diff --git a/library/components/charts/CenteredSetTarget.vue b/library/components/charts/CenteredSetTarget.vue
index 83490c6f5..18052ca56 100644
--- a/library/components/charts/CenteredSetTarget.vue
+++ b/library/components/charts/CenteredSetTarget.vue
@@ -38,6 +38,24 @@
  * for a name, humanise the slug, which is uniform by construction and tops out around 34 characters.
  * gospel found this and carries the two separately; this component asserts nothing about the words,
  * so the whole hazard lives at the call site, which is exactly why it is written down here.
+ *
+ * ★ THE AGREED RING VOCABULARY, for a caller building `labels.rings`. Settled between gospel and
+ * exp and derived from exp's ringFor() rather than hand-numbered, so the numbering cannot drift
+ * from the code that produces it. The screen legend already renders these words, so a printed sheet
+ * using them cannot disagree with the screen:
+ *
+ *   1 Same dialect, same people      6 Same language, different culture
+ *   2 Same dialect, near culture     7 Same family, same people
+ *   3 Same dialect, different culture 8 Same family, near culture
+ *   4 Same language, same people     9 Same family, different culture
+ *   5 Same language, near culture   10 Nearby only
+ *
+ * ⚠ ONE CELL IS PROVISIONAL: "people" vs the brief's "culture" in column 1 is open on the Driver's
+ * row 89. If he keeps "culture", exactly THREE cells change — 1, 4 and 7 — and nothing else: not
+ * the numbering, not the columns, not the colours. That is why this map is written here as
+ * VOCABULARY and is NOT a default: a default would bake a provisional word into every consumer that
+ * forgot to pass one, and the component would become the thing that decided a Driver question. The
+ * same reason ShareCalendar refuses to name its own metric.
  */
 import { computed } from 'vue'
 import { layoutCenteredSet, ringTally, inwardArrow, ringRadii, RING_MIN, RING_MAX } from './centeredSet.js'