The bus's objects are raised on every start, and one switch says which bus

Two of 1.7's three remaining pieces.

**Raised on every start, not created once at genesis.** A stream somebody deleted,
a mesh raised from a restored backup, or a bus whose data directory was replaced
all have records and no objects — and a node whose consumer is missing hears
nothing while everything else about it looks correct.

The order is not a preference: a consumer on a stream that does not exist is
refused *naming the stream*, so somebody reading that refusal goes looking for a
deletion instead of a reversed pair of lines. Pinned by a test, along with the one
thing about seats that reads like an omission and is not — a seat's work queue is
asserted whether or not anybody holds it, because work queues until a holder
appears, so installing the module a week later flushes the backlog instead of
having lost it.

Against a real server: every object accepted, asserting twice changes nothing (a
start that failed the second time is a controller that cannot restart), a machine
joining an already-raised bus is accepted, each node's consumer is bound to its own
declaration subject and no other's, and CONTROL does not dead-letter — because the
store window's bound belongs to the controller and a server that gave up first
would discard the push the stream exists to protect.

**Which bus this mesh is on is one fact, read in one place.** Every seam the change
went behind ships both implementations; this is what the rollout flips. Being told
about both is refused at start rather than warned about: a mesh half on each is one
where a declaration goes out on one bus and the report comes back on the other, and
every component logs success while it happens — ADR 0074's failure arriving through
configuration instead of through code. The refusal names both variables and says
which to unset, because whoever reads it has to choose and the wrong choice is a
rollout half done.

cmd/mesh-controller/push.go

@@ -77,12 +77,33 @@ func serve(ctx context.Context) error {
 			"reconnect. Set %s and %s.\n", broker.AddressVar, broker.CertificateVar)
 	}
 
+	// **Which bus this mesh is on, read once** (novox/hq ADR 0116 step 5). Both clients ship; both
+	// being live is refused, because a mesh half on each is one where a declaration goes out on one
+	// and the report comes back on the other, and every component logs success while it happens.
+	busAddress, onNATS, err := broker.OnNATS()
+	if err != nil {
+		return err
+	}
+	if err := broker.MustBeOneBus(os.Getenv(broker.AMQPVarName), busAddress); err != nil {
+		return err
+	}
+
 	work := link.Enrolment{Inventory: inv, Identity: ident, Management: management, Broker: known}
 	server, err := link.Connect(work, work)
 	if err != nil {
 		return err
 	}
 	defer server.Close()
+
+	// The bus's own objects, asserted on every start. **Not created once at genesis**: a stream
+	// somebody deleted, a mesh raised from a restored backup, or a bus whose data directory was
+	// replaced all have records and no objects — and a node whose consumer is missing hears nothing
+	// while everything else about it looks correct.
+	if onNATS {
+		if err := raiseTheBus(ctx, inv, busAddress); err != nil {
+			return err
+		}
+	}
 	// And build results nobody was waiting for. A build triggered any other way than `build`
 	// would otherwise be reported into the void, which is the same as not reporting it.
 	server.Records(builds{inv})
@@ -664,3 +685,34 @@ func wouldSend(ctx context.Context, open *stores,
 	}
 	return out, nil
 }
+
+// raiseTheBus asserts the streams and consumers the mesh's own traffic needs.
+//
+// **Every start, and it says what it did.** The objects are the mesh's, created by nothing else —
+// the controller is their only writer (design 25 §3) — so a mesh that came up without them is one
+// where nodes connect, authenticate, and hear nothing. Said rather than silent for the reason the
+// first line of `serve` is said: a log that is quiet on success and loud on failure reads as broken
+// when it is working.
+func raiseTheBus(ctx context.Context, inv *inventory.Inventory, address string) error {
+	js, err := broker.Dial(address)
+	if err != nil {
+		return fmt.Errorf("the mesh is on the bus at %s and this control plane cannot reach it: %w",
+			address, err)
+	}
+	defer js.Close()
+
+	nodes, err := inv.Nodes(ctx)
+	if err != nil {
+		return err
+	}
+	names := make([]string, 0, len(nodes))
+	for _, n := range nodes {
+		names = append(names, n.Name)
+	}
+	if err := broker.Raise(js, names); err != nil {
+		return err
+	}
+	fmt.Printf("the bus at %s has its streams, and %d machine(s) can hear a declaration\n",
+		address, len(names))
+	return nil
+}