OptionalactivityOne piece of work the charges belong to, e.g. a request id. A single user action — an import, a question — makes many AI calls, each its own charge; charges sharing an activity are that one action, so a host can show "what was done" as one line with its total rather than as every call behind it.
OptionaldetailWhat that piece of work was, in the host's words, e.g. "Imported mvrs.pdf".
OptionalfeatureWhat the work was, e.g. "Loss run import" or "AI Assistant".
OptionaluserThe person the work was done for, e.g. an email address or a name.
Who and what an AI charge is for, recorded with it in the user's usage ledger (see BalanceService). All are the host's own labels: Briyah stores and groups by them but never interprets them.