FROM docker.io/archlinux:base
RUN pacman -Syu --noconfirm && \
pacman -S --noconfirm \
base-devel \
git \
curl \
uv \
opencode && \
pacman -Scc --noconfirm
RUN mkdir -p /etc/opencode
WORKDIR /workspace
Unrelated: I enjoyed your latest blog entry. I recently starting thinking about how to show the work that is done with AI, and how we talk about it. I haven't come to any major conclusions (I wish!), but your post about the prompting being distinct from the actual work resonates with me. Reminds me somewhat of discussions about the art of photography compared to the art of editing photos as a distinct skill.
- Sandbox on Linux using Docker, Podman, containerd, gVisor, Kata, Firecracker
- Sandbox on Mac using Docker (Docker Desktop or Orbstack), Podman, Apple containers, Seatbelt, Tart (Tart lets you run simulators).
- Network restriction
- Secrets control (file mounts or credentials broker)
- NO ambient data (ENV is replaced with a minimal and local-to-sandbox one, no host-side filesystem access beyond what you explicitly allow)
- Workdir protection: Your work dir is never modified until you apply the changes, either standalone or as a git commit. You can also diff before applying. Git runs SANDBOX side in case the repo has filters.
- Uses copy-on-write if your filesystem supports it (most modern ones do)
- Has built-in support for claude, codex, gemini, aider, and opencode, but you can also launch it in "shell" mode and run whatever you want.
- Supports VS code tunnels, so you can remotely access in VS code if you don't want to use the terminal.
- Full lifecycle support: Launch, attach, stop, restart, wait, one-shot, clone, destroy
- MCP passthrough
- Layered API (golang) if you want to sandbox other things
- Self-contained binary. No external requirements other than the backends you want to use. Defaults to a ~/.yoloai dir for config/data, but you can point it anywhere.
- FOSS
> clawk network allow my-project api.example.com
Can you describe the implementation details? How did you implement the firewall without root?
I vibecoded virtdev, a virtual machine orchestration project just like this one:
https://github.com/matheusmoreira/virtdev
It was designed to not require root, and the nftables firewall ended up becoming the only exception. I'm very curious about how you implemented this. Did you find a better way?
Vagrant manages VMs and virtual networks, in Ruby.
ansible-molecule creates, converges, and destroys VM(s) and containers, in order to test ansible playbooks and ansible roles in clean build roots.
podman machine manages VMs:
- podman-container-tools/podman-machine-os: machine image files: https://github.com/podman-container-tools/podman-machine-os/...
`podman kube play` over `podman machine` might solve for agents that need multiple VMs/containers
- Podman Desktop can work with the same local k8s setups as Docker Desktop. Though there's certainly more state to manage with k8s for agent session farm, k8s probably has better logging and quotas than a VM management script on each node.
OpenShift on OpenStack is one way to do containers over VMs over bare metal.
Microshift also does container-selinux.
There is not an apparmor policy set for containers?
bwrap and liboverlayfs and libseccomp are almost but not quite containers.
There are stronger container isolation layers that are more like a full or lightweight VM, that might be better for agent sessions: gVisor, firecracker vm, Todo
Cloudflare workerd is the open source part of cloudflare workers, which run lightweight WASM and JS VMs with multi-tenant isolation.
It takes far less resources to run a cloudflare worker than to run a container on cloudflare. So, if it's possible for an agent to operate within a WASM runtime ~container, that's probably more optimal for agent sessions.
Cloudflare/artifact-fs does lazy shallow git clones with a FUSE filesystem.
- "Show HN: VM-curator – a TUI alternative to libvirt and virt-manager" https://news.ycombinator.com/item?id=46750437
https://news.ycombinator.com/item?id=46825026 ; amla sandbox, agentvm, ARM64 MTE
https://news.ycombinator.com/item?id=46825119 ; container2wasm , vscode-container-wasm-gcc-example ; build WASM containers with Dockerfiles
docker and podman support multiple WASM runtimes for running WASM containers, e.g. for agent sessiobs
Container is quite like a "separate user" except you can explicitly define what it can access.
