TL;DR
What did @marshal use Claude for?
A business owner had Claude compare an agency's invoices, contract, hours and emails, and the agency dropped the extra bill. The owner says the agency came back within 24 hours and agreed with the findings.
What they did
An agency sent an extra invoice on a project the owner thought was already paid in full. The owner gave Claude the invoices, the contract, the stated hours and all of their messages with the agency, and asked it to audit them. Claude found more discrepancies and laid out the case that nothing more was owed.
How it went
The owner says the agency came back within 24 hours and agreed with the findings.
"Claude saved me $19,000 today."
— @marshal
Worth knowing
- One person's account in a single post. The agency's side isn't public, and the post doesn't show the documents.
- Price check: Claude: free plan; Pro: US$20/month, or US$17/month on a yearly plan (US$200/year) (checked Nov 1, 2026).
Paying for Claude? See cheaper Claude alternatives.
Try it yourself
Paste this into a chatbot, then add your own details underneath.
Here are a vendor's invoices, our signed contract, the hours they reported and our email thread. List every place where the billing doesn't match the contract or the hours, quote the line that supports each point, and tell me what is still unclear.
Original post
See @marshal's original post on X → (Aug 12, 2026)
Filed under Money & Bookkeeping hacks
Sources
- @marshal on X, Aug 12, 2026 — the original post
- Claude pricing — checked Nov 1, 2026