The closest I’ve come to seeing RP ‘standards’ posted was on a Pern MUSH I didn’t stick with for long (Second Pass, I kinda got there at the end of its life, unfortunately), and it was more of an explanation of MUSH RP conventions than hard-and-fast rules. Their site is gone now, alas, but I found their old RP Etiquette Guide after some nosing around in The Way Back Machine.
Posing in general.
- Please make an effort to correct typos and use something resembling proper English grammar. If you have a writing-related disability, a spellchecker will catch the most egregious ones and people will be willing to cut you some slack on the rest if you warn them up front.
- There’s a place and time for the one-line pose and the twenty-line pose. Second Pass poses usually run between 3 and 6 lines, with a few outliers in either direction. In general, try to create a happy equilibrium. Keep in mind the time needs of other players when you tend towards longer poses, and their need to have something to respond to when you tend towards shorter poses.
- /Read things/. Read descs, read bbposts, read news files, read other people’s poses. Then try to retain at least a general sense of having read it.
I tend to think the middle part is pretty standard for MUSH RP, at least in its day (this copy-paste is from a 2016 capture), but even that varies pretty wildly depending on individual game culture. Mostly, I think, people figure out what the ‘vibe’ is in RP by the most active players and staffers and emulate it.