I am interested to see if these tools can be used to tackle tech debt, as often the argument for not addressing tech debt is a lack of time, or if they would just contribute it to it, even with thorough instructions and guardrails.

From my experience working with people who use them heavily, they introduce new ways of accumulating tech debt. Those projects usually end up having essays of feature spec docs, prompts, state files (all in prose of course), etc. Those files are anywhere from hundreds to thousands of lines long, and there's a lot of them. There's no way anybody is spending hours reading through enough markdown to fill twenty encyclopedia-sized books just to make sure it's all up-to-date. At least, I can promise that I won't be doing it, nor will anyone I know (including those using AI this way).