fcvm

Launches fcvm so an AI assistant can create disposable Firecracker microVM sandboxes to run commands, edit files, build images and fork snapshots.

What you can do

Run commands inside disposable microVM sandboxes and read or write files there, each sandbox booting its own kernel from an OCI image in about a second. Build images and commit prepared sandbox states. Snapshot a running VM and fork copies of it in roughly 150 ms. Control network access per sandbox: off, full, or an allowlist of hosts enforced by a logging proxy.

When to use it

Useful when an assistant needs to execute untrusted or experimental code on a Linux machine without touching the host, and when you want to branch from a prepared VM state quickly instead of rebuilding environments.

Requirements

A Linux host with KVM; the fcvm binary must be installed and set up separately, then found on PATH, in ~/.local/bin or /usr/local/bin, or pointed to with FCVM_BIN. The launcher runs via uvx from the fcvm-mcp PyPI package, so Python tooling is needed. Optional settings are environment variables such as FCVM_MCP_NETWORK, FCVM_MCP_TEMPLATE, FCVM_MCP_TTL, FCVM_MCP_IDLE_STOP, FCVM_MCP_SECRETS, FCVM_MCP_FORWARD, FCVM_MCP_CACHE and FCVM_MCP_JAIL.