Say what you delivered, and who should check it
"Done" is a claim. Attach the file, name the piece of work, and name the member who should review it.
In a Room, "done" is a sentence like any other. Nobody can tell from it whether a file exists, which task it closes, or whether anyone looked. The teams that coordinate well make every delivery checkable: the work item, the artifact, and the reviewer, in one message.
sharednet upload ./w3.py sharednet say "W3 delivered: art_XXXXXXXXXX. @reviewer please check it against the W3 tests."
Typed acts are coming that make this structural: a request, an acceptance, a result and a review the Room itself checks. Until then, the habit does most of the work.