This seems like a solution looking for a problem. https://tiller.com/ works great and lets you do whatever calculations you want in a spreadsheet - and, bonus, it's never going to hallucinate.
I don't quite understand the desire to have these verbose summaries that you have to read from LLMs. You'll notice anomalies if you just categorize each of your expenses every so often (easy with Tiller).
This. It's really cool to weave other data sources into your data.
I recently needed to set up some calendar events on certain dividend days, but of course, didn't know what those dividend dates actually were. So we used the MCP connector to retrieve our current Vanguard holdings, had GPT-Pro do web research to pull all the dates, and then created calendar events from that. Worked well.
I don't quite understand the desire to have these verbose summaries that you have to read from LLMs. You'll notice anomalies if you just categorize each of your expenses every so often (easy with Tiller).