Running Claude Code dangerously (safely)

(blog.emilburzo.com)

130 points | by emilburzo 3 hours ago

36 comments

  • Strongbad536 0 minutes ago
    i've low-key been running claude in dangerously skip permissions mode for at least like 4 months now and have yet to be bitten by a truly destructive action. YMMV but i think as long as you're guiding/prompting correctly, and don't just allow write access to your prod account DBs willy nilly, it's mostly fine. just keep an eye on it :shrug:
  • woof 1 minute ago
    sandbox-exec on MacOS (ie. https://github.com/neko-kai/claude-code-sandbox) seems like the perfect solution to me.

    Missing FreeBSD jails in 2026 is kind of weird (hello 1999)...

  • corv 54 minutes ago
    I'm pursuing a different approach: instead of isolating where Claude runs, intercept what it wants to do.

    Shannot[0] captures intent before execution. Scripts run in a PyPy sandbox that intercepts all system calls - commands and file writes get logged but don't happen. You review in a TUI, approve what's safe, then it actually executes.

    The trade-off vs VMs: VMs let Claude do anything in isolation, Shannot lets Claude propose changes to your real system with human approval. Different use cases - VMs for agentic coding, whereas this is for "fix my server" tasks where you want the changes applied but reviewed first.

    There's MCP integration for Claude, remote execution via SSH, checkpoint/rollback for undoing mistakes.

    Feedback greatly appreciated!

    [0] https://github.com/corv89/shannot

    • horsawlarway 14 minutes ago
      I'm struggling to see how this resolves the problem the author has. I still think there's value in this approach, but it feels to be in the same thrust as the built in controls that already exist in claude code.

      The problem with this approach (unless I'm misunderstanding - entirely possible!) is that it still blocks the agent on the first need for approval.

      What I think most folks actually want (or at least what I want) is to allow the agent to explore a space, including exploring possible dead ends that require permissions/access, without stopping until the task is finished.

      So if the agent is trying to "fix a server" it might suggest installing or removing a package. That suggestion blocks future progress.

      Until a human comes in and says "yes - do it" or "no - try X instead" it will sit there doing nothing.

      If instead it can just proceed, observe that the package doesn't resolve the issue, and continue exploring other solutions immediately, you save a whole lot of time.

    • Retr0id 45 minutes ago
      Very clever name!
      • corv 30 minutes ago
        Thank you, good to know it landed :)
  • fwystup 10 minutes ago
    I'm currently building a Docker dev environment for VSCode (github.com/dg1001/xaresaicoder) usable in a browser and hit the same issue. Without docker-in-docker it works well - I even was able to add transparent proxy in the Docker network to restrict outbound traffic and log all LLM calls (pretty nice in order to document your project). For docker-in-docker development and better security isolation, I'm considering Kata Containers instead of Vagrant. Which gives me real VM-level isolation with minimum perf overhead, while still be able to use my docker stuff. Still on my TODO list though. Has anyone actually run Kata with vs code server? Curious about real-world quirks - I've read that storage snapshot performance can be rough.
  • replete 1 hour ago
    It's a practical approach, I used vagrant many years ago mostly successfully. I also explored the docker-in-docker situation recently while working on my own agentic devcontainer[0]- the tradeoffs are quite serious if you are building a secure sandbox! Data exfil is what worries me most, so I spent quite some time figuring out a decent self-contained interactive firewall. From a DX perspective, devcontainer-integrated IDEs are quite a convenient workflow, though docker has its frustrating behaviours

    [0]: https://github.com/replete/agentic-devcontainer

  • azuanrb 1 hour ago
    I just learned that you can run `claude setup-token` to generate a long-lived token. Then you can set it via `CLAUDE_CODE_OAUTH_TOKEN` as a reusable token. Pretty useful when I'm running it in isolated environment.
  • mavam 1 hour ago
    For deploying Claude Code as agent, Cloudflare is also an interesting option.

    I needed a way to run Claude marketplace agents via Discord. Problem: agents can execute code, hit APIs, touch the filesystem—the dangerous stuff. Can't do that in a Worker's 30s timeout.

    Solution: Worker handles Discord protocol (signature verification, deferred response) and queues the task. Cloudflare Sandbox picks it up with a 15min timeout and runs claude --agent plugin:agent in an isolated container. Discord threads store history, so everything stays stateless. Hono for routing.

    This was surprisingly little glue. And the Cloudflare MCP made it a breeze do debug (instead of headbanging against the dashboard). Still working on getting E2E latency down.

