The mesh's own seats said who does a job and nothing about what may be said to
them or by them, and that gap showed up three times in one day looking like three
different problems: a build machine with three audiences for one outcome and no way
to derive a grant for any of them; an event genuinely about a role with nowhere to
live but the namespace of whichever module holds that role today; and a catalogue
catching up on builds, where every option needed a grant the design refuses.
One cause — the mesh has roles it cannot describe. So the `mesh-*` seats take the
same three fields a module's seat has, and the machinery that already derives
authority, queues and consumers from a declared seat does it for these too.
Builds become work submitted to a role, and `mesh.build.request`,
`mesh.control.built` and the BUILDS stream retire. A work queue shared by several
build machines is exactly what a seat's `accepts` is, so a second mechanism for it
was two places a permission could be wrong. The outcome is the seat's own event,
which means one publish still reaches whoever asked, the controller that records it
and the catalogue that places it — the fan-out a shared exchange gave for free,
written as a subject the mesh derived rather than a topology somebody configured.
That also avoids the grant that ruled out the alternatives: no holder needs
permission to publish into an asker's inbox.
The blocking gap is now named rather than incidental: the shared library has no way
for a module to publish on a seat. The build machine is Go and reaches the bus
directly, so it is unaffected; the artifact-store event waits.
