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

# ModelSelector

```ts theme={null}
type ModelSelector = string | ((prefs) => string);
```

Defined in: [client/sampling/types.ts:10](https://github.com/PrefectHQ/fastmcp-ts/blob/e4b6038f642b529f601463a576229747afebe9a4/src/client/sampling/types.ts#L10)

Resolve a concrete model name from the server's modelPreferences.
A plain string always uses that model; a function inspects the preferences.