I added the users BengaliHindu and Nedol to the #Tool-Labs project by visiting https://wikitech.wikimedia.org/w/index.php?title=Special:NovaProject&action=addmember&projectname=tools&member=BengaliHindu and https://wikitech.wikimedia.org/w/index.php?title=Special:NovaProject&action=addmember&projectname=tools&member=Nedol and clicking "Submit".
After a while, the resulting page (https://wikitech.wikimedia.org/wiki/Special:NovaProject) was empty. I looked at "Manage Projects" (same URL, but not reload with `POST` parameters, but a new request) and verified that the two users were now members of the #Tool-Labs project and marked the requests as done.
But subsequent inspection showed that they hadn't been given their shell access rights ("shell" at https://wikitech.wikimedia.org/wiki/Special:UserRights). I have fixed that for the two users in question since.