diff --git a/baseapp/baseapp.go b/baseapp/baseapp.go
index 4d32b92f5..e2159aa29 100644
--- a/baseapp/baseapp.go
+++ b/baseapp/baseapp.go
@@ -87,7 +87,6 @@ func NewBaseApp(name string, cdc *wire.Codec, logger log.Logger, db dbm.DB) *Bas
 		txDecoder:  defaultTxDecoder(cdc),
 	}
 	// Register the undefined & root codespaces, which should not be used by any modules
-	app.codespacer.RegisterOrPanic(sdk.CodespaceUndefined)
 	app.codespacer.RegisterOrPanic(sdk.CodespaceRoot)
 	return app
 }
@@ -137,7 +136,7 @@ func defaultTxDecoder(cdc *wire.Codec) sdk.TxDecoder {
 		// are registered by MakeTxCodec
 		err := cdc.UnmarshalBinary(txBytes, &tx)
 		if err != nil {
-			return nil, sdk.ErrTxDecode("").Trace(err.Error())
+			return nil, sdk.ErrTxDecode("").TraceSDK(err.Error())
 		}
 		return tx, nil
 	}
@@ -486,7 +485,6 @@ func (app *BaseApp) runTx(mode runTxMode, txBytes []byte, tx sdk.Tx) (result sdk
 	// Validate the Msg.
 	err := msg.ValidateBasic()
 	if err != nil {
-		err = err.WithDefaultCodespace(sdk.CodespaceRoot)
 		return err.Result()
 	}
 
diff --git a/examples/democoin/x/cool/types.go b/examples/democoin/x/cool/types.go
index b8640b211..77f49a0ba 100644
--- a/examples/democoin/x/cool/types.go
+++ b/examples/democoin/x/cool/types.go
@@ -41,13 +41,13 @@ func (msg MsgSetTrend) String() string {
 // Validate Basic is used to quickly disqualify obviously invalid messages quickly
 func (msg MsgSetTrend) ValidateBasic() sdk.Error {
 	if len(msg.Sender) == 0 {
-		return sdk.ErrUnknownAddress(msg.Sender.String()).Trace("")
+		return sdk.ErrUnknownAddress(msg.Sender.String()).TraceSDK("")
 	}
 	if strings.Contains(msg.Cool, "hot") {
-		return sdk.ErrUnauthorized("").Trace("hot is not cool")
+		return sdk.ErrUnauthorized("").TraceSDK("hot is not cool")
 	}
 	if strings.Contains(msg.Cool, "warm") {
-		return sdk.ErrUnauthorized("").Trace("warm is not very cool")
+		return sdk.ErrUnauthorized("").TraceSDK("warm is not very cool")
 	}
 	return nil
 }
@@ -91,7 +91,7 @@ func (msg MsgQuiz) String() string {
 // Validate Basic is used to quickly disqualify obviously invalid messages quickly
 func (msg MsgQuiz) ValidateBasic() sdk.Error {
 	if len(msg.Sender) == 0 {
-		return sdk.ErrUnknownAddress(msg.Sender.String()).Trace("")
+		return sdk.ErrUnknownAddress(msg.Sender.String()).TraceSDK("")
 	}
 	return nil
 }
diff --git a/types/errors.go b/types/errors.go
index 20d452464..65c258b0c 100644
--- a/types/errors.go
+++ b/types/errors.go
@@ -55,10 +55,7 @@ const (
 	CodeOutOfGas          CodeType = 12
 
 	// CodespaceRoot is a codespace for error codes in this file only.
-	// Notice that 0 is an "unset" codespace, which can be overridden with
-	// Error.WithDefaultCodespace().
-	CodespaceUndefined CodespaceType = 0
-	CodespaceRoot      CodespaceType = 1
+	CodespaceRoot CodespaceType = 1
 
 	// Maximum reservable codespace (2^16 - 1)
 	MaximumCodespace CodespaceType = 65535
@@ -141,49 +138,64 @@ func ErrOutOfGas(msg string) Error {
 //----------------------------------------
 // Error & sdkError
 
+type cmnError = cmn.Error
+
 // sdk Error type
 type Error interface {
-	Error() string
+	// Implements cmn.Error
+	// Error() string
+	// Stacktrace() cmn.Error
+	// Trace(offset int, format string, args ...interface{}) cmn.Error
+	// Data() interface{}
+	cmnError
+
+	// convenience
+	TraceSDK(format string, args ...interface{}) Error
+
 	Code() CodeType
 	Codespace() CodespaceType
 	ABCILog() string
 	ABCICode() ABCICodeType
-	WithDefaultCodespace(codespace CodespaceType) Error
-	Trace(msg string) Error
-	T() interface{}
 	Result() Result
 	QueryResult() abci.ResponseQuery
 }
 
-// NewError - create an error
-func NewError(codespace CodespaceType, code CodeType, msg string) Error {
-	return newError(codespace, code, msg)
+// NewError - create an error.
+func NewError(codespace CodespaceType, code CodeType, format string, args ...interface{}) Error {
+	return newError(codespace, code, format, args...)
 }
 
-func newErrorWithRootCodespace(code CodeType, msg string) *sdkError {
-	return newError(CodespaceRoot, code, msg)
+func newErrorWithRootCodespace(code CodeType, format string, args ...interface{}) *sdkError {
+	return newError(CodespaceRoot, code, format, args...)
 }
 
