Jobs and lanes.

A job is a branded entity — a JOB id with a property bundle — and its life is a small, leased state machine. Jobs.enqueue writes a waiting job; Jobs.claim leases it to a worker and makes it active; Jobs.complete finishes it, Jobs.retry returns it to waiting with a backoff, and a job that exhausts its tries fails. The lease is what makes the bus safe: a worker that dies holding a job loses the lease, and the job is reclaimable rather than lost.

A queue is not one line; it is a set of lanes, each named by a branded id, drained fairly. Lanes.claim is how every consumer takes work, and it spreads claims across lanes so no one lane starves the rest — the fair-lanes property. Group-aware pause and resume act on a lane without touching the queue, so one tenant can be held while the others run. Work that should ride a lane and is enqueued ungrouped is never claimed; the lane is the unit of fairness and of control.

Jobs depend on jobs, and a dependency is a relation, not a field. Flows.add records that a parent waits on its children; when the last child completes, the parent is released, its children’s values readable from the parent. A flow is a small graph of branded ids with its own rules — fan-in, failure policy, grandchildren — owned by the bus, the same move B2 made for edges: the relation is a system, referenced by id, not embedded in either job.