# Overview URL: /docs/runtimes/ai-sdk/overview Vercel AI SDK integration for assistant-ui across major versions. `@assistant-ui/react-ai-sdk` integrates assistant-ui with the [Vercel AI SDK](https://ai-sdk.dev/). It covers `useChat` flows, custom transports, frontend tools, attachments, quote context, multi-step agents, token usage, and cloud persistence. ## Pick a version \[#pick-a-version] | AI SDK | Runtime package | Docs | | ---------------------------- | ------------------------------------- | ---------------------------------------------- | | `ai@^6` + `@ai-sdk/react@^3` | `@assistant-ui/react-ai-sdk` (latest) | [v6 (current)](/docs/runtimes/ai-sdk/v6) | | `ai@^5` + `@ai-sdk/react@^2` | `@assistant-ui/react-ai-sdk@0.x` | [v5 (legacy)](/docs/runtimes/ai-sdk/v5-legacy) | | `ai@^4` | `@assistant-ui/react-data-stream` | [v4 (legacy)](/docs/runtimes/ai-sdk/v4-legacy) | New projects should target v6. v5 and v4 are documented for projects that have not migrated yet; both have known compatibility gaps and receive no new features. ## Architecture \[#architecture] `@assistant-ui/react-ai-sdk` is layered on `ExternalStoreRuntime` (see [architecture](/docs/runtimes/concepts/architecture)). Features that ship as runtime adapters work the same way they do everywhere else; see [adapters](/docs/runtimes/concepts/adapters). ## Choosing useChatRuntime vs useAISDKRuntime \[#choosing-usechatruntime-vs-useaisdkruntime] Both ship in the same package. * **`useChatRuntime`** (recommended) wraps the AI SDK's `useChat` hook and adds cloud thread support, the standard adapter slots, and `AssistantChatTransport` (which forwards system messages and frontend tools by default). Use this unless you have a reason not to. * **`useAISDKRuntime`** is a lower-level hook that takes an existing `useChat` instance you control directly. Use it when you need to share the chat instance with non-assistant-ui code or wire in a custom transport that does not inherit from `AssistantChatTransport`. ## Next \[#next]