Kosmos vs Arco
Start with What is Kosmos? if you need the product overview. This page is the naming boundary between the OS and the UI library.
| Kosmos | Arco | |
|---|---|---|
| What it is | Generative AI operating system | Generative UI library |
| Owns | Shell, workspaces, agent UX, focus model, app platform | Tokens, components, blocks, registry contract |
| User-facing name | "Kosmos" on the marketing site and in product copy | "Arco" in docs, spec, and library APIs |
| Hosted product | Kosmos Cloud / Kosmos Hosted (billing) | N/A — Arco ships inside each instance |
| Package / app | Kosmos-computer/Kosmos, Kosmos-computer/www marketing | Guide + Reference in these docs, src/components/ui/ in the prototype |
| Demo | http://localhost:4610 or your kosmos-*.fly.dev | https://docs.kosmos.computer/guide/what-is-arco |
How they connect
┌─────────────────────────────────────────┐
│ Kosmos shell (NavRail, windows, apps) │
├─────────────────────────────────────────┤
│ Workspaces: Chat, Studio, Settings… │
├─────────────────────────────────────────┤
│ Arco: tokens → ui/ → patterns/ → blocks│
├─────────────────────────────────────────┤
│ Engines: OpenClaw, OpenHands, Odysseus │
└─────────────────────────────────────────┘
When an agent generates UI:
- Kosmos provides context — which workspace, window, and entity is in focus.
- Arco provides vocabulary — which blocks and props are valid.
- The registry (planned) validates output and maps it to React renderers.
Naming in docs and code
- Use Kosmos when describing the OS, shell, workspaces, or end-user product.
- Use Arco when describing tokens, components, blocks, schemas, or the generative library.
- Use Kosmos Cloud for the managed hosted path and desktop Settings section; Kosmos Hosted appears in billing UI — see Concepts.
- The prototype repo is named
Kosmos; product branding on the website is Kosmos.
SDK
Programmatic access to a Kosmos environment uses the Kosmos SDK (@kosmos-computer/sdk) — not Arco. Arco appears in SDK integrations only when agents emit generative UI or os_ui events inside the shell.
See the Arco spec overview on the marketing site for architecture decisions.