Automatic Review

The change from "gpt-4.1-nano" to "gpt-5-nano" raises a potential issue related to completeness and error handling:

• If "gpt-5-nano" is not yet supported or recognized by the rest of the application or OpenAI API, this will likely cause runtime errors or failures when the app tries to use the default model.
• There is no fallback or validation logic shown here to handle the case where the specified model name is invalid or unavailable.
• If this new model is experimental or not yet released, it should be clearly documented or made configurable rather than hardcoded.

Suggestion:
Add validation or fallback for the default model to ensure it is supported, and/or document that this change assumes support for "gpt-5-nano". For example:

// Validate that DefaultOpenAIModel is supported at startup
func validateModel(model string) error {
    supportedModels := []string{"gpt-4.1-nano", "gpt-5-nano"}
    for _, m := range supportedModels {
        if model == m {
            return nil
        }
    }
    return fmt.Errorf("unsupported model: %s", model)
}

func init() {
    if err := validateModel(DefaultOpenAIModel); err != nil {
        log.Fatalf("Invalid default OpenAI model: %v", err)
    }
}

Alternatively, keep the old default and make the new model configurable until full support is confirmed.