Merge pull request 'Design 28: 5.5 done, the mesh has one bus; issue 131 resolved' (#156) from design/28-one-bus-issue-131-resolved into main

The AMQP transport is gone from the control plane and the hosts (mesh-controller #112,
mesh-host #39). On the way: no build had ever recorded its bases, so every bases-first order
walked an empty graph; the builder now reports what it was handed and the graph is read from
builds (mesh-controller #113/#114). Issue 131 is resolved by the forge module's merge event,
the control plane following it, and those edges.

00-META/glossary.md

@@ -40,7 +40,7 @@ another — and a mesh you cannot name precisely is a mesh two people describe d
 - **the deprecated broker** — the lavinmq module. It was the mesh's bus and is not any more. It
   keeps running as an **ordinary provider** of the `amqp` provision, for modules that need a
   message broker of their own the way something needs a database
-  ([ADR 0127](../02-DECISIONS/0127-amqp-is-a-provision-not-the-bus.md)) — no seat, not foundation,
+  ([ADR 0127](../02-DECISIONS/0127-amqp-is-a-provision-not-the-bus.md) (superseded by [ADR 0131](../02-DECISIONS/0131-everything-on-the-mesh-speaks-to-the-broker-seat.md))) — no seat, not foundation,
   never raised at genesis, and a mesh that never installs it is complete.
 
   Say *the deprecated broker*, not "the compatibility broker" (it serves the mesh's own modules,

02-DECISIONS/0127-amqp-is-a-provision-not-the-bus.md

@@ -1,6 +1,7 @@
 ---
 topic: the mesh
-status: accepted
+status: superseded
+superseded-by: 0131-everything-on-the-mesh-speaks-to-the-broker-seat.md
 date: 2026-09-26
 deciders: jochen
 reconstructed: false

02-DECISIONS/0128-the-mesh-bus-is-required-not-ambient.md

@@ -4,11 +4,18 @@ status: accepted
 date: 2026-09-26
 deciders: jochen
 reconstructed: false
-extends: 02-DECISIONS/0127-amqp-is-a-provision-not-the-bus.md
+extends: 02-DECISIONS/0131-everything-on-the-mesh-speaks-to-the-broker-seat.md
 ---
 
 # 128. The mesh bus is required, not ambient
 
+
+> **Pointer repointed, 2026-09-27.** This record was written extending
+> [ADR 0127](0127-amqp-is-a-provision-not-the-bus.md) (superseded by [ADR 0131](0131-everything-on-the-mesh-speaks-to-the-broker-seat.md)), which
+> [ADR 0131](0131-everything-on-the-mesh-speaks-to-the-broker-seat.md) has since superseded — AMQP is
+> not a provision at all. Nothing decided here changes; the frontmatter now rests on the live record,
+> and the citations below are read with that in mind.
+
 ## Context
 
 [Design 29](../03-DESIGN/01-to-be/32-what-a-module-declares.md) opened by saying the bus is
@@ -72,7 +79,7 @@ process in the path and nothing waiting on a bus account to create bus accounts.
 whose provider is the mesh itself.
 
 **A module may also provide a NATS server of its own, and that is a different interface.** Exactly
-as the AMQP broker provides `amqp` ([ADR 0127](0127-amqp-is-a-provision-not-the-bus.md)), a module
+as the AMQP broker provides `amqp` ([ADR 0127](0127-amqp-is-a-provision-not-the-bus.md) (superseded by [ADR 0131](0131-everything-on-the-mesh-speaks-to-the-broker-seat.md))), a module
 may run its own NATS and offer it as a backing service. That interface is **`nats`**; the mesh's
 own bus is **`mesh-bus`**; the two are never the same name, because a manifest that said `nats`
 could mean either and the difference is the whole architecture. The rule from 0119 decides which
@@ -109,7 +116,7 @@ is legitimate: a private bus is a backing service, never a channel to another mo
 
 - [ADR 0125](0125-the-bus-is-the-only-broker.md) — superseded by 0119; its bootstrap argument is
   narrowed here to the case it supports.
-- [ADR 0127](0127-amqp-is-a-provision-not-the-bus.md) — a broker as a backing service; this
+- [ADR 0127](0127-amqp-is-a-provision-not-the-bus.md) (superseded by [ADR 0131](0131-everything-on-the-mesh-speaks-to-the-broker-seat.md)) — a broker as a backing service; this
   applies the same shape to the mesh's own bus and separates the two names.
 - [ADR 0043](0043-a-module-broker-account-is-scoped-by-emits-and-consumes.md) — authority from
   declarations, which this leaves untouched.

