> ## Documentation Index
> Fetch the complete documentation index at: https://colin-feat-client-cache-mode.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# AuthCheck

```ts theme={null}
type AuthCheck = (token) => void | Promise<void>;
```

Defined in: [server/auth/authorization.ts:4](https://github.com/PrefectHQ/fastmcp-ts/blob/8976c37f79efa6b87809b884f29a1f235a8c4ad1/src/server/auth/authorization.ts#L4)

## Parameters

### token

[`AccessToken`](/api/server/interfaces/AccessToken)

## Returns

`void` | `Promise`\<`void`>