    • TheTaytay 26 minutes ago
      This sounds handy! Have you published any code by any chance?
  • raesene9 1 hour ago
    Of course it depends on exactly what you're using Claude Code for, but if your use-case involves cloning repos and then running Claude Code on that repo. I would definitely recommend isolating it (same with other similar tools).

    There's a load of ways that a repository owner can get an LLM agent to execute code on user's machines so not a good plan to let them run on your main laptop/desktop.

    Personally my approach has been put all my agents in a dedicated VM and then provide them a scratch test server with nothing on it, when they need to do something that requires bare metal.

    • intrasight 1 hour ago
      In what situations where it require bare metal?
      • raesene9 1 hour ago
        In my case I was using Claude Code to build a PoC of a firecracker backed virtualization solution, so bare metal was needed for nested virtualization support.
  • smallerfish 1 hour ago
    I've been working on a TUI to make bubblewrap more convenient to use: https://github.com/reubenfirmin/bubblewrap-tui

    I'm working on targeting both the curl|bash pattern and coding agents with this (via smart out of the box profiles). Early stages but functional. Feedback and bug reports would be appreciated.

  • danmaz74 13 minutes ago
    I'm using devcontainers for this, and I'm finding that a very good solution (coupled with VSCode).
  • samlinnfer 2 hours ago
    Here is what I do: run a container in a folder that has my entire dev environment installed. No VMs needed.

    The only access the container has are the folders that are bind mounted from the host’s filesystem. The container gets network access from a transparent proxy.

    https://github.com/dogestreet/dev-container

    Much more usable than setting up a VM and you can share the same desktop environment as the host.

    • phrotoma 1 hour ago
      This works great for naked code, but it kinda becomes a PITA if you want to develop a containerized application. As soon as you ask your agent to start hacking on a dockerfile or some compose files you start needing a bunch of cockeyed hacks to do containers-in-containers. I found it to be much less complicated to just stuff the agent in a full fledged VM with nerdctl and let it rip.
    • sampullman 1 hour ago
      I did this for a while, it's pretty good but I occasionally came across dependencies that were difficult to install in containers, and other minor inconveniences.

      I ended up getting a mini-PC solely dedicated toward running agents in dangerous mode, it's refreshing to not have to think too much about sandboxing.

      • laborcontract 1 hour ago
        I totally agree with you. Running a cheapo mac mini with full permissions with fully tracked code and no other files of importance is so liberating. Pair that with tailscale, and being able to ssh/screen control at any time, as well as access my dev deployments remotely. :chefs kiss:
  • sandGorgon 36 minutes ago
    Or...use wsl2 in windows. does the same thing - much much faster.

    Windows is the best (sandboxed) linux

    • strickjb9 33 minutes ago
      Real question - are you not worried about access to /mnt/c ?
  • bob1029 45 minutes ago
    My approach to safety at the moment is to mostly lean on alignment of the base model. At some point I hope we realize that the effectiveness of an agent is roughly proportional to how much damage it could cause.

    I currently apply the same strategy we use in case of the senior developer or CTO going off the deep end. Snapshots of VMs, PITR for databases and file shares, locked down master branches, etc.

    I wouldn't spend a bunch of energy inventing an entirely new kind of prison for these agents. I would focus on the same mitigation strategies that could address a malicious human developer. Virtual box on a sensitive host another human is using is not how you'd go about it. Giving the developer a cheap cloud VM or physical host they can completely own is more typical. Locking down at the network is one of the simplest and most effective methods.

  • FourSigma 36 minutes ago
    I've been exploring this space. There are some use cases where I'd love to run an isolated Claude agent asynchronously. I think running Docker in rootless mode might solve some of the OP's concerns—I believe Podman does this implicitly. Also, there are tools like Kaniko that does not need Docker to create container images. You can also try changing the underlying container runtime to something like gVisor if you want more security.

    Does anybody have experience using microVMs (Firecracker, Kata Containers, etc.) for this use case? Would love to hear your thoughts.

  • riadsila 1 hour ago
    Koyeb has great resources about running Claude Code in sandboxes: https://www.koyeb.com/tutorials/use-claude-agent-sdk-with-ko...
    • mavam 1 hour ago
      What's the startup latency? How long do I have to wait until Claude is operational?
  • crabmusket 2 hours ago
    What is the consensus on Claude Code's built-in sandboxing?

    https://code.claude.com/docs/en/sandboxing#sandboxing

    > Claude Code includes an intentional escape hatch mechanism that allows commands to run outside the sandbox when necessary. When a command fails due to sandbox restrictions (such as network connectivity issues or incompatible tools), Claude is prompted to analyze the failure and may retry the command with the dangerouslyDisableSandbox parameter.

