Overview and router for assistant-ui, the React library for building AI chat interfaces from composable primitives and a styled elements catalog. Use for high-level, cross-cutting, or architecture questions: choosing packages, picking a runtime, or understanding the layers (elements, primitives, the aui client with AuiConfig and AuiProvider, the runtime, adapters) and the message model. Covers `@assistant-ui/react` 0.15.x, `@assistant-ui/ai-sdk` for AI SDK v7 (`useChatRuntime`), `@assistant-ui/core`, `@assistant-ui/store`, `assistant-stream`, `assistant-cloud`, the LangGraph, LangChain, Google ADK, A2A, AG-UI, Eve, OpenCode, and Pi adapters, the `@assistant-ui/react-native` and `@assistant-ui/react-ink` bindings, and the `useAui`, `useAuiState`, and `useAuiEvent` hooks. For a specific area route to a focused sibling instead: setup, elements, primitives, runtime, tools, generative-ui, streaming, cloud, thread-list, copilots, markdown, react-mcp, observability, react-native, ink, or update.