ADR 0167: a membership carries what its module receives, and who the mesh is

Issue 191's route proxy needs to know who the mesh is to serve an
internal name correctly, and the first fix had it work that out alone.
The membership on the bus now carries it, from the same list the filter
uses. ADR 0138 gains an insight that the proxy is where internal reach
is kept; designs 08 and 25 say how.

03-DESIGN/01-to-be/08-connectivity.md

@@ -7,8 +7,9 @@ code:
   - mesh-controller internal/identity/authority.go
   - mesh-host internal/identity/serving.go
   - mesh-host internal/apply (the service that reflects a rule set)
-updated: 2026-09-30
+updated: 2026-10-02
 decisions:
+  - 02-DECISIONS/0167-a-membership-carries-what-its-module-receives-and-who-the-mesh-is.md
   - 02-DECISIONS/0148-the-meshs-names-are-resolved-not-copied-into-containers.md
   - 02-DECISIONS/0151-a-routes-internal-name-is-composed-under-the-node-that-serves-it.md
   - 02-DECISIONS/0147-a-module-anchors-the-meshs-authority.md
@@ -842,6 +843,18 @@ One value, three readers:
 | `public` | the machine port, to anywhere | the public name | the public authority |
 | `both` | the machine port, to anywhere | both names | each name's own authority |
 
+*2026-10-02.* **The proxy serves an internal name to the private network only**
+([ADR 0138](../../02-DECISIONS/0138-an-assignment-binds-an-endpoint-and-says-how-far-it-reaches.md),
+its insight of this date). It answers public and internal names on the same listeners, so the name a
+request carries is the request's own claim, not where the request came from. An internal name is
+served to the machines of the mesh and to the machine itself; to anyone else it is answered as a name
+never routed, in the handshake as well as the request. Without this, an endpoint with reach `internal`
+would be public under a name that is easy to guess
+([issue 191](../../04-ISSUES/191-a-route-with-only-an-internal-name-is-dropped/00-report.md)).
+The proxy is told who the mesh is, and its routes, in its membership on the bus — the same machine
+addresses the filter's "from the mesh" is rendered from
+([ADR 0167](../../02-DECISIONS/0167-a-membership-carries-what-its-module-receives-and-who-the-mesh-is.md)).
+
 **An endpoint that is not routed is reached and never named.** No route contribution means no name is
 composed and no certificate requested, while the filter still acts on it. That is the case the model
 could not express at all, and it is the ordinary case for anything that is not HTTP.