Send Mail reply using a rule

Hi, I’m trying to create a script that will send an automatic reply to messages with the subject line “Here’s your offer”. I am a BCC recipient of these messages, and I want to send the message to the actual recipient, not to the sender.

I created a rule to run an Applescript if the subject is “Here’s your offer” but it’s not doing anything. Even if it were working, I’m sure it’s missing the code to send the message to the recipient in the To: field of the triggering message. I’d love some input on this script:

using terms from application "Mail"
	
	on perform mail action with messages theMessages for rule theRule
		
		tell application "Mail"
			repeat with thisMessage in theMessages
				set AppleScript's text item delimiters to {""}
				set thisSender to sender of theMessages
				
				set theNewMessage to reply thisMessage with opening window
				tell theNewMessage
					set content to "Test message"
				end tell
				
				send theNewMessage
				
			end repeat
		end tell
		
	end perform mail action with messages
	
end using terms from