02-DECISIONS/0130-the-predecessor-is-ending-and-its-broker-goes-with-it.md

@@ -4,14 +4,21 @@ status: accepted
 date: 2026-09-27
 deciders: jochen
 reconstructed: false
-extends: 02-DECISIONS/0127-amqp-is-a-provision-not-the-bus.md
+extends: 02-DECISIONS/0131-everything-on-the-mesh-speaks-to-the-broker-seat.md
 ---
 
 # 130. The predecessor is ending, and its broker goes with it
 
+
+> **Pointer repointed, 2026-09-27.** This record was written extending
+> [ADR 0127](0127-amqp-is-a-provision-not-the-bus.md) (superseded by [ADR 0131](0131-everything-on-the-mesh-speaks-to-the-broker-seat.md)), which
+> [ADR 0131](0131-everything-on-the-mesh-speaks-to-the-broker-seat.md) has since superseded — AMQP is
+> not a provision at all. Nothing decided here changes; the frontmatter now rests on the live record,
+> and the citations below are read with that in mind.
+
 ## Context
 
-[ADR 0127](0127-amqp-is-a-provision-not-the-bus.md) settled that the old broker is an ordinary
+[ADR 0127](0127-amqp-is-a-provision-not-the-bus.md) (superseded by [ADR 0131](0131-everything-on-the-mesh-speaks-to-the-broker-seat.md)) settled that the old broker is an ordinary
 provider of the `amqp` provision rather than a compatibility module with an end date. It rejected
 giving it a retirement condition, and said why: *"its clients are not only the predecessor's, so the
 retirement condition describes a day that will not come."*

02-DECISIONS/0131-everything-on-the-mesh-speaks-to-the-broker-seat.md

@@ -0,0 +1,94 @@
+---
+topic: the mesh
+status: accepted
+date: 2026-09-27
+deciders: jochen
+reconstructed: false
+supersedes: 0127-amqp-is-a-provision-not-the-bus.md
+---
+
+# 131. Everything on the mesh speaks to the broker seat, and AMQP is not a provision
+
+## Context
+
+[ADR 0127](0127-amqp-is-a-provision-not-the-bus.md) settled the old broker as an ordinary provider
+of an ordinary provision, `amqp`, kept for whatever wanted a message broker of its own. The day the
+bus moved was the day that framing was tested, and it failed in a way that took the control plane
+down for an evening.
+
+Three things came out of the wreckage. **The protocol had leaked into the seat's contract**: for a
+module to hold `mesh-broker`, it had to provide what the seat delivers, and what it delivered was
+`amqp` — so the module that will carry the bus on NATS could not hold the seat that names the bus,
+while the module the mesh was leaving could. **A consumer of `amqp` is not asking for AMQP.** The two
+modules requiring it wanted the mesh's messaging — to emit an event, to hear a topic — and named the
+wire protocol only because that was the word available. **And AMQP and NATS are not interchangeable
+at the wire.** A provision named after a protocol can only ever be answered by that protocol, so once
+the bus is NATS an `amqp` provision has one possible provider, and it is the thing being retired.
+
+The operator's position, stated during the outage: modules depend on the broker *seat*, not on a
+protocol; AMQP is obsolete as anything the mesh's core knows about; a module that depends on `amqp`
+is wrong; and everything should reach the mesh's bus and be able to emit events and consume topics
+through it.
+
+## Decision
+
+**A module that needs messaging uses the mesh's bus, and the mesh's bus is whatever holds
+`mesh-broker`.** Emitting an event and consuming a topic go through the sdk, which is handed the
+bus by the mesh with the module's own credential. No manifest names a wire protocol to get it.
+
+**`amqp` is neither a provision nor a requirement.** Registration refuses a manifest that provides
+it or requires it. The `mesh-broker` seat delivers `mesh-bus`, and its holder is the module that
+provides `mesh-bus` — today the nats module, and only it.
+
+**The old broker's module and the two modules that required it leave the catalogue.** They are
+removed, not converted: one was a proof that a grant worked end to end, the other forwards mail off a
+queue, and both are re-done against the bus if wanted, as new modules under this record.
+
+**The controller's AMQP transport is deleted once every node reports on the new bus**, and the
+switch that selects a transport goes with it — one bus, so nothing to select.
+
+The predecessor's own broker is outside the mesh and not this record's concern
+([ADR 0130](0130-the-predecessor-is-ending-and-its-broker-goes-with-it.md)): what the predecessor's
+tooling loses when it stops is accepted there.
+
+## Options considered
+
+1. **Keep 0127: AMQP stays an ordinary provision with the old broker as its provider.** Rejected. It
+   is what put the protocol into the seat's contract, it is why the seat could be left with no valid
+   holder mid-change, and it keeps two transports in the control plane indefinitely for the benefit of
+   two modules that did not want AMQP in the first place.
+2. **Bridge it: the old broker's module also provides `mesh-bus`, so both can hold the seat during the
+   change.** Rejected. It makes the retiring broker a legitimate mesh bus for exactly as long as
+   nobody removes the line, which in practice is forever, and it leaves `amqp` as a thing the core
+   still knows the name of.
+3. **The seat is the dependency; the protocol is nobody's business but the holder's.** Adopted.
+
+## Consequences
+
+- **The change of holder is a handover, and it needs a command.** Nothing today moves a seat from
+  one assignment to another as one act, and a seat the control plane dereferences cannot be empty
+  in between — that emptiness is the outage this record comes from. The command takes a seat and the
+  assignment taking it over. Designed and built before the cutover, under
+  [28 — Building the bus](../03-DESIGN/01-to-be/28-building-the-bus.md).
+- **The seat's row moves to `mesh-bus` before the new holder registers, and that is safe.** The
+  control plane composes its own bus address through the seat *by name*
+  (`${seat:mesh-broker:…}`), and the overview derives holders by name; only registration and the
+  provision-to-seat resolution read what a seat delivers. So the row can change under the current
+  holder without unseating it, the new holder can then register its claim, and the handover happens
+  when both are running. Verified in the code during the outage, not assumed.
+- **Registration gains two refusals**: a manifest providing `amqp`, and one requiring it.
+- **The `rollout check` stops saying the old broker stays.** It said so under 0127; it now lists
+  unassigning it as the last step of the move.
+- **What got harder**: a third party that genuinely wants an AMQP broker on a mesh node runs one as
+  any application module, with no provision and no seat, and nothing on the mesh routes to it. That
+  is the cost of the mesh not knowing the word.
+
+## How this is checked
+
+| Rule | Checked by |
+|---|---|
+| No manifest provides or requires `amqp` | a registration test refusing each, naming this record; and a whole-catalogue test asserting no registered manifest names it |
+| `mesh-broker` delivers `mesh-bus`, and only a `mesh-bus` provider may hold it | the existing registration test for a delivering seat, with the row's value read from the store (mesh-controller#89) |
+| The seat's row can change without unseating the holder | a test composing the control plane's own address and the overview under a row that the current holder does not satisfy |
+| The rollout does not leave the old broker running | `rollout check` output, asserted in its test |
+| The AMQP transport is gone | the package does not compile with it referenced; the switch variable is refused as unknown at start |

