AI-drafted invoices for EU SMB operators in 2026 fail VAT audit at higher rates than human-drafted invoices specifically on cross-border treatment (OSS scheme wording, reverse-charge language, customer VAT-status verification), because LLM training data underweights post-2021 e-commerce VAT rules. The fix is a 4-line VAT-compliance prompt prefix that names the operator's VAT registration, the customer's VAT status, and the applicable scheme; most SMB invoicing tooling does not ship this by default.

Cross-domain: EU OSS scheme + reverse-charge VAT rules intersected with SMB AI-invoice tooling. The prompt prefix is the practical operator-side fix; pairs with OPS-039 (notary contracts) as an example of AI handling visible work but missing regulatory-context work.