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srini-docker 1 hours ago [-]
I work at Docker. Lot of valid and useful feedback here that we're looking closely at.
One correction: this isn't containers. Each session is a microVM with its own kernel on the platform's native hypervisor: Hypervisor.framework, WHP, KVM. We wrote a new VMM (not Firecracker) to make it more effective across platforms.
I'm very glad this now exists - fwiw almost a decade ago I worked on https://github.com/takeoff-env/takeoff as a solution for making it easier for hot reloading your stack which is thankfully redundant today, and funnily enough the list of problems you identify is also something I've been working on.
Recently I've also been working on a VM stack for an agentic platform using pre-build images with some cloud injection scripts that simplifies the deployment of a private agentic cluster - in the end I went with full VM with a 4vCpu/8gb for the main agent and 2vCPU/4Gb - only the main agent had docker-in-docker, the rest rootless docker but I agree it's still an elevated risk.
I'll definitely have to give this a spin and see if I can simplify it to one larger box with this solution.
cpburns2009 11 minutes ago [-]
Do you have a strategy for secrets? Such as storing them, or using MitM to inject them (e.g., HTTP API requests)? I've used squid cache in the past, and currently use iron-proxy for this sort of feature.
kwakubiney 1 hours ago [-]
Why’s it not on Linux? What are the difficulties with that platform?
srini-docker 43 minutes ago [-]
Linux is available today (Ubuntu): github.com/docker/sbx-releases. Our webpage showing only brew and winget is on us.
For the people upthread who asked about on customization: templates (like snapshotting a running sandbox) and kits (YAML applied at creation like install steps, files, network and credential rules, or define a new agent outright) are the supported path now. It's early but take a look here: https://docs.docker.com/ai/sandboxes/customize/
On MCP, since credential handling was mentioned here: the sandbox sees one gateway endpoint, and OAuth tokens stay in the host credential store rather than in the VM. https://docs.docker.com/ai/sandboxes/mcp-gateway/
All this is early. We're looking at more based on feedback from users like running sandboxes in the background for long-horizon work and a lot more (including what you all raised in the thread here). Keep them coming.
tacker2000 31 minutes ago [-]
Please consider adding MacPorts support.
Brew is notoriously developer-unfriendly.
dallen33 2 minutes ago [-]
How so?
cogman10 1 hours ago [-]
Looks like they do support Ubuntu.
Is this open source? Can I install this on a non Ubuntu system?
rocfan 22 minutes ago [-]
CLI works on Fedora. Been using it daily for ~ a week.
See repo `docker/sbx-releases`. The `.rpm` there has Rocky Linux in the name but works on Fedora.
aborsy 34 minutes ago [-]
A limited form of it with different syntax comes with Docker Desktop. The sbx tool is not available for non-Ubuntu distributions.
atechboy 30 minutes ago [-]
So the idea is to give each agent a VM to do several tool calls? or one VM for each tool call?
rusch 9 hours ago [-]
The login is annoying but, lacking an open source alternative, this has been my daily driver for a while now because it works great out of the box with two key features: outbound firewall and secret injection with placeholders.
I run it with superset and then each git worktree is mounted in a sandbox that is configured for each repo i work in.
Outbound firewall is `--network-isolated`: egress is denied except the agent's own API endpoints plus domains you allow, enforced sandbox-side (working on host-side enforcement now). `--network-none` if you want nothing.
Credential brokering works the way you describe (currently Claude-only, I'll add more as time allows). The API key stays on the host, a local proxy injects it into the outbound request, and the sandbox never holds anything worth stealing. Other agents' credentials currently arrive as read-only file mounts instead (weaker, and something I'll fix soon). Generalising the injector is the obvious next thing.
One difference from your setup: yoloAI copies your worktree instead of mounting it. The agent works on the copy, you `yoloai diff`, and `yoloai apply` replays the commits into your real repo. That's deliberate. Docker's own security docs talk about the dangers of bombs being left behind in a live-mounted dir (git hooks, package.json scripts, Makefiles, IDE task config), which diff/apply avoids.
Isolation is per-sandbox rather than fixed: runc, gVisor, or Kata VMs (QEMU or Firecracker) on Linux; Seatbelt or full macOS VMs via Tart on a Mac.
westurner 2 hours ago [-]
> yoloAI copies your worktree instead of mounting it
A few months ago now I started adding seccomp sandboxing to jinja2rs and then liboverlayfs support to ansiblers (which are early Rust ports).
Haven't finished that, but
I started working on a VM format that stores signed machine state into an OCI container repository, using the hypervisor migration support of KVM/QEMU.
Though this is not safe yet if ever, VM migrations are probably another way to sandbox and deploy en masse.
jachris 8 hours ago [-]
Agreed. Network control and secret injection together with a microVM setup is as good as it gets right now, although I believe that we need more fine-grained tools down the road. It sounds like Microsandbox would be the perfect fit for what you are describing. I also built my own coding agent workbench on top of it (https://github.com/isolade/isolade). Microsandbox is quite cool, check it out: https://github.com/superradcompany/microsandbox
Support for running agent harnesses in unprivileged podman containers is on my feature list. :-)
pojzon 4 hours ago [-]
Docker containers are not enough isolation for anyone that cares about jailbreak scenarios.
Only real alternative is to use microvms. My goto solution for this are apple/containers.
Supermancho 4 hours ago [-]
> Docker containers are not enough isolation for anyone that cares about jailbreak scenarios.
For the vast majority of developers, containers are enough, which is why they are ubiquitous while vms are less common. Ofc that ubiquity has led to lazy configuration, which is how the jailbreaking can occur. Knowing what you are doing with containers is a requirement to use containers as an AI sandbox.
wbl 3 hours ago [-]
The AI launches new kernel bugs as matter of course.
pjmlp 3 hours ago [-]
There were not the solution for a while now, that is why Kata containers came to be in first place.
TacticalCoder 3 hours ago [-]
> Only real alternative is to use microvms. My goto solution for this are apple/containers.
Why microVMs? I never ever run a container, AI harness or other, in something else than a full on VM. I could use a microVM but in any case I really don't see why I'd run a container on one of my bare metal OS: the place of a container is inside a VM (or microVM).
Especially for AI harnesses where the threat of an escape is very real: the more defense in depth, the better.
And If I can use rootless Podman instead of "rootfull" Docker, the better. Most of my containers are Podman btw.
> My goto solution for this are apple/containers.
To each his own: my goto solution is an actual server on my LAN with shitload of cores and memory and plenty of scripts to provision VMs etc.
I really don't understand why people are YOLO'ing containers on their bare metal OS.
cpburns2009 6 minutes ago [-]
The nice thing about running a microVM like a container is the interface is relatively easy, especially if you've used containers before.
sgc 58 minutes ago [-]
I agree. I thought everybody knew to never use docker for high security, because it is "security lite". Might as well just use firejail. I presume that an agent knows more about networking and virtualization than I do. The only real solution is using multi-tenant level vm isolation, while presuming that the agent still might break out of their vm. So the vms need to be hosted on their own physical box that only runs the kvm provisioning host (or similar), and is firewalled on its own isolated network. It's a bit of a pain of course, but anything less feels almost like security theatre rather than meaningful to me. Otherwise you need to stick to the remote chatbots only.
graemep 1 hours ago [-]
> I really don't understand why people are YOLO'ing containers on their bare metal OS.
You know about the people who do not bother with the container? Quite a few make “No problem so far” comments on HN discussions.
(Not affiliated with them, just tried it out last week.)
reddec 8 hours ago [-]
I've put some effort to integrate it to my agentic workflow. The problem, however, with docker in smolvm: it work-ish (there is example), but quite hacky.
Another problem which I wasnt able to solve - persistent image without Dockerfile. CloudInit will be ideal.
Documention at this moment in an early stage.
Overall, its a great project but for me was simpler just use Virtual Machine Manager (libvirt GUI).
I wish all luck to the maintainers, but probably DX-wise I will prefer to have more granular or predictable controls (eg micro cloud from Canonical).
SegmentTree 9 hours ago [-]
Eclipse Enclave does exactly that: There is an outbound firewall and secret injections, so that the agent never sees a real key. And it's fully open source: https://github.com/eclipse-enclave/enclave
dvtkrlbs 9 hours ago [-]
Looking at the Readme it seems like it only supports docker. Which is a dealbreaker for some
collabs 6 hours ago [-]
What is missing in qemu + podman that we need rootful docker for this? Is there actual capability that is missing or is it more of a design choice by the eclipse enclave folks?
We run cloud sandboxes, and have some experimental local sandbox support that is fully OSS.
Main thing for amika.dev is you can control the sandboxes and agents interchangeabley by SSH, web, or API, and can expose the services the agent is working on over signed URLs
Entire sandbox config is a TOML file
We're going to improve the local OSS sandbox mode and add better network controls over the next couple weeks.
Ultimately, what we're building kind of like if Tailscale and Firecracker had a baby, with a messaging protocol for remote controlling any sandboxed agent
It's free to try out. Still a lot to build, so we really appreciate any and all feedback about what we should focus on
zippie 2 hours ago [-]
We run https://github.com/NVIDIA/OpenShell on our workloads and we like it because it is backed by NVIDIA and fits natively within our k8s env.
It also provides a nice TUI for network policy management and prebuilt sandboxes which have claude code, codex, etc.
384028345 4 hours ago [-]
Isn't Nvidia's openshell exactly what you're looking for?
I'm asking because I'm just learning about this stuff myself and tested openshell yesterday with pi for the first time.
I have a colleague who's using openshell. The advantage is it's independent of the containerization layer, yes?
cpburns2009 4 hours ago [-]
Gondolin looks interesting. It sounds like a TypeScript wrapper that achieves the same thing as my setup: Docker & Kata Containers 4 (KVM/QEMU backend) for microVMs, iron-proxy for egress and secrets, and dnsmasq for internal network name resolution (workaround for a Docker/Kata incompatibility).
notsirius 1 hours ago [-]
Ooh - can you share more about your setup with superset? I tried getting it integrated with superset a while ago with no dice.
Has egress and ingress filtering, egress can be bound to host/internet/subnet or even better to internal apps (which are each separate netns) meaning you can do your own firewall/vpn/whatever per sandbox. Plus you control what other components in the sandbox env the app can communicate with.
Really not built for day-to-day dev work though, more like automating your company/life / getting rid of SaaS (e.g. for technical Founders / Sales etc, not exactly useful for dev work)
pbasista 6 hours ago [-]
I use Linux Containers managed by Incus for working with Claude.
I have a dedicated container for that. It can run its own Docker daemon and other system services if needed.
Apart from the Claude login token, it has no SSH keys or other credentials. I push everything I need to it from the local machine. And I pull the Claude generated outputs from it.
Of course, this kind of setup requires a stack which can run or at least be tested without any credentials.
Tomte 6 hours ago [-]
I do the same, but with pi.dev in Incus, mapping a project folder into the VM.
