> Thus, you may expect that effective prompting for Text-to-SQL should include structured schema definitions; indeed.

I found that the simpler the better, when testing lots of different SQL schema formats on https://www.sqlai.ai/. CSV (table name, table column, data type) outperformed both a JSON formatted and SQL schema dump. And not to mention consumed fewer tokens.

If you need the database schema in a consistent format (e.g. CSV) just have LLM extract data and convert whatever the user provides into CSV. It shines at this.