A short piece of fiction, written by API Evangelist. The reader is imagined; the post, and every number and quotation from it, is real: "Healthcare: The Shape Of The Answer," Kin Lane, October 21, 2026, https://apievangelist.com/2026/10/21/healthcare-the-shape-of-the-answer/
Priya worked as an integration engineer at a hospital group, and she read the post on her phone while the fax queue drained. Her job was mostly the thing the post opened with: someone reads a referral and retypes it into a system. Last spring she had tried to automate part of it with a model, and the results had been fine until they weren't.
She started out irritated. The post said healthcare was the industry that had done the most work writing its shapes down, and she thought that was easy to say from outside. Inside, a shape written down was not the same as a shape anyone enforced. Then she reached the part about US Core, which the post says describes itself as establishing "the floor" for US interoperability. She laughed a little. A floor was right. Her team had spent a year discovering how many ways there were to stand on one.
The section on determinism changed her mood. Her worst week had been a replay. A reviewer asked why a document produced a different Bundle on Tuesday than on Monday, and she had no answer except that the batch was different. The post's point was that batch-invariant output means the same document produces the same resources, so you can replay it. She wrote that on a sticky note, which felt old-fashioned.
She slowed down on the safety paragraph. The post says constraining output to the profile, with value sets as enums, means the model can't invent a code that isn't in the value set. It also admits the model can still pick the wrong one. Priya thought the second half was the more important one, and the post seemed to treat it as a footnote. A fabricated code fails loudly. A real code that is wrong sails through. She had once seen a dose that looked right and wasn't. The post even uses the phrase "looks right", and she thought that was the whole problem in two words. She did not disagree with the author so much as want the weight shifted. The check after generation was not a leftover step. It was the job.
What made her uncomfortable was the catalog section. Five of the 71 providers had a Claim-shaped contract the author could find, and much of the FHIR surface was the author's own work, split or generated from docs, not published by the providers. She read that twice. It was honest, and it also meant the numbers described a map someone had drawn, not the territory. She did not hold that against the post, which said so plainly. But she noticed she could not use any of it as evidence for her own vendors.
The closing line was "The shape was the hard part", and she decided that was true as far as it went. The hard part for her was that nobody had handed her the shape her own server enforced.
So she did one small thing before the queue emptied. She opened her test environment, pulled the CapabilityStatement from the FHIR server her group actually ran, and saved it into the repository beside the extraction prompt, where it had never been. She added a short note to the README saying this was the file to constrain against, not the generic R4 schema. She did not change the pipeline or promise anything to her manager. The file was committed by lunch, and the note was three lines long.