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tryboxiStar

Disposable microVMs for your agents. On your machine.

Give Cursor, Claude Code, and Codex a powerful Linux machine for agents to run the code securely.

Get startedHow it works
  • macOS 14+
  • Free, runs on your Mac

One daemon on your Mac, one microVM per agent

Your agent talks to sandboxd. sandboxd runs every sandbox as its own microVM.

architecture · your maclocal

Cursor, Claude Code, and Codex connect over MCP to sandbox-mcp, which calls sandboxd over HTTP on a unix socket. Your own code can call sandboxd directly. sandboxd runs each sandbox as a microVM and talks to it over vsock. Outbound traffic goes through the egress proxy to allowlisted hosts only.

$ sandboxctl doctor
  1. 01

    Ask

    Your agent calls sandbox_exec over MCP, or your code calls the HTTP API.

  2. 02

    Run

    sandboxd hands it a microVM in milliseconds and syncs your repo in.

  3. 03

    Contain

    Traffic goes through an allowlist proxy. Secrets never enter the VM.

Fast enough to throw one away

Agents start fresh as often as they like. A new sandbox costs milliseconds, not a minute of setup.

Warm pool create
20–50 ms
Snapshot restore
~0.5 s
Resume from disk
~0.5 s
Cold boot
~1.2 s
Cloud bill
$0

Measured on an M4 MacBook with 16 GB.

Install once, then connect your agent

Two steps in a terminal on your Mac. Both run from the folder you clone.

  1. Step 1: Install tryboxi

    Builds from source, so you need Go, plus Docker once to build the Ubuntu base image. The first build takes a few minutes. sandboxd install registers the daemon to start at login, and from then on it needs no Docker or root.

    macOS

    $git clone https://github.com/karthikponna/tryboxi && cd tryboxi
    $make images build
    $./_out/bin/sandboxd install --artifacts _out

  2. Step 2: Connect your agent

    Point --project at the repo your agent works in. It writes the MCP config and sandbox rules there. Building your own harness? Call the HTTP API on the unix socket instead.

    $./_out/bin/sandboxctl mcp install cursor --project ~/code/app
    wrote ~/code/app/.cursor/mcp.json
    wrote ~/code/app/.cursor/rules/sandbox.mdc
    Next: open Cursor Settings -> MCP and enable the 'sandbox' server

FAQs

A Mac with Apple Silicon on macOS 14 or later. VMs run on Apple's Virtualization.framework inside sandboxd, with no root, Lima, or Docker needed at runtime. For now you build it from source with Go; building the base Ubuntu image uses Docker once.