diff --git a/erkfc.go b/erk_fc.go
similarity index 89%
rename from erkfc.go
rename to erk_fc.go
index ccc0c5d..2cc99b7 100644
--- a/erkfc.go
+++ b/erk_fc.go
@@ -33,3 +33,11 @@ func NewErkFm(erkFc func(format string, args ...interface{}) *errors.Error, msg
 func NewErkFmx(erkFc func(format string, args ...interface{}) *errors.Error, msg string) func(erx error) *errors.Error {
 	return NewErkFm(erkFc, msg, "erx")
 }
+
+func As(erx error) (erk *errors.Error, ok bool) {
+	return erk, errors.As(erx, &erk)
+}
+
+func Is(erx error, target error) (ok bool) {
+	return errors.Is(erx, target)
+}
diff --git a/erk_fc_test.go b/erk_fc_test.go
new file mode 100644
index 0000000..d6b267c
--- /dev/null
+++ b/erk_fc_test.go
@@ -0,0 +1,59 @@
+package erkkratos
+
+import (
+	"testing"
+
+	"github.com/go-kratos/kratos/v2/errors"
+	"github.com/orzkratos/erkkratos/internal/errors_example"
+	"github.com/stretchr/testify/require"
+	"github.com/yyle88/erero"
+)
+
+func TestNewErkFsc(t *testing.T) {
+	erk := NewErkFsc(errors_example.ErrorServerDbError, "erk")(erero.New("wac"))
+	require.NotNil(t, erk)
+	require.True(t, errors_example.IsServerDbError(erk))
+	t.Log(erk)
+}
+
+func TestNewErkFmx(t *testing.T) {
+	erk := NewErkFmx(errors_example.ErrorServerDbError, "msg")(erero.New("wac"))
+	require.NotNil(t, erk)
+	require.True(t, errors_example.IsServerDbError(erk))
+	t.Log(erk)
+}
+
+func TestNewErkFmx2(t *testing.T) {
+	erk := NewErkFmx(errors_example.ErrorServerDbError, "msg")(erero.New("wac"))
+	require.NotNil(t, erk)
+	require.True(t, errors_example.IsServerDbError(erk))
+	t.Log(erk)
+
+	var err error
+	err = erk
+
+	var target *errors.Error
+	ok := errors.As(err, &target)
+	t.Log(ok)
+	t.Log(target)
+}
+
+func TestAs(t *testing.T) {
+	{
+		var erk = errors_example.ErrorServerDbError("wrong")
+		var erx error = erk
+		res, ok := As(erx)
+		require.True(t, ok)
+		t.Log(res)
+		require.NotNil(t, res)
+	}
+
+	{
+		var erk *errors.Error
+		var erx error = erk
+		res, ok := As(erx)
+		require.True(t, ok)
+		t.Log(res)
+		require.Nil(t, res)
+	}
+}
diff --git a/erkfc_test.go b/erkfc_test.go
deleted file mode 100644
index 8329a3e..0000000
--- a/erkfc_test.go
+++ /dev/null
@@ -1,23 +0,0 @@
-package erkkratos
-
-import (
-	"testing"
-
-	"github.com/orzkratos/erkkratos/internal/errors_example"
-	"github.com/stretchr/testify/require"
-	"github.com/yyle88/erero"
-)
-
-func TestNewErkFsc(t *testing.T) {
-	erk := NewErkFsc(errors_example.ErrorServerDbError, "erk")(erero.New("wac"))
-	require.NotNil(t, erk)
-	require.True(t, errors_example.IsServerDbError(erk))
-	t.Log(erk)
-}
-
-func TestNewErkFmx(t *testing.T) {
-	erk := NewErkFmx(errors_example.ErrorServerDbError, "msg")(erero.New("wac"))
-	require.NotNil(t, erk)
-	require.True(t, errors_example.IsServerDbError(erk))
