diff --git a/internal/artifact/artifact.go b/internal/artifact/artifact.go
index 6c77c51..206345f 100644
--- a/internal/artifact/artifact.go
+++ b/internal/artifact/artifact.go
@@ -1,6 +1,11 @@
 package artifact
 
-import "context"
+import (
+	"context"
+	"errors"
+)
+
+var ErrNotFound = errors.New("artifact not found")
 
 type Key struct {
 	Module    string
@@ -21,7 +26,7 @@ type Artifact struct {
 }
 
 type Store interface {
-	Get(ctx context.Context, key Key) (Artifact, bool, error)
+	Get(ctx context.Context, key Key) (Artifact, error)
 	Put(ctx context.Context, key Key, artifact Artifact) (Artifact, error)
 	Delete(ctx context.Context, key Key) error
 }
diff --git a/internal/artifact/gorm.go b/internal/artifact/gorm.go
index 7d12b50..effef96 100644
--- a/internal/artifact/gorm.go
+++ b/internal/artifact/gorm.go
@@ -38,7 +38,7 @@ func NewGormStore(db *gorm.DB) (*GormStore, error) {
 	return &GormStore{db: db}, nil
 }
 
-func (s *GormStore) Get(ctx context.Context, key Key) (Artifact, bool, error) {
+func (s *GormStore) Get(ctx context.Context, key Key) (Artifact, error) {
 	return s.get(ctx, key)
 }
 
@@ -83,18 +83,18 @@ func (s *GormStore) Delete(ctx context.Context, key Key) error {
 	return nil
 }
 
-func (s *GormStore) get(ctx context.Context, key Key) (Artifact, bool, error) {
+func (s *GormStore) get(ctx context.Context, key Key) (Artifact, error) {
 	var record artifactRecord
 	err := s.db.WithContext(ctx).
 		Where("module = ? AND version = ? AND matrix_str = ?", key.Module, key.Version, key.MatrixStr).
 		First(&record).Error
 	if errors.Is(err, gorm.ErrRecordNotFound) {
-		return Artifact{}, false, nil
+		return Artifact{}, ErrNotFound
 	}
 	if err != nil {
-		return Artifact{}, false, fmt.Errorf("get artifact: %w", err)
+		return Artifact{}, fmt.Errorf("get artifact: %w", err)
 	}
-	return record.artifact(), true, nil
+	return record.artifact(), nil
 }
 
 func (r artifactRecord) artifact() Artifact {
diff --git a/internal/artifact/gorm_test.go b/internal/artifact/gorm_test.go
index 032be94..cdeda90 100644
--- a/internal/artifact/gorm_test.go
+++ b/internal/artifact/gorm_test.go
@@ -3,6 +3,7 @@ package artifact
 import (
 	"context"
 	"database/sql"
+	"errors"
 	"strings"
 	"sync"
 	"testing"
@@ -25,12 +26,8 @@ func TestGormStoreGetMissAndPut(t *testing.T) {
 		Checksum: "abc",
 	}
 
-	got, ok, err := store.Get(ctx, key)
-	if err != nil {
-		t.Fatalf("Get miss: %v", err)
-	}
-	if ok {
-		t.Fatalf("Get miss ok = true, artifact = %+v", got)
+	if got, err := store.Get(ctx, key); !errors.Is(err, ErrNotFound) {
+		t.Fatalf("Get miss = %+v, %v; want ErrNotFound", got, err)
 	}
 
 	inserted, err := store.Put(ctx, key, want)
@@ -41,13 +38,10 @@ func TestGormStoreGetMissAndPut(t *testing.T) {
 		t.Fatalf("Put = %+v, want %+v", inserted, want)
 	}
 
-	got, ok, err = store.Get(ctx, key)
+	got, err := store.Get(ctx, key)
 	if err != nil {
 		t.Fatalf("Get hit: %v", err)
 	}
-	if !ok {
-		t.Fatalf("Get hit ok = false")
-	}
 	if got != want {
 		t.Fatalf("Get = %+v, want %+v", got, want)
 	}
@@ -149,10 +143,8 @@ func TestGormStoreDelete(t *testing.T) {
 	if err := store.Delete(ctx, key); err != nil {
 		t.Fatalf("Delete: %v", err)
 	}
-	if got, ok, err := store.Get(ctx, key); err != nil {
-		t.Fatalf("Get after Delete: %v", err)
-	} else if ok {
-		t.Fatalf("Get after Delete ok = true, artifact = %+v", got)
+	if got, err := store.Get(ctx, key); !errors.Is(err, ErrNotFound) {
+		t.Fatalf("Get after Delete = %+v, %v; want ErrNotFound", got, err)
 	}
 }
 
