> ## 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.

# OpenAPIClientOptions

Defined in: [server/openapi/execute.ts:21](https://github.com/PrefectHQ/fastmcp-ts/blob/main/src/server/openapi/execute.ts#L21)

HTTP client configuration for a generated OpenAPI server.

## Properties

### auth?

```ts theme={null}
optional auth?: {
  getHeaders: Promise<Record<string, string>>;
};
```

Defined in: [server/openapi/execute.ts:31](https://github.com/PrefectHQ/fastmcp-ts/blob/main/src/server/openapi/execute.ts#L31)

Async header provider, resolved per request (e.g. a token refresher).

#### getHeaders()

```ts theme={null}
getHeaders(): Promise<Record<string, string>>;
```

##### Returns

`Promise`\<`Record`\<`string`, `string`>>

***

### baseUrl?

```ts theme={null}
optional baseUrl?: string;
```

Defined in: [server/openapi/execute.ts:27](https://github.com/PrefectHQ/fastmcp-ts/blob/main/src/server/openapi/execute.ts#L27)

Base URL for requests. Defaults to the spec's first `servers` entry
(with server variables filled from their defaults). Required when the
spec has no absolute server URL.

***

### fetch?

```ts theme={null}
optional fetch?: {
  (input, init?): Promise<Response>;
  (input, init?): Promise<Response>;
};
```

Defined in: [server/openapi/execute.ts:33](https://github.com/PrefectHQ/fastmcp-ts/blob/main/src/server/openapi/execute.ts#L33)

Custom fetch implementation. Defaults to the global fetch.

#### Call Signature

```ts theme={null}
(input, init?): Promise<Response>;
```

[MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/fetch)

##### Parameters

###### input

`URL` | `RequestInfo`

###### init?

`RequestInit`

##### Returns

`Promise`\<`Response`>

#### Call Signature

```ts theme={null}
(input, init?): Promise<Response>;
```

[MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/fetch)

##### Parameters

###### input

`string` | `Request` | `URL`

###### init?

`RequestInit`

##### Returns

`Promise`\<`Response`>

***

### headers?

```ts theme={null}
optional headers?: Record<string, string>;
```

Defined in: [server/openapi/execute.ts:29](https://github.com/PrefectHQ/fastmcp-ts/blob/main/src/server/openapi/execute.ts#L29)

Default headers sent on every request. Request-specific headers win.

***

### timeoutMs?

```ts theme={null}
optional timeoutMs?: number;
```

Defined in: [server/openapi/execute.ts:35](https://github.com/PrefectHQ/fastmcp-ts/blob/main/src/server/openapi/execute.ts#L35)

Per-request timeout in milliseconds. Default 30 000.