    The ability for the agent itself to decide to disable the sandbox seems like a flaw. But do I understand correctly that this would cause a pause to ask for the user's approval?

  • loloquwowndueo 2 hours ago
    Shellbox.dev and sprites.dev were discussed recently on hacker news, they give you a sandbox machine where it’s likely safe to run coding agents in dangerous mode. Filesystem checkpoint and restore make it easy to recover from even catastrophic mistakes.
    • gcr 1 hour ago
      What about API calls? What about GitHub trusted CI deploys?

      One frustrating thing about these solutions is that they’re great to prevent Claude from breaking a machine, but there’s no pervasive sandbox for third party services

      • jermaustin1 51 minutes ago
        Rollback? Its the same as all dev work. Use a dev endpoint for APIs, and thankfully git is a great tool to undo fuckups.
      • loloquwowndueo 1 hour ago
        What about them?
  • clbrmbr 2 hours ago
    I have been running two or three Claude’s bare metal with dangerously skip permissions all day every day for two months now. It’s absolutely liberating.
    • Gazoche 1 hour ago
      Until it decides to delete your home directory:https://old.reddit.com/r/ClaudeAI/comments/1pgxckk/claude_cl...
      • giancarlostoro 6 minutes ago
        This could be avoided by aliasing rm to something else that stops you from deleting stupid things like your entire home directory / partition root.
      • pixl97 1 hour ago
        You're not running it on a filesystem that takes snapshots and is easily reversible?
        • giancarlostoro 9 minutes ago
          Many moons ago, I accidentally rm -rf'd the wrong directory with all my code inside poof, gone. I still had PyCharm open, I checked its built-in version tracker and lo and behold, my code as it was before I rm -rf'ed up my code. I believe Claude has ways to undo file changes, but something like rm is just outside of its scope.
        • coldtea 1 hour ago
          All 1 of them?
      • esperent 1 hour ago
        You can use the /hookify plugin to add hooks for preventing dangerous commands like this.
        • Gazoche 1 hour ago
          https://github.com/anthropics/claude-code/tree/main/plugins/...

          So it's basically adding "don't delete my files pretty please" to the prompt?

          EDIT: I misread, the natural language description of the rule is just a shortcut to generate the actual rule which is based on regexp patterns.

          Still, it only protects you against very specific commands. Won't help you if the LLM decides to fill your disk with `cat /dev/urandom > foo` for example.

          • simianwords 47 minutes ago
            it may not protect against an adversarial llm
    • croes 1 hour ago
      I have been driving without seat belt for two month now. It’s absolutely liberating.
    • coldtea 1 hour ago
      And that's as a dev. Then we expect uses to know better than e.g. to trust links to .sh style installers some FOSS suggests...
    • sixhobbits 1 hour ago
      same, it's made a couple of damaging mistakes but so far it has a better track record than me in terms of fat-fingering `rm` commands or what have you
  • csantini 47 minutes ago
    Just create a new user and setup pip/npm to install locally.

    And setup an .env for the project with user/password to access only a dev database.

  • tradziej 2 hours ago
  • denysvitali 1 hour ago
    Here's what I do (shameless plug): https://blog.denv.it/posts/im-happy-engineer-now/

    This allows you to use Claude Code from your mobile device, in a safe environment (restricted Kubernetes pod)

    • jeffrallen 1 hour ago
      Here's what I do (shameless plug, not an employee, just a satisfied user): https://exe.dev
      • denysvitali 1 hour ago
        Yes, this approach also looked nice! Maybe you can pair both (happy + exe.dev) for best results
  • mhb 49 minutes ago
    Forgive a naive question, but why not run it on an AWS (or equivalent) instance?
  • frankc 1 hour ago
    I think this makes sense but I wonder if firecracker would work better than vagrant for this? I haven't used it before, though. I guess it might if you are trying to run gas town level orchestration.
    • raesene9 1 hour ago
      Firecracker can solve the kind of problems where you want more isolation than Docker provides, and it's pretty performant.

      There's not a tonne of tooling for that use case now, although it's not too hard to put together I vibe-coded something that works for my use case fairly quickly (CC + Opus 4.5 seemed to understand what's needed)

  • RobinL 1 hour ago
    Does anyone have direct experience with Claude making damaging mistakes in dangerously skip permissions mode? It'd be great to have a sense of what the real world risk is.
    • prodigycorp 1 hour ago
      Claude is very happy to wipe remote dbs, particularly if you're using something like supabase's mcp server. Sometimes it goes down rabbitholes and tries to clean itself up with `rm -rf`.

