diff --git a/lib/content_block_tools/presenters/base_presenter.rb b/lib/content_block_tools/presenters/base_presenter.rb
index d2c9180..a7bb60b 100644
--- a/lib/content_block_tools/presenters/base_presenter.rb
+++ b/lib/content_block_tools/presenters/base_presenter.rb
@@ -29,12 +29,15 @@ def render
             content_block: "",
             document_type: content_block.document_type,
             content_id: content_block.content_id,
+            field_names: field_names.to_s,
           },
         )
       end
 
     private
 
+      attr_reader :content_block
+
       # The default representation of the content block - this can be overridden in a subclass
       # by overriding the content, default_content or content_for_fields methods
       #
@@ -57,14 +60,12 @@ def content_for_fields
       end
 
       def field_names
-        embed_code_match = ContentBlockReference::EMBED_REGEX.match(@content_block.embed_code)
+        embed_code_match = ContentBlockReference::EMBED_REGEX.match(content_block.embed_code)
         if embed_code_match.present?
           all_fields = embed_code_match[4]&.reverse&.chomp("/")&.reverse
           all_fields&.split("/")&.map(&:to_sym)
         end
       end
-
-      attr_reader :content_block
     end
   end
 end
diff --git a/spec/content_block_tools/presenters/base_presenter_spec.rb b/spec/content_block_tools/presenters/base_presenter_spec.rb
index 20ebb1f..6a7f1ae 100644
--- a/spec/content_block_tools/presenters/base_presenter_spec.rb
+++ b/spec/content_block_tools/presenters/base_presenter_spec.rb
@@ -18,7 +18,8 @@
         class="content-embed content-embed__something"
         data-content-block=""
         data-document-type="something"
-        data-content-id="#{content_id}">My content block</span>
+        data-content-id="#{content_id}"
+        data-field-names="">My content block</span>
     HTML
 
     expect(presenter.render.squish).to eq(expected_html.squish)
@@ -45,7 +46,8 @@
         class="content-embed content-embed__something"
         data-content-block=""
         data-document-type="something"
-        data-content-id="#{content_id}">hello world</span>
+        data-content-id="#{content_id}"
+        data-field-names="[:first_field, :second_field, :third_field]">hello world</span>
     HTML
 
     expect(presenter.render.squish).to eq(expected_html.squish)
@@ -72,7 +74,8 @@
         class="content-embed content-embed__something"
         data-content-block=""
         data-document-type="something"
-        data-content-id="#{content_id}"></span>
+        data-content-id="#{content_id}"
+        data-field-names="[:first_field, :second_field, :fake_field]"></span>
     HTML
 
     expect(presenter.render.squish).to eq(expected_html.squish)
diff --git a/spec/content_block_tools/presenters/email_address_presenter_spec.rb b/spec/content_block_tools/presenters/email_address_presenter_spec.rb
index c827eaa..c8749c6 100644
--- a/spec/content_block_tools/presenters/email_address_presenter_spec.rb
+++ b/spec/content_block_tools/presenters/email_address_presenter_spec.rb
@@ -19,7 +19,8 @@
         class="content-embed content-embed__something"
         data-content-block=""
         data-document-type="something"
-        data-content-id="#{content_id}">#{email_address}</span>
+        data-content-id="#{content_id}"
+        data-field-names="">#{email_address}</span>
     HTML
 
     expect(presenter.render.squish).to eq(expected_html.squish)
diff --git a/spec/content_block_tools/presenters/postal_address_presenter_spec.rb b/spec/content_block_tools/presenters/postal_address_presenter_spec.rb
index acd5dc3..af627b2 100644
--- a/spec/content_block_tools/presenters/postal_address_presenter_spec.rb
+++ b/spec/content_block_tools/presenters/postal_address_presenter_spec.rb
@@ -29,7 +29,8 @@
         class="content-embed content-embed__something"
         data-content-block=""
         data-document-type="something"
-        data-content-id="#{content_id}">#{postal_html_string}</span>
+        data-content-id="#{content_id}"
+        data-field-names="">#{postal_html_string}</span>
     HTML
 
     expect(presenter.render.squish).to eq(expected_html.squish)
@@ -63,7 +64,8 @@
         class="content-embed content-embed__something"
         data-content-block=""
         data-document-type="something"
-        data-content-id="#{content_id}">Somewhereville</span>
+        data-content-id="#{content_id}"
+        data-field-names="[:town_or_city]">Somewhereville</span>
       HTML
 
       expect(presenter.render.squish).to eq(expected_html.squish)
@@ -76,7 +78,8 @@
         class="content-embed content-embed__something"
         data-content-block=""
         data-document-type="something"
-        data-content-id="#{content_id}"></span>
+        data-content-id="#{content_id}"
+        data-field-names="[:nothing]"></span>
       HTML
 
       expect(presenter.render.squish).to eq(expected_html.squish)