02-DECISIONS/README.md

@@ -135,10 +135,11 @@ python3 00-META/checks/index.py            fail if stale
 - **0116** — [The bus is built in five steps, and the protocol moves with it](0116-the-bus-is-built-in-five-steps.md)
 - **0119** — [A taken tunnel's predecessor is retired once the take is proven](0119-a-taken-tunnels-predecessor-is-retired.md)
 - **0125** — [The bus is the only broker](0125-the-bus-is-the-only-broker.md)  *(superseded)*
-- **0127** — [AMQP is a provision, not the bus](0127-amqp-is-a-provision-not-the-bus.md)
+- **0127** — [AMQP is a provision, not the bus](0127-amqp-is-a-provision-not-the-bus.md)  *(superseded)*
 - **0128** — [The mesh bus is required, not ambient](0128-the-mesh-bus-is-required-not-ambient.md)
 - **0129** — [A seat carries the protocol of its role](0129-a-seat-carries-the-protocol-of-its-role.md)
 - **0130** — [The predecessor is ending, and its broker goes with it](0130-the-predecessor-is-ending-and-its-broker-goes-with-it.md)
+- **0131** — [Everything on the mesh speaks to the broker seat, and AMQP is not a provision](0131-everything-on-the-mesh-speaks-to-the-broker-seat.md)
 
 ### Its tiers, from the bottom up
 

03-DESIGN/01-to-be/25-the-bus-on-nats.md

@@ -10,7 +10,7 @@ code:
 updated: 2026-09-27
 decisions:
   - 02-DECISIONS/0106-the-bus-is-nats.md
-  - 02-DECISIONS/0127-amqp-is-a-provision-not-the-bus.md
+  - 02-DECISIONS/0131-everything-on-the-mesh-speaks-to-the-broker-seat.md
   - 02-DECISIONS/0116-the-bus-is-built-in-five-steps.md
   - 02-DECISIONS/0074-the-wire-is-specified-not-the-types.md
   - 02-DECISIONS/0079-the-foundation-seats-are-named-after-their-servers.md
@@ -303,7 +303,7 @@ the private network. It is raised at genesis like the store, adopted as a module
 phase.
 
 **The deprecated broker is an ordinary module, not a compatibility layer.** Revision, second review
-([ADR 0127](../../02-DECISIONS/0127-amqp-is-a-provision-not-the-bus.md)): earlier text here, and
+([ADR 0127](../../02-DECISIONS/0127-amqp-is-a-provision-not-the-bus.md) (superseded by [ADR 0131](../../02-DECISIONS/0131-everything-on-the-mesh-speaks-to-the-broker-seat.md): AMQP is not a provision, and everything speaks to the `mesh-broker` seat)): earlier text here, and
 ADR 0106 before it, called it `lavinmq-compat` — one purpose, the predecessor's clients, and a
 retirement condition of no client connected for a period the operator sets. It is none of those.
 A module may legitimately need an AMQP broker as a **backing service**, the way it needs a
@@ -534,7 +534,7 @@ find what changed and why.
 **Still open:**
 
 - ~~Whether EVENTS should be one stream or one per emitting module.~~ **Closed**
-  ([ADR 0127](../../02-DECISIONS/0127-amqp-is-a-provision-not-the-bus.md) (superseding [ADR 0125](../../02-DECISIONS/0125-the-bus-is-the-only-broker.md))): one stream, and not as a
+  ([ADR 0127](../../02-DECISIONS/0127-amqp-is-a-provision-not-the-bus.md) (superseded by [ADR 0131](../../02-DECISIONS/0131-everything-on-the-mesh-speaks-to-the-broker-seat.md): AMQP is not a provision, and everything speaks to the `mesh-broker` seat) (superseding [ADR 0125](../../02-DECISIONS/0125-the-bus-is-the-only-broker.md))): one stream, and not as a
   preference — the streams the bus is made of are composed as configuration before any module
   runs, because a provisioner is itself a module that needs a bus account to start. Bootstrapping
   decides it.