What I don‘t have compared to sbx is an outbound firewall, but my VM does not have any personal/interesting data, only a vanilla Fedora installation and the project dir with open source code, so I do not care much about exfiltration.
radlad 5 hours ago [-]
Love Incus and I'm using throwaway restricted projects for testing. Highly recommend incus-windows if you need to do any Windows testing. Having agents validate Windows behavior has reduced so much toil for me.
Internally uses a single VM + Incus containers, supports docker/Kubernetes in each sandbox, has integrated worktree management.
nzjrs 7 hours ago [-]
If you just need a python+venv sandbox with dev-first UX, no container build step needed, and no startup cost then I am using https://github.com/nzjrs/sandbubble in prod.
I havent used nor gondolin neither docker's solution, but curious to know what gondolin is missing (evaluating both for my personal use)? is it only the DX or something else, if DX, can you what exactly is missing?
thanks
codethief 5 hours ago [-]
In my experience it's mostly the UX/DX where Gondolin is lacking. For instance, I don't want to set up a JavaScript project every single time I need a sandbox. Instead, I just want to place a config file somewhere in my repo or my home dir and be done with it.
You can run the agent in the gondolin sandbox if you wish.
Their example implementation with pi uses a pi extension so that pi runs on the host but the read/write/bash/etc tools run in the guest. Doesn’t have to be that way though.
olejorgenb 3 hours ago [-]
Note that the pi-extension example in the gondolin repo is very outdated. Look in the pi repo instead.
9 hours ago [-]
_ink_ 9 hours ago [-]
Does secret injection really prevent that the agent send my GitHub key somewhere? If it has access to it via env var, can it not just paste it somewhere?
rusch 8 hours ago [-]
The env var is just a placeholder in the VM, so no real secret is in there.
llimllib 5 hours ago [-]
right, but say you give the agent access to github and it can push as you, or make a gist; now it can easily exfiltrate your secret.
And that's just an easy case - really if it has any network access at all it can come up with a clever way to route a request through the network such that the key comes back somewhere in the request. If you scan for it inbound too, the machine can obfuscate it.
Our agents are trained to be so intensely helpful and they have such intricate knowledge of how things work that they will do some incredibly clever tricks to do what you ask them to do.
skinfaxi 4 hours ago [-]
The agent has no access to the secret. It has a placeholder that is replaced at a higher level. When it makes the network request the secret is substituted but that is outside of the caller's worldview.
ruszki 21 minutes ago [-]
But how? Normally the TLS handshake and encryption/decryption happen in user space. Even the kernel doesn’t know anything about it.
Eldt 3 hours ago [-]
So what stops it from sending a network request to a git repo that pushes what that placeholder resolves to?
skinfaxi 3 hours ago [-]
How would that work? You don't control github.com servers so your repo would never see the secret.
edit: You may want to look into tokenizing proxies as the general application of this concept.
llimllib 3 hours ago [-]
Your agent writes secret.txt with the placeholder, and the tokenizing proxy replaces it with the token, then the agent reads secret.txt
skinfaxi 2 hours ago [-]
It only replaces the token in the HTTP header that is sent to the server. Whatever you wrote in your files isn't touched by the proxy.
messh 1 hours ago [-]
Couldn't it then just publish the mock in a public place... it would get replaced by the real secret.? How is this prevented
drdexebtjl 2 hours ago [-]
Maybe the tokenizing proxy could work both ways? If the agent tries to read secret.txt, it gets back the placeholder.
6 hours ago [-]
eli 7 hours ago [-]
It’s injected into an outbound api call, not into an env var the agent can read.
kellpossible2 6 hours ago [-]
what's to stop an agent creating an outbound call with the var to a malicious endpoint? (unless you whitelist what it has access to)
mpern 4 hours ago [-]
At least for gondolin and microsandbox, you bind a specific secret placeholder to the target host. i.e. your GH token is only replaced/injected for calls to api.github.com, not other hosts. And you can set up both with deny-by-default
messh 1 hours ago [-]
But then... why is replacent needed at all: just use sone permissions system.
messh 60 minutes ago [-]
Couldn't the agent post then the key in some public comment?
eglintondust 4 hours ago [-]
You just don't inject the real secret unless hostname/whatever rule matches the request, right? I don't know if that's how this works but it's my assumption.
mikesir87 1 hours ago [-]
On the Docker DevRel team... yes! This is it. The secret is injected only into headers in which the hostname matches.
There's also an ability to create kits where you can setup credential injection into other services as well.
skinfaxi 4 hours ago [-]
The replacement is on a url/host basis.
kellpossible2 6 hours ago [-]
or an outbound call to a trusted endpoint with the env var in a way that can get exposed to the agent via a subsequent call?
radlad 5 hours ago [-]
It's possible reflected instances are masked too, like GitHub Actions. But I don't know.
skinfaxi 4 hours ago [-]
How would that work, exactly? What are you envisioning?
https://github.com/pjlsergeant/byre -- slightly different security model, but lazer-focused on developer experience; my daily driver and I love it not just because I wrote it. The TUI is great for configuring and setting up instant boxes just how you want
https://pleasedonotescape.com/ -- a list of every other agent jail I could find, filterable by open-source and whatever else you want
What I run is one hardened QEMU/KVM VM per project holding the whole dev environment (editors, agents, containers), with nftables on the host allowing internet egress but dropping anything aimed at the host, the LAN, or any other private address, plus an allowlist for deliberate exceptions.
Basically, it's a plain QEMU/KVM VM on a stock Debian cloud image: device model stripped down to a virtio disk, a virtio NIC and a serial console, nested virt off, no passwordless sudo in the guest. It also ships a containment check that scans outward from inside the guest, so the network boundary is something you can verify.
Wrapping the whole environment rather than a single agent session puts supply chain attacks inside the boundary too. A poisoned npm or PyPI package, or a compromised editor extension, lands in the VM instead of on the host. That was the original reason I set this up; agents just made it more urgent.
There's no per-domain egress allowlist; the policy is "internet yes, private addresses no". Secret injection isn't built in either, though Infisical's agent-vault on the host as an egress proxy covers that part.
Wrote the whole setup up here, in case it's useful:
I currently do something similar, but this article was a nice read and gave me some new ideas.
TacticalCoder 3 hours ago [-]
Yeah I discovered your blog a few days ago: I've got a setup not unlike yours.
> So rather than pick one, this post advocates layering both, in the spirit of defense in depth: a sandbox VM wraps your containers along with the whole toolchain, and that sandbox reaches the internet but has no route to anything private.
Yup it's the only proper way.
And that is true not just for AI harnesses/agents (that shall try to escape), but also for stuff like Plex/Jellyfin/Immich/private pastebin etc.
If you care about security, there really simply is zero reason to run containers on the bare metal.
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Roark66 3 hours ago [-]
How about implementing proper permissions on the tool use or if you need more flexibility a dedicated model to analyse potential impact? (Like Claude Code's Autopilot but more configurable)?
I find solutions like this to be a like trying to patch a leaking boat on a lake with duct tape. It will help, but it's not a proper solution.
Also, often the tasks you want the AI to perform are in the outside world. Like "connect to my servers, and figure out X and Y".
The proper way is permission isolation. I run a small k8 cluster in the homelab and I have 3 types of pod/agent combinations for my AI agents. Read only, one that can change my gitops but it needs to create PRs that admin approves, and admin.
Likewise with code. I have a forgejo git instance where agents have ability to create feature branches and so on, but merging is gated.
Those things require "GH enterprise features".
In fact more and more things we do at home will require "enterprise features". Why? Because a person with AI is basically a small team, but some of team members behave like Chimps on crack... So security must be top notch.
AlotOfReading 1 hours ago [-]
What are the proper permissions for an agent? An agent shouldn't be able to read ~/.ssh, but that means a bash tool that spawns `cat` is different than one that spawns an ssh client. I don't allow my agents to use git commit, except sometimes I ask an agent to split up a complicated branch that I can't be bothered to split myself. rm'ing intermediary files is fine, but rm'ing committed files is bad, unless the agent has done *.bak renaming and is cleaning up itself, etc.
I don't think "proper" permissions are possible without dramatically limiting the way people use these tools.
iury-sza 2 hours ago [-]
Implementing that is trivial in the harness side. You code vibe that in minutes.
victor_edka 3 hours ago [-]
yea...I think k8s is de wae for running proper proper rbac sandboxes for agents.
kwakubiney 2 hours ago [-]
Any idea of anyone exploring this space? Sounds interesting
“microvms” are real vms but the hypervisor and vm (guest kernel) shed most of the hardware / device emulation, support, and discovery which makes traditional VMs look / feel like real computers, as well as most guest interactions. This gives them extremely low overhead.
Firecracker is designed to start a VM in under 125ms and 5MB. Netbsd advertises that you can direct-boot a MICROVM kernel configuration in under 10ms.
jsiepkes 8 hours ago [-]
If an agent fires up NPM, takes a boatload of memory, is that memory released back to the OS after NPM shuts down in the VM?
dist-epoch 8 hours ago [-]
In principle yes, in practice it's complicated, using something called "balloon drivers"
There’s also memory hotplugging via virtio-mem. But generally speaking downscaling live vm memory can’t be said to be a solved problem, it’s more of an active area of research.
frio 10 hours ago [-]
It’s real VMs, firecracker style.
vdfs 7 hours ago [-]
Your example is not complete, you have to show how it will run claude/codex, you have to do extra things to install run and mount folders there, this one does that with less config, also with this agents can run docker, lxd doesn't allow you to do that
TheqO 8 hours ago [-]
There are many devs that have little to no experience of Linux, like the hundreds of thousands of .Net and Java CRUD devs in enterprise companies using Windows.
There is a need for a Docker desktop like GUI for this market.
newsoftheday 3 hours ago [-]
Java CRUD devs have been getting into Linux a lot more in recent years since learning more about how DevOps does their work is important and integrated in with our projects, like the Dockerfile, Helm files, etc. I was already into Linux before Java was even released. I'd say even .Net devs are too since .Net Core is becoming more important in their world.
Izmaki 7 hours ago [-]
When I was a teen I had no experience with software development. Then I went to school and learned about it. Now I'm making money doing this thing because I became quite good.
The world didn't fit around me, so I made "me" fit around "the world". I bet those stubborn dinosaurs can learn a new trick or two also, if management lets them do it during working ours...
Also, WSL (Windows Subsystem for Linux) has been baked into Windows for a long time and makes it very easy to play with Linux, as does using the Hyper-V VM system. Any developer unfamiliar with Linux because they use Windows, has little excuse.
pjmlp 3 hours ago [-]
Agreed, even game devs that ignore Linux as target for their AAA games, actually tend to use Linux for game servers, the age of IIS with .NET/ISAPI is long gone, except for legacy code stuck in .NET Framework.
Modern .NET did not went cross platform by accident, and Java development has always been "develop on Windows deploy on UNIX", in corporations where Mac tends to have little presence.
