What the copy may lack is known when "+" is pressed, from the page on
screen: images still uploading, which the server leaves out, and edits
to the page the server refused, which it never had. Saying so then,
rather than guessing afterwards from what landed, holds whether the add
lands at once or later, and isn't fooled by a teammate's changes. The
wait for the server's answer now starts before sending, so a stalled
send still answers "+" in time. A page copy too large to make gets its
own message in the sync panel.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>