-	t.Log(erk)
-}
diff --git a/go.mod b/go.mod
index f7fdd82..a02648f 100644
--- a/go.mod
+++ b/go.mod
@@ -5,7 +5,7 @@ go 1.22.6
 require (
 	github.com/go-kratos/kratos/v2 v2.8.0
 	github.com/stretchr/testify v1.9.0
-	github.com/yyle88/erero v1.0.8
+	github.com/yyle88/erero v1.0.9
 )
 
 require (
@@ -18,7 +18,7 @@ require (
 	go.uber.org/zap v1.27.0 // indirect
 	golang.org/x/sys v0.24.0 // indirect
 	golang.org/x/text v0.17.0 // indirect
-	google.golang.org/genproto/googleapis/rpc v0.0.0-20240814211410-ddb44dafa142 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20240823204242-4ba0660f739c // indirect
 	google.golang.org/grpc v1.65.0 // indirect
 	google.golang.org/protobuf v1.34.2 // indirect
 	gopkg.in/natefinch/lumberjack.v2 v2.2.1 // indirect
diff --git a/go.sum b/go.sum
index 7bb83a8..a114c90 100644
--- a/go.sum
+++ b/go.sum
@@ -16,8 +16,8 @@ github.com/rogpeppe/go-internal v1.11.0 h1:cWPaGQEPrBb5/AsnsZesgZZ9yb1OQ+GOISoDN
 github.com/rogpeppe/go-internal v1.11.0/go.mod h1:ddIwULY96R17DhadqLgMfk9H9tvdUzkipdSkR5nkCZA=
 github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
-github.com/yyle88/erero v1.0.8 h1:UVXC5qGJ+UD7f2xsj75eVScLzVhiCKg7eXfP0yKNSqM=
-github.com/yyle88/erero v1.0.8/go.mod h1:+qbuev+H/83Hr/zVTjkea2BxxUxAZWNeDVkoFu7ckgk=
+github.com/yyle88/erero v1.0.9 h1:E6Llc9IsuSR151CPcE8Y97BapD+IgDR3yMwo+6CRnp4=
+github.com/yyle88/erero v1.0.9/go.mod h1:+qbuev+H/83Hr/zVTjkea2BxxUxAZWNeDVkoFu7ckgk=
 github.com/yyle88/mutexmap v1.0.3 h1:s5OqqR/oDW5ABhKZi25DLd4IE/KPPwlp6UyzqZayfXo=
 github.com/yyle88/mutexmap v1.0.3/go.mod h1:xUqVmNE2/y4AMz5a8O3a4ik9Ua5xskEaLQ+ICnAAl8E=
 github.com/yyle88/zaplog v0.0.7 h1:Kqwk+q4QatgS5Gyor2xGwSEQZ3U8Hai/ojkAz9BzOMY=
@@ -34,8 +34,8 @@ golang.org/x/sys v0.24.0 h1:Twjiwq9dn6R1fQcyiK+wQyHWfaz/BJB+YIpzU/Cv3Xg=
 golang.org/x/sys v0.24.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/text v0.17.0 h1:XtiM5bkSOt+ewxlOE/aE/AKEHibwj/6gvWMl9Rsh0Qc=
 golang.org/x/text v0.17.0/go.mod h1:BuEKDfySbSR4drPmRPG/7iBdf8hvFMuRexcpahXilzY=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20240814211410-ddb44dafa142 h1:e7S5W7MGGLaSu8j3YjdezkZ+m1/Nm0uRVRMEMGk26Xs=
-google.golang.org/genproto/googleapis/rpc v0.0.0-20240814211410-ddb44dafa142/go.mod h1:UqMtugtsSgubUsoxbuAoiCXvqvErP7Gf0so0mK9tHxU=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20240823204242-4ba0660f739c h1:Kqjm4WpoWvwhMPcrAczoTyMySQmYa9Wy2iL6Con4zn8=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20240823204242-4ba0660f739c/go.mod h1:UqMtugtsSgubUsoxbuAoiCXvqvErP7Gf0so0mK9tHxU=
 google.golang.org/grpc v1.65.0 h1:bs/cUb4lp1G5iImFFd3u5ixQzweKizoZJAwBNLR42lc=
 google.golang.org/grpc v1.65.0/go.mod h1:WgYC2ypjlB0EiQi6wdKixMqukr6lBc0Vo+oOgjrM5ZQ=
 google.golang.org/protobuf v1.34.2 h1:6xV6lTsCfpGD21XK49h7MhtcApnLqkfYgPcdHftf6hg=