> ## Documentation Index
> Fetch the complete documentation index at: https://docs.mcp-use.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Sampling

> Handle LLM completion requests from MCP servers

When a server tool needs an LLM during execution, it sends a `sampling/createMessage` request to your client. Provide `onSampling` to handle it.

```typescript theme={null}
import { MCPClient, type OnSamplingCallback } from "@mcp-use/client";

const onSampling: OnSamplingCallback = async (params) => {
  const text = await yourLLM.complete(params);
  return {
    role: "assistant",
    content: { type: "text", text },
    model: "your-model",
    stopReason: "endTurn",
  };
};

const client = new MCPClient(
  { mcpServers: { demo: { url: "http://localhost:3000/mcp" } } },
  { onSampling },
);

await client.connect("demo");
```

## Per-server override

Set `onSampling` on an individual server config to override the global default.

## React

With `useMcp`, pass `onSampling` in options. With `McpClientProvider`, handle `server.pendingSamplingRequests` and call `approveSampling` / `rejectSampling`.

## Reference

Runnable example: [sampling-client.ts](https://github.com/mcp-use/mcp-use/blob/main/libraries/typescript/packages/client/examples/node/communication/sampling-client.ts)