aiofthe.day

Reconcile vendor invoices overnight with one sub-agent per vendor

CodexUser storyJun 2026

An AI consultant described on Social Media Examiner how he set up Codex for a construction company to check hundreds of vendor invoices against its internal spreadsheet every week, a job that used to take staff days each month.

What they did

Staff drop vendor invoices into folders named by vendor. Every Sunday at 10pm a Codex automation starts one sub-agent per vendor folder, and each one runs a custom invoice reconciliation skill that looks for duplicates, outstanding balances and discrepancies against the spreadsheet, then writes a vendor report and a master summary.

What happened

The consultant says the reports are ready by Monday morning and the whole process now takes 15 to 30 minutes, down from two to three days a month by hand and a few hours with an earlier chat-based workflow.

Keep in mind

Told by the consultant who built it, about a client; there is no detail on error rates or who reviews the flagged items before payment.

Try it with your agent

In <your invoices folder> there is one subfolder per vendor, and <your vendor ledger spreadsheet> lists what we expect to pay. For each vendor folder, check every invoice against the spreadsheet and list duplicates, amounts that do not match, and invoices with no matching entry. Write one short report per vendor and a summary table across all vendors. Do not change the spreadsheet.

Replace the <angle brackets> with your own details.