An opt-in Self-Found ruleset for AzerothCore. A character that turns this on has to find its own gear: no trading, no auction house, no outgoing mail. You toggle it in chat with .selffound on | off | status.
While a character is flagged Self-Found the trade window will not open with anyone (bots included), the auction house stays shut (browse, post, bid, buyout) and sending mail is blocked. Grouping and questing are unaffected. The flag sits on the individual character and can be switched back off.
Receiving mail, by the way, is not blocked, so another player could in theory still send you items. For the solo challenge that is good enough.