MosoFin skill · expense-report-processor · learning guide

From one taxi with no receipt to the account that does not clear

This page shows how the skill checks expense reports, one level at a time. It starts with one line and one rule. It ends with the ledger checks and the limits of the run. The page quotes every rule from the skill itself and works every number in front of you.

The rules are the skill's ownThe page quotes each rule word for word, with the file and section it comes from.
Outside sources back the factsThey are three IRS pages, a GSA per-diem bulletin, an ACFE fraud study, the GAO Green Book and an HMRC page. Each one has a number and a link.
The page shows the mathOpen "Check it yourself" on any level. Follow every line on a calculator.
Your numbers, your checkAt the end, enter one employee's report. The page runs the Step 4 table.
Rule: quoted from the skill Fact: from a cited authority, numbered like 1 Example: made-up figures, calculated in full
How it thinks

Fourteen rules the whole skill runs on

Every level below applies one or more of these rules. The examples use one made-up company, Northbrook Trading, a US entity that keeps its books in US dollars. Its September reports come from Expensify. Its policy is version 3, dated 1 January. The policy asks for receipts above $25 and caps meals at $60 a head. It pays mileage at $0.45 a mile from 1 January. These figures are the company's own policy. They are not tax rates.

Learning path

Six levels, from simple to complex

Check it yourself

Put in your own employee

Enter the figures from one employee's report, or load an example. The page runs the Step 4 table from references/method.md and shows each line. The page sends nothing anywhere.

The report
Mileage

Enter the rate from your own policy, with its date. The skill never supplies one. Leave out miles that have no start, end or purpose. The skill holds those miles.

The page computes total submitted = report lines + miles × rate. Net reimbursable = total submitted − company-paid − disallowed − personal. Amount to pay = net reimbursable − Due from Employee offset. The "Priya Nair, September" preset gives $1,450.00 + 120 × $0.45 = $1,504.00. Then $1,504.00 − $790.00 − $442.00 − $0.00 = $272.00, with no offset. The "Marcus Bell" preset gives $166.59 − $15.99 = $150.60, with no mileage and no offset. A figure from the calculator is a proposal. A manager still approves each line.

Using it

What it asks, needs and gives back

Asks firstDo you want to use MosoFin for this run, or upload the data yourself? Which reports, which employees and which period? What is your expense policy? Where are the receipts? Which mileage rate and per-diem table are in force, and from which date? Which tax jurisdiction and rules apply? For foreign claims, which exchange-rate source do you use? Do you book card charges to a clearing account or to expense? Who approved each report?
NeedsThe skill needs every line of the expense reports. It uses the chart of accounts for coding, and the posted transactions and card activity for the duplicate check. The approved reports not yet paid are for the payable test. You type in the policy, the rates and the exchange-rate source, because no ledger holds them. An employee list makes the result better.
Gives backThe skill gives back six sheets: a summary, the line detail, the exceptions, the posting inputs, the ledger checks and a coverage sheet. It asks before it makes an Excel file.
NeverThe skill never approves, rejects, pays or posts anything. It never supplies a rate, a threshold or an account number from memory. It never reports a receipt as verified. It never saves names, claims or amounts.
Sources

Where every fact on this page comes from

The rules are the skill's own. The facts below come from seven outside sources. They are three IRS pages, a GSA per-diem bulletin, an ACFE fraud study, the GAO Green Book and an HMRC page. MosoFin checked each one on 27 October 2026 from search results and did not open the pages. Follow the link for today's wording.

    Not backed by an outside authority. The six stages, the ±3 day match window, the 90-day look-back, the three severities and the six output sheets are the skill's own. The mileage rate, the receipt threshold and the meal cap in the examples are Northbrook's made-up policy. They are not tax rates. The page marks them where they appear.