diff --git a/docker/Dockerfile b/docker/Dockerfile
index 990899e..4e29dff 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -26,10 +26,10 @@ ARG BUILD_GID=1001
 
 FROM ubuntu:24.04
 
-# ARGs above do not cross FROM boundaries; re-declare for this stage
-# (overridable at build time: --build-arg BUILD_UID=$(id -u) etc.)
-ARG BUILD_UID
-ARG BUILD_GID
+# ARGs above do not cross FROM boundaries; re-declare with defaults for this
+# stage (overridable at build time: --build-arg BUILD_UID=$(id -u) etc.)
+ARG BUILD_UID=1001
+ARG BUILD_GID=1001
 
 ENV DEBIAN_FRONTEND=noninteractive \
     TZ=UTC \