I agree with this, what you put into the prompt will reflect in what you get out, so just be more detailed.
One of the frustrating aspects of using prompts to generate code is that the output can vary quite a bit even with the same prompt. Creating an API which use the OpenAI APIs for mission critical solutions feels a bit scary and unpredictable. For structured output, I know people use libraries like Pydantic with Python. I don't now the best approach to deal with this with regards to code generation, though. For now, I guess having an experienced software engineer examine the code is essential.