diff --git a/app/models/metadata_array.rb b/app/models/metadata_array.rb
index 5c0b16f7..5f43b790 100644
--- a/app/models/metadata_array.rb
+++ b/app/models/metadata_array.rb
@@ -13,6 +13,14 @@ class MetadataArray < MetadataTemplate
     false
   end
 
+  def indexable?
+    true
+  end
+
+  def to_s
+    value.join(', ')
+  end
+
   private
 
   # TODO: Sanitizar otros valores
diff --git a/app/models/metadata_content.rb b/app/models/metadata_content.rb
index 525f38ab..546e08c8 100644
--- a/app/models/metadata_content.rb
+++ b/app/models/metadata_content.rb
@@ -19,6 +19,14 @@ class MetadataContent < MetadataTemplate
     document.content
   end
 
+  def indexable?
+    true
+  end
+
+  def to_s
+    sanitizer.sanitize value, tags: [], attributes: []
+  end
+
   private
 
   # Detectar si el contenido estaba en Markdown y pasarlo a HTML
diff --git a/app/models/metadata_document_date.rb b/app/models/metadata_document_date.rb
index 39e68735..a52cd051 100644
--- a/app/models/metadata_document_date.rb
+++ b/app/models/metadata_document_date.rb
@@ -11,6 +11,10 @@ class MetadataDocumentDate < MetadataTemplate
     document.date
   end
 
+  def indexable?
+    true
+  end
+
   # El valor puede ser un Date, Time o una String en el formato
   # "yyyy-mm-dd"
   def value
diff --git a/app/models/metadata_related_posts.rb b/app/models/metadata_related_posts.rb
index 9a73dea9..bcc18d86 100644
--- a/app/models/metadata_related_posts.rb
+++ b/app/models/metadata_related_posts.rb
@@ -18,6 +18,10 @@ class MetadataRelatedPosts < MetadataArray
     false
   end
 
+  def indexable?
+    false
+  end
+
   private
 
   # Obtiene todos los posts y opcionalmente los filtra
diff --git a/app/models/metadata_string.rb b/app/models/metadata_string.rb
index ed50bc88..724c2ef3 100644
--- a/app/models/metadata_string.rb
+++ b/app/models/metadata_string.rb
@@ -7,6 +7,10 @@ class MetadataString < MetadataTemplate
     super || ''
   end
 
+  def indexable?
+    true
+  end
+
   private
 
   # No se permite HTML en las strings
diff --git a/app/models/metadata_template.rb b/app/models/metadata_template.rb
index 58000596..2fa8a61e 100644
--- a/app/models/metadata_template.rb
+++ b/app/models/metadata_template.rb
@@ -7,6 +7,12 @@
 MetadataTemplate = Struct.new(:site, :document, :name, :label, :type,
                               :value, :help, :required, :errors, :post,
                               :layout, keyword_init: true) do
+
+  # Determina si el campo es indexable
+  def indexable?
+    false
+  end
+
   def inspect
     "#<#{self.class} site=#{site.name.inspect} post=#{post.id.inspect} value=#{value.inspect}>"
   end