diff --git a/benchmark/Dockerfile b/benchmark/Dockerfile
index 66d8ca7d..60f81708 100644
--- a/benchmark/Dockerfile
+++ b/benchmark/Dockerfile
@@ -3,7 +3,8 @@ FROM node:22-trixie
 # A toolchain for every benchmarked ecosystem (npm, git and curl come with
 # the base image), so agents can query registries and generate lockfiles as
 # on a dev machine. Containers run as the host uid with HOME=/tmp, so caches
-# land under /tmp; the rust image's toolchain dirs are already world-writable.
+# land under /tmp; COPY recreates the rust toolchain dirs non-writable, so chmod
+# them back as the rust image does.
 COPY --from=rust:1-trixie /usr/local/rustup /usr/local/rustup
 COPY --from=rust:1-trixie /usr/local/cargo /usr/local/cargo
 COPY --from=golang:1-trixie /usr/local/go /usr/local/go
@@ -12,7 +13,8 @@ COPY --from=maven:3 /usr/share/maven /usr/share/maven
 COPY --from=ghcr.io/astral-sh/uv:latest /uv /uvx /usr/local/bin/
 ENV RUSTUP_HOME=/usr/local/rustup CARGO_HOME=/usr/local/cargo JAVA_HOME=/opt/java/openjdk \
     PATH=/usr/local/cargo/bin:/usr/local/go/bin:/opt/java/openjdk/bin:/usr/share/maven/bin:$PATH
-RUN apt-get update && apt-get install -y --no-install-recommends python3-pip python3-venv python-is-python3 gh \
+RUN chmod a+w /usr/local/cargo /usr/local/rustup && rustup component add clippy rustfmt \
+    && apt-get update && apt-get install -y --no-install-recommends python3-pip python3-venv python-is-python3 gh \
     && rm -rf /var/lib/apt/lists/*
 
 RUN npm install -g @anthropic-ai/claude-code