diff --git a/pkg/scaffold/error.go b/pkg/scaffold/error.go
deleted file mode 100644
index 439f270f..00000000
--- a/pkg/scaffold/error.go
+++ /dev/null
@@ -1,9 +0,0 @@
-package scaffold
-
-import "errors"
-
-var (
-	errDocumentMustBeOne = errors.New("the number of document in aqua.yaml must be one")
-	errBodyFormat        = errors.New("fails to parse a configuration file. Format is wrong. body must be *ast.MappingNode or *ast.MappingValueNode")
-	errPkgsNotFound      = errors.New("the field 'packages' isn't found")
-)
diff --git a/pkg/scaffold/insert.go b/pkg/scaffold/insert.go
deleted file mode 100644
index c7d3b6b1..00000000
--- a/pkg/scaffold/insert.go
+++ /dev/null
@@ -1,101 +0,0 @@
-package scaffold
-
-import (
-	"errors"
-	"fmt"
-	"os"
-
-	"github.com/goccy/go-yaml"
-	"github.com/goccy/go-yaml/ast"
-	"github.com/goccy/go-yaml/parser"
-	"github.com/sirupsen/logrus"
-	"github.com/suzuki-shunsuke/logrus-error/logerr"
-)
-
-func generateInsert(cfgFilePath, pkgFilePath string) error {
-	b, err := os.ReadFile(cfgFilePath)
-	if err != nil {
-		return fmt.Errorf("read a configuration file: %w", err)
-	}
-	file, err := parser.ParseBytes(b, parser.ParseComments)
-	if err != nil {
-		return fmt.Errorf("parse configuration file as YAML: %w", err)
-	}
-
-	if len(file.Docs) != 1 {
-		return logerr.WithFields(errDocumentMustBeOne, logrus.Fields{ //nolint:wrapcheck
-			"num_of_docs": len(file.Docs),
-		})
-	}
-
-	if err := updateASTFile(file.Docs[0].Body, []map[string]string{
-		{
-			"import": pkgFilePath,
-		},
-	}); err != nil {
-		return err
-	}
-
-	stat, err := os.Stat(cfgFilePath)
-	if err != nil {
-		return fmt.Errorf("get configuration file stat: %w", err)
-	}
-	if err := os.WriteFile(cfgFilePath, []byte(file.String()), stat.Mode()); err != nil {
-		return fmt.Errorf("write the configuration file: %w", err)
-	}
-	return nil
-}
-
-func getPkgsAST(values []*ast.MappingValueNode) *ast.MappingValueNode {
-	for _, mapValue := range values {
-		if mapValue.Key.String() != "packages" {
-			continue
-		}
-		return mapValue
-	}
-	return nil
-}
-
-func getMappingValueNodeFromBody(body ast.Node) []*ast.MappingValueNode {
-	switch b := body.(type) {
-	case *ast.MappingNode:
-		return b.Values
-	case *ast.MappingValueNode:
-		return []*ast.MappingValueNode{b}
-	}
-	return nil
-}
-
-func appendPkgsNode(mapValue *ast.MappingValueNode, node ast.Node) error {
-	switch mapValue.Value.Type() {
-	case ast.NullType:
-		mapValue.Value = node
-		return nil
-	case ast.SequenceType:
-		if err := ast.Merge(mapValue.Value, node); err != nil {
-			return fmt.Errorf("merge packages: %w", err)
-		}
-		return nil
-	default:
-		return errors.New("packages must be null or array")
-	}
-}
-
-func updateASTFile(body ast.Node, pkgs []map[string]string) error {
-	node, err := yaml.ValueToNode(pkgs)
-	if err != nil {
-		return fmt.Errorf("convert packages to node: %w", err)
-	}
-
-	values := getMappingValueNodeFromBody(body)
-	if values == nil {
-		return errBodyFormat
-	}
-
-	mapValue := getPkgsAST(values)
-	if mapValue == nil {
-		return errPkgsNotFound
-	}
-
-	return appendPkgsNode(mapValue, node)
-}