Show HN: I Built a Sandbox for Agents

using sandboxes makes a lot of sense now a days, but this is nowhere near the prod sandboxes the market has, they have a lot of work and optimizations going on! but yeah its little fun side project! thanks for the compliments :)

canadiantim• 6 months ago

This relies on the agent requesting a sandbox... which seems like the fox guarding the hen house, no?

vrn2114• 6 months ago

tbh, this is kind of a gray area, i should have thought little bit more on how it should have been architectured,

for me this was the ideal scenario: a cloud model on web with its own sandbox (something like claude with read/write to files and run commands)

i dont really think this could be considered as a fox guarding the hen house, its not that ai wants to infect your computer with its commands, if ai is provided the mcp server, it will it instead of using the tools like bash in most cases [if in a local setup]. I feel its more of a lumberjack guarding his weapons.

monomial• 6 months ago

Is this a common pattern to have an agent request a sandbox? I feel like I'd want the whole agent running in it's own sandbox to begin with. Firecracker does look like a decent solution for that.

mccraveiro• 6 months ago

I agree. I'm testing https://sprites.dev/ because of that.

vrn2114• 6 months ago

When I started to design the system, I thought of creating a way for an agent on the cloud to have access to a filesystem, such that they can read, write files and run commands. I can't really say that the startups in the space's main source of income is this, most of them rely on sdks for other platforms. I could adjust the core to work as a sdk as well, but right now the main interface is just a mcp server that a client can use

cr125rider• 6 months ago

Is firecracker instead of a docker container worth the hassle?

kernc• 6 months ago

Probably not. Maybe Bubblewrap and sandbox-run. It's an anything-is-already-way-better-than-nothing type of thing.

[0] https://github.com/containers/bubblewrap

[1] https://github.com/sandbox-utils/sandbox-run

sahiljagtapyc• 6 months ago

interesting

debarshri3• 6 months ago

Can someone elaborate with whats wrong with having containers for sandbox?

binsquare6• 6 months ago

It's because containers share the kernel with the host. Generally it's just not considered a security boundary. (Note that containers have come a longer way in the security side btw)

So it's a mostly security thing.

debarshri3• 6 months ago

But in the context of agents. Does it matter?

ATechGuy2• 6 months ago

What about VMs? They offer strong isolation, as they don't share kernels, and have long been a foundational piece for multi-tenant computing. Then, why would we put an extra layer on top and rebrand it as an AI agent sandboxing solution? I'm genuinely curious what pushes everyone to build their own and launch here Is it one of those tarpit ideas: driven by own need and easy to build?

Ronsenshi• 6 months ago

From what I read others say at some point on HN:

- resources

- security

- setup speed?

I suppose a lot depends on how and in what environment you're dealing with agents.

Resources might be an issue on Mac if you have bunch of agents running different things, trying to execute code in different containers. But that's the issue of Mac and the way containers are running in a VM there.

Security-wise there were concerns with prompt injection telling agent to execute certain steps to escape from container. Possible, but I'm not aware if there were actually cases of that.

vrn2114• 6 months ago

Luis wrote an excellent blog about it btw: https://www.luiscardoso.dev/blog/sandboxes-for-ai

tomasphan• 6 months ago

Seems these thing pop up here ever so often. Either using firecracker or docker/containers. How is this different from the other sandboxes? BTW I love that you got LLM testimonials lol

binsquare6• 6 months ago

I'm building an alternative to firecracker here if you're looking for something wayy different: https://github.com/smol-machines/smolvm

aghilmort5• 6 months ago

we've considered docker, firecracker, will add smol to working roster

context <> building something with QEMU

* required has to support LMW+AI (linux/mac/windows + android/ios)

there are scenarios in which we might spin micro vms inside that main vm, which by default is almost always Debian Linux distro with high probability.

one scenario is say ETL vm and AI vm isolated for various things

curious why building another microVM other than sheer joy of building, what smol does better or different, why use smol, etc. (microVMs to avoid etc also fair game :)

binsquare6• 6 months ago

Cool option, I'm building in the same space. We should chat!

