Standards map
Arco sits inside a broader open-standards landscape. This page summarizes the posture from docs/open-standards-map.md in the Kosmos prototype repo.
Three postures
| Posture | Meaning |
|---|---|
| Adopt | Use an existing open standard as-is |
| Bridge | Keep internal format; map at boundaries |
| Define | Arco publishes the spec — no adequate existing standard |
Where Arco defines
| Subsystem | Arco's role |
|---|---|
| Generative UI language | Grammar, vocabulary, binding contract |
| Component vocabulary | JSON Schema profiles (chat vs reactive app) |
| Live data binding | Query/Mutation → host tools without LLM round-trip |
| Patch semantics | Statement-level merge for agent-driven app evolution |
| Design tokens | --arco-* with planned DTCG export |
| Block registry | Manifest shape, adaptivity, validation |
Where Arco adopts
| Standard | Use |
|---|---|
| MCP | Tool interop (client + outward server) |
| ACP | External coding agents (Claude Code, Codex, Gemini) |
| JSON Schema | Parameter schemas across tools and intents |
| Markdown + GFM | Chat prose |
| WebRTC / Pipecat | Voice transport |
Where Arco bridges
| Area | Bridge |
|---|---|
| Design tokens | CSS vars today → DTCG file as canonical source |
| Agent events | Custom SSE stream; track AG-UI for future mapping |
| Calendar data | Custom os.calendar@1 + planned iCal import/export |
Arco open standard modules
The nine "define" areas group into four spec modules:
- UI language + binding — grammar, profiles, host contract, patches
- Capabilities (os.**) — versioned intent contracts exposed as MCP tools
- App packaging + bridge — manifest + postMessage/HTTP host API
- Agent surface — event stream and cursor protocol
Generative stack today
@openuidev/lang-core → grammar (future: Arco spec)
@openuidev/react-ui → vocabulary (future: block registry)
@openuidev/react-lang → renderer (reference impl)
Arco tokens + ui/ → theming and shell primitives
Fork trigger: when upstream blocks the binding contract or React decoupling — not for styling differences alone.
For the full subsystem table, see docs/open-standards-map.md in the Kosmos prototype repository.