diff --git a/.dev-updater.ron b/.dev-updater.ron
new file mode 100644
index 0000000..1c249c0
--- /dev/null
+++ b/.dev-updater.ron
@@ -0,0 +1,33 @@
+// Read by Dev Updater. Structured as the body of the config: no outer
+// parentheses, so nothing here is indented for the sake of a wrapper.
+//
+// This file sits at the checkout root because the project Dev Updater
+// serves is the whole repository -- one checkout producing two things.
+// Each component says where it lives with `cwd`, relative to this
+// directory, rather than one of them reaching out of the other with `../`.
+
+// What to call this project before there is a build to read a label from.
+// A built APK wins: it is the authority on what will actually install.
+label: "AI Sessions",
+
+// Walked in order, and the order is the point: the backend is built and
+// delivered first, so a failing APK build leaves the phone the APK it
+// already had rather than half of a matched pair.
+components: [
+    Server(
+        name: "backend",
+        build: "cargo build --release",
+        cwd: "server",
+        // Installs into whichever user-service manager is here, and is how
+        // ai-server is started, stopped and asked about. See the script.
+        service: "server/service",
+    ),
+    Apk(
+        name: "app",
+        // Resolved against this directory, and run in `app/` -- the script
+        // cds to its own directory anyway, so the cwd is here to say where
+        // the app is rather than because the build needs it.
+        build: "app/build-apk.sh",
+        cwd: "app",
+    ),
+],
diff --git a/app/.dev-updater.ron b/app/.dev-updater.ron
deleted file mode 100644
index 9ef6078..0000000
--- a/app/.dev-updater.ron
+++ /dev/null
@@ -1,21 +0,0 @@
-// Read by Dev Updater. Structured as the body of the config: no outer
-// parentheses, so nothing here is indented for the sake of a wrapper.
-
-label: "AI Sessions",
-
-// The server is built and delivered before the APK: if the APK build then
-// fails, the phone keeps being offered the one it already had rather than
-// half of a matched pair.
-components: [
-    Server(
-        name: "backend",
-        build: "cargo build --release --manifest-path ../server/Cargo.toml",
-        // Installs into whichever user-service manager is here, and is how
-        // this server is started, stopped and asked about. See the script.
-        service: "../server/service",
-    ),
-    Apk(
-        name: "app",
-        build: "./build-apk.sh",
-    ),
-]
diff --git a/server/service b/server/service
index 6ff5831..da8911b 100755
--- a/server/service
+++ b/server/service
@@ -3,6 +3,12 @@
 # drive from the phone -- and for you to drive by hand, which is the same
 # thing.
 #
+# Declared as the Server component of this checkout in `.dev-updater.ron`
+# at the repository root, so the card drives it like any other project's.
+# One button is worth knowing about before pressing it: on a phone that
+# reaches ai-server through the tunnel rather than through Dev Updater,
+# Stop leaves this server down until someone starts it again here.
+#
 #   ./service install | uninstall | start | stop | restart | status
 #
 # `status` prints exactly one of `running`, `stopped` or `not-installed`
@@ -16,7 +22,10 @@
 # with a message telling you to run it yourself once instead.
 #
 # User services on purpose: a system unit needs root to install, and a
-# build machine's own account is where a dev server belongs.
+# build machine's own account is where a dev server belongs. Note that a
+# user service stops at logout unless lingering is enabled
+# (`loginctl enable-linger $USER`), which you want for this one: the phone
+# reaches this server whether or not anyone is logged in at the desk.
 set -eu
 
 SCRIPT_DIR=$(cd "$(dirname "$0")" && pwd)