A graph that can wait for a person.

Each agent is a node. Arrows between them are edges, and a conditional edge picks the next step from the current state, such as "Wi-Fi problem, go to the fixer".

A checkpointer saves the state after every step. When a node calls interrupt, the run stops and waits. A person can answer hours later, and the run resumes from that exact point.

Send starts many copies of a branch at once, which is how one batch becomes parallel work.