Month-end close agent environment

Reconcile ledgers, chase missing documents and produce a close pack inside a sandboxed accounting system with synthetic company books.

Here an agent plays the part of a junior accountant closing a month. It has a sandboxed ledger, bank feed, document inbox and a simulated client who sometimes replies slowly. To succeed, it must reconcile accounts, post accruals, request missing receipts and produce a final close pack. The 182 company-months use synthetic books modeled on patterns from small Japanese businesses, with injected problems such as duplicate payments, miscoded expenses and missing invoices. Grading compares final balances with a known correct answer, checks each injected problem and reviews the requests sent to the client. Tax treatment is simplified, and the environment shouldn't be used as a guide to Japanese tax rules. Scenarios are available in Japanese and English, although the Japanese versions contain more of the realistic messiness. It ships as a Docker image with a SQL-backed ledger and a documented tool API.