Agent teams: every child is narrower than its parent
Delegation is narrowing. A planner can hand work to workers without any of them being able to do more than the planner could. The reservation makes it arithmetic: the children cannot collectively spend more than the root was granted.
Principle honored
Least privilege and bounded blast radius, applied to delegation. The same narrow-only rule that applies to a claim applies to a child.
What changes
One task_id across the whole tree, so the flight recorder shows a team as one story.
Depth is capped at 3 and children at a per-definition limit, so a runaway spawn loop stops.
Closing a parent closes the tree; tripping a parent freezes it.
Proved in code
This is tested as a property: in 200 random sequences of spawn, spend and close, no session ever overspends and no tree ever exceeds what the root was granted. That test is in the repository.