Validation rules

BR-AG-05 — EN 16931 rule

An IPSI (M) line must have a VAT rate (BT-152) of 0 or greater.

Rule: BR-AG-05 — official EN 16931 / XRechnung rule
Severity: error
Business term: BT-152 — Line VAT rate
Field in your JSON: invoice.lines[*].vat
Detected by: tier 3 — KoSIT validator (authoritative)
Reachability: Only reachable when validating your own XML — normbill-generated documents cannot trigger it

The request schema requires line.vat >= 0, so generated documents always satisfy this.

How to fix it

Set a non-negative Percent on the line's ClassifiedTaxCategory in your XML.

BR-AG-05 auf Deutsch — was bedeutet der Fehler?

Eine IPSI-Position (Kategorie M) muss einen Steuersatz (BT-152) von 0 oder größer tragen. Das Anfrage-Schema erzwingt line.vat >= 0, generierte Dokumente erfüllen die Regel daher immer; die Meldung betrifft extern erzeugtes XML.

So beheben Sie den Fehler

Setzen Sie in Ihrem XML ein nicht-negatives Percent an der ClassifiedTaxCategory der Position.

Related rules

BR-S-05 — A standard-rated (S) line must have a VAT rate greater than zero.
BR-Z-05 — A zero-rated (Z) line must have a VAT rate of exactly 0.
BR-E-05 — A VAT-exempt (E) line must have a VAT rate of 0.
BR-AE-05 — A reverse-charge (AE) line must have a VAT rate of 0.
BR-O-05 — A line "not subject to VAT" (O) must not carry a VAT rate.
NB-VAT-RATE — A line has neither a VAT rate nor a VAT category — the category cannot be determined.

Official sources

Every 422 from the API lists the rule id, the path in your request JSON, a plain-language message and a suggested fix — see the docs overview for the report format.

Or try it live: drop any XRechnung XML on the free validator — same KoSIT-backed report, no account.