      There is definitely a real world risk. You should browse the ai coding subreddits. The regularity of `rm -rf` disasters is, sadly, a great source of entertainment for me.

      I once was playing around, having Claude Code (Agent A) control another instance of Claude Code (Agent B) within a tmux session using tmux's scripting. Within that session, I messed around with Agent B to make it output text that made Agent A think Agent B rm -rf'd entire codebase. It was such a stupid "prank", but seeing Agent A's frantic and worried reaction to Agent B's mistake was the loudest and only time I've laughed because of an LLM.

      • gregoriol 1 hour ago
        Why in the hell would it be able to access a _remote_ database?! In no acceptable dev environment would someone be able to access that.
        • heartbreak 37 minutes ago
          Everywhere I’ve ever worked, there was always some way to access a production system even if it required multiple approvals and short-lived credentials for something like AWS SSM. If the user has access, the agent has access, no matter how briefly.
          • gregoriol 28 minutes ago
            Not if you require auth with a Yubikey, not if you run the LLM client inside a VM which doesn't have your private ssh key, ...
        • prodigycorp 37 minutes ago
          Supabase virtually encouraged it last year haha. I tried using it once and noped out after using it for an hour, when claude tried to do a bunch of migrations on prod instead of dev.

          https://web.archive.org/web/20250622161053/https://supabase....

          Now, there are some actual warnings. https://supabase.com/docs/guides/getting-started/mcp#securit...

    • azuanrb 1 hour ago
      One recent example. For some reason, recently Claude prefer to write scripts in root /tmp folder. I don't like this behavior at all. It's nothing destructive, but it should be out of scope by default. I notice they keep adding more safeguards which is great, eg asking for permissions, but it seems to be case by case.
      • giancarlostoro 47 minutes ago
        If you're not using .claude/instructions.md yet, I highly recommend it, for moments like this one you can tell it where to shove scripts. Trickery with the instructions file is Claude only reads it during a new prompt, so any time you update it, or Claude "forgets" instructions, ask it to re-read it, usually does the trick for me.
    • coldtea 1 hour ago
    • ra120271 1 hour ago
      When approving actions "for this project" I actively monitor .claude\settings.local.json

      as

      "Bash(az resource:)",

      is much more permissive than

      "Bash(az resource show:)",

      It mostly gets it right but I instantly fix the file with the "readonly" version when it gets it too open.

    • MattGaiser 1 hour ago
      Claude has twice now thought that deleting the database is the right thing to do. It didn't matter as it was local and one created with fixtures in the Docker container (in anticipation of such a scenario), but it was an inappropriate way of handling Django migration issues.
  • letmetweakit 2 hours ago
    I run Claude in a Proxmox VM, generally the experience has been great. In my experience it also behaves better than gemini cli, that likes to create files all over the place if set loose (lesson learned to add that requirement to the relevant .md files)
    • vidarh 2 hours ago
      Something that contains Claude even more in this respect is if you explicitly gives it a directory that you tell it is entirely under its control, and tells it to write md files and other intermediate work products there (and this seems to work better than telling it where it isn't allowed to leave things).
      • onionisafruit 54 minutes ago
        That sounds like a good idea. When I have a one-off need for misc files I tell it to put them in the project’s ./tmp because that’s already in my global gitignore. That generally works, but I still run into surprise files it leaves in source dirs like a puppy leaves turds on a rug. I’ll try adding that to my instructions instead of doing it one-off.
      • jermaustin1 50 minutes ago
        I've often found that LLMs don't listen to "Don't do" commands with anywhere near the same gusto as "Do" commands.
        • NitpickLawyer 9 minutes ago
          People don't usually think about pink elephants, unless you ask them not to think about pink elephants :)
    • emilburzo 2 hours ago
      This was also the direction I was initially headed, but then I realized I wanted one-VM-per-project so it can really do anything it wants on the complete VM. So the blast-from-the-past-Vagrant won because of the Vagrantfile + `vagrant up` easiness.
      • letmetweakit 2 hours ago
        I use Proxmox snapshots to get back to a clean state. I’ll take a look at Vagrant too though.
    • scalemaxx 2 hours ago
      In installed Gemini as an extension in VS Code and it kept wanting to index all my files. Still trying to figure out what it was doing outside of the VS Code folder I had set it to work on.
  • skybrian 2 hours ago
    I'm doing this with a remote VM on exe.dev and it's quite nice. Well, actually with their own coding agent but they have Claude Code preinstalled too.

    Syncthing works well for getting a local copy of a directory from the VM.

