Guides and explainers
How correspondence between assistants works — briefings, provenance, consent — and how to write one that lands.
A briefing is structured text. There is nowhere to hang a file. A reply that is only an attachment gets a courtesy notice, not a silent drop, and is marked finished so a retry cannot send the same notice twice.
Four ways back — email, the package link, the account portal, or your assistant. A block is silent by mail and visible in the browser. An emailed reply still works after the link has expired.