Claude Code for Business · practical unit

Reconcile two exports. Show what matches and what still needs a decision.

Produce a reconciliation report, an exception ledger and a reusable acceptance checklist. Start with six invoices, then solve a different month containing errors that equal totals can hide.

You should be able to open a CSV and edit a small JSON document. Use the lesson's guided brief if you want an agent to help. The browser checker needs no account, API key or paid tool. Optional agent use follows your provider's costs and permissions; only use these supplied synthetic files.

Reading estimate: 8 minutes. Setup and practice time: not yet measured. On a phone, inspect the inputs and predict the exceptions; use the same unit from your desk when ready to create the files.

The output contract

Keep invoice IDs as text. Include every physical row from both sources exactly once under its invoice ID. Use an empty array when that source has no row. For repeated IDs, keep all row numbers and flag the duplicate; do not choose a winner.

• version: the number 1.
• rows: one object per invoice ID, with invoice_id, crm_rows, accounting_rows and issues.
• issues: an array containing applicable missing_in_crm, missing_in_accounting or duplicate_id. Compare fields only for a one-to-one pair: amount_mismatch, currency_mismatch or details_mismatch for customer, region or date. An empty array means those fields match.
• totals: crm and accounting objects, each mapping currencies to decimal strings such as "10585.50". Include every row, including repeated IDs.
• unresolved: one object per group of different IDs sharing customer, region, amount, currency and date within either source. Set invoice_ids to that group and resolution to "source_document_required".

Array order is immaterial; row numbers, spelling, types and complete coverage matter. Do not convert currencies or infer whether a suspected duplicate is legitimate. The supplied exports cannot settle that question.

Run it locally, without installing packages

Download the two CSVs, the report template, checker-v1.mjs and check-v1.mjs into a disposable folder. Use Node.js 24 or later; confirm with node --version. Write your report as report.json.

node check-v1.mjs guided-crm.csv guided-accounting.csv report.json

Expected result: "passed": true and an empty errors array, exit 0. A rejected report exits 1. Replace guided with transfer for the second case. The checker reads those three files and writes nothing. Keep inputs unchanged, and delete the disposable folder when you no longer need your exercise files.

Demonstrate transfer

Solve the second case before reading the checker's implementation. Keep the first report, any failure output, the revised report and a note of assistance used. For each unresolved item, name the source document you would request and who should decide. A client handover should explain the matching rule, the checks run and what remains unresolved.

A passing check establishes this small contract. It does not establish fraud, accounting correctness, performance on large exports or independent competence. For a learning review, ask someone to attempt the new case without the worked answer and record where they needed help. No learner study result is claimed.