# FAQ

## How is this different from OrbStack or Docker Desktop?

OrbStack and Docker Desktop manage the Docker / Linux-VM world. Runbay is a GUI for
**Apple's own `container` runtime** — the one announced at WWDC 2025 that reached CLI 1.0.0 in June
2026. Each container runs in its own lightweight VM with a dedicated IP and sub-second startup, with
no shared kernel. Apple ships that runtime **CLI-only**; Runbay adds the GUI, plus three
things none of the alternatives have for this runtime: compose-style [Stacks](stacks.md), a restart
[Supervisor](supervisor.md), and a two-way [MCP bridge](agent-setup.md) for coding agents. It is not
a Docker wrapper, and it does not expose a Docker socket.

## Does it work on macOS 15, or do I need macOS 26?

It runs on both, but macOS 26 Tahoe is the full experience. Apple officially supports the `container`
CLI **only on macOS 26**, where you get custom networks and container-to-container networking. On
macOS 15 you lose container-to-container networking and `container network create` — that's an Apple
constraint, not ours, and the app tells you so honestly in-app. **Apple Silicon is required either
way**; the framework does not support Intel.

## Is my data local? What leaves my machine?

Everything runs on your Mac. Containers, logs, stats, and the SQLite cache are all local. The MCP
server listens on a local Unix socket or localhost TCP only, rate-limited. There is no telemetry
backend, no hosted agent compute, and no config, license, or sync server on our side. The only
outbound network call in normal use is license validation to Polar (using a public organization ID) —
see [licensing](licensing.md).

## What is MCP, and why does it matter here?

MCP (the Model Context Protocol) is the open standard coding agents use to discover and call tools.
Runbay **is** an MCP server: every running container automatically becomes a set of tools
(`logs__`, `stats__`, `exec__`, and `db_query__` for databases), plus live resources and lifecycle
events. Your agent can read logs, check stats, run a read-only query, or spin up a disposable sandbox
without you writing any glue. Full detail in the [agent setup guide](agent-setup.md).

## Can my coding agent touch my host filesystem or credentials?

Not by default. [Agent Sandboxes](sandboxes.md) are disposable `container machine` VMs, and the only
host-filesystem lever the CLI offers is `--home-mount none|ro|rw`. The default is **Isolated
(`none`)** — your `$HOME`, SSH keys, and cloud tokens stay invisible. Choosing `ro` or `rw` exposes
your home directory, and the app warns you in red before you do.

## What are the license terms?

Free for personal and non-commercial use, with every feature included. Commercial use at a company
requires an ~$8/user/month subscription (honor-system license key, like OrbStack). See
[licensing](licensing.md) for how activation and offline grace work.

## What doesn't work yet (honest limitations)?

Honesty is the point — here's the real list.

- **macOS 15 has no container-to-container networking** and no `container network create`. That's an
  Apple constraint; the full experience needs macOS 26.
- **The app can't restart a fully-dead engine by itself.** Under the App Sandbox, launchd refuses job
  submission from a sandboxed process, so the watchdog degrades to a guided "Restart in Terminal"
  button and self-heals on the next poll. The fully-automatic fix needs a non-sandboxed helper — the
  detail is in the [supervisor doc](supervisor.md) (decision D017).
- **Image builds are slow upstream.** Apple's `container` build is currently ~4–5× slower than
  OrbStack / Docker Desktop, and Dockerfiles at or above ~16 KB can fail. Our Dockerfile build UI is
  deliberately unshipped until we can preflight those traps and frame the performance honestly.
- **`linux/amd64` emulation can segfault JIT-heavy workloads** (Node, .NET, MSSQL). Prefer arm64
  images.
- **No Docker socket.** Apple's runtime exposes none, so Docker-socket tools — including
  Testcontainers — don't work today. A bridge is under evaluation.
- **No `pause` / `unpause` / `attach`.** These aren't in CLI 1.0.0; attach flows use `exec -it` or
  `start -a -i`.
- **Volume *data* doesn't migrate automatically** from Docker/OrbStack. Images re-pull; volume data
  you move yourself. See [migration](migration.md).
- **MCP has no TLS yet.** It's localhost-only and rate-limited (100/min, 1000/hr per client) — keep it
  to your machine.

## Why should I trust an honest limitations list over a polished one?

Because it's the whole pitch. Every claim on this site traces to the project's own tracking docs, and
the capability matrix in the README leads with what *doesn't* work. If something here is wrong or out
of date, that's a bug we want to fix — not a line we're trying to hold.