diff --git a/Dockerfile b/Dockerfile
index f076baa..c13f583 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,9 +1,10 @@
 FROM node:26-trixie-slim@sha256:a1d9d671994fc2d26e297ac56b4b1522a8bc7fa71c43b14cd1b1fe6c5116f7dc
 
-# OS packages used to fetch sources and deploy output
+# OS packages used to fetch sources and deploy output; strace lets the pandoc
+# cache record which files each pandoc run reads
 RUN apt-get update \
  && apt-get install -y --no-install-recommends \
-     git git-lfs openssh-client rsync curl ca-certificates \
+     git git-lfs openssh-client rsync curl ca-certificates strace \
  && rm -rf /var/lib/apt/lists/*
 
 # Quarto setup.
@@ -19,4 +20,4 @@ RUN curl -fsSL -o /tmp/quarto.tar.gz \
  && rm /tmp/quarto.tar.gz \
  && quarto --version
 
-COPY --from=ghcr.io/prefix-dev/pixi:0.71.2 /usr/local/bin/pixi /usr/local/bin/pixi
+COPY --from=ghcr.io/prefix-dev/pixi:0.81.0 /usr/local/bin/pixi /usr/local/bin/pixi