Dockerfile

# claude-code-docker: run Anthropic's Claude Code CLI in a container.
#
#   docker build -t claude-code-docker .
#   docker build --build-arg CLAUDE_CODE_VERSION=2.1.227 -t claude-code-docker .   # pin another release
#
# Design notes:
# - debian:bookworm-slim + the official native installer, which ships a
#   self-contained binary: no Node.js at runtime, so this image ships none.
# - Runs as a non-root user. This is not a style choice: claude refuses
#   --dangerously-skip-permissions when running as root.
# - CLAUDE_CONFIG_DIR keeps ALL state (OAuth credentials, settings, history) under
#   /home/claude/.claude, so one volume mount survives container rebuilds. Without
#   it, account state in ~/.claude.json would live outside the volume.

FROM debian:bookworm-slim

ARG CLAUDE_CODE_VERSION=2.1.235
# Match your host UID/GID so files created in the bind-mounted /workspace are yours
# (Linux hosts; Docker Desktop on macOS/Windows maps ownership automatically).
ARG UID=1000
ARG GID=1000

# git, curl, ripgrep, procps: what Claude Code actually uses day to day.
# iptables, ipset, dnsutils, jq, sudo: only for the optional egress firewall
# (init-firewall.sh), inert unless you start the container with FIREWALL=1.
RUN apt-get update && apt-get install -y --no-install-recommends \
    ca-certificates \
    curl \
    git \
    ripgrep \
    procps \
    iptables \
    ipset \
    dnsutils \
    jq \
    sudo \
    && rm -rf /var/lib/apt/lists/*

RUN groupadd -g "$GID" claude \
    && useradd -m -u "$UID" -g "$GID" -s /bin/bash claude

COPY init-firewall.sh entrypoint.sh /usr/local/bin/
RUN chmod 755 /usr/local/bin/init-firewall.sh /usr/local/bin/entrypoint.sh \
    # ipset needs the legacy iptables backend inside containers.
    && update-alternatives --set iptables /usr/sbin/iptables-legacy \
    && update-alternatives --set ip6tables /usr/sbin/ip6tables-legacy \
    # The firewall needs root for iptables; this is the ONLY thing claude may sudo.
    # SETENV lets the entrypoint pass FIREWALL_ALLOW_DOMAINS through.
    && echo "claude ALL=(root) NOPASSWD:SETENV: /usr/local/bin/init-firewall.sh" > /etc/sudoers.d/claude-firewall \
    && chmod 440 /etc/sudoers.d/claude-firewall

USER claude
WORKDIR /home/claude

ENV PATH="/home/claude/.local/bin:${PATH}" \
    CLAUDE_CONFIG_DIR=/home/claude/.claude \
    # Containers should be rebuilt deliberately, not self-mutate mid-session.
    DISABLE_AUTOUPDATER=1

# Official installer, pinned. The binary lands in ~/.local/bin/claude.
RUN curl -fsSL https://claude.ai/install.sh | bash -s "$CLAUDE_CODE_VERSION"

WORKDIR /workspace

ENTRYPOINT ["entrypoint.sh"]
CMD ["claude"]