fcvm MCP Server

What the code does

We read the source, 4 d ago · rules 995398eba69f

Found in continuous integration, deployment or infrastructure files, or in a neighbouring package of the same monorepo. None of this is installed when you add the server: it describes how the project is built and released. We list it because a leaked key in a build pipeline is still a real problem, but it is not something this server does on your machine.

        if (setgroups(ng, groups) < 0 || setgid(gid) < 0 || setuid(uid) < 0) {

        subprocess.run(["mkfs.ext4", *opts, "-d", root, *rest], check=True)

        proc = subprocess.Popen(args.cmd, stdin=slave, stdout=slave, stderr=slave, start_new_session=True)

        subprocess.run(args.on_exit, shell=True, env=env)

        link = os.path.join(args.link_dir, name)

    async def exec(self, name, d):

  exec(command: string | undefined, opts?: ExecOptions & { background?: false }): Promise<ExecResult>;

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Connect this server

This server runs on your own machine — install it with the package manager and the client starts it for you. Package name taken from the official registry entry.

claude mcp add fcvm -- uvx fcvm-mcp

{
  "mcpServers": {
    "fcvm": {
      "command": "uvx",
      "args": [
        "fcvm-mcp"
      ]
    }
  }
}

[mcp_servers.fcvm]
command = "uvx"
args = ["fcvm-mcp"]

{
  "mcpServers": {
    "fcvm": {
      "command": "uvx",
      "args": [
        "fcvm-mcp"
      ]
    }
  }
}

{
  "servers": {
    "fcvm": {
      "type": "stdio",
      "command": "uvx",
      "args": [
        "fcvm-mcp"
      ]
    }
  }
}

Optional settings from the registry entry, left out of the block above: FCVM_MCP_NETWORK (Pin the network policy for every sandbox: none, or an allowlist such as @pypi,@github), FCVM_MCP_TEMPLATE (Template used when the agent names neither an image nor a template, e.g. python-sandbox), FCVM_MCP_TTL (Stop sandboxes this long after boot unless the agent sets a lifetime, e.g. 4h), FCVM_MCP_IDLE_STOP (Stop sandboxes that saw no exec or file operation for this long, e.g. 30m), FCVM_MCP_SECRETS (Names of environment variables passed into every sandbox as secrets, e.g. GITHUB_TOKEN), FCVM_MCP_FORWARD (Host credentials relayed into every sandbox: ssh-agent, git), FCVM_MCP_CACHE (1: restricted sandboxes fetch pip and npm packages through the host's mirror), FCVM_MCP_JAIL (0: don't run sandboxes under the Firecracker jailer even when it is set up), FCVM_BIN (Path of the fcvm command, when it isn't on PATH, in ~/.local/bin or in /usr/local/bin).