docs: dire l'effet et non le canal, et n'exiger le NURI en dur que d'un index global

test/only-grows.test.ts

@@ -154,6 +154,29 @@ test("an index declaring no field at all is still refused", async () => {
   await expect((await indexing(ownerPort)).read(ordinary)).rejects.toThrow(/declares no index field/);
 });
 
+test("curating a document that declares no field refuses, and writes nothing", async () => {
+  const network = new FakeNextGraph();
+  const ownerPort = network.portFor("alice");
+  const bobPort = network.portFor("bob");
+
+  // A document of Alice's with an inbox open and a reference waiting in it, and no
+  // field declared. This is also the shape an INDEX arrives in when it could not be
+  // read — the real `readUnion` turns a failed read into `[]` — so the two are one
+  // case here, and the refusal has to hold for both.
+  const noField = await ownerPort.createPublicDocument();
+  await ownerPort.openInbox(noField);
+  const article = await publishObject(bobPort, FIELD, "2026-01-01");
+  await (await indexing(bobPort)).refer(noField, article);
+
+  await expect(curate(ownerPort, noField)).rejects.toThrow(/declares no index field/);
+
+  // It refused instead of curating on a field it does not have, and it refused
+  // BEFORE writing: the document is still empty, so no entry was invented for it,
+  // and the deposit is still in the inbox for a run that knows what to do with it.
+  expect(await ownerPort.readDocument(noField)).toEqual([]);
+  expect(await ownerPort.readDeposits(noField)).toHaveLength(1);
+});
+
 test("a field that could never match an object is refused at creation", async () => {
   const owner = await indexing(new FakeNextGraph().portFor("alice"));
   // It cannot be corrected later — nothing here deletes — so it is refused now.