  • tobyhinloopen 2 hours ago
    How about running Claude as a different user with very limited permissions?
    • gregoriol 2 hours ago
      This breaks the non-interactive mode the post want to achieve. Claude will not be able to install some things and will require user action, which is not desired here.
      • progval 2 hours ago
        Like what? It can already use npm/pip/etc. And if it needs a new APT package or config in /etc/ then you would want to know because you need to document it.
        • gregoriol 1 hour ago
          If you make claude work with c/c++, it may need apt for libraries or build tools.

          Even with npm/pip, these may not be available on a base linux box.

          Even then, some complex projects may need other tools that are not part of a base system (command line tools, redis, ...).

    • emilburzo 2 hours ago
      I tried this approach for a while, but I really wanted it to be able to do anything (install system packages, build/run Docker containers, the works).

      With these powers there's a lot less back-and-forth with me running commands, copying the output, pasting it to Claude, etc.

      I'm sure you've had the case where you had to instruct someone to do something (e.g. playing tech support with family, helping another engineer, etc). While it helps the other person learn, it feels soooo slow vs just doing it yourself :) And since I don't have to teach the agent, I think this approach makes sense.

    • delaminator 2 hours ago
      I run it with sudo enabled - true story

      just give it its own machine and let it check out any code

      I PXE boot it from a known image when I feel the need

      • tobyhinloopen 2 hours ago
        Running it remotely on a VM seems like a very sensible option. Just don't give it permission to nuke the remote repository hah (EG don't allow force-push, use protected branches, only allow write access to branches it created)
  • szmarczak 43 minutes ago
    What about Docker rootless?
  • Retr0id 1 hour ago
    > VirtualBox 7.2.4 shipped with a regression that causes high CPU usage on idle guests. What are the odds.

    I have such a love/hate relationship with VirtualBox. It's so useful but so buggy. My current installation has a bug that causes high network latency, but I'm afraid to upgrade in case it introduces new, worse bugs.

    VMware is a million times better, but it is also Proprietary™

    • intrasight 1 hour ago
      As VMWare Workstation is now free on Linux and Windows, and allows you to create and rollback snapshots. Why not use it even if proprietary?
      • Retr0id 1 hour ago
        It's a good question and I'm pretty on the fence about it, and next time I'm reinstalling things I might switch.

        I do believe in the whole RMS "respects the user's freedoms" spiel, so all things being equal I prefer FOSS, even if it's worse - but there are limits.

  • cyberpunk 39 minutes ago
    docker sandbox run claude? seems to work for me…
  • athrowaway3z 1 hour ago
    `useradd claude`
  • supermatt 54 minutes ago
    > now you need Docker-in-Docker

    Or you can just mount the socket and call docker from within docker.

    • emilburzo 4 minutes ago
      Correct, which I wanted to avoid because:

      > Mounting the Docker socket grants the agent full access to your Docker daemon, which has root-level privileges on your system. The agent can start or stop any container, access volumes, and potentially escape the sandbox. Only use this option when you fully trust the code the agent is working with.

      https://docs.docker.com/ai/sandboxes/advanced-config/#giving...

  • firasd 2 hours ago
    I noticed something in Claude across all product surfaces

    There's a bug in that it can't output smart quotes “like this”

    Sonnet, Opus et al think they output it but something in the pipeline is rewriting it

    https://github.com/firasd/vibesbench/blob/main/docs/2026/A/t...

    Try it in Claude Code and you'll see what I mean! Very weird

  • ompogUe 6 days ago
    Keeping in mind with Vagrant: if you are using a synced_folder in your host as a source folder in the VM, those files in the synced_folder will be modified on the host.
    • gregoriol 2 hours ago
      If the folder is versioned and commited regularly there is no problem. It also allows you to open the files in your IDE, do some other tasks or fixes for claude. It prevents claude from accessing any other folder, which is the idea of the post.
      • gcr 1 hour ago
        I’ve seen Claude rm .git in rare occasions to “fix rebase hiccups”

        Version control ain’t a match for a good backup

        • gregoriol 1 hour ago
          So? if it removes .git, just clone the project again and you are ok
    • emilburzo 6 days ago
      Good point. For me, that was intentional, since all my projects are in git I don't care if it messes something up. Then you get the benefit of being able to use your regular git tooling/flows/whatever, without having to add credentials to the VM.

      But if you need something more strict, 'config.vm.synced_folder' also supports 'type rsync', which will copy the source folder at startup to the VM, but then it's on you to sync it back or whatever.

      • ompogUe 6 days ago
        I like this workflow a lot, actually. Docker is great and all, but depending on the project, Vagrant helps "keep it simple".

        Thanks

    • ninadwrites 2 hours ago
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  • nirdiamant 1 hour ago
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