> ## 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.

# CompleteCallback

```ts theme={null}
type CompleteCallback = (value, context?) => 
  | string[]
  | CompletionResult
  | Promise<string[] | CompletionResult>;
```

Defined in: [server/completion.ts:48](https://github.com/PrefectHQ/fastmcp-ts/blob/e4b6038f642b529f601463a576229747afebe9a4/src/server/completion.ts#L48)

A completion callback. Receives the partial `value` the user has typed and the
optional resolved-argument `context`, and returns suggestions — either a bare
`string[]` or a [CompletionResult](/api/server/interfaces/CompletionResult) with explicit pagination hints. May be
async.

## Parameters

### value

`string`

### context?

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

## Returns

\| `string`\[]
\| [`CompletionResult`](/api/server/interfaces/CompletionResult)
\| `Promise`\<`string`\[] | [`CompletionResult`](/api/server/interfaces/CompletionResult)>