When several agents pull from the same backlog, the classic failure is two of them picking up the same task. Both do the work, both open a pull request, and a person has to sort out the mess.

Quiel has one dispatcher, and only the dispatcher can assign a task. A task leaves the queue for exactly one agent, together with a lease.

While the agent works, its client sends a heartbeat. As long as heartbeats arrive, the lease stays alive and nobody else can take the task.

If the client dies, the laptop sleeps or the network drops, the heartbeats stop. The moment the lease expires, the task goes back to the queue for the next agent with that role.

The result is simple to state and easy to test: no duplicates, no orphans, and no task that silently disappears.