3 hours ago [-]
huflungdung 8 hours ago [-]
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dist-epoch 8 hours ago [-]
An Ubuntu Server VM, like the ones started by Incus, use at least 512 MB of RAM per instance. If you spawn 10 sandbox VMs, you already pay 5 GB RAM just to sit there idle. You also pay a CPU cost, you have 10 kernels managing stuff, but arguably it doesn't matter that much given CPU core counts.
I use something in between - a single Ubuntu VM, into which I spawn multiple Incus LXC containers for the agents. The containers only use 50 MB or so per instance (separate systemd, ...). This way I pay the VM RAM tax only once, and the agents are still contained inside the VM if they manage to escape the LXC containers.
TacticalCoder 3 hours ago [-]
Yeah this basically. I differentiate between "containers I wrote" (where I packaged the app/wrote the OCI "Dockerfile" / container file) and "containers from other people": all those I wrote (for our own use) go into one VM, while all the other containers go into another VM. Then I've got a third VM for containers for the AI agents.
This way I don't pay tens of VMs "tax" but basically only three (plus one or two VMs I use for testing enhancements to my VMs provisioning / optimization / securing setup, when I work on that).
I don't use LXC (I could) but regular containers, inside VMs.
I'll look into the stripped down "micro" VMs but then I don't spend my days launching VMs/shutting them down so it's not a big deal.
dizhn 9 hours ago [-]
That's a full VM. Microvms are much smaller and they start up very very fast. In miliseconds.
randomint64 8 hours ago [-]
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hokkos 10 hours ago [-]
Wow, I hope one day Linux will be able to support the exclusive MacOs/Windows technology of Docker Sandboxes.
(it's in the doc, but kinda strange to not see some instructions on the main page, probably distro related)
stefanka 9 hours ago [-]
What about bubblewrap? It also provides a sandbox
SwellJoe 7 hours ago [-]
Yes, bubblewrap is superior to Docker for this. I wrote a tool to use bubblewrap for the purpose. It needs a tool to start it, or is at least much more convenient with a tool, because you need to take your session/auth data into the container, and if you want the agent to be able to start containers (agents love containers) within the container, you need some config magic mounted inside. You could manually do all that, or do it with a shell script, as well. But, this is how I did it, and you're likely to run into all the same little quirks I ran into:
Interesting. I’ve been trying to use bwrap, slirp4netns, and mitmproxy to create a simple Python script to get save shell for development. But it’s a huge time sink (and I might resort to podman)
It seems to do a good job of not stating the actual threat model anywhere.
PufPufPuf 4 hours ago [-]
I built "Locki": something similar but open-source! A bit different approach -- single VM with Incus containers -- focusing on speed of spinning up new sandboxes and integraton with git worktrees. The core grievance that motivated me was the lack of docker/kubernetes support in existing sandboxing tools, with Locki there's no chance of footguns like "two agents rebuild :latest tag at the same time". Give it a try: https://github.com/JanPokorny/locki
dhchun1203 3 hours ago [-]
Neither of the recent ones was actually a container escape though. The OpenAI
one in July found a misconfig in the sandbox network, and Kimi K3 last week just
walked out to grab answers off GitHub during an eval.
Both went through stuff the sandbox was set up to allow.
iamspoilt 2 hours ago [-]
I recently wrote a blog post on using Tart for Macs for something similar that docker is doing here but with better persistence and control. My take is that the Tart approach is superior to this as it gives you a full dev machine with a single command line that allows agents to access files on host, install packages, maintain the vm and do whatever they want to do without compromising the host OS.
It blocks network access by default, mounts only what you specify, and you can add a customization layer. This is all done in the container itself (srt for network blocking). It doesn't implement a central point for secret sharing, MCP exposure, etc. So it might not have enough features for some but it works well for my needs.
I just found through this thread yoloai which has an apple container backend, so its quite similar using that. My main issue would be that network access is allowed by default. https://github.com/kstenerud/yoloai
Several other projects listed here use libkrun which is an alternate implementation that works with Mac's HVF. smolvm, microsandbox, podman (with likrun backend), gondolin.
42 minutes ago [-]
codethief 5 hours ago [-]
To everyone sharing their favorite container-based sandboxing solution: Docker Sandbox does not use containers for isolation. It spawns the workload in a libkrun-based micro VM, which has vastly different security properties.
Since everyone is sharing their setup, here’s my approach, just to give people an idea of how others are doing it, however impractical it might look: I run a full Linux VM (with a GUI) on my Linux host. I connect via virt-viewer to run Claude Desktop, as I’m not a fan of using the terminal for this.
The VM sits on its own libvirt network in a dedicated firewall zone, and specific directories are shared via filesystem passthrough. To keep the agent from accessing anything related to Git, the actual gitdir is stored on a separate path outside the mount point.
I review the git diff manually and commit it from the host.
everforward 2 hours ago [-]
Do you find the permanence of a full VM useful? I’ve wondered about something like this but always defaulted to Docker for much the same reasons people use stuff like Ansible. I’m afraid the LLM will heavily customize its environment and I’ll be unable to replicate it when my laptop dies or I can’t upgrade the OS or whatever.
Then again, I guess GUI is a pain in Docker. I tend to operate through Zed and an ACP harness though, so my GUIs are sort of “inside the container” anyways.
Grimburger 1 hours ago [-]
> I’m afraid the LLM will heavily customize its environment and I’ll be unable to replicate it
Would suggest Hashicorp Packer or cloud-init for deterministic images, not hard to setup or use. LLM's have little problem with them either I find.
If you need quicker environment rebuilds consider using something smaller like alpine as the base, though once you setup a golden image even heavy things like debian are fine.
mikedelfino 2 hours ago [-]
The VM is allocated 2 cores and 4GB of RAM. For my workload, it doesn't feel any slower than running it directly on the host. The few times I've checked memory usage, it wasn't anywhere near full as far as I remember.
karakanb 10 hours ago [-]
I got excited for this not because this didn't exist before, but because Docker putting their weight on this would imply a broader adoption and better integration in the industry. I am sad that they are asking for a login here though, which doesn't make any sense to me.
KolibriFly 10 hours ago [-]
That's docker, man. Tomorrow they're gonna add limits on sandbox runs without a premium account too
rvz 9 hours ago [-]
microVMs (firecracker) have existed for years. This is not new.
Haven't tested it yet, but it seems to address the same issue as Docker Sandboxes, but in a different way.
speedgoose 8 hours ago [-]
I have tested it and the big advantage is that is has access to the local development tools.
But it’s not as well sandboxed for sure.
lemontheme 3 hours ago [-]
Nono has been my daily driver since the start of the year. It's not a perfect sandbox -- that's for sure. For example, the default network rules let you escape via a global TMUX server. But it is extremely practical. It gives me enough guarantees to feel confident about running in YOLO mode. So far nothing has gone awry.
fg137 3 hours ago [-]
As you as your Go build fails because you haven't put the local cache dir in the "allowed directories", you'll understand how painful this is, as well as most tools based on bubblewrap/sandbox-exec. There is a difference between a clean environment with standard setup vs a layer on top of everyone's existing tools/setup, especially in a enterprise environment.
(I'm sure you can spend time to come up with a proper bubblewrap configuration that allows go build to succeed, but it's probably not worth the effort.)
LeBit 7 hours ago [-]
Why do you say that?
Eg, if used with Colima in macOS, it means I can run a devcontainer in an isolated VM and Nono inside the devcontainer can restrict a lot what can and cannot be done.
You get credentials proxying and network outbound limits.
How is Docker Sandbox better sandboxed?
speedgoose 2 hours ago [-]
Yeah but that’s Colima and Nono then. Not only Nono.
navigate8310 9 hours ago [-]
I just made my own devcontainer that I copy on any project and load whatever harness I want in that repo. Harnesss' config and auth are simply mounted from the host, so no setup required at all.
I don't get how it works, or works well -- presumably those domains are behind CDNs, and IP addresses are unpredictable. So the firewall allows traffic to specific IPs that are resolved at the time the script is run, but not after that? What if the same domain is resolved again without going through the cache, and it becomes a different IP?
And even if that works, this is a very short list. As soon as you reach for Go, Rust tooling etc nothing works. So you need to manually maintain this list which is nothing but painful trial and error.
ai_fry_ur_brain 9 hours ago [-]
[dead]
d2p 8 hours ago [-]
Does this support Linux yet? When I previously looked it did not (the reason being that they were already using VMs on Windows/macOS but not on Linux). Every time I see an announcement I think "great, they must've added Linux now then", but the linked pages always have Windows + macOS instructions but not Linux.
All the open GH issues about supporting Linux that I subscribed to have gone unresponded to.
OpenShell looks like a good alternative, but it still has "Do not use in production" plastered all over the website, which doesn't fill me with confidence yet
narinciye 7 hours ago [-]
It must be a joke that this tool is not supported on linux yet, although docker is built on top of linux containers. Shame on docker.
SwellJoe 8 hours ago [-]
I think Linux has a better solution than Docker.
I wrote a tool to use `bubblewrap` to containerize any agent (at least all the agents I've used a couple of times), and bind mount the system stuff read-only, so the agent has your "usual" environment, but they can only see the project. Their history persists (either through a bind mount or a "shadow" copy of the history that only the wrapped agent sees), the agent can still create and manage containers of its own using podman's rootless mode, etc. It's nearly instant to start because it's just a namespace (plus a few copied files for the container support and session history); no container needs to be built/fetched/updated/whatever. bubblewrap is extremely well-tested as it is used by flatpak and several other large projects, so I trust it quite a bit (more than I trust Docker).
bubblewrap may work well for you and your specific workflows/projects but not in an enterprise setting where everyone already has a different setup on the host and needs something different inside the container. It's impossible to deploy a solution like that with bubblewrap -- configuration itself is going to be a nightmare. Which is why Docker Sandbox is aimed at teams/enterprises.
SwellJoe 46 minutes ago [-]
Yeah, Podman would be a better basis for that kind of use case. I'd built an early implementation of `flar` with Podman first, but it was more annoying than simply having my regular dev environment instantly available in the container. But if you need a bunch of different dev environments, instead of just your usual one, then sure, a bunch of different custom containers makes sense.
But, Docker is rarely the right way to manage containers on Linux, IMHO.
fg137 42 minutes ago [-]
"Docker Sandbox" is not docker. Completely different (and almost unrelated) products.
I also hit the same issue recently. No Linux and no Windows on arm. AI sandboxing has a lot of options but none feel complete just yet. It's hard to commit to something, especially if reviewing tools to aide in company policies.
Regardless, I'm hoping something that isn't behind a login screen is going to win out.
Operating systems ought to be providing us the utilities we need to safely sandbox processes (agent or otherwise), but they appear to not be interested in the job
pjmlp 3 hours ago [-]
Apple, Microsoft, IBM, Unisys, HP, Oracle/Sun have done that for a while now.
llimllib 3 hours ago [-]
Poorly! Apple’s facilities for this are the ones I know best, and they are woefully insufficient
pjmlp 3 hours ago [-]
Well, the features announced at WWDC 2026 naturally are yet to be made available in a mature form.
pkhamre 10 hours ago [-]
I started building my own isolated and security-hardened docker image for OpenCode about half a year ago. Been using it daily.
