A number, or a guess.

A statement is a closed document. It prints its own totals, and those totals are arithmetic that either works or does not. Ezra reads the lines out of the statement, adds them up itself, and sets its own sums against the ones the bank printed.

On a checking statement that is deposits, withdrawals, and the roll: the opening balance less the net of every line has to arrive at the printed closing balance. On a card statement it is the summary box, line by line: purchases, payments, credits, fees and interest, each against the total the issuer printed for it. Agreement is to about a penny, so a rounding artifact is not treated as a discrepancy and a real one has nowhere to hide.

That is the whole idea, and it is not clever. It is the check a careful bookkeeper does by hand and the check software skips, because doing it means sometimes having to report a failure. Ezra is that bookkeeper, and reporting the failure is part of the job rather than an exception to it.

It ties

The lines are booked and the statement is recorded as reconciled, with the checks it passed kept beside it. This is the ordinary case and it is the only one that produces figures Ezra has nothing to say about.

It parses but does not tie

The file is kept. The lines are booked carrying the flag unreconciled, the statement is recorded as not reconciled, and the checks that failed are stored with it so you can see which total disagreed and by how much. Ezra accepts nothing silently, and throws nothing away either: a statement that does not tie is usually the most interesting document you own.

It is not recognized

The file is kept, nothing is booked, and the answer says why in words rather than failing quietly. A PDF that is not a statement, or a statement from a bank Books cannot yet read, is a fact about Books, and Books says so.

A failing statement never overwrites a passing one

If a statement that already reconciles covers the same books, the same account and the same period, a new file that does not reconcile is kept and flagged but books nothing. The good month stays the good month.

Uploading twice does not double anything

A statement is identified by the hash of its contents, so the same document uploaded again lands on the same record and replaces itself. Renaming the file does not make it a second statement.

Activity exports are marked, not scored

A CSV or Numbers export the bank hands out prints no totals, so there is nothing to check it against. Those book their lines and record no reconciliation at all, rather than recording a pass they did not earn or a failure they could not have avoided.

A balance says what kind of balance it is

What the bank reported at a moment, a statement rolled forward by the ledger, and a printed closing balance with nothing after it are three different claims. Ezra never averages two of them together and never swaps one for another, and a figure with nothing behind it is shown as absent rather than as zero.

A profit and loss summary drawn from an unreconciled ledger looks exactly like one drawn from a reconciled ledger. Same layout, same confident totals, same chart. The difference is that one of them has been checked against a document the bank printed and the other has not, and you cannot tell by looking. That is what makes it worth doing continuously rather than at the end.

It is also the answer to the only hard question an accountant asks about a set of books they did not keep: how do you know this is all of it. Ezra answers that with a list of statements, each with its period and its checks, included in the year-end package.