@@ -183,7 +175,7 @@ func TestGormStoreDatabaseErrors(t *testing.T) {
 		Metadata: "-lz",
 		Checksum: "abc",
 	}
-	if _, _, err := store.Get(ctx, key); err == nil {
+	if _, err := store.Get(ctx, key); err == nil {
 		t.Fatal("Get with closed database = nil, want error")
 	}
 	if _, err := store.Put(ctx, key, value); err == nil {
diff --git a/internal/artifact/kodo.go b/internal/artifact/kodo.go
index b4170eb..87832a0 100644
--- a/internal/artifact/kodo.go
+++ b/internal/artifact/kodo.go
@@ -5,7 +5,6 @@ import (
 	"encoding/base64"
 	"encoding/json"
 	"errors"
-	"fmt"
 	"strings"
 
 	qiniuclient "github.com/qiniu/go-sdk/v7/client"
@@ -43,20 +42,20 @@ func NewKodoArtifact(cfg KodoArtifactConfig) Store {
 	}
 }
 
-func (s *kodoArtifact) Get(ctx context.Context, key Key) (Artifact, bool, error) {
+func (s *kodoArtifact) Get(ctx context.Context, key Key) (Artifact, error) {
 	objectName := s.objectName(key)
 	object, err := s.objects.Bucket(s.bucket).Object(objectName).Stat().Call(ctx)
 	if err != nil {
 		if kodoArtifactObjectNotFound(err) {
-			return Artifact{}, false, nil
+			return Artifact{}, ErrNotFound
 		}
-		return Artifact{}, false, err
+		return Artifact{}, err
 	}
 	got, ok := kodoArtifactFromMetadata(object.Metadata)
 	if !ok {
-		return Artifact{}, false, fmt.Errorf("read kodo artifact metadata for %s", objectName)
+		return Artifact{}, ErrNotFound
 	}
-	return got, true, nil
+	return got, nil
 }
 
 func (s *kodoArtifact) Put(ctx context.Context, key Key, art Artifact) (Artifact, error) {
diff --git a/internal/artifact/kodo_test.go b/internal/artifact/kodo_test.go
index b33390f..bc1fccf 100644
--- a/internal/artifact/kodo_test.go
+++ b/internal/artifact/kodo_test.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/base64"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"net/http"
 	"net/http/httptest"
@@ -102,13 +103,10 @@ func TestKodoArtifactGetPutDeleteWithFakeKodo(t *testing.T) {
 		t.Fatalf("Put = %+v, want %+v", got, want)
 	}
 
-	got, ok, err := store.Get(context.Background(), key)
+	got, err = store.Get(context.Background(), key)
 	if err != nil {
 		t.Fatalf("Get: %v", err)
 	}
-	if !ok {
-		t.Fatal("Get missed object")
-	}
 	if got != want {
 		t.Fatalf("Get = %+v, want %+v", got, want)
 	}
@@ -126,12 +124,8 @@ func TestKodoArtifactGetErrors(t *testing.T) {
 		defer server.Close()
 		store := newFakeKodoArtifactStore(server.URL, "bucket", "")
 
-		got, ok, err := store.Get(context.Background(), key)
-		if err != nil {
-			t.Fatalf("Get: %v", err)
-		}
-		if ok {
-			t.Fatalf("Get = %+v, true; want miss", got)
+		if got, err := store.Get(context.Background(), key); !errors.Is(err, ErrNotFound) {
+			t.Fatalf("Get = %+v, %v; want ErrNotFound", got, err)
 		}
 	})
 
@@ -141,8 +135,8 @@ func TestKodoArtifactGetErrors(t *testing.T) {
 		defer server.Close()
 		store := newFakeKodoArtifactStore(server.URL, "bucket", "")
 
-		if got, ok, err := store.Get(context.Background(), key); err == nil {
-			t.Fatalf("Get = %+v, %v, nil; want metadata error", got, ok)
+		if got, err := store.Get(context.Background(), key); !errors.Is(err, ErrNotFound) {
+			t.Fatalf("Get = %+v, %v; want ErrNotFound", got, err)
 		}
 	})
 }
@@ -235,13 +229,10 @@ func TestKodoArtifactE2E(t *testing.T) {
 		t.Fatalf("Put = %+v, want %+v", got, want)
 	}
 
-	got, ok, err := store.Get(ctx, key)
+	got, err = store.Get(ctx, key)
 	if err != nil {
 		t.Fatalf("Get: %v", err)
 	}
-	if !ok {
-		t.Fatal("Get missed uploaded object")
-	}
 	if got != want {
 		t.Fatalf("Get = %+v, want %+v", got, want)
 	}