Installation

Prerequisites

• Docker — jackin❯ uses Docker to create isolated containers. Make sure Docker is installed and the Docker daemon is running.
• macOS or Linux — jackin❯ currently supports macOS and Linux. Windows support via WSL2 is possible but untested.

Install jackin❯

The easiest way to install on macOS or Linux is via Homebrew. The Homebrew formulae are maintained in the jackin-project/homebrew-tap repository.

brew tap jackin-project/tap

# Active early-development channel
brew install jackin@preview

cargo install --git https://github.com/jackin-project/jackin.git jackin --locked

Verify installation

jackin --version

You should see the jackin❯ version and the banner:

jackin 0.6.0-dev

Docker setup

jackin❯ requires Docker to be running. Verify with:

docker info

For faster local image builds, use a Docker daemon with the containerd image store enabled. OrbStack already reports a containerd snapshotter in docker info; Docker Desktop exposes the setting under Settings → General → Use containerd for pulling and storing images on versions where it is not already enabled. jackin❯ does not change daemon settings for you, but launch diagnostics note when the active daemon is using the slower non-containerd store.

Apple Container (macOS 26 ARM, optional)

On macOS 26 (Tahoe) with Apple Silicon, jackin❯ can use Apple Container as an alternative runtime backend. Each agent session gets its own dedicated Linux kernel via Virtualization.framework — stronger isolation than the default Docker backend.

Install apple/container:

# Via Homebrew (homebrew/core):
brew install container

# Or download from GitHub Releases:
open https://github.com/apple/container/releases

Verify:

container --version

Use with jackin❯:

# Load an agent using the Apple Container backend:
jackin load the-architect . --backend apple-container

# Or set as default in ~/.config/jackin/workspaces/my-project.toml:
# [runtime]
# backend = "apple-container"

What gets installed

jackin❯ installs the host CLI plus the matching in-container runtime. Homebrew installs the jackin-capsule Linux binary beside the CLI so the first agent load does not need an extra GitHub download. Source installs can still fetch or build that runtime on first use.

When you first load an agent, jackin❯ will:

1. Pull the construct image — the shared Debian-based base image every agent extends
2. Fetch the role repository — cached locally so subsequent loads of the same role do not re-clone
3. Build a derived image — layers the role's tools and the agent runtime on top of the construct
4. Create a per-agent Docker network — for isolation between agents

Subsequent loads of the same role are typically fast: Docker's layer cache is reused, the role-repo cache is reused, and only changed layers rebuild. Pass --rebuild when you want jackin❯ to refresh the agent-runtime install layer (for example, to pick up a newer agent release).

Next steps

Ready to go? Head to the Quick Start to load your first agent.