ADR 0156: an artifact is what a build produces, and the store's seat is named for its scope

Issue 123 resolved; glossary corrected; design 26 and ADR 0121 point at the rename.

02-DECISIONS/0121-a-system-seat-is-named-for-its-scope-and-modules-define-their-own.md

@@ -81,7 +81,9 @@ closed set stays what its name says it is: the *system's* roles, not everyone's.
 - **`the-uplink` → `node-uplink`** ([ADR 0125](0117-a-machines-uplink-is-a-seat.md)). Unheld, so it
   renames with no migration.
 - **The registry seats — `the-artifact-store`, `npm-package-registry` (→ `mesh-artifact-store`,
-  `mesh-npm-package-registry`) — and `git` (→ `mesh-git`) — are decided but deferred.** They each
+  `mesh-npm-package-registry`) — and `git` (→ `mesh-git`) — are decided but deferred.** *(The
+  mechanism changed — 2026-09-30, by ADR 0156: `the-artifact-store` is renamed, one update and one
+  alias under ADR 0122; the other two stay deferred.)* They each
   *deliver* a provision, so renaming them is a delivering-seat migration: a holder that stops
   resolving mid-flight takes a provision away from every consumer. That risk is not worth carrying in
   the same pass as the node-* renames, so they keep their names until done deliberately.

02-DECISIONS/0156-an-artifact-is-what-a-build-produces-and-the-store-is-named-for-its-scope.md

@@ -0,0 +1,83 @@
+---
+topic: the mesh
+status: accepted
+date: 2026-09-30
+deciders: jochen
+reconstructed: false
+extends: 02-DECISIONS/0075-two-stores-and-which-provides-what.md
+---
+
+# 156. An artifact is what a build produces, the artifact store serves every kind, and its seat is named for its scope
+
+## Context
+
+[Issue 123](../04-ISSUES/123-the-image-registry-is-named-after-a-role/00-report.md) found three
+wordings disagreeing about the mesh's registry. The glossary defined *artifact* as "an OCI image, by
+digest"; the manifest's build vocabulary names four kinds — `image`, `upstream`, `bundle`, `archive` —
+and the catalogue builds all four; the seat was `the-artifact-store`, the last of the mesh's own seats
+named after the job it does rather than for the mesh
+([ADR 0121](0121-a-system-seat-is-named-for-its-scope-and-modules-define-their-own.md) decided the
+rename and deferred it). The issue asked whether the seat and provision should be renamed after
+images, and whether the mesh needs two registry implementations at all.
+
+Reading what the store actually serves settles the first question the other way. A kept reference
+has two shapes — `artifact-store://<module>/<artifact>@sha256:…` for an image and
+`artifact-store://<module>/<artifact>/blobs/sha256:…` for an archive — and both are served by the
+same OCI registry, by digest. [ADR 0075](0075-two-stores-and-which-provides-what.md) already
+defined the provision that way: *content-addressed blobs, pinned by digest, no versions, no ranges;
+what the mesh delivers to machines*. The provision was never an image registry. Only the glossary said
+so, and only the seat's name was odd.
+
+## Considered Options
+
+**1. Rename the seat and the provision after images.** Rejected. The store serves archives too, by the
+same protocol; naming it for one kind would be the glossary's mistake made permanent, in the name
+every manifest uses.
+
+**2. Fix the word, rename the seat for its scope, keep the provision.** Chosen. The rename ADR 0121
+deferred as a delivering-seat migration is, since [ADR 0122](0122-a-seat-is-data-a-rename-is-a-database-update.md),
+one update and one alias: the former name resolves forever, a held record follows by cascade, a claim
+written with the old name still holds.
+
+**On two implementations:** left as 0075 decided. Two provisions because two protocols; the OCI
+registry the genesis installs because something must serve images before the mesh can build; the
+forge may provide `artifact-store` too and a mesh may choose it. The bootstrap argument is weaker than
+it reads, as 123 says, and the day the forge is raised at genesis and adopted in place is the day to
+retire the second server — a migration a mesh performs, not a decision to take here.
+
+## Decision
+
+- **An artifact is anything a build produces** — an image, a mirrored upstream image, a bundle, an
+  archive — and the glossary says so. *Image* is one kind. A module is not an image; a module may
+  build several artifacts and install none.
+- **The artifact store serves artifacts of every kind a machine fetches**, images and archives, by
+  digest, over the OCI registry protocol. The provision keeps its name.
+- **The seat is `mesh-artifact-store`.** `the-artifact-store` is its alias. The catalogue's registry
+  module claims the new name; a definition elsewhere claiming the old one still holds.
+- The two other deferred renames — `npm-package-registry` and `git` — stay deferred, and for the
+  same reason no longer. They are one migration each when wanted; nothing here needs them.
+
+## Consequences
+
+- The glossary stops contradicting the manifest vocabulary, and a reader of `artifact-store` reads
+  it as what it is: where the mesh's built things are kept.
+- One migration on the seat table; no manifest but the registry's changes; no consumer of the
+  provision changes, because the provision did not.
+- **What got harder:** nothing measurable. A record that says `the-artifact-store` is read through the
+  alias; design 26's table already carried the new name as intent.
+
+## How this is checked
+
+| Rule | Checked by |
+|---|---|
+| The former name resolves to the seat once the store's aliases are loaded | a catalogue test |
+| The seat is in the compiled set under its new name, delivering `artifact-store` | the seat tests, updated |
+| The registry module holds the seat under the new name on the live mesh | `seats` after the rollout |
+| The glossary's *artifact* matches the build kinds a manifest may declare | design 18's table and the showcase module list the kinds; the glossary names the same four |
+
+## References
+
+- [issue 123](../04-ISSUES/123-the-image-registry-is-named-after-a-role/00-report.md)
+- [ADR 0075](0075-two-stores-and-which-provides-what.md) — extended: the provision as defined stands, the word is corrected
+- [ADR 0121](0121-a-system-seat-is-named-for-its-scope-and-modules-define-their-own.md), [ADR 0122](0122-a-seat-is-data-a-rename-is-a-database-update.md) — the rename, decided and made cheap
+- mesh-controller migration 0048; mesh-catalog `modules/distribution`

02-DECISIONS/README.md

@@ -169,6 +169,7 @@ python3 00-META/checks/index.py            fail if stale
 - **0134** — [The mesh says what it applied](0134-the-mesh-says-what-it-applied.md)
 - **0142** — [The mesh delivers its own components as binaries, not as container images](0142-the-mesh-delivers-its-own-components-as-binaries.md)
 - **0154** — [The mesh's own verbs are the mesh-controller seat's tools, and which verbs those are](0154-the-meshs-own-verbs-are-the-controller-seats-tools.md)
+- **0156** — [An artifact is what a build produces, the artifact store serves every kind, and its seat is named for its scope](0156-an-artifact-is-what-a-build-produces-and-the-store-is-named-for-its-scope.md)
 
 ### Its tiers, from the bottom up