diff --git a/content/v2.0/actions/formats-and-mime-types.md b/content/v2.0/actions/formats-and-mime-types.md
index 51906948..787a1edd 100644
--- a/content/v2.0/actions/formats-and-mime-types.md
+++ b/content/v2.0/actions/formats-and-mime-types.md
@@ -188,6 +188,7 @@ If you need your actions to work with additional MIME types, you can configure t
 
 module Bookshelf
   class App < Hanami::App
+    # config.actions.formats.add :html
     config.actions.formats.add :custom, "application/custom"
   end
 end
@@ -195,6 +196,8 @@ end
 
 This will add the `:custom` format for the `"application/custom"` MIME type and also configure your actions to use this format.
 
+The **first format added will be the default format**, so you likely want to add `:html` or `:json` before any custom formats.
+
 You can also configure a format to map to multiple MIME types:
 
 ```ruby
diff --git a/content/v2.1/actions/formats-and-mime-types.md b/content/v2.1/actions/formats-and-mime-types.md
index 51906948..787a1edd 100644
--- a/content/v2.1/actions/formats-and-mime-types.md
+++ b/content/v2.1/actions/formats-and-mime-types.md
@@ -188,6 +188,7 @@ If you need your actions to work with additional MIME types, you can configure t
 
 module Bookshelf
   class App < Hanami::App
+    # config.actions.formats.add :html
     config.actions.formats.add :custom, "application/custom"
   end
 end
@@ -195,6 +196,8 @@ end
 
 This will add the `:custom` format for the `"application/custom"` MIME type and also configure your actions to use this format.
 
+The **first format added will be the default format**, so you likely want to add `:html` or `:json` before any custom formats.
+
 You can also configure a format to map to multiple MIME types:
 
 ```ruby
diff --git a/content/v2.2/actions/formats-and-mime-types.md b/content/v2.2/actions/formats-and-mime-types.md
index 51906948..787a1edd 100644
--- a/content/v2.2/actions/formats-and-mime-types.md
+++ b/content/v2.2/actions/formats-and-mime-types.md
@@ -188,6 +188,7 @@ If you need your actions to work with additional MIME types, you can configure t
 
 module Bookshelf
   class App < Hanami::App
+    # config.actions.formats.add :html
     config.actions.formats.add :custom, "application/custom"
   end
 end
@@ -195,6 +196,8 @@ end
 
 This will add the `:custom` format for the `"application/custom"` MIME type and also configure your actions to use this format.
 
+The **first format added will be the default format**, so you likely want to add `:html` or `:json` before any custom formats.
+
 You can also configure a format to map to multiple MIME types:
 
 ```ruby