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# 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/8976c37f79efa6b87809b884f29a1f235a8c4ad1/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)>