A simple, portable script to run multiple coding harnesses in a container (Claude Code, Pi, OpenCode)

agcon

#!/usr/bin/env bash
#
# agcon — run a coding agent (or a shell) inside a minimal, disposable Docker
# container with the current directory and the agent's config bind-mounted in.
#
# The invoked name selects the agent. Symlink this script to get per-agent
# commands; the base name `agcon` (or any unknown name) uses DEFAULT_AGENT:
#
#   ln -s agcon clcon   # clcon -> claude
#   ln -s agcon picon   # picon -> pi
#   ln -s agcon occon   # occon -> opencode
#
# Agents (image and config are per-agent; host config is mounted in):
#   claude    @anthropic-ai/claude-code     ~/.claude + ~/.claude.json
#   pi        @earendil-works/pi-coding-agent  ~/.pi
#   opencode  opencode-ai                   ~/.config/opencode + ~/.local/share/opencode
#             (env-key providers: pass keys via -e, e.g.
#              occon -e OPENROUTER_API_KEY="$OPENROUTER_API_KEY")
#
# Usage:
#   agcon [shell] [docker-run-args...] [-- command-args...]
#
#   agcon                      # run DEFAULT_AGENT in ./
#   picon                      # run pi (via symlink)
#   agcon shell                # start a bash shell instead
#   agcon --network=host       # forward flags straight to `docker run`
#   agcon -- --resume          # pass args to the inner command
#   agcon shell -e FOO=bar     # combine: shell + forwarded docker flags
#
# Mounts:
#   $PWD          -> /workspace            (your project, read-write)
#   <agent config> -> <container home>     (per-agent; see profiles below)
#   agcon-history -> /commandhistory       (named volume; bash history)
#
# Everything between the leading options and `--` is passed verbatim to
# `docker run`; everything after `--` is passed to the in-container command.
# The container is removed on exit (--rm); only the mounts persist.
#
# The image is rebuilt every run from the Dockerfile heredoc below, but
# Docker's layer cache makes that near-instant unless something changed.
# To extend it, add apt packages to the apt-get line; per-agent npm packages
# come from the profiles below.

set -euo pipefail

# --- agent selection --------------------------------------------------------
DEFAULT_AGENT="claude"

case "$(basename "$0")" in
  clcon) AGENT="claude" ;;
  picon) AGENT="pi" ;;
  occon) AGENT="opencode" ;;
  *)     AGENT="$DEFAULT_AGENT" ;;
esac

# --- agent profiles ---------------------------------------------------------
# Each profile sets the npm package to install, the default command, and the
# host->container config mount(s). Add an agent by adding a case arm here (and
# a name above if you want a dedicated symlinked command).
AGENT_MOUNTS=()
case "$AGENT" in
  claude)
    AGENT_PKG="@anthropic-ai/claude-code"
    AGENT_CMD="claude --dangerously-skip-permissions"
    AGENT_MOUNTS+=(-v "$HOME/.claude:/home/node/.claude")
    # Claude also keeps a stray dotfile beside the dir; mount it if present.
    [ -f "$HOME/.claude.json" ] && AGENT_MOUNTS+=(-v "$HOME/.claude.json:/home/node/.claude.json")
    ;;
  pi)
    AGENT_PKG="@earendil-works/pi-coding-agent"
    AGENT_CMD="pi"
    # pi keeps everything in a single ~/.pi dir.
    [ -d "$HOME/.pi" ] && AGENT_MOUNTS+=(-v "$HOME/.pi:/home/node/.pi")
    ;;
  opencode)
    AGENT_PKG="opencode-ai"
    AGENT_CMD="opencode"
    # opencode uses XDG paths: config in ~/.config/opencode, auth/state in
    # ~/.local/share/opencode. (For env-key auth, pass -e VARS via docker args.)
    [ -d "$HOME/.config/opencode" ]      && AGENT_MOUNTS+=(-v "$HOME/.config/opencode:/home/node/.config/opencode")
    [ -d "$HOME/.local/share/opencode" ] && AGENT_MOUNTS+=(-v "$HOME/.local/share/opencode:/home/node/.local/share/opencode")
    ;;
  *)
    echo "agcon: unknown agent '$AGENT'" >&2; exit 1 ;;
esac

IMAGE="agcon-$AGENT:latest"
HISTORY_VOLUME="agcon-history"

# --- detect host timezone (best-effort) for the image build -----------------
HOST_TZ="${TZ:-}"
if [ -z "$HOST_TZ" ]; then
  if [ -f /etc/timezone ]; then
    HOST_TZ="$(cat /etc/timezone)"
  elif [ -L /etc/localtime ]; then
    HOST_TZ="$(readlink /etc/localtime | sed 's#.*/zoneinfo/##')"
  fi
fi
HOST_TZ="${HOST_TZ:-UTC}"

# --- parse leading script options (order-independent) -----------------------
CMD="$AGENT_CMD"
while [ $# -gt 0 ]; do
  case "$1" in
    shell) CMD="bash"; shift ;;
    *)     break ;;
  esac
done

# --- docker args (everything up to `--`) ------------------------------------
DOCKER_ARGS=()
while [ $# -gt 0 ] && [ "$1" != "--" ]; do
  DOCKER_ARGS+=("$1"); shift
done

# --- inner command args (everything after `--`) -----------------------------
CMD_ARGS=()
if [ "${1:-}" = "--" ]; then
  shift
  CMD_ARGS=("$@")
fi

# --- build the image (cached; quietly rebuilds only changed layers) ---------
echo "(Re)building the container if necessary. This may take a moment..." >&2
docker build -q \
  --build-arg "TZ=$HOST_TZ" \
  --build-arg "AGENT_PKG=$AGENT_PKG" \
  -t "$IMAGE" - >/dev/null <<'DOCKERFILE'
FROM node:lts-slim

ARG TZ
ENV TZ="$TZ"

# Minimal toolset. Add packages here as needed.
RUN apt-get update && apt-get install -y --no-install-recommends \
      curl \
      git \
      jq \
      less \
      locales \
      nano \
      ripgrep \
      tzdata \
    && rm -rf /var/lib/apt/lists/*

# Generate a UTF-8 locale.
RUN sed -i '/en_US.UTF-8/s/^# //g' /etc/locale.gen && locale-gen en_US.UTF-8

# Coding agent (selected per-agent by the calling script).
ARG AGENT_PKG
RUN npm install -g "$AGENT_PKG"

# Bash history persists via a named volume mounted at /commandhistory.
RUN mkdir /commandhistory && touch /commandhistory/.bash_history \
    && chown -R node:node /commandhistory

ENV SHELL=/bin/bash \
    EDITOR=nano \
    VISUAL=nano \
    LANG=en_US.UTF-8 \
    LANGUAGE=en_US:en \
    LC_ALL=en_US.UTF-8 \
    NODE_OPTIONS=--max-old-space-size=4096 \
    HISTFILE=/commandhistory/.bash_history \
    PROMPT_COMMAND="history -a"

# node:slim ships a non-root `node` user (uid 1000).
USER node
WORKDIR /workspace
DOCKERFILE

# --- run --------------------------------------------------------------------
exec docker run --rm -it \
  --name "agcon-$AGENT" \
  -v "$PWD:/workspace" \
  -v "$HISTORY_VOLUME:/commandhistory" \
  ${AGENT_MOUNTS[@]+"${AGENT_MOUNTS[@]}"} \
  -w /workspace \
  ${DOCKER_ARGS[@]+"${DOCKER_ARGS[@]}"} \
  "$IMAGE" \
  $CMD ${CMD_ARGS[@]+"${CMD_ARGS[@]}"}