I would suggest you don't get Claude to process your json files, but create tools in scripts (eg python) that will do what you want, and enable repetition at the same time
IMO Gemini is surprisingly good at working with Json files but you also have to approach it appropriately. I use a lengthy detailed GEMs instruction (~10 pages). Then also feed it in an example structure and it's quite good at making edits. I've also used it to create a few thousand line tag structure and one shot it. But as with everything, need to always verify the results.