How to use sandboxed Claude with PHP

I use Claude Code more and more for various tasks and I always manually accept any edit or command because I think it would be insane to let an AI run code on my machine without supervision.

Recently someone on Reddit mentioned how they lost their full home directory because Claude Code decided to add ~/ to an rm -rf command.

Whether it’s clickbait or not, I still think it’s a very bad idea to give Claude direct access to your file system.

It’s unfortunate because I would love to be able to let Claude run in the background for a complex task without me pressing the Enter key every minute. I saw yesterday this very interesting tweet from Matt Pocock about his setup to let Claude running commands in an autonomous way. I would love to try it, but I would never do it without a sandbox.

Docker sandbox

Fortunately, I realized yesterday that Docker now provides a few commands to easily sandbox AI agents.

Here is the claude sandbox documentation.

The image runs Claude Code with access to your current directory only, and with the --dangerously-skip-permissions flag. It automatically copies your Git config into the container so that Claude can commit changes if needed. It also runs as a non-root user inside the container for better security.

Are there some development tools installed there? Yes, there are:

The docker/sandbox-templates:claude-code image includes Claude Code with automatic credential management, plus development tools (Docker CLI, GitHub CLI, Node.js, Go, Python 3, Git, ripgrep, jq).

This is great for many people, but I wanted to use it with PHP and Laravel. Laravel now provides Laravel Boost which installs an MCP server allowing Claude to check your codebase, your db schema and run migrations.

It took me a while to figure out how to make this work with my Laravel app using Postgres, on Manjaro Linux.

Docker desktop

docker sandbox is a command provided by Docker Desktop. I never needed Docker Desktop (I only used the Docker daemon) until now, so I first had to install it on Manjaro.

I first needed to remove docker-buildx and docker-compose:

sudo pacman -R docker-buildx docker-compose

Then I downloaded the latest release of Docker Desktop for Arch from here (4.55.0 in my case).

I then installed the package with pacman:

sudo pacman -U ./docker-desktop-x86_64.pkg.tar.zst

I then disabled the “classical” Docker service and enabled the Docker Desktop one:

sudo systemctl disable --now docker
systemctl --user enable --now docker-desktop

docker context ls

This should confirm that Docker Desktop is running instead of the classical Docker daemon (see the asterisk *):

NAME              DESCRIPTION                               DOCKER ENDPOINT                                     ERROR
default           Current DOCKER_HOST based configuration   unix:///var/run/docker.sock                         
desktop-linux *   Docker Desktop                            unix:///home/einenlum/.docker/desktop/docker.sock  

A window should appear asking you to accept the terms of service.

Running the default claude sandbox

You can now try to run the default claude sandbox in your project directory:

docker sandbox run claude

It should open claude asking you a few questions to get started (and allowing you to log in).

It worked for me, but as soon as I tried to make a change, it failed to use the MCP server because PHP was not installed.

Creating a custom claude sandbox with PHP

To create a custom claude sandbox with PHP, I had to create a Dockerfile based on the default sandbox image.

I wanted it to be available in all may projects so I put it ~/.docker/sandbox-templates/claude-php-8.4/Dockerfile. I used php-8.4 as the directory name because I will want to use different versions of PHP later.

FROM docker/sandbox-templates:claude-code

# we switch to root to install packages
USER root

# The base image is based on Ubuntu, so we use apt
# to install PHP 8.4 and common extensions
RUN apt-get update && apt-get install -y \
    php8.4 \
    php8.4-cli \
    php8.4-common \
    php8.4-curl \
    php8.4-mbstring \
    php8.4-mysql \
    php8.4-pgsql \
    php8.4-sqlite3 \
    php8.4-xml \
    php8.4-zip \
    composer \
    && rm -rf /var/lib/apt/lists/*

# we switch back to the agent user
# This is the default user in the docker/sandbox-templates images
USER agent

You can then build the image with:

docker build -t claude-php-8.4 .

Now you can delete the existing sandbox (if any):

$ docker sandbox ls
SANDBOX ID     ...
f04f3f995ed7   ...

$ docker sandbox rm f04f3f995ed7

And we can pass a template option to use our custom image when running the sandbox.

We go to the root of our Laravel project and run:

docker sandbox run -t claude-php-8.4 claude

We need to answer the initial questions again, and login, but now Claude has access to PHP and composer.

Make it access the Postgres db

To make it access the Postgres database, I had to make a few changes.

First, in my .env file, I hade to change the DB_HOST from localhost to host.docker.internal so that the container can access the database running on my host machine.

To make sure I don’t have to switch all the time my .env file when working inside or outside the sandbox, I added this to my /etc/hosts file:

127.0.0.1	host.docker.internal

This way both my host machine and the container can resolve host.docker.internal to my local machine.

Finally, I had to edit two Postgres configuration files to allow connections from the Docker container.

In /var/lib/postgres/data/postgresql.conf I had to uncomment listen_addresses and set it to '*':

listen_addresses = '*'	

Maybe not great, but my local Postgres is not accessible from the internet anyway, and it only contains gibberish test data.

Then in /var/lib/postgres/data/pg_hba.conf I added this line at the end of the file:

# Allow Docker containers
host    all    all    192.168.65.0/24    md5

Now I could restart Postgres:

sudo systemctl restart postgresql

And finally, I could start the sandbox again:

docker sandbox run -t claude-php-8.4 claude

docker sandbox run -D -t claude-php-8.4 claude


               Claude Code v2.0.76
 * ▐▛███▜▌ *   Opus 4.5 · Claude Max
* ▝▜█████▛▘ *  /home/einenlum/Prog/php/fzlaravel
 *  ▘▘ ▝▝  *   

> check the state of the db 

laravel-boost - database-query (MCP)(query: "SELECT \n  (SELECT COUNT(*) FROM users) as users_count,\n  (SELECT COUNT(*) FROM locations) as locations_count,\n  (SELECT COUNT(*) FROM
                                      reviews) as reviews_count,\n  (SELECT COUNT(*) FROM friend_requests) as friend_requests_count,\n  (SELECT COUNT(*) FROM friendships) as
                                      friendships_count,\n  (SELECT COUNT(*) FROM notifications) as notifications_count")
  ⎿  [                                                                                                                                                                                
         {
             "users_count": 9,
     … +7 lines (ctrl+o to expand)

● Here's the current state of the database:

  Database Engine

  PostgreSQL with PostGIS extension (for geospatial data)

  Tables (19 total)

  Domain Tables

  | Table           | Records | Description                                                      |
  |-----------------|---------|------------------------------------------------------------------|
  | users           | 9       | User accounts with auth, colors, avatar, locked_location         |
  ...

I hope this can help someone!