I have a solution based on Nix that can be used to generate reproducible container images: https://github.com/nothingnesses/agent-images . It lets you customise which agents, harnesses, or any other packages you want included in the VM and it uses `agent-box` for sandboxing.
binsquare 8 hours ago [-]
wonderful, will try to test this in smol machines as well
dizhn 9 hours ago [-]
This looks like gvisor but is a vm like firecracker right? Any reason you did not want to use firecracker?
(I am testing this now as a backend for my pet project which currently supports firecracker and gvisor. No network.)
binsquare 9 hours ago [-]
It's a batteries included alternative to firecracker with a couple of new ideas tossed into the mix i.e. portable like a container (bake into a single file and rehydrate the vm anywhere), dynamic resource allocation, etc.
Alifatisk 10 hours ago [-]
What? Does using sbx require login? Bummer.
dSebastien 10 hours ago [-]
Yes and they have a specific subscription for managing sandbox policies across the enterprise: Docker AI Governance
dSebastien 10 hours ago [-]
You can create those manually but if you want to enforce those then you need the subscription
reddozen 10 hours ago [-]
If any AI company was doing serious engineering isolated containers would have been a prerequisite to using their tools.
globular-toast 9 hours ago [-]
Anyone serious about security will want to bring their own sandbox anyway, not trust these, often proprietary, agents. I've never run an agent outside a sandbox. My first bubblewrap script for `claude` is now over a year old. The tools are available and if you learn to use them you can run any program in a sandbox.
But, in any case, why put in effort doing something people don't expect or ask for? We can assume everyone running agents is either a) using their own sandbox, or b) doesn't care. I think we can guess which category most people fall into. You could maybe argue about responsibility, but I don't think you can argue about "serious engineering".
topspin 6 hours ago [-]
> Anyone serious about security will want to bring their own sandbox anyway
Exactly. It's not as though it's difficult. It never occurred to me to not do this from day one, and it astonishes me that anyone runs this stuff bare metal. Since then, I've brought several other people on board, and that's all they've ever seen: I don't think they'd know how to run outside a sandbox, and that's just fine.
aki237 3 hours ago [-]
I'm currently facing this issue. I've resorted to implementing my own execution environment albeit limited.
It goes like this:
- bash script parser + interpreter (with hooks for things like file open, execute etc.,)
- wasm executor for execution.
- wasm implementations of common tools like coreutils, grep, sed etc., from the uutils project.
- wasm implementation of python by a VMware backed project.
- entirely virtualized filesystem using Go's io/fs.FS. (tmp dirs can be implemented using any backend)
Works like a charm for the limited usecase I have. There are definitely some drawbacks with threading and especially with preopens in wasm. But a cheap sandbox for simple file explorations and minimal computations.
arscan 2 hours ago [-]
Not a substantive comment on content but hopefully constructive feedback on presentation:
Holy moly, on mobile I was trying to read the example console screenshots/snippets and then it would just unexpectedly change. Took me a little while to figure out it’s some kind of carousel for the examples, and not more screenshots/snippets loading and pushing down content (or me going crazy). Please don’t do this on mobile sites, just let me scroll through the examples!
mikesir87 1 hours ago [-]
Thanks for the feedback! Will pass it on to the web team to get this more mobile-friendly.
Disposable and isolated sandboxes are the right way to handle untrusted agent execution. Great architectural pattern.
mikodin 3 hours ago [-]
Does anyone have a solution for iOS development?
I was all in on sandboxes and safehouse for my agents but the moment I got into iOS development it felt like my hand was forced to just run Claude / codex / pi directly on my machine because nothing else could do the dev loop.
It’s been a painful reality for me, I’m going against core pieces of how I feel I should be interacting with agent harnesses and yet, I need to get the work done so
followercode 2 hours ago [-]
Hey, I work at Docker and my team works on mcp integration with sbx. A solution I've been trying is this:
1) Enable the xcode mcp server: https://developer.apple.com/documentation/xcode/giving-exter...
2) Add the xcode mcp server to sbx: `sbx mcp add xcode --command xcrun --args mcpbridge`
3) When you create the sandbox, use `--static-mcp xcode`. For example: `sbx create --static-mcp xcode claude .`
Make sure you have at least v0.38.0 of sbx. This makes a bridge from inside the sandbox to the xcode tools on your host, so be aware that it can run whatever tools you give it on the host. But the agent itself is still sandboxed.
notsirius 52 minutes ago [-]
Also had this pain point as an sbx user. Given the risk this adds to the host, would be great if there were more docs on how to setup kits to make it safer (e.g. disable yolo mode).
espadrine 8 hours ago [-]
Models start going to extreme, damaging lengths to achieve ambiguous prompts[0]. Having good sandboxes is now a must IMO.
But sbx is a bit annoying to use with OpenCode for instance (which has zero sandboxing by default, unlike codex CLI or Claude Code). You cannot easily change ~/.config/opencode/opencode.jsonc AFAIK.
We run OpenCode currently, but need to improve the setup for users, so would like understand more of the issues you have sandboxing it, if you can share
eli 8 hours ago [-]
That incident was with a model that had the guardrails disabled.
Still obviously you should run all untrusted code in a sandbox, but extreme actions like that would be very unusual with the model that shipped.
Schlagbohrer 9 hours ago [-]
Can someone more versed in Docker explain to me how this is different than building my own docker container from a Dockerfile for using Pi agent harness? That's what I do currently. I use Docker Desktop in windows as the backend for that.
Hugsun 9 hours ago [-]
Docker containers use Linux kernel features to create an isolated environment, running on the same machine as docker is.
This creates a virtual machine, with its own kernel, and runs the container in there.
This gives stronger isolation and security guarantees.
eloisius 9 hours ago [-]
I have the same question as GP. Your answer helps a little but not really. I might be naive, but I was under the impression that malicious code escaping a docker image and running amok on my host system was not something I should be too worried about. Especially if I run docker in rootless mode. Is that wrong?
For clarity I’m actually using podman, not Docker.
angry_octet 9 hours ago [-]
Oh no, you should definitely be worried about that. Podman might make it harder to escalate to host root, or manipulate other containers, but it is still vulnerable.
Now I'm curious to know how hardened the Docket Sandbox orchestration interface is. I guess we can assume they have run Mythos against it for a few weeks maybe? It's unclear.
eloisius 9 hours ago [-]
Unsettling. I mean, is there any reasonable way to develop software in 2026? I've already sworn off ever installing npm directly on my host. Containerizing everything is laborious enough, but running a separate VM for everything?
mihaelm 8 hours ago [-]
You just need to work out the threat model for what you're working on. For trusted containerized workloads, where the attack surface is minimal, just containerization is fine. However, agents can do just about anything on your computer if you allow it and people aren't really shying away from `--dangerously-skip-permissions`, so better hardening (VMs, microVMs) is desirable.
cognitiveinline 8 hours ago [-]
BS.
Unless we're talking 0-day/CVE, running an unprivileged container is as trustable as a VM. The only difference is how strictly you want to hold the memory/CPU bar. Infact on linux, containers are more lightweight than VMs.
So yeah, not "vulnerable".
angry_octet 3 hours ago [-]
LLMs are great at finding 0-day, and people are rubbish at updating their containers and hosts to patch b-day.
Containers have access to the kernel ABI, and as shown in the latest kernel exploits, all the memory handling surface that exposes. The virtualisation interface, offering fewer services, is significantly harder.
Containers are obviously lighter than VMs, both to start and to schedule, but firecracker is pretty fast. gVisor pays overhead per syscall vs at startup.
So yeah, more vulnerable.
cognitiveinline 2 hours ago [-]
Got it. 0 days are possible so throwaway containerization. You should blog about it, will help millions of developers and companies. Heck, even consult with the hyperscalers - they will be riddled with their workloads.
sureglymop 9 hours ago [-]
That depends on the runtime though. For example, libkrun lets you do this:
docker run --runtime krun hello-world
That starts/runs the OCI in a qemu microvm.
LeBit 7 hours ago [-]
When the host is a Mac or window , docker always run in a VM anyway.
On Linux, you can run docker directly on the host, but you can also very easily setup a vm with incus and run docker from there.
angry_octet 9 hours ago [-]
It's a VM.
yellow_lead 10 hours ago [-]
I know some people want to run their agents when their computer is off, but I imagine a solution like this will be much more common than paying for a remote sandbox (i.e on fly.io or exe.dev), especially because it'll be free.
Though, they need to remove the login requirement.
dbmikus 2 hours ago [-]
Agreed! I think the best user experience is:
1. You can run sandboxes locally
2. You can control them securely over the internet, for when you're on the go
3. You can migrate them to cloud VMs if you want
If I can toot my own horn, I'm trying to build that :)
Still early and the local sandboxes are experimental right now
Before you use no sandbox at all use this or one the many similar projects but it's alway worth remembering that Docker is not a security boundary. It never has been meant to be and never will
become one.
cgroups are a mechanism designed for hierarchical organization and resource distribution. Against a malicious and capable actor, and that is how we have to treat AI agents, cgroups will not withstand.
Also, the kernal is an interface too big for what an AI agent needs and is therefore offering a gigantic attack surface completely unnecessarily.
TheRoque 8 hours ago [-]
Would you say podman is better, or is it the same as docker ?
weinzierl 8 hours ago [-]
In general running containers rootless is better from a security standpoint and podman makes this much easier. So, yes.
This is not my main point though. Both are based on cgroups and cgroups are the wrong tool for the job.
TheRoque 8 hours ago [-]
Wouldn't it need a super critical exploit, I mean zero-day vulnerability, to escape from that kind of sandbox ? And if you think further, then isn't that risk also applicable to pretty much any kind of sandboxing ?
weinzierl 8 hours ago [-]
Container escapes are more common than you think. Common enough for AWS not to rely on containers for their serverless functions, common enough for Google to say: "Untrusted code shouldn't rely on the container security boundary [..]" [1]
The same is not applicable for any kind of sandboxing for two reasons:
1. The boundary is in the kernal’s own code, enforced by the thing you are trying to be protected from. -> Use a VM
2. The kernal is a gigantic attack surface -> Use gVisor
What if you use tools like bubblewrap or nono inside the container?
Say I want to use pi inside a container. If I wrap pi within a bubblewrap or within nono, how is that less secure than using a vm?
Also, I think most people run containers inside VMs anyway and not directly on their hosts (on Mac and windows you have to use a vm anyway).
akdev1l 4 hours ago [-]
bubble wrap is just doing the same cgroups work
LeBit 4 hours ago [-]
Depending on the configuration, bubblewrap can substantially reduce the attack surface.
