Demand
How much more service a child could usefully take right now — the child's advertised appetite, and nothing about its authority.
A busy child says "I could keep another targetOutstanding units of unspent entitlement usefully occupied, and don't hand me more than maximumUsefulGrant in one go." A child with no work advertises NONE. The parent folds every live child's demand when it decides who to serve next (design §6, §7.3).
Demand is advisory, never authority. It can be stale, duplicated, or lost and the worst outcome is entitlement briefly parked in the wrong pocket — it can never authorize a spend, because spends check the ledger's holdings, which are blind to demand. That separation is the whole reason demand rides a non-durable presence channel while entitlement rides the ledger (design §6): here in the pure policy it is simply an immutable value the caller supplies per edge.