A general ledger is the complete record of every financial transaction a business has posted, organised by the accounts in its chart of accounts. Each entry shows the date, account, debit or credit, amount and a reference to its source. The trial balance and financial statements are produced from it, which makes it the system of record for the books.
Why does the general ledger matter once agents act?
The general ledger is where an agent's work stops being a suggestion and becomes the company's numbers. A draft in an inbox can be ignored. An entry in the ledger flows into the trial balance, the management accounts, tax returns and, eventually, the audited statements. That is why access to it should be granted in steps, and each step earned.
It also works in the other direction. For a finance agent, the ledger is the most authoritative source it reads. Figures the agent reports should trace to ledger entries, not to a spreadsheet extract someone saved last week. Building that discipline into AI agents for finance is what keeps the books auditable.
How does it work in practice?
Most ledgers receive two kinds of entry. System postings arrive from sub-ledgers and operational systems: invoices, receipts, payroll, depreciation. Manual journals are entered by people for accruals, corrections and adjustments. Both should carry a reference back to their evidence.
For an agent, access usually grows through four stages:
- Read: query balances and entries to answer questions and prepare analysis.
- Draft: prepare journals that a person reviews and posts.
- Post routine entries: recurring journals within set amounts and accounts, after certification.
- Never: posting to a closed period, editing posted entries or changing the chart.
Before stage 3, run the agent against past periods where the correct answer is known. The method is set out in how do you test an AI agent before it touches the general ledger?
What does that look like in an example?
A payroll run produces a summary journal: gross pay, tax, pension and net pay. An agent compares the payroll report with what reached the ledger and finds the pension line is 2,000 lower in the ledger. The cause is one department's costs posted to an old account that was closed in the chart but not blocked in the payroll mapping. The agent drafts the correcting journal and a note for the payroll team to fix the mapping. This kind of check is detailed in how to reconcile payroll to the general ledger with an AI agent, and the same logic applies to reconciling bank accounts to the general ledger.
How is a general ledger different from a sub-ledger?
A sub-ledger holds the detail for one area, such as every customer invoice or every fixed asset, and passes a summary to a control account in the general ledger. The general ledger holds the summary for every area, plus manual journals. You look in the receivables sub-ledger to see what one customer owes; you look in the general ledger to see what all customers owe in total. When the two disagree, something has been posted to the control account directly or a feed has failed.
Which related terms should you know?
- Chart of accounts: the list of accounts the ledger is organised by.
- Journal entry: a single balanced posting to the ledger.
- Trial balance: a list of every ledger account balance at a date.
- Period close: the lock that stops further posting to a finished month.
Questions people ask
Should an AI agent have write access to the general ledger?
Not at first, and never without limits. Start with read access, move to drafting journals that people post, and allow direct posting only for routine, recurring entries the agent has been certified on. Each posting should carry its evidence and the reason it was allowed.
Is the general ledger the same as the accounting system?
No. The accounting system contains the general ledger along with sub-ledgers, workflows and reports. The general ledger is the core record inside it, which is why controls on who may post to it matter more than controls on most other parts of the system.