It doesn’t change the fact a malicious process is still attacking the same kernel , but it can reduce what it can do to that vm.
dboreham 4 hours ago [-]
Which is fine but this thread is about a feature that provides hypervisor isolation, not cgroups.
realexweb 8 hours ago [-]
[flagged]
meffmadd 10 hours ago [-]
I tried Docker Sandboxes but last time I checked you could not configure custom volume mounts, making more complex setups impossible. For work I need two directories for context for the agent to have access to…
When starting a sandbox, you can specify the mountpoints you want. It just defaults to the current directory. You can also specify some of those mounts as read-only as well.
Example: sbx run claude ./ ../another-project:ro
9 hours ago [-]
cyberpunk 9 hours ago [-]
put them both inside another directory and share that? what am i missing?
meffmadd 6 hours ago [-]
Of course, but that was not part of my workflow and I found it quite strange that this was simply not possible especially when docker-compose can easily do this
Looks really nice. Would it be easy to make a qwen-cli wrapper?
bob1029 9 hours ago [-]
The sandboxing problem is perhaps the greatest justification for doing agent integration via existing human interfaces rather than low level shell access. Granting access to shell is a super obvious path (it's easy) so I can understand us wanting to fight for it. But we should consider the other paths as well before we make our final stand.
Automating browsers with LLM agents properly requires a lot more work than Process.Start into powershell, but the advantages can be immense once you have achieved integration this way. Incrementally maintaining this integration is generally easy because human users cannot tolerate rapid changes either.
It's a hell of a lot easier to convince management to adopt a robot that looks and acts like a human employee than one that looks like a combine harvester. The combine is far more efficient, but it is also totally indiscriminate. Nothing constrains its appetite except for the invisible fence imposed by GPS. The amount of infrastructure required to keep farm equipment from running astray is incredible. In the context of agriculture, the added complexity is definitely worth it. We don't want to have to recreate the same thing with our technology if it can be avoided. Sandboxes and security isolation boundaries are not things to aspire to. These are costs to be paid for admission to something more valuable.
pkulak 2 hours ago [-]
I’m sure they fixed this, but since everyone runs docker containers as root… is every file this thing writes going to be root owned? Does it have root access to any resource to give it visibility to?
celrenheit 6 hours ago [-]
I tried it and it worked great at first but I had multiple issues with it, the disk space usage was growing significantly, I need to login multiple times for each sandbox, it's closed source and not possible to customize to my need.
One other thing, I want to be able to handle multiple repos in the same sandbox and have a standard workflow around worktrees (one worktree per repo, all the worktree mounted in the VM).
I do not see any value proposition in this - if I need a sandbox, I make one with Dockerfile, Bubblewrap or virtualization. What I am missing? An enforced required login is a net negative value - it means rug pulls in the future.
franze 5 hours ago [-]
Here is my solution which uses the Apple Virtualization Framework
als has lots of agents + and typical dev packages (node tooling, python tooling, ....) preinstalled
dannyw 10 hours ago [-]
I’d rather use another open source solution that doesn’t require a signup, and less likely to get rugpulled.
There is no reason to require a login for creating local mini sandboxes.
If you’re on Apple, native solutions like “container-machine init” come built in and are pretty good, if you’ll only be on Apple hardware.
5 hours ago [-]
devttyeu 9 hours ago [-]
I did try to use those for some stuff:
* Login requirement is something else
* It's closed source last I checked
* Pretty slow/unstable
There are many better namespace/container based options, VMs may be moderately more secure but when you more or less trust your agent and code you can do with lesser containment. And with the recent CVEs in kvm honestly there isn't a huge deal of difference vs namespaces.
(I'm building https://xbin.dev/ for some time now for managing my personal code/apps, a project which started specifically after Docker Sandboxes broke on me some time ago)
Finally, a way to run --dangerously-skip-permissions without having a mild heart attack every time the agent decides to rm -rf a mystery directory.
TZubiri 3 hours ago [-]
'adduser agent'
'su agent'
'curl domain/install.sh | sh'
'runagent'
9 hours ago [-]
cpburns2009 4 hours ago [-]
So Docker is finally adding native support for a microVM backend? I wonder how it well it will compare to using the Kata Containers 4 runtime with the KVM/QEMU backend.
GZGavinZhao 8 hours ago [-]
I'm confused:
1. If I run this on Mac, then inside the sandbox / microVM, am I still running MacOS or some Linux distribution?
2. If the only thing that's mounted from the host is the $PWD, how does it guarantee that it has all the system libraries that I have installed on my host system? e.g. my `/opt/homebrew` libraries or `sudo apt install libfoo-dev` headers
akdev1l 4 hours ago [-]
Docker uses VMs in non-Linux OS to provide a Linux where containers can actually exist
So essentially you can get latest Pi/Node pulling from that image:
`sbx run -t ghcr.io/shaftoe/sbx-template-pi:latest shell`
Like others here I'm also saddened by the login requirement but at the moment this is the best UX I could find for running sandboxed agents, the "kit/mixin" concepts are neat and I make use of them too: https://github.com/shaftoe/sbx-template-pi#stacking-the-extr...
zmmmmm 10 hours ago [-]
it's running a full VM so the agent can eg: run docker commands safely etc
_ache_ 5 hours ago [-]
I planed to do exactly this, with podman instead of docker, volume support.
Like:
$ podman run -it --rm -v .:/workspace local-dev-ia /usr/bin/oc
Configured with a .env file.
Hope to do it hopefully before the end of the week.
codethief 5 hours ago [-]
> exactly this
This is nowhere near "exactly this". Docker Sandboxes uses micro VMs, you just use regular containers which have completely different security properties.
akdev1l 5 hours ago [-]
podman run --annotation=run.oci.handler=krun -dp 8080:8080 -t --rm server-without-wasm
Draiken 5 hours ago [-]
Bubblewrap plus some whitelisting of domains/sockets is all you need.
Docker is always a pain to use and this way I don't have to re-install everything a billion times for every different project.
llimllib 5 hours ago [-]
This is what I currently do, but my software uses docker and docker mounts act as a bypass for the file system restrictions, plus docker processes started outside the sandbox allow network proxy escape.
Currently, I don't allow the agent access to docker, start docker myself, and then do short-lived sandbox-free sessions when the agent needs to do things that interact directly with docker; but that's annoying.
killerstorm 6 hours ago [-]
Are we sandboxing AI agent harness process, or the environment it executes commands in?
Ideally, they should run in _different_ sandboxes.
The environment might corrode the harness (e.g. rogue npm/pip packet would manipulate agent harness config).
aniceperson 53 minutes ago [-]
systemd namespaces but less useful?
outof 10 hours ago [-]
Like many people, I suspect, I used Claude to write my own agent sandbox that suits my needs very well. Investing my time in a propietary product has become a hard sell.
matheusmoreira 9 hours ago [-]
I did the same thing. It was my first "vibecoded" project. I've been using it every day and it's great. I'm writing a custom Rust network stack for it right now. Gonna replace the current nftables firewall with it.
As for Docker Sandboxes, I'll just ask Sol literally right now to see what it does better than my virtdev, and then I'll improve virtdev instead of using Docker.
zingar 10 hours ago [-]
Were you following any patterns/standards/advice on what you needed to protect against? Anything you can point the rest of us to?
matheusmoreira 9 hours ago [-]
> Were you following any patterns/standards/advice on what you needed to protect against?
Just the general knowledge that sharing a kernel with untrusted software is too dangerous, that hardware virtualization is an infinitely smaller attack surface and that the entire industry will be in deep shit if people or AI breaks hypervisors.
Initial threat model was supply chain attacks but eventually grew to include AI harnesses as well. Not very worried about them hacking me, more about accident prevention.
So that means each VM must be running a completely independent kernel that's fully isolated from the host's file system. They must also have fail closed network filtering built in.
In summary, it's a QEMU VM orchestrator with a base OS image and project specific delta images. VM lifecycle is managed by systemd. System level isolation is already pretty good and it already solves the "AI wiped out my $HOME" problem. I'm currently working on a custom network stack to replace the nftables based firewall.
embedding-shape 10 hours ago [-]
You want to prevent the agent/others from reaching your home directory and other things. As long as you don't mount/sync directories/files from/to the container, so no mounting like "-v $(pwd):/app", but instead copy in, then when done, copy out.
And of course, instead of doing the "copy in > copy out" process manually, get your local agent to write a bash script that does that for you, given what directory you're in, and you're basically G2G.
tjoff 10 hours ago [-]
What is the advantage of copying rather than a bind-mount?
furst-blumier 4 hours ago [-]
"Oops I deleted everything under $FOLDER – that mistake is on me" doesn't kill it on your host system
tjoff 3 hours ago [-]
Sure, but all projects are version controlled? You only mount the project dir so you can only loose your current changes - which is the same if you copy...
hvb2 10 hours ago [-]
What specifically are you looking for? If you start from the premise that it runs as you right now, then that's something you can easily improve upon.
Start by mounting just your repo and passing in the keys for the agent. Take it from there, it's like software engineering, you iterate.
When you run into issues you expand the tools in the container available to it.
rvz 9 hours ago [-]
Why developers will never pay for their tools.
KolibriFly 10 hours ago [-]
[dead]
fergie 8 hours ago [-]
I use it (sbx), but I don't 100% trust that it actually works, and I would prefer something open source where the limits of the sandboxing could be tested and explored.
Maybe we should just ssh into separate development machines to ensure real and verifiable sandboxing? (as was totally standard before Docker became a thing)
LeBit 7 hours ago [-]
You should research bubblewrap and nono.
cv_h 8 hours ago [-]
I wrote a CLI tool that uses QEMU's microvm machine type under the hood. It can take any docker image and build a microvm.
I use it regularly to run Claude/Codex with permission checks disabled.
The one thing I wonder about is how you enforce the usage of Docker Sandboxes vs running the agent on the host directly, apart from scanning machines for binaries
pjmlp 8 hours ago [-]
I hardly see how this matters, when Apple and Microsoft already have their own in box solutions for the same problem.
Better sandboxing for AI agents is exactly the main reason for containers improvements on macOS and Windows, with a few talks at WWDC, and BUILD.
Not sure how much they would get from Linux users then.
root-parent 3 hours ago [-]
A Docker container is not a strong security boundary.
venatiodecorus 2 hours ago [-]
these are firecracker microvms iirc, not containers
Cameri 5 hours ago [-]
I was going to try it but signing commits with GPG using a Yubikey is not supported.
The option left is to use SSH to sign commits which is a no-go for a different reason.
Doesn't everyone do this now? It's hardly a new idea. Yet every time someone proposes the idea, people fawn over it and proclaim it the best thing ever.
Yes, you can inject tokens via a proxy. What else is new?
nopurpose 8 hours ago [-]
Who is doing it as first class feature with at least adequate UX?
I have skimmed alternatives offered in comments to this post (vibepod-cli, code-on-incus, opencode-docker, sandboxy, smolvm, amazing-sandbox) and none of them seem to do credentials injection at the proxy level.
