	Code crp.ErrorCode `json:"code"` /* required */
-
-	// A String providing a short description of the error.
-	// The message SHOULD be limited to a concise single sentence.
-	Message string `json:"message"` /* required */
-
-	// A Primitive or Structured value that contains additional information about the error.
-	Data interface{} `json:"data"` /* optional */
-}
-
-func (e *Error) Error() string {
-	return e.Message
-}
diff --git a/protocol/json/server_request.go b/protocol/json/server_request.go
index 3362642..be143ea 100644
--- a/protocol/json/server_request.go
+++ b/protocol/json/server_request.go
@@ -40,7 +40,7 @@ func newServerRequestCodec(buf []byte) (protocol.ServerRequestCodec, error) {
 	err := json.Unmarshal(buf, req)
 
 	if err != nil {
-		err = &Error{
+		err = &crp.Error{
 			Code:    crp.E_PARSE,
 			Message: err.Error(),
 			Data:    req,
@@ -48,7 +48,7 @@ func newServerRequestCodec(buf []byte) (protocol.ServerRequestCodec, error) {
 	}
 
 	if req.Version != Version {
-		err = &Error{
+		err = &crp.Error{
 			Code:    crp.E_INVALID_REQ,
 			Message: "jsonrpc must be " + Version,
 			Data:    req,
@@ -93,7 +93,7 @@ func (src *ServerRequestCodec) ReadParams(args []interface{}) error {
 		// Note: if scr.request.Params is nil it's not an error, it's an optional member.
 		// JSON params structured object. Unmarshal to the args object.
 		if err := cuej.SetValueWithJSONStringArray(*src.req.Params, args); nil != err {
-			src.err = &Error{
+			src.err = &crp.Error{
 				Code:    crp.E_INVALID_REQ,
 				Message: err.Error(),
 				Data:    src.req.Params,
@@ -110,7 +110,7 @@ func (src *ServerRequestCodec) Params() ([]string, error) {
 		var values []string
 
 		if err := json.Unmarshal(*src.req.Params, &values); err != nil {
-			src.err = &Error{
+			src.err = &crp.Error{
 				Code:    crp.E_INVALID_REQ,
 				Message: err.Error(),
 				Data:    src.req.Params,
@@ -128,9 +128,9 @@ func (src *ServerRequestCodec) NewResponse(reply interface{}) ([]byte, error) {
 	return src.newServerResponse(res)
 }
 func (src *ServerRequestCodec) NewError(status int, err error) ([]byte, error) {
-	jsonErr, ok := err.(*Error)
+	jsonErr, ok := err.(*crp.Error)
 	if !ok {
-		jsonErr = &Error{
+		jsonErr = &crp.Error{
 			Code:    crp.E_SERVER,
 			Message: err.Error(),
 		}
diff --git a/protocol/json/server_response.go b/protocol/json/server_response.go
index 4038b55..f6a4138 100644
--- a/protocol/json/server_response.go
+++ b/protocol/json/server_response.go
@@ -2,6 +2,8 @@ package json
 
 import (
 	"encoding/json"
+
+	crp "git.loafle.net/commons_go/rpc/protocol"
 )
 
 // ----------------------------------------------------------------------------
@@ -20,7 +22,7 @@ type serverResponse struct {
 	// An Error object if there was an error invoking the method. It must be
 	// null if there was no error.
 	// As per spec the member will be omitted if there was no error.
-	Error *Error `json:"error,omitempty"`
+	Error *crp.Error `json:"error,omitempty"`
 
 	// This must be the same id as the request it is responding to.
 	ID *json.RawMessage `json:"id,omitempty"`