diff --git a/go.mod b/go.mod
index 3ef9ba8..9e04148 100644
--- a/go.mod
+++ b/go.mod
@@ -19,6 +19,7 @@ require (
 	github.com/urfave/cli/v3 v3.11.0
 	golang.org/x/sync v0.22.0
 	golang.org/x/sys v0.47.0
+	google.golang.org/grpc v1.83.2
 	gopkg.in/yaml.v3 v3.0.1
 )
 
@@ -82,7 +83,6 @@ require (
 	golang.org/x/net v0.58.0 // indirect
 	golang.org/x/text v0.41.0 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20260904194346-d0f1323225a4 // indirect
-	google.golang.org/grpc v1.83.2 // indirect
 	google.golang.org/protobuf v1.36.12 // indirect
 	gopkg.in/natefinch/lumberjack.v2 v2.2.1 // indirect
 )
diff --git a/store/core/workload.go b/store/core/workload.go
index e0ed2ee..21b9a83 100644
--- a/store/core/workload.go
+++ b/store/core/workload.go
@@ -10,7 +10,8 @@ import (
 	"time"
 
 	pb "github.com/projecteru2/core/rpc/gen"
-	coretypes "github.com/projecteru2/core/types"
+	"google.golang.org/grpc/codes"
+	grpcstatus "google.golang.org/grpc/status"
 
 	"github.com/projecteru2/agent/types"
 )
@@ -37,13 +38,7 @@ func (s *Store) WorkloadExists(ctx context.Context, ID string) (bool, error) {
 	_, err := call(ctx, s, func(ctx context.Context) (*pb.Workload, error) {
 		return s.client().GetWorkload(ctx, &pb.WorkloadID{Id: ID})
 	})
-	switch {
-	case err == nil:
-		return true, nil
-	case strings.Contains(err.Error(), coretypes.ErrInvaildCount.Error()), strings.Contains(err.Error(), coretypes.ErrWorkloadNotExists.Error()):
-		return false, nil
-	}
-	return false, err
+	return workloadLookupResult(err)
 }
 
 func (s *Store) SetWorkloadStatus(ctx context.Context, status *types.WorkloadStatus) error {
@@ -94,3 +89,13 @@ func getCacheTTL(ttl int64) time.Duration {
 	delta := rand.Int64N(max(ttl, 1)) / 4 //nolint:gosec // cache ttl jitter needs no csprng
 	return time.Duration(ttl-ttl/8+delta) * time.Second
 }
+
+func workloadLookupResult(err error) (bool, error) {
+	switch {
+	case err == nil:
+		return true, nil
+	case grpcstatus.Code(err) == codes.NotFound:
+		return false, nil
+	}
+	return false, err
+}
diff --git a/store/core/workload_test.go b/store/core/workload_test.go
new file mode 100644
index 0000000..6d66a9c
--- /dev/null
+++ b/store/core/workload_test.go
@@ -0,0 +1,33 @@
+package core
+
+import (
+	"errors"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"google.golang.org/grpc/codes"
+	grpcstatus "google.golang.org/grpc/status"
+)
+
+func TestWorkloadLookupResult(t *testing.T) {
+	transport := errors.New("dial core: connection refused")
+	legacy := grpcstatus.Error(1051, "workload not exists")
+	tests := []struct {
+		name    string
+		err     error
+		exists  bool
+		wantErr error
+	}{
+		{"found", nil, true, nil},
+		{"not found", grpcstatus.Error(codes.NotFound, "workload not exists"), false, nil},
+		{"per-rpc code", legacy, false, legacy},
+		{"transport", transport, false, transport},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			exists, err := workloadLookupResult(tt.err)
+			assert.Equal(t, tt.exists, exists)
+			assert.Equal(t, tt.wantErr, err)
+		})
+	}
+}