(Even if all your daemons have good auth, it's now quite common for _apps_ to open listening sockets without much auth...)
If you're just concerned about "agent messing up and taking the rules in some markdown files more laxly than I would have", then running it as a seperate user is totally enough...
Side note, just 6 days ago a Linux VM escape exploit was disclosed.
I'm worried about supply chain attacks on npm, pip, cargo and everything else. Don't want to get compromised if I install some stupid package.
My virtdev project has essentially split my computer into two systems: my "real" trusted system with software coming directly from my Linux distribition's repositories, and the VMs for everything else.
> just 6 days ago a Linux VM escape exploit was disclosed
Well, shit. Details?
All that stuff should also go into the agent user's home directory.
CVE-2026-43499 - https://nebusec.ai/research/ionstack-part-2/
Security is riddled by traps. If you can afford best possible level of isolation, why not do it?
A separate user is a good start but LLM tests themselves show they can cleverly bypass guardrails if they figure out they are in a sandboxed environment of some kind, right?
So, I read those test results as: an LLM is less likely to do something crazy if it thinks it has the whole environment to itself.
You have far too much data in unsecured locations, and you have far too little understanding of what an agent would do, to go "I trust whatever this user account will be doing on my machine".
Seems like both projects are following very similar approaches.
So should be noted it's mostly macOS out of the box with some Linux support if I understand right.
I saw this project enables ssh-agent forwarding, so my question; is this a non-issue to begin with? Or just not your focus currently.
I’m quite happy with exe.dev for this. My laptop is asleep upstairs but I have an agent coding away in a browser tab on the tablet I’m using. I could also check on it from my phone.
But it might also be nice if a setup similar to exe.dev were available for self-hosting. I have a Mac Mini that I don’t really use much.
Runs 24/7 completely air gapped from your laptop.
You also want a service proxy so the sandbox can access GitHub or Stripe without keys accessible to the agent. I haven't seen many of the laptop sandbox tools do this, where exe.dev does it out of the box with their "integrations".
I usually drop my own binary agent coding toolkit inside the sandbox so I have things like a code browsing and review right there in every sandbox too.
https://github.com/housecat-inc/scratch
Like you I also have a Mac Mini I've thought about making into my own 24/7 dev box, but building this vs buying 50 VMs from exe.dev for $20/mo doesn't add up for me.
It is possible to simply not do that. Laptops work just fine as servers. They even have a builtin monitor and UPS.
Bitrise has been doing macOS VMs for CI for 10 years, so we extended the existing product to this use-case.
Which is just a front for systemd-nspawn. It's annoying you have to edit the config.nspawn to mount a directory if you start it with the "shell" command, instead of booting. But apart from that, it's brilliant.
https://github.com/daitangio/take-ai-control
It is docker + vscode friendly. I tested it with major systems (copilot, codex, Claude Code and pi.dev) Comments Wellcome!
Cursor has something similar. I don't know about Claude Code but I assume it does as well since Anthropic has open sourced their own sandboxing tool.
Sprites arguably has the better security boundary, since the agent isn’t sitting adjacent to my laptop and home network.
Literally everyone has the option to use a VM - it's built into Windows, UTM on MacOS, Docker on Linux. Yes, "a tool that automatically builds a VM" is useful, but we've had a third option (four, if you count "actually I disagree with the idea that it's only useful if it's fully agentic") from day one.
Would have thrown Mythos at it if I had access to it.
Opus did manage to iron out a lot of fail open bugs during development though, and Fable's like a hundred times more relentless than Opus. I'm not saying it's a definitive result or that my VM firewall thingy is unhackable... I'm just saying it put a smile on my face.
You might prefer byre's simplicity, transparency, and ease of reasoning about: one local container, explicit access grants, readable generated Docker, and a workflow that stays close to normal development rather than introducing a larger sandbox platform. It's also very very easy to eject from if you want to stop using it.
Did you know that before reinventing the wheel, you can ask LLM your requirements, and they can find the most suited already existing tool ?
There is absolutely nothing wrong with reinventing the whell. It's entirely possible to do it and end up discovering you've made a better wheel.
Tl libraries, no frameworks. Let AI recreate it from scratch … every time