Think of it like this: don't ask it to construct the query, ask it for the parts of the query, in a predefined format. Then populate one of many pre-defined templates with the values.

For example, you might have ten types of queries. Each query will have parameters and a classification/description. Get the classification, and get the parameters, and stick them into your respective template.

This gives you way more safety and predictability.

I've gone through the whole gamut to do this since first using the GPT's API in early 2023.

As first I was asking for HTML with few-shot since getting reliable JSON was impossible. Then I switched to function calling with JSON mode when that was released later in 2023, but still with fallbacks because sometimes it would spit out markdown with JSON inside, and other fun mistakes. Finally summer 2024 strict mode became available which "guarantees" a well-formed JSON response corresponding to a given schema. I've run hundreds of thousands of queries through that and have not had a formatting issue (yet).