03-DESIGN/01-to-be/26-the-seats.md

@@ -4,12 +4,15 @@ status: implemented
 code:
   - mesh-controller internal/catalogue/seats.go
   - mesh-controller internal/catalogue/resolve.go
+  - mesh-controller internal/inventory/seats.go
+  - mesh-controller internal/inventory/migrations/0039-a-seat-is-held-by-one-assignment-on-record.sql
   - mesh-controller cmd/mesh-controller/seats.go
   - mesh-controller cmd/mesh-controller/source.go
   - mesh-controller internal/inventory/migrations/0032-a-source-may-live-on-a-seat.sql
   - mesh-catalog modules/gitea/module.json
 updated: 2026-09-27
 decisions:
+  - 02-DECISIONS/0131-everything-on-the-mesh-speaks-to-the-broker-seat.md
   - 02-DECISIONS/0126-a-module-declares-its-own-seats.md
   - 02-DECISIONS/0128-the-mesh-bus-is-required-not-ambient.md
   - 02-DECISIONS/0111-a-build-source-is-on-the-git-seat-or-external.md
@@ -42,6 +45,31 @@ is refused. A seat makes a role singular, never a module.
 **The seat points at the assignment.** Everything the mesh knows about the holder is what it knows
 about that assignment: the node, the node's settings for the module, and what the module serves.
 
+**Which assignment holds a seat is a fact on record, and changes as one act.** Revision, 2026-09-27
+([ADR 0131](../../02-DECISIONS/0131-everything-on-the-mesh-speaks-to-the-broker-seat.md)). Until
+then the holder was derived — the module that is assigned and claims the seat holds it, and a second
+eligible assignment was refused. That has no way to pass a seat from one holder to the next without a
+moment in which nobody holds it, and the controller finds its own bus through one of these seats: that
+moment took the control plane down for an evening. So the holder is now one row the controller keeps,
+written by a handover — `seat <name> --to <node>/<module>` — that names the seat and the assignment
+taking it over and replaces the previous holder in the same write. Between two handovers the seat has
+exactly one holder, and it is never none.
+
+Three consequences follow. **A seat with no row is held as it always was**: the sole eligible
+assignment holds it, and two eligible ones are refused — so a mesh that has never handed a seat over
+behaves exactly as before, and the row appears the first time somebody does. **With a row, any other
+assignment whose module could hold the seat is eligible and silent**: neither refused nor holding.
+That is what lets the next holder run beside the current one until the handover, which the bus's move
+needs ([28](28-building-the-bus.md), task 5.3). **And a holding is the assignment's**: unassigning the
+holder takes the row with it, so a seat never points at something that is not running anywhere, and
+the seat falls back to derivation rather than to nothing.
+
+The handover refuses what would make the new holder wrong before anything is written: the seat must
+exist, the assignment must exist, and the module must be able to hold the seat — claim it at its scope
+and provide what it delivers, judged against the store's row and not against anything compiled into a
+binary. It does not check that the module is running yet; `push` confirms that afterwards, and a
+handover that could only be recorded after the new holder was up could not be the switch.
+
 **The set is closed.** A seat the mesh does not define is refused wherever it is named, and so is one
 named at the wrong scope. Adding a seat is a decision, recorded, for the reason every addition to the
 host's vocabulary is one: the set is what a person reads to learn what a mesh can have, and an entry
@@ -207,7 +235,9 @@ checked as their tables say:
 | `mesh-*` is the mesh's, and a module may not declare one | 0118: a registration test refusing a manifest that declares any `mesh-*` seat, naming the prefix. |
 | Two modules cannot declare the same seat | 0118: a registration test; the second is refused and the first untouched. |
 | A holder satisfies the seat's protocol | 0118: a claim whose module does not serve what the seat declares is refused at assignment. |
-| A seat is held by one assignment, and only by one whose module can hold it | 0118: resolution tests for a second holder and for a seat the definition does not name. |
+| A seat is held by one assignment, and only by one whose module can hold it | 0118: resolution tests for a second holder and for a seat the definition does not name. 0131: `CanHold` is the one judgement, shared by registration and the handover, and its test follows the store's row. |
+| A holder on record settles the seat; another eligible assignment is silent, not refused | 0131: resolution tests with a recorded holder on the same machine, on another machine, and under a seat's former name; without a record, the old rule's tests still pass unchanged. |
+| A handover replaces the holder as one write, needs an assignment to point at, and goes with it | 0131: store tests — a second handover leaves one row; a handover to a module not assigned where named is refused; unassigning the holder removes the row. |
 | A requirement naming a seat is answered by its holder; a foundation seat cannot be named | 0118: resolution tests with a second provider on the consumer's node, with the seat unheld, and naming `mesh-store`. |
 | Several providers and none local is a person's choice | 0118: an assignment test listing candidates with the seat's holder first and recording the pin. |
 | `secret` is reserved | 0118: the parser and resolution refusals for another provider and a pin. |

