diff --git a/dankclaw/voiceservice/Containerfile.engine b/dankclaw/voiceservice/Containerfile.engine
index 932a096..4efc980 100644
--- a/dankclaw/voiceservice/Containerfile.engine
+++ b/dankclaw/voiceservice/Containerfile.engine
@@ -110,7 +110,16 @@ RUN apt-get update -qq \
 # Same unprivileged uid as the frank-tts façade (10000): the voice packs and the
 # model directory are host state mounted read-only, and one uid across the pair
 # means one thing to remember about what is world-readable.
-RUN adduser --system --uid 10000 --home /app --shell /usr/sbin/nologin tts
+#
+# `useradd`, NOT `adduser`: this trimmed ubuntu:24.04 base ships no `adduser` at
+# all (verified 2026-10-18 against this digest — `adduser` is absent from the
+# base and is not pulled in by ca-certificates/curl/libgomp1 either), so an
+# `adduser` line dies at image-build time with crun's "executable file `adduser`
+# not found in $PATH". `useradd --system --uid 10000` succeeds and prints one
+# cosmetic warning (`uid 10000 is greater than SYS_UID_MAX 999`); the uid is the
+# point, and it is what matches the façade. The alpine façade Containerfile keeps
+# its own busybox `adduser -D -u 10000` — different base, different tool, same uid.
+RUN useradd --system --uid 10000 --home-dir /app --shell /usr/sbin/nologin tts
 
 WORKDIR /app
 COPY --from=build /src/build/tts-server /src/build/*.so* /app/