diff --git a/modules/n8n/Dockerfile b/modules/n8n/Dockerfile
new file mode 100644
index 00000000..7d15a2bf
--- /dev/null
+++ b/modules/n8n/Dockerfile
@@ -0,0 +1,20 @@
+# n8n with what its workflows reach for beyond the upstream image.
+#
+# The base is named, not pinned here (novox/hq issue 044): module.json's `build.on` declares N8N_BASE
+# as the upstream image by digest, and the mesh hands the build its own copy (ADR 0097).
+ARG N8N_BASE
+FROM ${N8N_BASE}
+
+USER root
+# - `media` (GID 2000), with `node` in it: the shared media library is group-writable by the
+#   operator's media group, and a workflow files downloads into it. A container resource cannot add
+#   a supplementary group, so the image's own /etc/group carries it. 2000 is the operator's media
+#   group today; novox/hq 153 proposes reading it from the accessed data (${access:<id>:gid}).
+# - uuid, pinned to the version the workflows were written against: Code nodes require() it
+#   (NODE_FUNCTION_ALLOW_EXTERNAL=*), and a Code node can only require what is installed.
+RUN apk add --no-cache shadow \
+ && groupadd -g 2000 media \
+ && usermod -aG media node \
+ && npm install -g uuid@14.0.1
+
+USER node
diff --git a/modules/n8n/README.md b/modules/n8n/README.md
index 751b5f70..c911c864 100644
--- a/modules/n8n/README.md
+++ b/modules/n8n/README.md
@@ -1,10 +1,6 @@
 # n8n
 
-The `n8n` module of the mesh catalogue: runs the upstream image `n8nio/n8n` by digest with the `uuid` package mounted into it (ADR 0480 clauses 1, 3, 7 and 8); runs the container image `redis`; runs the container image `selenium/standalone-chrome`.
-
-- The `server` container no longer comes from a Dockerfile. Its program is the upstream image's, bit for bit the one the module built on before (digest `4846eb2f...`; the running container reports release 1.71.3).
-- `uuid` 14.0.1, which Code nodes `require`, is fetched once by its pinned sha256 from the package registry and mounted read-only at `/usr/local/lib/node_modules/uuid` (where `npm install -g` put it in the image the module built).
-- The server joins the media library's group as a supplementary group, `groups` from the config key `media-gid`; the key has no default, so a machine that does not say it refuses n8n.
+The `n8n` module of the mesh catalogue: runs the container image `redis`; runs the container image `selenium/standalone-chrome`.
 
 ## Files it does not know
 
@@ -12,5 +8,4 @@ Each directory or archive this module declares says how it treats a file it did
 
 - `${dir:state}`: everything in it is the program's; the mesh moves nothing out (ADR 0422 §2).
 - `${dir:data}`: everything in it is the program's; the mesh moves nothing out (ADR 0422 §2).
-- `${dir:state}/uuid`: everything in it is the program's; the mesh moves nothing out (ADR 0422 §2).
 - `${dir:cache}`: everything in it is the program's; the mesh moves nothing out (ADR 0422 §2).
diff --git a/modules/n8n/module.json b/modules/n8n/module.json
index 04bec8ff..975247fa 100644
--- a/modules/n8n/module.json
+++ b/modules/n8n/module.json
@@ -30,15 +30,6 @@
       "mode": "read-write"
     }
   ],
-  "config": {
-    "media-gid": {
-      "type": "number",
-      "description": "The number of the group that owns the media library on this machine, which the server joins as a supplementary group so a workflow can file into the library (novox/hq ADR 0480 clause 7). Set per machine; until the container takes it from the media library itself (issue 1618) nothing writes a default, so a machine that does not say it refuses n8n by name.",
-      "minimum": 1,
-      "required": true,
-      "trusted": true
-    }
-  },
   "listens": [
     {
       "name": "web",
@@ -101,13 +92,6 @@
       "mode": "0600",
       "template": "files/server.env"
     },
-    {
-      "id": "uuid",
-      "type": "archive",
-      "path": "${dir:state}/uuid",
-      "artifact": "uuid",
-      "unknown": "program"
-    },
     {
       "id": "net",
       "type": "network",
@@ -135,11 +119,7 @@
       "volumes": [
         "${dir:data}:/home/node/.n8n",
         "${dir:state}/n8n-database.secret:/run/secrets/database:ro",
-        "${dir:state}/uuid:/usr/local/lib/node_modules/uuid:ro",
         "${access:media}:/media-library"
-      ],
-      "groups": [
-        "${config:media-gid}"
       ]
     },
     {
@@ -171,22 +151,17 @@
     }
   ],
   "build": {
+    "on": [
+      {
+        "arg": "N8N_BASE",
+        "image": "n8nio/n8n@sha256:4846eb2f4b874ab04cde7fc1e249d2ddaec66e9aea64439beb2972cfea88e3c0"
+      }
+    ],
     "artifacts": [
       {
         "name": "server",
-        "kind": "upstream",
-        "from": "n8nio/n8n@sha256:4846eb2f4b874ab04cde7fc1e249d2ddaec66e9aea64439beb2972cfea88e3c0"
-      },
-      {
-        "name": "uuid",
-        "kind": "archive",
-        "url": "https://registry.npmjs.org/uuid/-/uuid-14.0.1.tgz",
-        "sha256": "e062c57ed120ea135478f305da04802bf69eab23fbc0ca2bae6989b6855390c4",
-        "version": "14.0.1",
-        "within": "package",
-        "names-on-purpose": {
-          "registry.npmjs.org": "the npm registry publishes the uuid package there; the build seat fetches it once, by its pinned sha256 (novox/hq ADR 0316 §2, ADR 0480 §8)"
-        }
+        "kind": "image",
+        "from": "Dockerfile"
       },
       {
         "name": "files",