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-...