A briefing is a question with a way back. There are four, and they are not interchangeable.
Reply to the notification. The Reply-To is a token address, not the sender's mailbox. RelayLink matches the token, writes a reply package, and notifies the original sender.
The page at the link expires. The reply to the email does not, not for a while. The link is good for thirty days; an emailed reply is accepted for sixty days past that. Somebody answering a two-month-old message is doing something ordinary. The expired page is not a reason to throw away what they typed.
Past even that window you get one courtesy notice per token per day — not if the mail looks automated (Auto-Submitted, bulk precedence, a list id). Replying to an autoresponder is how a mail loop starts.
A reply that is only an attachment gets a different courtesy. Attachments are out of scope; the wording says so, rather than pretending the link died.
The package page
The same token the email used. A box under the briefing, send, done. No account required. The page has no script; the form posts.
If the link is dead, you get a page that says so — not a JSON sentence in a tab — and that you can still reply to the email. An invalid token and an expired one look the same. "Expired" is the honest word for almost every real arrival.
The account portal
If you have signed in, the thread is in your inbox. Reply there. The wording is yours from the start, labelled as typed in the portal — not "verbatim" (that label has one producer) and not "via the link" (that label means a token and a heuristic strip of quoted mail).
Participation in the thread is not enough on its own. A block is checked here too. Without that, the portal would be a permanent channel after the token paths had closed.
Your assistant
draft_package in the thread, then you approve. Same labels, same gate. The assistant does not send because you said "reply" in a conversation. You still see the wording.
When a block is in the way
Every reply path checks it. The answers differ on purpose.
- You are watching — the portal form, the package page. You get the refusal on the page. You asked synchronously.
- You sent mail. Nothing comes back. Mail saying "your reply was not delivered" discloses the block however carefully it is worded. The row is finished, not failed; there is nothing to retry.
That is the one terminal outcome where typed words vanish without a notice. The block is the only control a recipient can reach from an email, and it is worth more than the courtesy.
If you sent the original briefing, what the sender sees is a Replied line when a reply lands — not a fetch of the link.