agentuiindex · coming soon
Which agent UI stack should you actually use?
A neutral, React-dev-run index of agent frontend libraries and protocols — CopilotKit, assistant-ui, ChatKit, AG-UI, A2UI, MCP Apps — with a compatibility matrix and a live demo for every pairing. No vendor docs spin.
- Compatibility matrix
Which UI lib works with which agent backend and protocol. - Same agent, every UI
One reference agent wired into each library, side by side. - Release changelog
Breaking changes and new specs, tracked in one place.
Preview: the matrix
| Tool | What it is | Plays with |
|---|---|---|
| AG-UI | Transport protocol: agent backend ↔ frontend, real-time state sync (by CopilotKit) | LangChain, Mastra, PydanticAI, CrewAI; carries A2UI |
| A2UI | Declarative JSON UI format (Apache 2.0); agent can only request components from your trusted catalog | Web & Flutter renderers; A2A and AG-UI transports |
| MCP Apps | MCP extension (SEP-1865): servers ship pre-built HTML via ui://, rendered in sandboxed iframes | MCP hosts |
| CopilotKit | Agent frontend SDK: chat, generative UI, shared state, human-in-the-loop | React, Angular, Vue, React Native, Slack, Teams |
| assistant-ui | Composable React primitives; generative-UI package with a 35-component default vocabulary | LangGraph data UI; consumes A2UI over AG-UI |
| ChatKit | OpenAI's chat UI kit, tightly integrated with the OpenAI ecosystem | OpenAI agents |
Sources: project docs and repos, checked Oct 2026. Full matrix + demos at launch.
You'll also get “What changed in agent UI” — one short email a week on new releases, spec changes and breaking changes. Unsubscribe anytime.