`createXai().responses` causes request to fail unless my own key is set in BYOK

#### Problem

Using `ai@6.0.105` calling `generateText` like below, i receive the error above. Setting a key in the BYOK section of the dashboard fixes this.

#### Error:
```
✘ [ERROR] Uncaught AI_APICallError: No or an invalid authentication header was provided on the request. Please make sure you pass your API key in the corresponding HTTP header. Error
```

#### Code to Reproduce:
```
generateText({
system: composePrompts(systemPrompt),
model: aigateway([createXai().responses("grok-4")]),
})
```

Doing this is necessary for using provider defined tools. I would like to have cloudflares unified system manage the api key and billing instead of having to use my own API keys. Any help with this would be greatly appreciated!