diff --git a/file.go b/file.go
index 719fd28..9491770 100644
--- a/file.go
+++ b/file.go
@@ -32,7 +32,7 @@ import (
 
 type file struct {
 	path string
-	Meta map[string]interface{}
+	Meta map[string]Meta
 
 	reader *bytes.Reader
 	asset  string
@@ -93,12 +93,12 @@ func (f *file) Path() string {
 	return f.path
 }
 
-func (f *file) Value(key string) (interface{}, bool) {
+func (f *file) Value(key string) (Meta, bool) {
 	value, ok := f.Meta[key]
 	return value, ok
 }
 
-func (f *file) SetValue(key string, value interface{}) {
+func (f *file) SetValue(key string, value Meta) {
 	f.Meta[key] = value
 }
 
diff --git a/types.go b/types.go
index 2451a9a..a66bb1e 100644
--- a/types.go
+++ b/types.go
@@ -46,8 +46,8 @@ func New(srcDir, dstDir string) Goldsmith {
 type File interface {
 	Path() string
 
-	Value(key string) (interface{}, bool)
-	SetValue(key string, value interface{})
+	Value(key string) (Meta, bool)
+	SetValue(key string, value Meta)
 	CopyValues(src File)
 
 	Read(p []byte) (int, error)
@@ -58,7 +58,7 @@ type File interface {
 func NewFileFromData(path string, data []byte) File {
 	return &file{
 		path:   path,
-		Meta:   make(map[string]interface{}),
+		Meta:   make(map[string]Meta),
 		reader: bytes.NewReader(data),
 	}
 }
@@ -66,7 +66,7 @@ func NewFileFromData(path string, data []byte) File {
 func NewFileFromAsset(path, asset string) File {
 	return &file{
 		path:  path,
-		Meta:  make(map[string]interface{}),
+		Meta:  make(map[string]Meta),
 		asset: asset,
 	}
 }
@@ -105,3 +105,5 @@ type Finalizer interface {
 }
 
 type Plugin interface{}
+
+type Meta interface{}