-func newError(codespace CodespaceType, code CodeType, msg string) *sdkError {
-	if msg == "" {
-		msg = CodeToDefaultMsg(code)
+func newError(codespace CodespaceType, code CodeType, format string, args ...interface{}) *sdkError {
+	if format == "" {
+		format = CodeToDefaultMsg(code)
 	}
 	return &sdkError{
 		codespace: codespace,
 		code:      code,
-		err:       cmn.NewErrorWithT(code, msg),
+		cmnError:  cmn.NewError(format, args...),
 	}
 }
 
 type sdkError struct {
 	codespace CodespaceType
 	code      CodeType
-	err       cmn.Error
+	cmnError
 }
 
 // Implements ABCIError.
+func (err *sdkError) TraceSDK(format string, args ...interface{}) Error {
+	err.Trace(1, format, args...)
+	return err
+}
+
+// Implements ABCIError.
+// Overrides err.Error.Error().
 func (err *sdkError) Error() string {
-	return fmt.Sprintf("Error{%d:%d,%#v}", err.codespace, err.code, err.err)
+	return fmt.Sprintf("Error{%d:%d,%#v}", err.codespace, err.code, err.cmnError)
 }
 
 // Implements ABCIError.
@@ -209,33 +221,7 @@ Code:      %v
 ABCICode:  %v
 Error:     %#v
 === /ABCI Log ===
-`, err.codespace, err.code, err.ABCICode(), err.err)
-}
-
-// Add tracing information with msg.
-func (err *sdkError) Trace(msg string) Error {
-	return &sdkError{
-		codespace: err.codespace,
-		code:      err.code,
-		err:       err.err.Trace(msg),
-	}
-}
-
-// Implements Error.
-func (err *sdkError) WithDefaultCodespace(cs CodespaceType) Error {
-	codespace := err.codespace
-	if codespace == CodespaceUndefined {
-		codespace = cs
-	}
-	return &sdkError{
-		codespace: codespace,
-		code:      err.code,
-		err:       err.err,
-	}
-}
-
-func (err *sdkError) T() interface{} {
-	return err.err.T()
+`, err.codespace, err.code, err.ABCICode(), err.cmnError)
 }
 
 func (err *sdkError) Result() Result {
diff --git a/x/bank/msgs.go b/x/bank/msgs.go
index 48e62d835..1a871979e 100644
--- a/x/bank/msgs.go
+++ b/x/bank/msgs.go
@@ -27,28 +27,28 @@ func (msg MsgSend) ValidateBasic() sdk.Error {
 	// this just makes sure all the inputs and outputs are properly formatted,
 	// not that they actually have the money inside
 	if len(msg.Inputs) == 0 {
-		return ErrNoInputs(DefaultCodespace).Trace("")
+		return ErrNoInputs(DefaultCodespace).TraceSDK("")
 	}
 	if len(msg.Outputs) == 0 {
-		return ErrNoOutputs(DefaultCodespace).Trace("")
+		return ErrNoOutputs(DefaultCodespace).TraceSDK("")
 	}
 	// make sure all inputs and outputs are individually valid
 	var totalIn, totalOut sdk.Coins
 	for _, in := range msg.Inputs {
 		if err := in.ValidateBasic(); err != nil {
-			return err.Trace("")
+			return err.TraceSDK("")
 		}
 		totalIn = totalIn.Plus(in.Coins)
 	}
 	for _, out := range msg.Outputs {
 		if err := out.ValidateBasic(); err != nil {
-			return err.Trace("")
+			return err.TraceSDK("")
 		}
 		totalOut = totalOut.Plus(out.Coins)
 	}
 	// make sure inputs and outputs match
 	if !totalIn.IsEqual(totalOut) {
-		return sdk.ErrInvalidCoins(totalIn.String()).Trace("inputs and outputs don't match")
+		return sdk.ErrInvalidCoins(totalIn.String()).TraceSDK("inputs and outputs don't match")
 	}
 	return nil
 }
@@ -107,11 +107,11 @@ func (msg MsgIssue) Type() string { return "bank" } // TODO: "bank/issue"
 func (msg MsgIssue) ValidateBasic() sdk.Error {
 	// XXX
 	if len(msg.Outputs) == 0 {
-		return ErrNoOutputs(DefaultCodespace).Trace("")
+		return ErrNoOutputs(DefaultCodespace).TraceSDK("")
 	}
 	for _, out := range msg.Outputs {
 		if err := out.ValidateBasic(); err != nil {
-			return err.Trace("")
+			return err.TraceSDK("")
 		}
 	}
 	return nil
diff --git a/x/ibc/types.go b/x/ibc/types.go
index 4924aec4b..a311b9869 100644
--- a/x/ibc/types.go
+++ b/x/ibc/types.go
@@ -65,7 +65,7 @@ func (p IBCPacket) GetSignBytes() []byte {
 // validator the ibc packey
 func (p IBCPacket) ValidateBasic() sdk.Error {
 	if p.SrcChain == p.DestChain {
-		return ErrIdenticalChains(DefaultCodespace).Trace("")
+		return ErrIdenticalChains(DefaultCodespace).TraceSDK("")
 	}
 	if !p.Coins.IsValid() {
 		return sdk.ErrInvalidCoins("")