fix max chars to 1024

app/serializers/rest/instance_serializer.rb

@@ -12,7 +12,7 @@ class REST::InstanceSerializer < ActiveModel::Serializer
 
   attributes :domain, :title, :version, :source_url, :description,
              :usage, :thumbnail, :icon, :languages, :configuration,
-             :registrations, :api_versions
+             :registrations, :api_versions, :max_toot_chars
 
   has_one :contact, serializer: ContactSerializer
   has_many :rules, serializer: REST::RuleSerializer
@@ -119,6 +119,10 @@ class REST::InstanceSerializer < ActiveModel::Serializer
     Mastodon::Version.api_versions
   end
 
+  def max_toot_chars
+    StatusLengthValidator::MAX_CHARS
+  end
+
   private
 
   def registrations_enabled?

app/validators/status_length_validator.rb

@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 class StatusLengthValidator < ActiveModel::Validator
-  MAX_CHARS = 500
+  MAX_CHARS = 1024
   URL_PLACEHOLDER_CHARS = 23
   URL_PLACEHOLDER = 'x' * 23