Autoreply to Filtered Gmail Messages with Google Scripts

This Google Script, originally published by @rboyd, scans for lengthy emails in your Gmail mailbox (messages that have more than 100 words) and sends an auto-reply requesting the sender to resend the email after editing to less than 100 words. The long email is archived (moved away from the Inbox) after the auto-reply has been sent. You can set it up as a trigger to auto-run every 15 minutes.

Also see: Email Auto-responder for Gmail