diff --git a/script/migrations/convert-relative-attachment-urls-to-absolute.rb b/script/migrations/convert-relative-attachment-urls-to-absolute.rb
new file mode 100644
index 000000000..4b201f34f
--- /dev/null
+++ b/script/migrations/convert-relative-attachment-urls-to-absolute.rb
@@ -0,0 +1,127 @@
+#!/usr/bin/env ruby
+
+# Rollback script: Convert relative attachment URLs back to absolute URLs.
+# Use this if you need to rollback the relative URL changes and want to
+# convert rich texts created during the rollout back to absolute URLs.
+#
+# Run locally:
+#   bin/rails runner script/migrations/convert-relative-attachment-urls-to-absolute.rb --help
+#
+# Run via Kamal:
+#   kamal app exec -d <stage> -p --reuse "bin/rails runner script/migrations/convert-relative-attachment-urls-to-absolute.rb --help"
+
+class ConvertRelativeAttachmentUrlsToAbsolute
+  # Match relative URLs pointing to Active Storage routes (with account slug)
+  RELATIVE_URL_PATTERN = %r{\A(/\d+/rails/active_storage/[^"']+)\z}
+
+  attr_reader :host, :since
+
+  def initialize(host:, since:)
+    @host = host
+    @since = since
+  end
+
+  def run
+    puts "Converting relative attachment URLs to absolute URLs"
+    puts "Host: #{host}"
+    puts "Processing rich texts created since: #{since}"
+
+    puts "\nPress ENTER to continue running or CTRL-C to bail..."
+    gets
+
+    puts "\nRunning..."
+
+    seconds = Benchmark.realtime do
+      suppressing_turbo_broadcasts do
+        convert_urls
+      end
+    end
+
+    puts "\n\n"
+    puts "Finished in %.2f seconds." % seconds
+  end
+
+  private
+    def suppressing_turbo_broadcasts
+      Board.suppressing_turbo_broadcasts do
+        Card.suppressing_turbo_broadcasts do
+          yield
+        end
+      end
+    end
+
+    def convert_urls
+      scanned = 0
+      fixed = 0
+      urls_converted = 0
+
+      action_texts_scope.find_each do |rich_text|
+        scanned += 1
+
+        body = rich_text.body
+
+        edited = false
+        conversions = 0
+
+        body.send(:attachment_nodes).each do |node|
+          url = node["url"]
+          next unless url
+
+          if url.match?(RELATIVE_URL_PATTERN)
+            node["url"] = "#{host}#{url}"
+            edited = true
+            conversions += 1
+          end
+        end
+
+        if edited
+          record = rich_text.record
+          puts " - modifying #{record.class.name} #{record.to_param} (account: #{record.account&.external_account_id}) - #{conversions} URL(s)"
+
+          rich_text.update! body: body.fragment.to_html
+
+          fixed += 1
+          urls_converted += conversions
+        end
+      end
+
+      puts "\n\nConversion complete!"
+      puts "  Rich texts examined: #{scanned}"
+      puts "  Rich texts modified: #{fixed}"
+      puts "  URLs converted: #{urls_converted}"
+    end
+
+    def action_texts_scope
+      ActionText::RichText.joins(:embeds_attachments).where("action_text_rich_texts.created_at >= ?", since)
+    end
+end
+
+require "optparse"
+require "time"
+
+options = {}
+
+OptionParser.new do |opts|
+  opts.banner = "Usage: bin/rails runner #{__FILE__} [options]"
+
+  opts.on("--host HOST", "Host to prepend (e.g., https://app.fizzy.do)") do |host|
+    options[:host] = host
+  end
+
+  opts.on("--since TIME", "Process rich texts created since this time (ISO 8601 format)") do |time|
+    options[:since] = Time.parse(time)
+  end
+
+  opts.on("-h", "--help", "Show this help message") do
+    puts opts
+    exit
+  end
+end.parse!
+
+if options[:host].nil? || options[:since].nil?
+  puts "Error: --host and --since are required"
+  puts "Example: bin/rails runner #{__FILE__} --host https://app.fizzy.do --since 2026-01-14T10:00:00Z"
+  exit 1
+end
+
+ConvertRelativeAttachmentUrlsToAbsolute.new(**options).run