assistant-ui

Overview and router for assistant-ui, the React library for building AI chat interfaces from composable primitives. Use for high-level, cross-cutting, or architecture-overview questions: choosing packages, picking a runtime, or understanding the layered model (RuntimeCore, Runtime, context hooks, primitives) and message model. Covers the `@assistant-ui/react` core plus `@assistant-ui/react-ai-sdk`, `@assistant-ui/react-langgraph`, `assistant-stream`, and `assistant-cloud`; `AssistantRuntimeProvider`; the primitives `ThreadPrimitive`, `MessagePrimitive`, `ComposerPrimitive`; the hooks `useAui`, `useAuiState`, `useAuiEvent`; and runtime selection across `useChatRuntime`, `useExternalStoreRuntime`, `useLangGraphRuntime`, `useLocalRuntime`. For a specific area route to a focused sibling instead: setup, runtime, primitives, tools, streaming, cloud, thread-list, or update. Not for hands-on tasks already owned by those siblings.