assistant-ui Skill | Agent Skills

assistant-ui

Always consult assistant-ui.com/llms.txt for latest API.

React library for building AI chat interfaces with composable primitives.

References

./references/architecture.md -- Core architecture and layered system
./references/packages.md -- Package overview and selection guide

When to Use

| Use Case | Best For | |----------|----------| | Chat UI from scratch | Full control over UX | | Existing AI backend | Connects to any streaming backend | | Custom message types | Tools, images, files, custom parts | | Multi-thread apps | Built-in thread list management | | Production apps | Cloud persistence, auth, analytics |

Architecture

┌─────────────────────────────────────────────────────────┐
│                  UI Components (Primitives)             │
│    ThreadPrimitive, MessagePrimitive, ComposerPrimitive │
└─────────────────────────┬───────────────────────────────┘
                          │
┌─────────────────────────▼───────────────────────────────┐
│                   Context Hooks                         │
│   useAui, useAuiState, useAuiEvent │
└─────────────────────────┬───────────────────────────────┘
                          │
┌─────────────────────────▼───────────────────────────────┐
│                    Runtime Layer                        │
│  AssistantRuntime → ThreadRuntime → MessageRuntime      │
└─────────────────────────┬───────────────────────────────┘
                          │
┌─────────────────────────▼───────────────────────────────┐
│                   Adapters/Backend                      │
│   AI SDK · LangGraph · Custom · Cloud Persistence       │
└─────────────────────────────────────────────────────────┘

Pick a Runtime

Using AI SDK?
├─ Yes → useChatRuntime (recommended)
└─ No
   ├─ External state (Redux/Zustand)? → useExternalStoreRuntime
   ├─ LangGraph agent? → useLangGraphRuntime
   ├─ AG-UI protocol? → useAgUiRuntime
   ├─ A2A protocol? → useA2ARuntime
   └─ Custom API → useLocalRuntime

Core Packages

| Package | Purpose | |---------|---------| | @assistant-ui/react | UI primitives & hooks | | @assistant-ui/react-ai-sdk | Vercel AI SDK v6 adapter | | @assistant-ui/react-langgraph | LangGraph adapter | | @assistant-ui/react-markdown | Markdown rendering | | assistant-stream | Streaming protocol | | assistant-cloud | Cloud persistence |

Quick Start

import { AssistantRuntimeProvider } from "@assistant-ui/react";
import { Thread } from "@/components/assistant-ui/thread";
import { useChatRuntime, AssistantChatTransport } from "@assistant-ui/react-ai-sdk";

function App() {
  const runtime = useChatRuntime({
    transport: new AssistantChatTransport({ api: "/api/chat" }),
  });
  return (
    <AssistantRuntimeProvider runtime={runtime}>
      <Thread />
    </AssistantRuntimeProvider>
  );
}

State Access

import { useAui, useAuiState } from "@assistant-ui/react";

const api = useAui();
api.thread().append({ role: "user", content: [{ type: "text", text: "Hi" }] });
api.thread().cancelRun();

const messages = useAuiState(s => s.thread.messages);
const isRunning = useAuiState(s => s.thread.isRunning);

Related Skills

/setup - Installation and configuration
/primitives - UI component customization
/runtime - State management deep dive
/tools - Tool registration and UI
/streaming - Streaming protocols
/cloud - Persistence and auth
/thread-list - Multi-thread management
/update - Version updates and migrations

Agent Skills: assistant-ui

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