Accounts payable AI agents for contractors

We build two single-job agents for a contractor's accounts payable team. The invoice check agent reads every supplier invoice and flags overcharges, duplicate bills (same vendor, same amount or PO, a different invoice number), quantities beyond the PO, freight the terms don't allow, missing rebates and math errors. The AP coding agent codes each invoice to the right account, job and cost code. Your team decides every item.

Two agents, one job each

They're separate builds. Start with the one that costs you more today; the paid assessment below measures that.

What the invoice check agent checks

• Prices over what was agreed. Each line against the PO price or the supplier's price list on the invoice date, including a price increase billed on a PO placed before the increase.
• Duplicate invoices. The same invoice sent twice, and the same bill under a new number: same vendor, same amount or PO, a different invoice number.
• Quantities beyond the PO. Tracked across partial shipments, so 30 billed against 24 ordered shows up even when it arrives on two invoices.
• Freight the terms don't allow. Delivery charges on orders the supplier agreement says ship free.
• Rebates and credits owed but not applied.
• Math errors. Line extensions and invoice totals that don't add up.

Lines it can't match to anything go to a person, with the reason. It doesn't guess.

What the AP coding agent does

• Sorts every email in the AP inbox. A new invoice, a resend of one already received, or not an invoice at all: statements, quotes, order confirmations, packing slips.
• Reads the invoice wherever it is. A PDF, a spreadsheet or the body of the email: vendor, invoice number, dates, PO, total and every line.
• Codes each line. Vendor, GL account, job, cost code and location, from the PO, the job number or site address, and how that vendor has been coded before.
• Names the approver from the approval rules you already use, by amount and type.
• Holds anything it shouldn't decide alone, such as a vendor it doesn't know, a request to change bank details, a scanned page it can't read, a credit memo, a PO from another vendor or a closed job. Each one goes to a person with the reason, and stays out of the coded bills file.

What your team still decides

• Every exception and every coded invoice. The agents never pay, short-pay, hold, dispute or approve an invoice, and never email or call a supplier.
• Anything about bank details. A request to change payment details always goes to a person, to verify by phone on the number you already have.
• Lines the agent couldn't place. Where an optional AI step suggests a match, it's marked "confirm" and a person decides.
• What gets loaded. The coding agent writes a file; your AP team loads it into the accounting system. Neither agent writes to it.

The acceptance test

Before go-live, each agent has to pass a test on your own documents, written into the scope.

For the invoice check agent, you pick past invoices we didn't use to build it and plant errors in copies of them. You keep the answer key. The agent runs 10 times on that sample, each from a clean start. By default it has to catch at least 90% of the planted errors across the 10 runs and at least 80% in every run, with no more than 1 false flag per 25 invoices on average. Lines it sends to a person don't count as caught. The bar is set with you in the scope.

For the coding agent, the same 10 runs use a held-out set of invoices your team has already coded, and the bar for lines coded exactly right is written into the scope.

It's a go-live check, not a promise of dollars recovered or hours saved. The second half of the build isn't due until the agent passes it.

What it costs

The invoice check agent is scoped to go live within 30 days of kickoff. The clock starts when the NDA is signed and the documents are in, and pauses while we wait on data. Where an agent uses an AI model, the provider bills your own account at its list price; we don't mark it up. For how this compares with other agent builders, see what a custom AI agent costs.

Who it fits

• Owner-run HVAC, plumbing, electrical and roofing companies with about $10 to $40 million in revenue and someone doing AP or purchasing.
• Private equity backed home services platforms and commercial building services platforms, where every add-on brings more suppliers.
• Companies buying from a handful of distributors on price lists, increase letters and rebate programs.

It isn't worth it if you get a few dozen invoices a month, or if your current process already catches all of the above. The assessment tells you which, in numbers.

See a sample on a call

On a 20-minute call we look at how your supplier invoices get checked today and walk through a sample exceptions report. The sample is made-up data: two fictional suppliers and 25 fictional invoices, built so you can see the weekly list before anyone shares a document. Book a 20-minute invoice check review, or write to hello@curbandcode.com. For the other agents we build, see AI agents for home service companies.

FAQ

How does duplicate invoice detection work?

The agent compares each new invoice with the ones already received from that supplier. It flags the same invoice sent again and the same bill under a new number: same vendor, same amount or PO, different invoice number. Each flag goes on the weekly list for your AP team to decide.

Can it find duplicate payments we've already made?

Its first run covers a backlog of past invoices from a date you pick, so earlier duplicates and overcharges show up in the first report. Asking a supplier for the money back is your team's call; the agent never contacts suppliers.

We already have AP software that matches invoices to POs. Do we need this?

Keep it: PO matching is what that software does well. This checks the things around the PO: each supplier's price list and increase letters, freight terms, rebates owed, and the same bill resent under a new number. It works from the inbox you already have, with no software switch.

Does it connect to our field software?

No. Both agents work from your AP inbox and the exports your team already pulls, not your field software's API.

Does it write to our accounting system?

No. The invoice check agent writes a report and a CSV. The coding agent writes a coded bills file your AP team checks and loads.

Does it use AI?

Mostly plain rules: one reader per supplier invoice layout, then matching against your records. An optional AI step can suggest a match for a line the rules can't read, and every suggestion is marked "confirm" for a person.

How do you handle our invoices and data?

We sign a mutual NDA before any documents change hands. The agent is set up in accounts you own, with us added as a user you can remove at any time, and we delete what we hold when the work ends.

What does an AP agent cost?

A paid assessment from $1,000, credited to the build; a build from $15,000 per agent, half at kickoff and half at go-live; maintenance of $500, $1,000 or $2,000 a month.

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