Agent sandbox (Lima VM)

Isolated Ubuntu VM (Lima) for running agentic workflows (e.g. opencode) without mounting host directories.

Prereqs

• macOS + Lima (limactl) installed

Create + start (recommended)

Use start.sh to create (or reuse) the VM and copy a repo into it:

./start.sh --lima-file ./lima.yaml --src-dir .

Enter the VM

start.sh drops you into the copied repo automatically. If you want to skip that (e.g. for CI), pass --no-enter.

Manual entry:

limactl shell agent-sandbox

If you need Homebrew tools on PATH in a plain bash shell:

eval "$(/home/linuxbrew/.linuxbrew/bin/brew shellenv)"

Stop / delete

limactl stop agent-sandbox
limactl delete agent-sandbox

Repo sync into the VM

This VM intentionally has no host mounts and no SSH keys. All data transfer is explicit.

start.sh packages a repo on the host and copies it into the VM at:

/home/lima/repo

The copy:

• Includes .git/ so you can commit inside the VM
• Includes uncommitted files
• Copies everything by default
• Optionally excludes files via --ignore-file

Ignore file (optional)

By default, the repo copy includes everything. To exclude files, pass an explicit ignore file (syntax matches .gitignore):

./start.sh --lima-file ./lima.yaml --src-dir . --ignore-file path/to/ignore

node_modules/
dist/
.env
*.log

Git identity (commits inside VM)

Git identity and shell tooling are provisioned inside the VM via your dotfiles bootstrap (runs from lima.yaml).

Verify inside the VM:

git config --get user.name
git config --get user.email

Run agent

limactl shell agent-sandbox -- opencode run

Copy repo out of the VM

Use ./copy-out.sh to extract the VM repo onto the host (defaults to ~/dev/lima-repo, replacing any existing folder):

./copy-out.sh --name agent-sandbox

Override destination and output folder name:

./copy-out.sh --dest-dir ~/dev --out-name gemhog-repo

Notes

• No host mounts (mounts: []); all data transfer is explicit.
• Port forwarding is disabled for all ports except SSH.
• Updating lima.yaml does not change an existing instance config; recreate the instance to apply provisioning changes.

License

MIT (see LICENSE).