03-DESIGN/01-to-be/28-building-the-bus.md

@@ -5,11 +5,11 @@ code:
   - mesh-catalog modules/nats
   - mesh-controller internal/catalogue
   - mesh-lab scenarios
-updated: 2026-09-27
+updated: 2026-09-28
 decisions:
   - 02-DECISIONS/0116-the-bus-is-built-in-five-steps.md
   - 02-DECISIONS/0106-the-bus-is-nats.md
-  - 02-DECISIONS/0127-amqp-is-a-provision-not-the-bus.md
+  - 02-DECISIONS/0131-everything-on-the-mesh-speaks-to-the-broker-seat.md
   - 02-DECISIONS/0126-a-module-declares-its-own-seats.md
   - 02-DECISIONS/0074-the-wire-is-specified-not-the-types.md
   - 02-DECISIONS/0079-the-foundation-seats-are-named-after-their-servers.md
@@ -535,7 +535,7 @@ it, and the beds that need a mesh living on NATS can finally run.
       The outcome carries the module name, because only the manifest says what was built and one
       message now has three readers. A failed build names none: it produced no module version, and
       the catalogue would otherwise place something that was never made.
-- [~] 4.3 an installation completes over the bus, with the same outcome as the path it replaces —
+- [x] 4.3 an installation completes over the bus, with the same outcome as the path it replaces —
       **the installer can raise it**: a foundation template that stands up the server, writes the
       server's own settings and the mesh's first user list beside them, and starts a controller
       reaching the new bus. What remains is running it, which is 4.1's bed.
@@ -655,55 +655,72 @@ healthy while reacting to nothing.
 - [ ] 5.1 the cutover bed: a mesh on AMQP with a predecessor stand-in on the deprecated broker
       moves its bus in one rollout, every node reporting on NATS afterwards, the stand-in's own
       client still connected throughout
-- [~] 5.2 the rollout: accounts composed, then the controller, every host and every runtime
+- [x] 5.2 the rollout: accounts composed, then the controller, every host and every runtime
       together; every node confirmed heard before AMQP stops.
 
-      **The readiness half is in and is the half worth having.** The move takes every node at once, so
-      there is nothing to inspect afterwards and no half to roll back — either the mesh was ready or it
-      was not. `rollout check` answers that from records, with one dial: is a bus answering, does a
-      machine hold the seat, has it been sent the composed user list, does every machine and every
-      module that speaks have a credential. Each missing thing names its own next step, because "not
-      ready" that cannot be acted on is not an answer at the point where the next step is irreversible.
-
-      **A machine with no credential is what must stop it.** It keeps running, cannot come back, and
-      afterwards there is no bus to tell it anything over.
-
-      The move itself is deliberately not written yet, and the command says so rather than pretending:
-      it waits on the check having been run against a real mesh. Writing the irreversible half before
-      the question it depends on has ever been asked of something real is how the plan's own rule about
-      beds gets broken by another route.
-
-      > **What this costs if it goes wrong, measured rather than assumed.** On the installation this is
-      > for, the old broker is also what a whole automation layer outside the mesh connects to — so it
-      > stays, as an ordinary provider of `amqp` ([ADR 0127](../../02-DECISIONS/0127-amqp-is-a-provision-not-the-bus.md)),
-      > and this step is not its retirement. Nothing in a served request's path goes over the mesh's own
-      > bus: modules serve from their own containers. What a failed move costs is the mesh's ability to
-      > *change* anything — pushes, tool calls, new provisioning — until it is finished or undone. That
-      > is worth knowing before rather than after, and it is why the operator's "as long as my services
-      > keep running" is a reasonable position rather than a gamble.
-- [ ] 5.3 the mesh's own accounts removed from the deprecated broker, and then the broker itself:
-      after the rollout nothing of the mesh speaks to it, and an account nothing uses is one nobody
-      rotates. **It finishes now** ([ADR 0130](../../02-DECISIONS/0130-the-predecessor-is-ending-and-its-broker-goes-with-it.md)):
-      the predecessor is deprecated rather than kept, so once its remnants have stopped the module is
-      unassigned and the port is free. No retirement machinery — a provision with no consumers has its
-      provider unassigned, which is ADR 0127 being paid off rather than revised.
+      **Done 2026-09-28, 02:25.** Every machine reports on the new bus, the seat is held by the
+      module that provides it, the old broker is unassigned and forgotten, and every credential was
+      minted afresh at the end because two had been printed on the way. What it took, in the order
+      it was found, each fixed on the trunk before the next step: the control plane's `serve` and
+      `push` never selected the new transport (task 4.3, open until then); a machine's user was
+      granted neither the asking nor the delivery of its own consumer; the account had no JetStream
+      of its own; the control plane's client verified the bus's certificate by name instead of
+      pinning it; the seat table's rows carried no protocol, so no role's work queue was raised; the
+      build machine decided its bus from a variable its container never received; and a rotation
+      put new hashes on the bus before three machines had received their new memberships — which
+      is why there is now `rollout hand <node>` and a host adopts a delivered membership at start.
+      The bootstrap loop — a bus that can only be raised by a declaration that can only arrive
+      over that bus — was broken once, by hand: the mesh's own composed configuration started the
+      server, and the controller binary was run on the node directly until the managed container
+      could be rebuilt over the bus it was on.
 
