Loop cut

Ping and pong pass an answer back and forth, each forwarding to whoever it answered, so the two adapters run in turn: start, pong, ping, pong. Nothing watches the loop from outside; each neuron carries maxHops: 5, and the drop with the reason hops is what ends it.

Loops are allowed and bounded (SPEC 5.3): the hop count rides on the signal, and the neuron whose next send would cross the limit refuses and reports the drop. There is no scheduler patrolling the graph, because the limit is where the crossing happens.

Not a budget: a hop cap is a count, not a spend, and what a spend limit per trace looks like is the budgets demo’s separate answer.