Mast

Desktop cockpit for Sail. Mast connects to your Sail control plane over SSH and gives you the spec board, agent rooms where an agent's reply streams in as it is written, live agent logs, a terminal into any project container, and a file workbench.

macOS only today. The build is universal, so it runs on Apple Silicon and Intel.

Install

Download Mast_<version>_universal.dmg from the latest release, open it, and drag Mast to your Applications folder.

The app is signed with a Developer ID certificate and notarized by Apple, so it opens on first launch without a Gatekeeper warning.

Mast updates itself. It checks a few seconds after launch, and you can check on demand from the user menu, which also shows the version you are running.

Connecting

Paste the connect code your box's owner sent you (the one sail fde pair prints) into Mast's first screen and press Connect. Mast keeps what the code carried in ~/.sail/mast.yaml and ~/.sail/keys/, readable only by you, and from then on reaches the box and its project containers with nothing else on the Mac, refusing any box whose SSH host key is not the one the code named. "Forget this box" in the user menu deletes those files; the box keeps its side of the pairing until its owner runs sail fde unpair.

Without a connect code

When ~/.sail/mast.yaml is absent, Mast falls back to the configuration the sail CLI writes:

• ~/.sail/config.yaml gives it the host and the control-plane address. Run sail host config to write it; with neither file Mast shows the connect code screen.
• ~/.ssh/config gives it the route. Mast dials the host and follows every ProxyJump in the chain to reach project containers.
• Authentication tries your ssh-agent first, then key files: IdentityFile, the key: in ~/.sail/config.yaml, then the default ~/.ssh/id_*. Run ssh-add if your agent is empty.

Signing in to the control plane on this path is a passkey ceremony. Mast forwards 127.0.0.1:7070 to the devbox, opens your browser at that origin, and captures the session token the login page hands back.

Development

You need Bun 1.3.14, a stable Rust toolchain (edition 2021, 1.77+), and macOS to run or build the app. Typecheck and tests run anywhere Bun does.

bun install
bun run dev        # tauri dev, rebuilding the web bundle first
bun test           # webview DOM + core, happy-dom preload
bun run typecheck  # tsc --noEmit
bun run build      # tauri build

CI runs typecheck, bun test, and cargo test on macos-15 for every pull request. Pushing a mast-v* tag builds, signs, notarizes, and cuts a release.

Layout

src-tauri/         Rust core
  src/ssh.rs       connection, ProxyJump chain, sftp, terminal channels, SSE streams
  src/login.rs     passkey ceremony over a temporary local forward
  src/lib.rs       the commands the webview can call
src/
  mainview/        React 19 UI: board, rooms, terminal, file workbench, updater
  mainview/tauri/  the Tauri transport, invoke plus events
  shared/          Sail API models and RPC types
docs/decisions/    ADR-per-fix records

The Rust core exposes about two dozen commands to the webview: sail_request for the control-plane REST API, stream_open for SSE tails, fs_* for the workbench over sftp, and terminal_* for interactive shells. Terminal rendering is ghostty-web.

License

MIT. See LICENSE.