The assistant settings of one user (phoenix_kit_agent_user_settings, keyed by user_uuid). A nil field means "the module default" (PhoenixKitAgent.Config); enabled: false switches the assistant off for this user even with the agent permission.

notify_user_uuids are extra people told when this user hits a limit (the uuid of a deleted user is removed from every row, see PhoenixKitAgent.UserDeletion). busy_since / busy_turn_ref are the "one turn in flight per user" lock (PhoenixKitAgent.Turns.Locks, which leaves updated_at alone) and updated_by_uuid the last admin who changed the row: both are set by the caller, never cast. Money is in micro-dollars ($1 = 1_000_000).

Two changesets, for the two people who write a row: admin_changeset/2 — the switch, the model, the admin's prompt, the limits and the notices, for a caller that has checked agent.manage; personal_changeset/2 — the user's own personal_instructions, nothing else. Neither casts the lock columns, updated_by_uuid or the key. Never upsert this row with on_conflict: :replace_all: that would wipe a live turn lock.