feat: simplify safetensors model creation by removing config archive dependency

Author: ilopezluna

cmd/mdltool/main.go

@@ -283,16 +283,21 @@ func cmdPackage(args []string) int {
 	// Create builder based on model type
 	var b *builder.Builder
 	if isSafetensors {
+		fmt.Println("Creating safetensors model")
+		b, err = builder.FromSafetensors(safetensorsPaths)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Error creating model from safetensors: %v\n", err)
+			return 1
+		}
+
+		// Add config archive if provided
 		if configArchive != "" {
-			fmt.Printf("Creating safetensors model with config archive: %s\n", configArchive)
-			b, err = builder.FromSafetensorsWithConfig(safetensorsPaths, configArchive)
+			fmt.Printf("Adding config archive: %s\n", configArchive)
+			b, err = b.WithConfigArchive(configArchive)
 			if err != nil {
-				fmt.Fprintf(os.Stderr, "Error creating model from safetensors with config: %v\n", err)
+				fmt.Fprintf(os.Stderr, "Error adding config archive: %v\n", err)
 				return 1
 			}
-		} else {
-			fmt.Fprintf(os.Stderr, "Error: config archive is required for safetensors models\n")
-			return 1
 		}
 	} else {
 		b, err = builder.FromGGUF(source)

pkg/distribution/builder/builder.go

@@ -28,9 +28,9 @@ func FromGGUF(path string) (*Builder, error) {
 	}, nil
 }
 
-// FromSafetensorsWithConfig returns a *Builder that builds model artifacts from safetensors files with a config archive
-func FromSafetensorsWithConfig(safetensorsPaths []string, configArchivePath string) (*Builder, error) {
-	mdl, err := safetensors.NewModelWithConfigArchive(safetensorsPaths, configArchivePath)
+// FromSafetensors returns a *Builder that builds model artifacts from safetensors files
+func FromSafetensors(safetensorsPaths []string) (*Builder, error) {
+	mdl, err := safetensors.NewModel(safetensorsPaths)
 	if err != nil {
 		return nil, err
 	}
@@ -80,6 +80,19 @@ func (b *Builder) WithChatTemplateFile(path string) (*Builder, error) {
 
 // WithConfigArchive adds a config archive (tar) file to the artifact
 func (b *Builder) WithConfigArchive(path string) (*Builder, error) {
+	// Check if config archive already exists
+	layers, err := b.model.Layers()
+	if err != nil {
+		return nil, fmt.Errorf("get model layers: %w", err)
+	}
+
+	for _, layer := range layers {
+		mediaType, err := layer.MediaType()
+		if err == nil && mediaType == types.MediaTypeVLLMConfigArchive {
+			return nil, fmt.Errorf("model already has a config archive layer")
+		}
+	}
+
 	configLayer, err := partial.NewLayer(path, types.MediaTypeVLLMConfigArchive)
 	if err != nil {
 		return nil, fmt.Errorf("config archive layer from %q: %w", path, err)