Sandboxing and security

Run Kent in a container or VM to limit the files, secrets, and networks available to its tools.

Outside-workspace edits

Kent allows manual edits inside attached workspaces and operating-system temporary directories. Kent requires approval for other paths unless allow_non_cwd_edits = true. Edits in other Kent-managed worktrees are blocked.

Container image shape

A Kent sandbox image should contain:

A kent binary compatible with the client version you use.
Mandatory server dependencies: shell, rg and git, for normal operation of the server.
A config.toml file with your setup.
Optional tools: language toolchains, package managers, fd, jq, patch, curl, gh, wget, python and project-specific CLIs.
An (ideally persistent) workspace directory such as /workspace.
A writable Kent persistence root, usually under the sandbox user’s home.
Network access limited to what the task requires.

Mount only the workspace, caches, and credentials required for the task.

Example Dockerfile

Add the language runtimes and project tools your workflows require.

FROM debian:bookworm-slim

ENV DEBIAN_FRONTEND=noninteractive
ENV HOME=/home/kent
ENV SHELL=/bin/bash
ARG KENT_VERSION=

RUN apt-get update \
  && apt-get install -y --no-install-recommends \
    bash \
    ca-certificates \
    curl \
    fd-find \
    file \
    git \
    jq \
    less \
    netcat-openbsd \
    openssh-client \
    patch \
    procps \
    python3 \
    python3-pip \
    python3-venv \
    ripgrep \
    tar \
    tini \
    unzip \
    xz-utils \
    zip \
  && ln -sf /usr/bin/fdfind /usr/local/bin/fd \
  && useradd --create-home --shell /bin/bash kent \
  && mkdir -p /workspace /home/kent/.kent \
  && chown -R kent:kent /workspace /home/kent

SHELL ["/bin/bash", "-o", "pipefail", "-c"]
RUN curl -fsSL https://kent.sh/install.sh \
  | KENT_PREFIX=/usr/local KENT_VERSION="${KENT_VERSION}" sh

USER kent
WORKDIR /workspace
EXPOSE 53082

ENTRYPOINT ["tini", "--"]
CMD ["kent", "serve"]

The image installs the latest release by default. Pin a release with docker build --build-arg KENT_VERSION=vX.Y.Z -t kent-sandbox ..

Run the server so it listens inside the container and is reachable from the host:

docker run --name kent-sandbox --rm -it \
  -p 127.0.0.1:53082:53082 \
  -e KENT_SERVER_HOST=0.0.0.0 \
  -e KENT_SERVER_PORT=53082 \
  -v "$PWD:/workspace" \
  kent-sandbox

In another terminal, point the local client at that server:

export KENT_SERVER_HOST=127.0.0.1
export KENT_SERVER_PORT=53082
kent project create --path /workspace --name sandbox
kent

The project path is /workspace because that is the path visible to the server.