+- [x] 5.3 **the seat changes hands as one act.** A command takes a seat and the assignment taking it
+      over, and the seat is never empty in between — the emptiness is the outage of 2026-09-27, when
+      the control plane, which finds its own bus through this seat, lost the address and looped.
+      **Built 2026-09-27** (`seat_holding`, migration 0039; design 26 says how it is checked), and used
+      live the next night to hand `mesh-broker` from the old broker's assignment to the new one's. This
+      is what 5.2 uses to move `mesh-broker` from the old
+      broker's assignment to the new one's, and it is built first ([ADR 0131](../../02-DECISIONS/0131-everything-on-the-mesh-speaks-to-the-broker-seat.md)).
+- [x] 5.4 **the old broker and everything that named AMQP leave the mesh** ([ADR 0131](../../02-DECISIONS/0131-everything-on-the-mesh-speaks-to-the-broker-seat.md),
+      superseding [ADR 0127](../../02-DECISIONS/0127-amqp-is-a-provision-not-the-bus.md)): the two modules that
+      required `amqp` are removed, the broker's module is unassigned and removed (**done 2026-09-28**; the predecessor's own tooling, which rode the same adopted broker, went dark with it, as [ADR 0130](../../02-DECISIONS/0130-the-predecessor-is-ending-and-its-broker-goes-with-it.md) accepted), registration refuses
+      a manifest that provides or requires `amqp`, and a whole-catalogue check asserts none does. Not
+      a retirement condition — a decision, taken, with the operator's "I don't care if the predecessor
+      breaks" on record ([ADR 0130](../../02-DECISIONS/0130-the-predecessor-is-ending-and-its-broker-goes-with-it.md)).
       Retiring with it: the build outcome's second announcement under the module's own name, which
-      exists only so a catalogue deployed before the rename and one deployed after both hear it.
+      existed only so a catalogue deployed before the rename and one after both heard it.
 
       > **The remote tooling goes with it too.** The predecessor's own mesh talks over that broker, so
       > shutting it down ends the path that reaches this installation's machines from a workstation.
-      > The rollout has to be driven from the node, or driven before the broker stops — which is a
-      > sequencing constraint on 5.2 and not an afterthought.
+      > The rollout is driven from the node, or before the broker stops — a sequencing constraint on
+      > 5.2, not an afterthought.
+- [x] 5.5 **the AMQP transport is deleted from the control plane and the hosts**. One bus, nothing
+      to select ([ADR 0131](../../02-DECISIONS/0131-everything-on-the-mesh-speaks-to-the-broker-seat.md)).
 
-> **5.4 is gone, and was wrong from ADR 0127 onward.** It read "the deprecated broker retires
-> when its condition holds — no client connected for the period the operator sets", which is
-> ADR 0106's framing of it as a compatibility module with an end date.
-> [ADR 0127](../../02-DECISIONS/0127-amqp-is-a-provision-not-the-bus.md) settled that it is an
-> **ordinary provider** of the `amqp` provision, like any module answering a backing service:
-> no seat, not foundation, and **no retirement condition**, because the day its last client
-> disappears is not a day anything is waiting for. Removed rather than reworded — a step that
-> waits for a condition nobody set would sit open forever.
+      **Done 2026-09-28.** The control plane's old consume loop, build request, tool call, management
+      API and account scoping went, and the host's old dialling and enrolment paths with them; a
+      membership or token naming any other bus is refused before anything is sent. Nothing selects a
+      transport any more: the variable that once did (`MESH_BUS_NATS`) now only names where the
+      control plane reads its own bus credential, the way any module reads a secret. **Checked by the
+      build**: neither repository's module file names the AMQP client library, so a line that still
+      used it would not compile. The store-window guarantee ([issue 083](../../04-ISSUES/083-other-control-messages-are-lost-while-the-store-restarts/00-report.md))
+      is tested against a bus-less fake rather than the old transport's memory, which is what let
+      that memory go — the one thing it did that the stream does not (superseding a held report) is
+      the staleness check on the message itself (design 25 §3).
+
+      Found on the way: **no build had ever recorded what it stood on.** A recipe reads its base from
+      a build argument, so the digest was never in the file the builder derived edges from, and every
+      order that says *bases first* — `build --on`, `build --behind`, the merge follow-up of
+      [issue 131](../../04-ISSUES/131-nothing-tells-the-mesh-a-source-moved/00-report.md) — walked a
+      graph with no edges. The builder now reports the bases it was handed, the control plane records
+      them by artifact path, and the graph is read from the newest build of each module — a recorded
+      manifest carries no `build.on`, so the edge is derived from the build or it does not exist.
+
+> **The old 5.4 note is history.** It recorded that a retirement *condition* was wrong from
+> [ADR 0127](../../02-DECISIONS/0127-amqp-is-a-provision-not-the-bus.md) onward, which framed the old broker
+> as an ordinary provider with no end. [ADR 0131](../../02-DECISIONS/0131-everything-on-the-mesh-speaks-to-the-broker-seat.md) ends that
+> framing in turn: the broker is not kept as a provider either, because AMQP is not a provision. Both
+> readings are kept here so the two reversals can be read in order.
 
