# ThreadRuntime
URL: /docs/api-reference/runtimes/thread-runtime

Runtime for thread state, messages, and viewport management.

`useAui` (Thread Actions) \[#useaui-thread-actions]

Access thread actions via `useAui`:

```tsx
import { useAui } from "@assistant-ui/react";

const aui = useAui();
aui.thread().cancelRun();
aui.thread().append({ role: "user", content: [{ type: "text", text: "Hello" }] });
```

<ParametersTable />

`useAuiState` (Thread State) \[#useauistate-thread-state]

Access the thread state reactively:

```tsx
import { useAuiState } from "@assistant-ui/react";

const isRunning = useAuiState((s) => s.thread.isRunning);
const isLoading = useAuiState((s) => s.thread.isLoading);
const messages = useAuiState((s) => s.thread.messages);
```

<ParametersTable />

`useThreadViewport` \[#usethreadviewport]

Manage thread viewport state (e.g., scrolling):

```tsx
import { useThreadViewport } from "@assistant-ui/react";

const threadViewport = useThreadViewport();
const isAtBottom = useThreadViewport((m) => m.isAtBottom);
```

<ParametersTable />