Build a weekly money review skill for your AI assistant
If my spending went up last week, the first thing I want to know is which purchase I’d actually want to do something about. A total can tell me to take a closer look. It takes the transactions to tell me where.
In the first article, we turned Casey’s bank and card records into a weekly review. This time we’ll give an AI assistant a small set of instructions it can use again. That’s the skill. Casey and the transactions in the download are fictional. You can try the skill before putting any of your own numbers into a chat.
Give the review a routine
Open SKILL.md in the download. The instructions tell the assistant which dates to compare, how to count a refund, and when to go back to individual purchases. The calculator does the arithmetic. The assistant’s job is to explain the change and answer your next question.
Take the $300 credit card payment in the bank file. The card file also shows the payment arriving. Neither entry belongs in the spending total. The purchases it paid for are already there. Saving that rule in the skill means you don’t have to remember to mention it every week.
Try a first review
Unzip the download. In a chat that accepts files, attach SKILL.md, example-result.json and both CSVs from the data folder. If your chat accepts only text, paste their contents instead. The JSON contains the calculated totals for this example. The CSVs let you check which purchases sit behind them.
Use the weekly money review skill and the attached files. Compare October 19 to 25, 2026 with October 12 to 18. What changed most in my spending? Show me the purchases that explain it.
If you use an assistant that can run local code, open the unzipped folder with it and give it the same question. Ask it to run the calculator. To reproduce the numbers yourself, open a terminal in the folder containing review.py and run this with Python 3.10 or later.
python3 review.py --start 2026-10-19 --end 2026-10-25Ask about the dinner
Once you get the first answer, stay in the same chat and ask a question the weekly total alone can’t answer.
If I leave out the largest dining purchase, how does that week compare with the one before?
Check both answers against the records
Spending across the two files rose from $248 to $356, an increase of $108. Dining accounted for $82 of that change. The first week had a $22 cafe purchase and a $40 restaurant meal, totaling $62. The next had an $88 restaurant meal on October 19, $36 of takeout and a $20 cafe purchase, totaling $144.
Leave out the $88 meal and the second week comes to $56. That’s $6 less than the first week. Across all categories, spending without the dinner comes to $268, which is $20 more than the prior week. There was one more dining purchase in the second week, but the bigger question for my budget would be whether that dinner was a special occasion or something I expect to do again.
Use it again next week
Keep the instructions. For a new review, supply the new week’s posted purchases and the preceding week for comparison. Give the assistant the dates and have it calculate fresh totals. The sample calculator understands the two file layouts in this download. If your export uses different columns or signs, adapt the importer before relying on its answer.
With the DIY version, you keep the files current. In Cash Coach AI, the Weekly Wrap already happens automatically. You can open it and ask which purchase changed your week while the transactions are still in front of you.
Comments