A journal entry is a record of a transaction in the books, with at least one debit and one credit of equal total, a date, the accounts affected and a narrative explaining why. Some are generated automatically by systems; others, called manual journals, are entered by people for accruals, corrections and adjustments. Manual journals carry the most risk.
Why does a journal entry matter once agents act?
Manual journals are the one place in most accounting systems where someone can move any amount between any two accounts with a sentence of explanation. That is why auditors test them closely, and why an agent that prepares or posts journals needs tighter bounds than one that codes invoices.
An agent is also good at the part people skimp on: support. It can attach the calculation, the source document and the reasoning to every entry it drafts, consistently. In finance agents, that discipline is the difference between a ledger that looks right and one that can be shown to be right, a theme in AI agents for finance and in a finance agent's figures must trace to an entry.
What does a journal entry contain?
- Date and period: when it takes effect, which must be an open period.
- Lines: each with an account, a debit or credit, an amount and, where used, a department or project.
- Balance: total debits equal total credits.
- Narrative: what the entry does and why, in words a reviewer can test.
- Support: the invoice, contract, calculation or reconciliation it relies on.
- Preparer and approver: two different parties, recorded.
- Reversal flag: whether it reverses automatically next period, as many accruals do.
A journal entry support template gives a layout for the support pack.
How should an agent handle journals in practice?
Begin at drafting. The agent prepares the entry and support; a person reviews and posts it. This is set out in how to draft journal entries for a person to post with an AI agent. Once an agent has been certified on a class of routine entries, such as monthly rent accruals within a fixed amount, it may post those directly. Corrections, one-off adjustments and anything touching equity, tax or intercompany stay drafted. Whether and when to go further is discussed in can an AI agent post journal entries?
What does that look like in an example?
A retailer receives an electricity bill in the second week of the month for the previous month's usage. At month end the agent drafts an accrual: debit utilities 3,200, credit accruals 3,200, narrative "estimated electricity for the month based on the average of the last three bills, reversing on day one of next period". It attaches the three bills and the calculation. The finance manager approves and posts. When the bill arrives at 3,350, the difference of 150 falls into the next month, and the reversal means nothing is counted twice.
How is a manual journal different from a system-generated entry?
A system-generated entry is a by-product of a process: an approved invoice in payables, a payroll run, a depreciation schedule. Its controls live in the process that created it. A manual journal is created directly in the ledger, so its only controls are the review and the support attached to it. An agent preparing invoices for payables is feeding a controlled process. An agent drafting manual journals is acting in the least controlled part of the books, and its bounds should reflect that.
Questions people ask
Can an AI agent reverse a journal entry?
It can draft a reversal with the reason and the original entry referenced. Posting a reversal is posting a new journal, so the same bounds apply as for any journal it posts. Editing or deleting the original entry should never be possible; corrections are new entries. The detail is in can an AI agent reverse a journal entry?
What makes a journal narrative good enough?
A reviewer who was not involved should be able to say what the entry does, why, and where the numbers came from, without asking anyone. "Month-end adjustment" fails that test. "Accrue December cleaning invoice not yet received, per contract rate of 1,200 a month" passes it.