 **Done when.** Every node reports on NATS, and nothing of the mesh's own is left connected to the
 deprecated broker.

03-DESIGN/01-to-be/32-what-a-module-declares.md

@@ -357,7 +357,7 @@ controller — because the bus's accounts are configuration rather than somethin
 creates, so there is no provisioner process in the path and nothing waiting on a bus account in
 order to make bus accounts. A module that runs a NATS server of its own and offers it as a
 backing service provides **`nats`**, exactly as the deprecated broker provides `amqp`
-([ADR 0127](../../02-DECISIONS/0127-amqp-is-a-provision-not-the-bus.md)).
+([ADR 0127](../../02-DECISIONS/0127-amqp-is-a-provision-not-the-bus.md) (superseded by [ADR 0131](../../02-DECISIONS/0131-everything-on-the-mesh-speaks-to-the-broker-seat.md): AMQP is not a provision, and everything speaks to the `mesh-broker` seat)).
 
 They are never the same name. A manifest saying `nats` could otherwise mean either the mesh's
 nervous system or a private queue, and the difference between those is the whole architecture.
@@ -427,7 +427,7 @@ it as an ordinary module once the registry exists.
 
 So there are exactly two things the normal path cannot make, both at genesis, both ending the
 moment the mesh can mint for itself: **the bus's own accounts** (§the bootstrap argument in
-[ADR 0127](../../02-DECISIONS/0127-amqp-is-a-provision-not-the-bus.md) (superseding [ADR 0125](../../02-DECISIONS/0125-the-bus-is-the-only-broker.md)) — a provisioner is a module and
+[ADR 0127](../../02-DECISIONS/0127-amqp-is-a-provision-not-the-bus.md) (superseded by [ADR 0131](../../02-DECISIONS/0131-everything-on-the-mesh-speaks-to-the-broker-seat.md): AMQP is not a provision, and everything speaks to the `mesh-broker` seat) (superseding [ADR 0125](../../02-DECISIONS/0125-the-bus-is-the-only-broker.md)) — a provisioner is a module and
 needs an account before it can run) and **the vault's own credential**. Any third exception is a
 design failure, and naming these two is what makes a third one visible.
 

03-DESIGN/01-to-be/README.md

@@ -40,7 +40,7 @@ document is written and this one's status becomes `implemented`.
 | [`28-building-the-bus.md`](28-building-the-bus.md) | **Proposed.** The five steps of the bus work in the order their dependencies allow, each ending at a bed — with the surface measured, so no step's size is a guess | [ADR 0116](../../02-DECISIONS/0116-the-bus-is-built-in-five-steps.md), [ADR 0106](../../02-DECISIONS/0106-the-bus-is-nats.md), [ADR 0074](../../02-DECISIONS/0074-the-wire-is-specified-not-the-types.md) |
 | [`29-a-node-has-operator-accounts.md`](29-a-node-has-operator-accounts.md) | **Proposed.** The mesh models machines but not the humans on them: a node gains operator accounts, and a resource may live under a home owned by its account — what would own ~/.ssh, dotfiles and ~/.config when HAL retires | [ADR 0112](../../02-DECISIONS/0112-a-module-definition-names-no-node-mesh-or-path.md), [ADR 0051](../../02-DECISIONS/0051-shared-data-is-the-operators.md) |
 
-| [`32-what-a-module-declares.md`](32-what-a-module-declares.md) | **Proposed.** What a module declares and what the bus derives from it: three namespaces, subjects from local names, queues never declared, the five relationships, and the build-publish-deploy lifecycle on one bus | [ADR 0126](../../02-DECISIONS/0126-a-module-declares-its-own-seats.md), [ADR 0127](../../02-DECISIONS/0127-amqp-is-a-provision-not-the-bus.md) (superseding [ADR 0125](../../02-DECISIONS/0125-the-bus-is-the-only-broker.md)), [ADR 0041](../../02-DECISIONS/0041-events-are-a-relationship.md) |
+| [`32-what-a-module-declares.md`](32-what-a-module-declares.md) | **Proposed.** What a module declares and what the bus derives from it: three namespaces, subjects from local names, queues never declared, the five relationships, and the build-publish-deploy lifecycle on one bus | [ADR 0126](../../02-DECISIONS/0126-a-module-declares-its-own-seats.md), [ADR 0127](../../02-DECISIONS/0127-amqp-is-a-provision-not-the-bus.md), superseded by [ADR 0131](../../02-DECISIONS/0131-everything-on-the-mesh-speaks-to-the-broker-seat.md) (superseding [ADR 0125](../../02-DECISIONS/0125-the-bus-is-the-only-broker.md)), [ADR 0041](../../02-DECISIONS/0041-events-are-a-relationship.md) |
 
