Installs and configures assistant-ui in a project via the CLI, and picks the right runtime for a backend. Use for first-time install, scaffold, or config: `npx assistant-ui@latest create my-app` (templates default, minimal, cloud, cloud-clerk, langgraph, mcp), `npx assistant-ui@latest init [--yes] [--overwrite]` in an existing Next.js app, or `npx assistant-ui@latest add` registry components (markdown-text, thread-list). Also use to choose a runtime hook for a backend: useChatRuntime (AI SDK), useLangGraphRuntime, useAgUiRuntime, useA2ARuntime, useLocalRuntime (custom streaming API), or useExternalStoreRuntime (Redux/Zustand). Covers Vite/TanStack Start setup, shadcn styling, the playground --preset flag, and avoiding the deprecated @assistant-ui/styles and @assistant-ui/react-ui packages. For upgrading an existing install or post-upgrade breakage use update; for building UI from raw parts use primitives.
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.
Sets up assistant-ui Cloud persistence and authorization with the assistant-cloud package and AssistantCloud client. Use when adding cross-session thread/message persistence, multi-device chat history, file uploads, or auth to an assistant-ui app: passing the cloud option to useChatRuntime (with AssistantChatTransport from @assistant-ui/react-ai-sdk), configuring AssistantCloud with authToken (JWT), apiKey plus userId/workspaceId (server-side), or anonymous mode, and wiring auth providers like NextAuth, Clerk, or Firebase. Covers cloud.threads.list/get/create/update/delete, cloud.threads.messages(threadId), cloud.files.generatePresignedUploadUrl, the aui/v0 message format, custom adapters (CloudMessagePersistence, createFormattedPersistence, ThreadHistoryAdapter, RemoteThreadListAdapter), auto title generation, external_id/metadata mapping, and env vars NEXT_PUBLIC_ASSISTANT_BASE_URL and ASSISTANT_API_KEY. For the thread-list sidebar UI itself use thread-list.
Grounding an assistant in your app with assistant-ui copilots (@assistant-ui/react). Use when steering assistant behavior with useAssistantInstructions, feeding lazy app-state context via useAssistantContext({ getContext }), exposing rendered components with makeAssistantVisible(Component, { clickable, editable }), building two-way interactable state with useAssistantInteractable and Interactables(), or registering instructions and tools imperatively through useAui().modelContext().register({ getModelContext }). Reach for this when the assistant should read the current page, click or edit UI, or read and update component state through auto-generated update_{name} tools. For LLM tools and tool-call UI use the tools skill; for runtime and thread state use the runtime skill.
Render and customize assistant message text as markdown in assistant-ui. Use when displaying model output as formatted markdown with MarkdownTextPrimitive from @assistant-ui/react-markdown wired into the MessagePrimitive.Parts text branch, configuring remarkPlugins (remark-gfm, remark-math) and rehypePlugins (rehype-katex), or memoizing components with unstable_memoizeMarkdownComponents. Covers code-block syntax highlighting via react-shiki or react-syntax-highlighter registered as SyntaxHighlighter in components/componentsByLanguage, LaTeX math rendering with KaTeX, Mermaid diagrams gated on stream completion, custom math delimiters via preprocess, and the StreamdownTextPrimitive alternative from @assistant-ui/react-streamdown with built-in Shiki/KaTeX/Mermaid and block streaming. For general chat UI composition route to primitives.
Adds tracing, telemetry, and observability to an assistant-ui backend. Use when wiring an AI SDK route handler (streamText/generateText, toUIMessageStreamResponse) to a tracing backend: Langfuse via OpenTelemetry (LangfuseSpanProcessor and NodeSDK in instrumentation.ts, experimental_telemetry isEnabled, propagateAttributes with traceName/userId/sessionId, langfuseSpanProcessor.forceFlush on serverless), LangSmith via wrapAISDK(ai) from langsmith/experimental/vercel (createLangSmithProviderOptions, awaitPendingTraceBatches), or Helicone via createOpenAI baseURL https://oai.helicone.ai/v1 with the Helicone-Auth header. Also covers rendering collected spans with @assistant-ui/react-o11y headless primitives (SpanResource, SpanPrimitive Root/Indent/CollapseToggle/StatusIndicator/TypeBadge/Name/Children, SpanByIndexProvider, SpanData/SpanState) mounted via useAui/AuiProvider from @assistant-ui/store. Use for missing or empty traces, edge vs nodejs runtime telemetry, serverless flush issues, or trace waterfalls.
Builds and customizes assistant-ui chat UI from composable, unstyled @assistant-ui/react primitives that follow Radix-style part composition. Use when assembling or styling a custom Thread, Composer, message rendering, action bar, or branch picker from building blocks: ThreadPrimitive (.Root, .Viewport, .Messages, .Empty, .ScrollToBottom), ComposerPrimitive (.Input, .Send, .Cancel, .Attachments), MessagePrimitive (.Parts/.Content, .Error), ActionBarPrimitive (.Copy, .Edit, .Reload, .Speak, feedback, .ExportMarkdown), BranchPickerPrimitive, AttachmentPrimitive, ThreadListPrimitive, ThreadListItemPrimitive. Covers MessagePrimitive.Parts children render functions for text, image, reasoning, and tool-call parts; conditional rendering with AuiIf (deprecated .If); and gotchas like wrapping in AssistantRuntimeProvider and adding className since primitives ship unstyled. For prebuilt drop-in UI and scaffolding use setup; for multi-thread sidebar behavior use thread-list.
Lets end users add, authenticate, and manage MCP servers from the browser in assistant-ui apps with @assistant-ui/react-mcp. Use when building user-managed MCP server UIs: mounting McpManagerResource via useAui({ mcp }), declaring presets with defineConnector, dropping in McpConfigDialog, or composing McpManagerPrimitive (Root, Connectors, CustomServers, AddCustomTrigger), McpServerPrimitive (Root, Name, Icon, Status, ConnectButton, DisconnectButton, OAuthLink, RemoveButton, Error), and McpAddFormPrimitive (NameField, UrlField, AuthSelect, AuthFields, Submit, Cancel). Covers auth modes none/bearer/oauth, the OAuth flow with McpOAuthCallback, connection states, storage via McpLocalStorage/McpMemoryStorage/McpCustomStorage, reading state with useAuiState (s.mcp, s.mcpServer), and imperative addCustomServer/connect/callTool. Distinct from developer-defined backend @ai-sdk/mcp tools in the tools skill. Reach for this when connected-server tools are missing, OAuth never completes, or servers do not persist.