vrn2114• 6 months ago

hi, you could find my socials at https://vrn21.com, feel free to dm :)

avaer• 6 months ago

Given that this is using Firecracker, is it Linux only?

vrn2114• 6 months ago

yes, it is supposed to be hosted on bare metal linux machines; anyone on any machine can use it as a sandbox after adding the mcp server to the client

coip• 6 months ago

Anyone have any thoughts on this path if using macOS? Been using it, seems to do the trick pretty well out of the box.

https://developer.apple.com/documentation/Virtualization/run...

vrn2114• 6 months ago

i think https://github.com/trycua/cua has some sort of it working

aghilmort5• 6 months ago

interesting is the idea the agent calls it or just alt to terminal bash etc tool calls hey your tool calls are all microvms, containers, isoshells, raw term, clawd/molt all credentials with weaker and weaker security demarcs?

vrn2114• 6 months ago

my ideal scenario is a cloud web model getting access to a sandbox to run commands and read/write to files. but yeah it could be used as an alternative to bash and read write tools.

I did not get your second question exactly, but yeah microvms can be considered one of the secure ways to run your agent

aghilmort5• 6 months ago

Basically, just thinking that it’s more ideal to have the tool call the micro VM versus the agent, doing it in the sense of its mandated by the tool call

FEELmyAGI• 6 months ago

Great idea that is already implemented as a feature by major AI providers, several well funded startups, countless unfunded startups, and trivially solved per-user with any handful of existing technologies.

Truly baffling its in the top 5 of the front page. My first thought was bot army upvoting but the total points are quite low. That means this is some mod's personal idea of an especially interesting submission?

arscan• 6 months ago

Having testimonials attributed to Gemini 3 Pro and Claude 4.5 Opus is... interesting. I'm curious what prompt was used to get those quotes.

vrn2114• 6 months ago

lol thanks for the compliments, generated both the testimonials after giving the mcp server to both opus and gemini and asked their feedback on it.

it is supposed to be directly used by agents, so they are kind of my end users, hence it made sense to get their testimonials :)

ATechGuy2• 6 months ago

Congrats on launching, and great testimonials!

What problem does it solve compared to bazillion code execution sandboxing agents (and containers/VMs)?

Overall, a lot of people are building their own code execution sandboxing agents around containers/VMs. Curious to know what's missing that makes people DIY this?

Here's my list of code execution sandboxing agents launched in the last year alone:

1. E2B 2. AIO Sandbox 3. Sandboxer 4. AgentSphere 5. Yolobox 6. Exe.dev 7. yolo-cage 8. SkillFS ERA Jazzberry Computer Vibekit Daytona Modal Cognitora YepCode Run Compute CLI Fence Landrun Sprites pctx-sandbox pctx Sandbox Agent SDK Lima-devbox OpenServ Browser Agent Playground Flintlock Agent Quickstart Bouvet Sandbox Arrakis Cellmate (ceLLMate) AgentFence Tasker

vrn2114• 6 months ago

Thanks for the compliments! I can't really say that it has a unique differentiator between all the other sandboxes out in the market, this was supposed to be a poc version on how i could be building a sandbox for agents, this had been haunting me since a few months, tried out what could happen!

the actual sandboxes in the market are doing a lot of work in optimizing the system end to end, and most of it is pretty hard. this project just scratches the surface

vrn2114• 6 months ago

yes this is pretty busy market, but it is just pure infra/OS problem and many of it has already been solved in the past decades, right now its just who can fit everything together fastest

nadis3• 6 months ago

Getting a 404 page not found for this project - how can I try it?

vrn2114• 6 months ago

Sorry about the link, here's the og link: https://github.com/vrn21/bouvet/

nadis3• 6 months ago

Thanks!

vrn2114• 6 months ago

Sorry for the issue with the link, the accurate link is: https://github.com/vrn21/bouvet

cadamsdotcom• 6 months ago

You built a voluntary sandbox and it also uses lots of tokens in the context to load in the MCP definition?

Just looking to understand if the sandbox can be bypassed?

Show HN: I Built a Sandbox for Agents

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