Go SDK panic: index out of range in ChatCompletion handler

[YueSun233133]

• This is actually a bug report in Go SDK.

What Model are you using?

• gpt-4.1-nano-2025-04-14

Describe the bug
pkg/instructor/providers/openai/chat.go line 157 throws a panic

runtime panic: runtime error: index out of range [0] with length 0

To Reproduce
Just normal call, this issue happens from time to time, not able to reproduce manually, it looks like none was return by llm engine

messages := []openai.ChatCompletionMessage{
{
Role: openai.ChatMessageRoleSystem,
Content: systemPrompt,
},
}
if userPrompt != "" {
messages = append(messages, openai.ChatCompletionMessage{
Role: openai.ChatMessageRoleUser,
Content: userPrompt,
})
}
resp, err = client.CreateChatCompletion(
ctx,
openai.ChatCompletionRequest{
Model: model,
Messages: messages,
},
&out,
)

Expected behavior
Panic should be handled gracefully

Screenshots

[jxnl]

Hey, this is the Python repository.