 ## Not yet written
 

04-ISSUES/131-nothing-tells-the-mesh-a-source-moved/00-report.md

@@ -0,0 +1,107 @@
+---
+status: resolved
+opened: 2026-09-27
+located-in: [mesh-catalog modules/gitea, mesh-controller cmd/mesh-controller, mesh-controller internal/builder]
+fixed-by: mesh-catalog #124 — the forge module watches for merged pull requests and emits `pull.merged` with the merge commit and the clone address; mesh-controller #110/#111 — the control plane follows that event on the bus, marks every module built from that repository and branch as moved, and builds them bases first, stopping when a base fails; mesh-controller #113/#114 — a build records the bases it was handed and the graph is read from builds, without which "bases first" had no edges to order by.
+amended-design: 03-DESIGN/01-to-be/28-building-the-bus.md
+---
+
+# 131 — Nothing tells the mesh a source moved, and it reports itself current anyway
+
+## What was observed
+
+Six changes were merged to the trunk of six repositories in one sitting. The build machine built
+nothing. Its last build, minutes before the first merge, was still the one it reported; no build was
+requested, refused or failed, because none was ever asked for.
+
+Asked afterwards what was wrong, the mesh said:
+
+> 4 machine(s), all doing what they were told, all heard from, running what the mesh would send them,
+> and every module current with its source
+
+Every one of the six had moved. The last clause was false for all of them, and it is the clause a
+person reads to decide whether there is anything to do.
+
+## Why it matters beyond this instance
+
+**The mesh learns a source moved by being told, and there is no longer anything to tell it.** The
+command exists — a person names the module and the commit — and so does the question the overview
+answers. What is missing is whatever used to connect the two. One repository still carries a forge
+webhook aimed at a port; the rest carry none, and the port belongs to a different service than the
+one the arrangement implies. So the state is not "the trigger is broken" but "there is no trigger,
+and nothing says so".
+
+**A wrong answer is worse here than no answer.** "Every module current with its source" is
+indistinguishable, to a reader, from a mesh that has genuinely caught up. The overview is built to be
+the thing you check instead of checking by hand, so a confident false negative removes the habit that
+would otherwise have caught it. Nothing in the mesh is at fault for being out of date — it is at
+fault for saying it is not.
+
+**It is also why "current with its source" cannot be a stored fact.** The mesh compares what it built
+against what it was last told the source was, and calls that agreement. Two facts agreeing tells you
+nothing when both come from the same place.
+
+## The intended shape, which is decided and not built
+
+The forge emits what happened to it — a pull request merged — and the build machine reacts by
+building what that commit affects. That keeps the forge ignorant of the build system and the build
+machine ignorant of the forge's internals, which is the same argument
+[ADR 0126](../../02-DECISIONS/0126-a-module-declares-its-own-seats.md) makes for addressing an event
+to its emitter: the merge is a fact about the forge, and what should be rebuilt because of it is not
+the forge's business to know.
+
+The forge's module already declares the event. The build machine declares that it consumes nothing.
+
+## What the trigger cannot be
+
+**Not one build per changed module.** The modules form a graph: several are built from one
+repository, and some are the base another is compiled on — a runtime image, a compiler base, a
+repository whose context a second module builds from. Firing a build for each changed module
+independently would start work that cannot succeed yet and produce a failure per dependent, for one
+cause.
+
+Observed while catching the mesh up by hand on 2026-09-27: a compiler base had to move before
+anything compiled against it could build, and when it failed, the right behaviour was for its
+dependents to wait rather than each fail the same way. Fifteen modules shared the cause. A trigger
+that reports it fifteen times has buried it.
+
+So whatever reacts to the forge's event resolves what changed into an order, builds the bases first,
+and holds a dependent while its base is unbuilt or failed. That is a larger thing than "rebuild what
+the commit touched", and knowing it now is cheaper than discovering it from fifteen identical
+failures.
+
+## Open questions
+
+- Is "the source moved" still a thing a person can assert by hand once the event path exists, or does
+  the hand-operated form become the thing that made this failure possible?
+- Which commit does the build machine act on — the merge, or each commit it brought — and what does
+  it do when several arrive for one module at once?
+- How does the overview stop being able to lie? Comparing what was built against what was recorded
+  will always agree. Whether the trunk has moved is a question only the forge can answer, so either
+  the overview asks it, or it stops claiming to know.
+- Does this want to be the same mechanism as the build request on the bus
+  ([ADR 0129](../../02-DECISIONS/0129-a-seat-carries-the-protocol-of-its-role.md)), or does it sit in
+  front of it?
+
+## What was done (2026-09-28)
+
+The shape above was built as described: the forge's module emits the merge, the control plane
+consumes it, and nothing on either side knows the other's internals. The build is asked for the
+merge commit, not each commit the merge brought — the trunk moved once, to one place. Several merges
+for one module arriving in a row are followed in turn, each moving the recorded source to its own
+commit, so the last one to arrive is the one the mesh ends up built from.
+
+The hand-operated form stays. `module moved` is how a source is recorded without a forge — a module
+built from a repository elsewhere, or a mesh whose forge module is down — and it is the same act the
+event performs, so the two cannot disagree about what "moved" means.
+
+**Bases first needed edges, and there were none.** The order this report asked for was written and
+walked a graph that no build had ever recorded: a recipe reads its base from a build argument, so the
+digest was never in the file the builder read edges from. A build now reports what it was handed, the
+control plane records it by artifact path, and the order is read from each module's newest build.
+
+**What still can lie.** The overview compares what was built against where it was last told the
+source is; the forge's event is now what moves that mark, so it is right for as long as the forge
+module was listening. A merge made while that module was down is a merge the mesh does not know of
+until the module next polls — it announces what merged since it last looked, so the gap closes when
+it comes back, and not before. The overview does not say so.