Groups

Group, channel, and forum conversations use the same message model as direct chats.

• type = "group" | "channel" | "forum"
• Creator is owner
• Additional users are member unless addParticipant specifies admin or moderator
• Only owners and admins can add participants
• Direct conversations cannot add participants

Blocked identities cannot be invited (createGroup / createChannel / createForum / addParticipant). The error matches a missing user. Members who already share the room may still send ordinary messages and thread replies. See messaging.

Mentions are structured IDs in metadata.mentions. Body text is not parsed. Autocomplete is conversations.membersForMention for that conversation only, not identities.list. There is no separate mention table.

See community for threads and reactions, and retention for optional policy on create.