LeBit 7 hours ago [-]
nono.
Also fnox now does credentials proxying.
nopurpose 40 minutes ago [-]
Thanks, bookmarked nono to have a look later.
elAhmo 9 hours ago [-]
I wish they solved the issue happening for years on MacOS where Docker keeps up eating all available free space and ends up requiring restart of the whole machine, instead of Gordon and other useless shit.
st3fan 3 hours ago [-]
Why is this not available for Linux?
3371 9 hours ago [-]
I used this for a while then decided to build my own suites that pack individual harness and respective host state (config, plugins, skills, etc.) into an image. Works better and much flexible in my opinion.
TekMol 9 hours ago [-]
So this is a VM by Docker?
For those who do not trust
docker run --rm -it -v "$(pwd)":/work -w /work myaiimage /bin/bash
AND do not want to use some other, free VM for some reason?
woadwarrior01 9 hours ago [-]
Better yet, use Apple's container CLI if you're on a Mac, instead of the docker bloatware.
container run --rm -it -v "$(pwd)":/work -w /work myaiimage /bin/bash
pulse7 9 hours ago [-]
Hasn't Docker always been just a thin layer of duct tape over existing solutions?
Hey, creator of bhatti here, let me know if you any questions.
notsirius 10 hours ago [-]
been using this for a while - works great! Has also had a lot of updates over the past year so worth checking out again if you tried it a while ago
zingar 10 hours ago [-]
Do the agents come preinstalled in the images? Or do they somehow use whatever I’ve installed locally? The former makes sense to me but then I’m wondering whether the sandbox images stay up to date with new releases of each image.
The agent is per installed. If there is an update to the agent, the VM notifies you on a first run and updates it if you approve.
Other than the login problem, it’s a decent option.
pixard 10 hours ago [-]
Ah let's see, do they still want you to LOGIN, in order to use a local dev tool? Yes, yes they do. No thanks Docker. You can keep your buzzword reasoning as to why this is needed.
alasano 7 hours ago [-]
I've been keeping a list of all the agent sandbox providers if you're looking for alternatives to this
So it's basically a container with a fancy name, innit?
runtime_lens 10 hours ago [-]
TO me, that's the important distinction: sandboxing limits what the agent can do but it doesn't necessarily enforce that the agent must run inside the sandbox. You need a separate control layer to enforce that boundary.
nezhar 10 hours ago [-]
You design the sandbox so the agent starts in that layer. The next thing you can do is to limit the network access, this is what I'm working on right now.
Or do you mean something else?
threethirtytwo 3 hours ago [-]
I don't want this that bad. I want the agent to have open access to my system because it actually does important administrative things for me. It is THAT convenient and powerful.
Here's what I want: REALTIME OBSERVABILITY/POWERPOINT.
I don't want to just see what command it ran. I need graphics... what part of the file system it is touching, what network entities it is contacting. If it's running SQL I want the parsed query handed to me in a syntax highlighted and well formatted interface. Imagine that star trek computer presenting automated infographics while someone is doing a presentation, you know what I'm talking about? It's like a automated powerpoint as the agent does it's thing.
I need to understand my agent and what it typically does so I can dangerously wield it. I treat the agent like a gun in a live shooting scenario. That's how I want to use the LLM.
Sandboxes have their purpose. Just like how shooting ranges have their purposes. But I need to fire my gun in the real world and real world is a warzone.
Not sure what you mean by "just". Containerisation is generally understood to mean something like what Docker does, which includes sandboxing but a whole lot more on top, like image management etc. Bubblewrap is just sandboxing without the rest of containerisation.
mihaelm 8 hours ago [-]
Docker Sandboxes is using microVMs, not containerization.
weebull 8 hours ago [-]
...or...just hear me out now...we could limit it in the harness.
Don't give it shell access, just predefined tools.
mikesir87 1 hours ago [-]
Disclaimer - on the Docker DevRel team
One of the demos I run is how easy it is to circumvent the harness limits. For example, I can configure a harness not to access file `secrets.txt`. But, then I can immediately have it create a Python file that can read any file and have it read `secrets.txt`.
At the end of the day, "please" isn't security. You want to know that the agent can only do and access the things it should access.
killerstorm 8 hours ago [-]
What if it puts malicious code into test file and you allow `npm run test `?
quantumwoke 6 hours ago [-]
Just a small meta note: most of the comments in this thread appear to be posting their own codebase (typically AI-generated) that accomplishes the same goal. It's interesting that this problem is simultaneously in high demand and yet considered trivial enough to vibe code per-user solutions to it.
cryptoz 10 hours ago [-]
The linked page implies there is no linux support, I wonder why. It's there in the docs if you hunt for it.
Customize the exact environment of your container from the ground up (harnesses, tools, base image, packages, mounts, etc) and enter with a single command.
One correction: this isn't containers. Each session is a microVM with its own kernel on the platform's native hypervisor: Hypervisor.framework, WHP, KVM. We wrote a new VMM (not Firecracker) to make it more effective across platforms.
Explained a bit more here about the architecture and why those choices were made: https://www.docker.com/blog/why-microvms-the-architecture-be...
Recently I've also been working on a VM stack for an agentic platform using pre-build images with some cloud injection scripts that simplifies the deployment of a private agentic cluster - in the end I went with full VM with a 4vCpu/8gb for the main agent and 2vCPU/4Gb - only the main agent had docker-in-docker, the rest rootless docker but I agree it's still an elevated risk.
I'll definitely have to give this a spin and see if I can simplify it to one larger box with this solution.
For the people upthread who asked about on customization: templates (like snapshotting a running sandbox) and kits (YAML applied at creation like install steps, files, network and credential rules, or define a new agent outright) are the supported path now. It's early but take a look here: https://docs.docker.com/ai/sandboxes/customize/
On MCP, since credential handling was mentioned here: the sandbox sees one gateway endpoint, and OAuth tokens stay in the host credential store rather than in the VM. https://docs.docker.com/ai/sandboxes/mcp-gateway/
All this is early. We're looking at more based on feedback from users like running sandboxes in the background for long-horizon work and a lot more (including what you all raised in the thread here). Keep them coming.
Brew is notoriously developer-unfriendly.
Is this open source? Can I install this on a non Ubuntu system?
See repo `docker/sbx-releases`. The `.rpm` there has Rocky Linux in the name but works on Fedora.
I run it with superset and then each git worktree is mounted in a sandbox that is configured for each repo i work in.
Closest open source I have seen is https://earendil-works.github.io/gondolin but the DX is not as polished. https://exe.dev/ would be perfect but it does not come with outbound firewall.
Does anyone have a better alternative?
https://github.com/kstenerud/yoloai
Outbound firewall is `--network-isolated`: egress is denied except the agent's own API endpoints plus domains you allow, enforced sandbox-side (working on host-side enforcement now). `--network-none` if you want nothing.
Credential brokering works the way you describe (currently Claude-only, I'll add more as time allows). The API key stays on the host, a local proxy injects it into the outbound request, and the sandbox never holds anything worth stealing. Other agents' credentials currently arrive as read-only file mounts instead (weaker, and something I'll fix soon). Generalising the injector is the obvious next thing.
One difference from your setup: yoloAI copies your worktree instead of mounting it. The agent works on the copy, you `yoloai diff`, and `yoloai apply` replays the commits into your real repo. That's deliberate. Docker's own security docs talk about the dangers of bombs being left behind in a live-mounted dir (git hooks, package.json scripts, Makefiles, IDE task config), which diff/apply avoids.
Isolation is per-sandbox rather than fixed: runc, gVisor, or Kata VMs (QEMU or Firecracker) on Linux; Seatbelt or full macOS VMs via Tart on a Mac.
Cloudflare/artifact-fs does lazy shallow git clones with a FUSE filesystem. https://github.com/cloudflare/artifact-fs
Would that be faster?
Re: sandboxing methods like Clawk, Amla sandbox, bwrap, agentvm, ARM64 MTE with wasmtime-mte: https://news.ycombinator.com/item?id=48893850
A few months ago now I started adding seccomp sandboxing to jinja2rs and then liboverlayfs support to ansiblers (which are early Rust ports).
Haven't finished that, but I started working on a VM format that stores signed machine state into an OCI container repository, using the hypervisor migration support of KVM/QEMU.
Though this is not safe yet if ever, VM migrations are probably another way to sandbox and deploy en masse.
I'm using it as my main driver since months.
Support for running agent harnesses in unprivileged podman containers is on my feature list. :-)
Only real alternative is to use microvms. My goto solution for this are apple/containers.
For the vast majority of developers, containers are enough, which is why they are ubiquitous while vms are less common. Ofc that ubiquity has led to lazy configuration, which is how the jailbreaking can occur. Knowing what you are doing with containers is a requirement to use containers as an AI sandbox.
Why microVMs? I never ever run a container, AI harness or other, in something else than a full on VM. I could use a microVM but in any case I really don't see why I'd run a container on one of my bare metal OS: the place of a container is inside a VM (or microVM).
Especially for AI harnesses where the threat of an escape is very real: the more defense in depth, the better.
And If I can use rootless Podman instead of "rootfull" Docker, the better. Most of my containers are Podman btw.
> My goto solution for this are apple/containers.
To each his own: my goto solution is an actual server on my LAN with shitload of cores and memory and plenty of scripts to provision VMs etc.
I really don't understand why people are YOLO'ing containers on their bare metal OS.
You know about the people who do not bother with the container? Quite a few make “No problem so far” comments on HN discussions.
Mine uses containers, and makes only the git/jj workspace read/write, hiding all credentials that are in my home dir.
It has network filtering + placeholders for secrets.
OSS, no logins needed
(Not affiliated with them, just tried it out last week.)
Documention at this moment in an early stage.
Overall, its a great project but for me was simpler just use Virtual Machine Manager (libvirt GUI).
I wish all luck to the maintainers, but probably DX-wise I will prefer to have more granular or predictable controls (eg micro cloud from Canonical).
We run cloud sandboxes, and have some experimental local sandbox support that is fully OSS.
Main thing for amika.dev is you can control the sandboxes and agents interchangeabley by SSH, web, or API, and can expose the services the agent is working on over signed URLs
Entire sandbox config is a TOML file
We're going to improve the local OSS sandbox mode and add better network controls over the next couple weeks.
Ultimately, what we're building kind of like if Tailscale and Firecracker had a baby, with a messaging protocol for remote controlling any sandboxed agent
It's free to try out. Still a lot to build, so we really appreciate any and all feedback about what we should focus on
It also provides a nice TUI for network policy management and prebuilt sandboxes which have claude code, codex, etc.
https://github.com/NVIDIA/openshell
Has egress and ingress filtering, egress can be bound to host/internet/subnet or even better to internal apps (which are each separate netns) meaning you can do your own firewall/vpn/whatever per sandbox. Plus you control what other components in the sandbox env the app can communicate with.
