maybe the build file is at root?

Dockerfile

@@ -27,10 +27,10 @@ ARG STATIC_SPACE
 # The Hugging Face token must be passed as a secret (https://huggingface.co/docs/hub/spaces-sdks-docker#buildtime)
 # 1. get README.md from the site space
 RUN --mount=type=secret,id=HF_TOKEN,mode=0444,required=true \
-    huggingface-cli download --token=$(cat /run/secrets/HF_TOKEN) --repo-type=space --local-dir=/tmp/app/build $STATIC_SPACE README.md && rm -rf /tmp/app/build/.cache
+    huggingface-cli download --token=$(cat /run/secrets/HF_TOKEN) --repo-type=space --local-dir=/build $STATIC_SPACE README.md && rm -rf /build/.cache
 # 2. upload the new build to the site space, including README.md
 RUN --mount=type=secret,id=HF_TOKEN,mode=0444,required=true \
-    huggingface-cli upload --token=$(cat /run/secrets/HF_TOKEN) --repo-type=space $STATIC_SPACE /tmp/app/build . --delete "*"
+    huggingface-cli upload --token=$(cat /run/secrets/HF_TOKEN) --repo-type=space $STATIC_SPACE /build . --delete "*"
 
 # Halt execution because the code space is not meant to run.
 CMD ["true"]