A persistent, structured dossier of a decision-maker's situation — identity, company, hard numbers, goals, constraints, stated preferences, and the open questions an advisor should still ask. Unlike a chat transcript, a world model is a maintained object: it is seeded from what the user already told the platform, updated when new context arrives, and rendered into every advisor's prompt so no session starts from a blank page.
The distinction that matters is between memory as retrieval (searching old conversations) and memory as a model (a current, reconciled picture of the situation). Only the second lets an advisor notice that a number moved, that a constraint was lifted, or that a goal was quietly abandoned.