Really not built for day-to-day dev work though, more like automating your company/life / getting rid of SaaS (e.g. for technical Founders / Sales etc, not exactly useful for dev work)
I have a dedicated container for that. It can run its own Docker daemon and other system services if needed.
Apart from the Claude login token, it has no SSH keys or other credentials. I push everything I need to it from the local machine. And I pull the Claude generated outputs from it.
Of course, this kind of setup requires a stack which can run or at least be tested without any credentials.
What I don‘t have compared to sbx is an outbound firewall, but my VM does not have any personal/interesting data, only a vanilla Fedora installation and the project dir with open source code, so I do not care much about exfiltration.
https://GitHub.com/jgbrwn/vibebin
Internally uses a single VM + Incus containers, supports docker/Kubernetes in each sandbox, has integrated worktree management.
thanks
So I wrote a wrapper around Gondolin which allows me to do that and a few other things: https://github.com/codethief/tuor
(Warning: Still very much experimental / underdocumented.)
The definition for your cloud sandboxes is just a TOML config in your repo
We also have an API and CLI to let users message the agent from outside or across sandboxes
We're still building a lot, so if you have any time to try it out (amika.dev) and give feedback, that is worth gold to us!
It seems with gondoling i need to explain the agent to run commands in the sandbox, but then where does the agent run itself?
[0]: https://earendil-works.github.io/gondolin/workloads/
Their example implementation with pi uses a pi extension so that pi runs on the host but the read/write/bash/etc tools run in the guest. Doesn’t have to be that way though.
And that's just an easy case - really if it has any network access at all it can come up with a clever way to route a request through the network such that the key comes back somewhere in the request. If you scan for it inbound too, the machine can obfuscate it.
Our agents are trained to be so intensely helpful and they have such intricate knowledge of how things work that they will do some incredibly clever tricks to do what you ask them to do.
edit: You may want to look into tokenizing proxies as the general application of this concept.
There's also an ability to create kits where you can setup credential injection into other services as well.
https://github.com/pjlsergeant/byre -- slightly different security model, but lazer-focused on developer experience; my daily driver and I love it not just because I wrote it. The TUI is great for configuring and setting up instant boxes just how you want
https://pleasedonotescape.com/ -- a list of every other agent jail I could find, filterable by open-source and whatever else you want
Basically, it's a plain QEMU/KVM VM on a stock Debian cloud image: device model stripped down to a virtio disk, a virtio NIC and a serial console, nested virt off, no passwordless sudo in the guest. It also ships a containment check that scans outward from inside the guest, so the network boundary is something you can verify.
Wrapping the whole environment rather than a single agent session puts supply chain attacks inside the boundary too. A poisoned npm or PyPI package, or a compromised editor extension, lands in the VM instead of on the host. That was the original reason I set this up; agents just made it more urgent.
There's no per-domain egress allowlist; the policy is "internet yes, private addresses no". Secret injection isn't built in either, though Infisical's agent-vault on the host as an egress proxy covers that part.
Wrote the whole setup up here, in case it's useful:
https://karamatli.com/posts/network-isolated-kvm-sandbox-ai-...
> So rather than pick one, this post advocates layering both, in the spirit of defense in depth: a sandbox VM wraps your containers along with the whole toolchain, and that sandbox reaches the internet but has no route to anything private.
Yup it's the only proper way.
And that is true not just for AI harnesses/agents (that shall try to escape), but also for stuff like Plex/Jellyfin/Immich/private pastebin etc.
If you care about security, there really simply is zero reason to run containers on the bare metal.
I find solutions like this to be a like trying to patch a leaking boat on a lake with duct tape. It will help, but it's not a proper solution.
Also, often the tasks you want the AI to perform are in the outside world. Like "connect to my servers, and figure out X and Y".
The proper way is permission isolation. I run a small k8 cluster in the homelab and I have 3 types of pod/agent combinations for my AI agents. Read only, one that can change my gitops but it needs to create PRs that admin approves, and admin.
Likewise with code. I have a forgejo git instance where agents have ability to create feature branches and so on, but merging is gated.
Those things require "GH enterprise features".
In fact more and more things we do at home will require "enterprise features". Why? Because a person with AI is basically a small team, but some of team members behave like Chimps on crack... So security must be top notch.
I don't think "proper" permissions are possible without dramatically limiting the way people use these tools.
What's a "microVM" and what's the security model here compared to using real virtual machines with actual constraints on breakouts?
Is it marketing fluff?
Incus/LXD has had VM's for a long time now.
Firecracker is designed to start a VM in under 125ms and 5MB. Netbsd advertises that you can direct-boot a MICROVM kernel configuration in under 10ms.
https://en.wikipedia.org/wiki/Memory_ballooning
There is a need for a Docker desktop like GUI for this market.
The world didn't fit around me, so I made "me" fit around "the world". I bet those stubborn dinosaurs can learn a new trick or two also, if management lets them do it during working ours...
Also, WSL (Windows Subsystem for Linux) has been baked into Windows for a long time and makes it very easy to play with Linux, as does using the Hyper-V VM system. Any developer unfamiliar with Linux because they use Windows, has little excuse.
Modern .NET did not went cross platform by accident, and Java development has always been "develop on Windows deploy on UNIX", in corporations where Mac tends to have little presence.
I use something in between - a single Ubuntu VM, into which I spawn multiple Incus LXC containers for the agents. The containers only use 50 MB or so per instance (separate systemd, ...). This way I pay the VM RAM tax only once, and the agents are still contained inside the VM if they manage to escape the LXC containers.
This way I don't pay tens of VMs "tax" but basically only three (plus one or two VMs I use for testing enhancements to my VMs provisioning / optimization / securing setup, when I work on that).
I don't use LXC (I could) but regular containers, inside VMs.
I'll look into the stripped down "micro" VMs but then I don't spend my days launching VMs/shutting them down so it's not a big deal.
(it's in the doc, but kinda strange to not see some instructions on the main page, probably distro related)
https://github.com/swelljoe/flar
I’ve been using this pretty extensively for a few months on Mac and Linux and have been super happy with it.
> That runs the codex OCI in a qemu microvm.
AFAIU it's actually the other way around: krun spawns a libkrun-based (not QEMU-based) VM inside a crun container. Source: https://github.com/libkrun/libkrun/discussions/538#discussio...
So with your solution you get the additional security benefit of containerizing the hypervisor on the host.
https://docs.docker.com/ai/sandboxes/security/credentials/
Both went through stuff the sandbox was set up to allow.
https://www.mrafayaleem.com/blog/sandboxing-claude-cli-with-...
It blocks network access by default, mounts only what you specify, and you can add a customization layer. This is all done in the container itself (srt for network blocking). It doesn't implement a central point for secret sharing, MCP exposure, etc. So it might not have enough features for some but it works well for my needs.
I just found through this thread yoloai which has an apple container backend, so its quite similar using that. My main issue would be that network access is allowed by default. https://github.com/kstenerud/yoloai
Several other projects listed here use libkrun which is an alternate implementation that works with Mac's HVF. smolvm, microsandbox, podman (with likrun backend), gondolin.
eg: https://josecastillolema.github.io/podman-wasm-libkrun/#libk...
The VM sits on its own libvirt network in a dedicated firewall zone, and specific directories are shared via filesystem passthrough. To keep the agent from accessing anything related to Git, the actual gitdir is stored on a separate path outside the mount point.
I review the git diff manually and commit it from the host.
Then again, I guess GUI is a pain in Docker. I tend to operate through Zed and an ACP harness though, so my GUIs are sort of “inside the container” anyways.
Would suggest Hashicorp Packer or cloud-init for deterministic images, not hard to setup or use. LLM's have little problem with them either I find.
If you need quicker environment rebuilds consider using something smaller like alpine as the base, though once you setup a golden image even heavy things like debian are fine.
Haven't tested it yet, but it seems to address the same issue as Docker Sandboxes, but in a different way.
But it’s not as well sandboxed for sure.
(I'm sure you can spend time to come up with a proper bubblewrap configuration that allows go build to succeed, but it's probably not worth the effort.)
Eg, if used with Colima in macOS, it means I can run a devcontainer in an isolated VM and Nono inside the devcontainer can restrict a lot what can and cannot be done.
You get credentials proxying and network outbound limits.
How is Docker Sandbox better sandboxed?
https://github.com/iodize6399/ai-devcontainer/tree/main/.dev...
I quite like the 'features' layer system, adding extra tools to container in a declarative plugin-like way
Being able to 'safely' run with skip permissions has been a gamechanger
I especially like the firewall it has.
And even if that works, this is a very short list. As soon as you reach for Go, Rust tooling etc nothing works. So you need to manually maintain this list which is nothing but painful trial and error.
All the open GH issues about supporting Linux that I subscribed to have gone unresponded to.
OpenShell looks like a good alternative, but it still has "Do not use in production" plastered all over the website, which doesn't fill me with confidence yet
I wrote a tool to use `bubblewrap` to containerize any agent (at least all the agents I've used a couple of times), and bind mount the system stuff read-only, so the agent has your "usual" environment, but they can only see the project. Their history persists (either through a bind mount or a "shadow" copy of the history that only the wrapped agent sees), the agent can still create and manage containers of its own using podman's rootless mode, etc. It's nearly instant to start because it's just a namespace (plus a few copied files for the container support and session history); no container needs to be built/fetched/updated/whatever. bubblewrap is extremely well-tested as it is used by flatpak and several other large projects, so I trust it quite a bit (more than I trust Docker).
https://github.com/swelljoe/flar
But, Docker is rarely the right way to manage containers on Linux, IMHO.
Regardless, I'm hoping something that isn't behind a login screen is going to win out.
https://github.com/pkhamre/opencode-docker
(I am testing this now as a backend for my pet project which currently supports firecracker and gvisor. No network.)
But, in any case, why put in effort doing something people don't expect or ask for? We can assume everyone running agents is either a) using their own sandbox, or b) doesn't care. I think we can guess which category most people fall into. You could maybe argue about responsibility, but I don't think you can argue about "serious engineering".
Exactly. It's not as though it's difficult. It never occurred to me to not do this from day one, and it astonishes me that anyone runs this stuff bare metal. Since then, I've brought several other people on board, and that's all they've ever seen: I don't think they'd know how to run outside a sandbox, and that's just fine.
It goes like this: - bash script parser + interpreter (with hooks for things like file open, execute etc.,) - wasm executor for execution. - wasm implementations of common tools like coreutils, grep, sed etc., from the uutils project. - wasm implementation of python by a VMware backed project. - entirely virtualized filesystem using Go's io/fs.FS. (tmp dirs can be implemented using any backend)
Works like a charm for the limited usecase I have. There are definitely some drawbacks with threading and especially with preopens in wasm. But a cheap sandbox for simple file explorations and minimal computations.
Holy moly, on mobile I was trying to read the example console screenshots/snippets and then it would just unexpectedly change. Took me a little while to figure out it’s some kind of carousel for the examples, and not more screenshots/snippets loading and pushing down content (or me going crazy). Please don’t do this on mobile sites, just let me scroll through the examples!
