diff --git a/.github/workflows/check-developer-experience.yml b/.github/workflows/check-developer-experience.yml
index cacdb7f1..70d2aaf5 100644
--- a/.github/workflows/check-developer-experience.yml
+++ b/.github/workflows/check-developer-experience.yml
@@ -7,7 +7,8 @@
 
 # Production artifacts are produced in a sterile environment (in another CI workflow).
 name: Developer Experience
-on: [ push ]
+on:
+  - push
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.event.after }}
diff --git a/justfile b/justfile
index 54b1383b..3b052961 100644
--- a/justfile
+++ b/justfile
@@ -114,7 +114,8 @@ compile-env *args: fill-out-dev-env-template
     declare tmp_link
     tmp_link="$(mktemp -p "$(pwd)/sterile" -d --suffix=dataplane-compile-env.link)"
     declare -r tmp_link
-    mkdir -p FAKE_HOME;
+    declare FAKE_HOME="$(pwd)/sterile/FAKE_HOME"
+    mkdir -p "${FAKE_HOME}"
     cleanup() {
       rm -r "${tmp_link}"
       rm -r FAKE_HOME
@@ -131,7 +132,7 @@ compile-env *args: fill-out-dev-env-template
       --rm \
       --name dataplane-compile-env \
       --tmpfs "/tmp:uid=$(id -u),gid=$(id -g),nodev,noexec,nosuid" \
-      --mount "type=bind,source=$(pwd)/FAKE_HOME,destination=/home/runner,bind-propagation=rprivate" \
+      --mount "type=bind,source=${FAKE_HOME},destination=/home/${USER:-runner},bind-propagation=rprivate" \
       --mount type=bind,source="$(pwd),destination=/work,bind-propagation=rprivate" \
       --mount type=bind,source="${tmp_link},destination=/work/compile-env,bind-propagation=rprivate" \
       --mount type=bind,source="$(pwd)/dev-env-template/etc/passwd,destination=/etc/passwd,readonly" \
@@ -281,10 +282,13 @@ fake-nix refake="":
 fill-out-dev-env-template:
     {{ _just_debuggable_ }}
     mkdir -p dev-env-template/etc
+    if [ -z "${UID:-}" ]; then
+      >&2 echo "ERROR: environment variable UID not set"
+    fi
     declare -rxi UID
     GID="$(id -g)"
     declare -rxi GID
-    declare -rx USER=runner
+    declare -rx USER="${USER:-runner}"
     envsubst < dev-env-template/etc.template/group.template > dev-env-template/etc/group
     envsubst < dev-env-template/etc.template/passwd.template > dev-env-template/etc/passwd