簡単な回答
Use a lorebook for durable world facts such as locations, factions, timelines, side characters, family histories, magic rules, or recurring objects that should not fill the prompt on every turn.
平易な言葉の意味
A lorebook is not the live chat and not the main character card. It is a reference shelf the app can pull from when the scene needs a specific fact.
Lorebook searches attract advanced roleplay users comparing Chub, SillyTavern, SpicyChat, and guided apps.
OnlyKin does not need to expose every advanced lorebook switch, but it should explain the concept and simplify the benefits for story-first users.