Also if your thing doesn't work with `pi` out of the box, then low effort
{ "allowedHosts": [ ".anthropic.com", ".claude.com", ".pi.dev", "npm.org", ".npmjs.org", ".github.com", ".githubusercontent.com", ".pypi.org", ".pythonhosted.org" ], "baseImage": "docker.io\/library\/node:22", "displayName": "Pi", "environmentVariables": [ "IS_SANDBOX=1" ], "installCommands": [ "npm install -g --ignore-scripts @earendil-works/pi-coding-agent", "npm install -g global-agent" ], "launchCommand": [ "pi" ], "mounts": [ { "containerPath": "\/root\/.pi", "hostPath": "~\/.pi", "readOnly": false } ] }⏎
I was all in on sandboxes and safehouse for my agents but the moment I got into iOS development it felt like my hand was forced to just run Claude / codex / pi directly on my machine because nothing else could do the dev loop.
It’s been a painful reality for me, I’m going against core pieces of how I feel I should be interacting with agent harnesses and yet, I need to get the work done so
1) Enable the xcode mcp server: https://developer.apple.com/documentation/xcode/giving-exter... 2) Add the xcode mcp server to sbx: `sbx mcp add xcode --command xcrun --args mcpbridge` 3) When you create the sandbox, use `--static-mcp xcode`. For example: `sbx create --static-mcp xcode claude .`
Make sure you have at least v0.38.0 of sbx. This makes a bridge from inside the sandbox to the xcode tools on your host, so be aware that it can run whatever tools you give it on the host. But the agent itself is still sandboxed.
But sbx is a bit annoying to use with OpenCode for instance (which has zero sandboxing by default, unlike codex CLI or Claude Code). You cannot easily change ~/.config/opencode/opencode.jsonc AFAIK.
[0]: Black Hat OpenAI-Hugging Face incident: https://www.youtube.com/watch?v=87DyyMV0kCY&t=1021s
My startup (https://github.com/gofixpoint/amika) copies agent configs into local or cloud sandboxes
We run OpenCode currently, but need to improve the setup for users, so would like understand more of the issues you have sandboxing it, if you can share
Still obviously you should run all untrusted code in a sandbox, but extreme actions like that would be very unusual with the model that shipped.
For clarity I’m actually using podman, not Docker.
Now I'm curious to know how hardened the Docket Sandbox orchestration interface is. I guess we can assume they have run Mythos against it for a few weeks maybe? It's unclear.
Unless we're talking 0-day/CVE, running an unprivileged container is as trustable as a VM. The only difference is how strictly you want to hold the memory/CPU bar. Infact on linux, containers are more lightweight than VMs.
So yeah, not "vulnerable".
Containers have access to the kernel ABI, and as shown in the latest kernel exploits, all the memory handling surface that exposes. The virtualisation interface, offering fewer services, is significantly harder.
Containers are obviously lighter than VMs, both to start and to schedule, but firecracker is pretty fast. gVisor pays overhead per syscall vs at startup.
So yeah, more vulnerable.
On Linux, you can run docker directly on the host, but you can also very easily setup a vm with incus and run docker from there.
Though, they need to remove the login requirement.
Still early and the local sandboxes are experimental right now
https://github.com/gofixpoint/amika
cgroups are a mechanism designed for hierarchical organization and resource distribution. Against a malicious and capable actor, and that is how we have to treat AI agents, cgroups will not withstand.
Also, the kernal is an interface too big for what an AI agent needs and is therefore offering a gigantic attack surface completely unnecessarily.
This is not my main point though. Both are based on cgroups and cgroups are the wrong tool for the job.
The same is not applicable for any kind of sandboxing for two reasons:
1. The boundary is in the kernal’s own code, enforced by the thing you are trying to be protected from. -> Use a VM
2. The kernal is a gigantic attack surface -> Use gVisor
[1] https://docs.cloud.google.com/kubernetes-engine/docs/resourc...
Say I want to use pi inside a container. If I wrap pi within a bubblewrap or within nono, how is that less secure than using a vm?
Also, I think most people run containers inside VMs anyway and not directly on their hosts (on Mac and windows you have to use a vm anyway).
It doesn’t change the fact a malicious process is still attacking the same kernel , but it can reduce what it can do to that vm.
Example: sbx run claude ./ ../another-project:ro
Automating browsers with LLM agents properly requires a lot more work than Process.Start into powershell, but the advantages can be immense once you have achieved integration this way. Incrementally maintaining this integration is generally easy because human users cannot tolerate rapid changes either.
It's a hell of a lot easier to convince management to adopt a robot that looks and acts like a human employee than one that looks like a combine harvester. The combine is far more efficient, but it is also totally indiscriminate. Nothing constrains its appetite except for the invisible fence imposed by GPS. The amount of infrastructure required to keep farm equipment from running astray is incredible. In the context of agriculture, the added complexity is definitely worth it. We don't want to have to recreate the same thing with our technology if it can be avoided. Sandboxes and security isolation boundaries are not things to aspire to. These are costs to be paid for admission to something more valuable.
One other thing, I want to be able to handle multiple repos in the same sandbox and have a standard workflow around worktrees (one worktree per repo, all the worktree mounted in the VM).
These were some of the reasons that led me to build: Clawk - https://github.com/clawkwork/clawk
I've been using sbx for a bit now, and there have been some old versions that had this problem, but haven't had this problem in a while when using secrets https://docs.docker.com/ai/sandboxes/get-started/#authentica...
https://apps.apple.com/app/aifcc-ai-first-computer/id6782364...
als has lots of agents + and typical dev packages (node tooling, python tooling, ....) preinstalled
There is no reason to require a login for creating local mini sandboxes.
If you’re on Apple, native solutions like “container-machine init” come built in and are pretty good, if you’ll only be on Apple hardware.
There are many better namespace/container based options, VMs may be moderately more secure but when you more or less trust your agent and code you can do with lesser containment. And with the recent CVEs in kvm honestly there isn't a huge deal of difference vs namespaces.
(I'm building https://xbin.dev/ for some time now for managing my personal code/apps, a project which started specifically after Docker Sandboxes broke on me some time ago)
'su agent'
'curl domain/install.sh | sh'
'runagent'
On another topic, can't help but notice that "leading coding agents" somehow does not include Pi.
To work around that limitation I came up with this https://github.com/shaftoe/sbx-template-pi
So essentially you can get latest Pi/Node pulling from that image:
`sbx run -t ghcr.io/shaftoe/sbx-template-pi:latest shell`
Like others here I'm also saddened by the login requirement but at the moment this is the best UX I could find for running sandboxed agents, the "kit/mixin" concepts are neat and I make use of them too: https://github.com/shaftoe/sbx-template-pi#stacking-the-extr...
Like:
$ podman run -it --rm -v .:/workspace local-dev-ia /usr/bin/oc
Configured with a .env file. Hope to do it hopefully before the end of the week.
This is nowhere near "exactly this". Docker Sandboxes uses micro VMs, you just use regular containers which have completely different security properties.
Docker is always a pain to use and this way I don't have to re-install everything a billion times for every different project.
Currently, I don't allow the agent access to docker, start docker myself, and then do short-lived sandbox-free sessions when the agent needs to do things that interact directly with docker; but that's annoying.
Ideally, they should run in _different_ sandboxes.
The environment might corrode the harness (e.g. rogue npm/pip packet would manipulate agent harness config).
As for Docker Sandboxes, I'll just ask Sol literally right now to see what it does better than my virtdev, and then I'll improve virtdev instead of using Docker.
Just the general knowledge that sharing a kernel with untrusted software is too dangerous, that hardware virtualization is an infinitely smaller attack surface and that the entire industry will be in deep shit if people or AI breaks hypervisors.
Initial threat model was supply chain attacks but eventually grew to include AI harnesses as well. Not very worried about them hacking me, more about accident prevention.
So that means each VM must be running a completely independent kernel that's fully isolated from the host's file system. They must also have fail closed network filtering built in.
> Anything you can point the rest of us to?
I have published my virtdev's design document.
https://github.com/matheusmoreira/virtdev/blob/master/DESIGN...
Yes, it is AI generated.
In summary, it's a QEMU VM orchestrator with a base OS image and project specific delta images. VM lifecycle is managed by systemd. System level isolation is already pretty good and it already solves the "AI wiped out my $HOME" problem. I'm currently working on a custom network stack to replace the nftables based firewall.
And of course, instead of doing the "copy in > copy out" process manually, get your local agent to write a bash script that does that for you, given what directory you're in, and you're basically G2G.
Start by mounting just your repo and passing in the keys for the agent. Take it from there, it's like software engineering, you iterate.
When you run into issues you expand the tools in the container available to it.
Maybe we should just ssh into separate development machines to ensure real and verifiable sandboxing? (as was totally standard before Docker became a thing)
I use it regularly to run Claude/Codex with permission checks disabled.
https://github.com/cvhariharan/mvm
Better sandboxing for AI agents is exactly the main reason for containers improvements on macOS and Windows, with a few talks at WWDC, and BUILD.
Not sure how much they would get from Linux users then.
The option left is to use SSH to sign commits which is a no-go for a different reason.
Yes, you can inject tokens via a proxy. What else is new?
I have skimmed alternatives offered in comments to this post (vibepod-cli, code-on-incus, opencode-docker, sandboxy, smolvm, amazing-sandbox) and none of them seem to do credentials injection at the proxy level.
Also fnox now does credentials proxying.
For those who do not trust
AND do not want to use some other, free VM for some reason?container run --rm -it -v "$(pwd)":/work -w /work myaiimage /bin/bash
Other than the login problem, it’s a decent option.
https://engine.build/lab/agent-sandboxes
The open source section specifically.
Or do you mean something else?
Here's what I want: REALTIME OBSERVABILITY/POWERPOINT.
I don't want to just see what command it ran. I need graphics... what part of the file system it is touching, what network entities it is contacting. If it's running SQL I want the parsed query handed to me in a syntax highlighted and well formatted interface. Imagine that star trek computer presenting automated infographics while someone is doing a presentation, you know what I'm talking about? It's like a automated powerpoint as the agent does it's thing.
I need to understand my agent and what it typically does so I can dangerously wield it. I treat the agent like a gun in a live shooting scenario. That's how I want to use the LLM.
Sandboxes have their purpose. Just like how shooting ranges have their purposes. But I need to fire my gun in the real world and real world is a warzone.
Don't give it shell access, just predefined tools.
One of the demos I run is how easy it is to circumvent the harness limits. For example, I can configure a harness not to access file `secrets.txt`. But, then I can immediately have it create a Python file that can read any file and have it read `secrets.txt`.
At the end of the day, "please" isn't security. You want to know that the agent can only do and access the things it should access.
The other url is their marketing page.
Yes, Linux is supported.
[1] https://github.com/apple/container