diff --git a/src/brainy.ts b/src/brainy.ts
index 61f8a8bb..632719c9 100644
--- a/src/brainy.ts
+++ b/src/brainy.ts
@@ -9288,6 +9288,13 @@ export class Brainy<T = any> implements BrainyInterface<T> {
       // true: every public write path requires subtype on every type.
       // { except: [...] }: strict, but listed types may omit subtype.
       // Becomes the default in 8.0.0.
+      // Subtype enforcement default. Brainy 8.0's subtype contract
+      // (BRAINY-8.0-SUBTYPE-CONTRACT § C-1) flips this to `true`; that's
+      // staged as a focused commit alongside a sweep of the ~235 test
+      // sites that need to start passing subtype explicitly. For now, the
+      // 7.x default (`false`) ships; per-type and per-brain enforcement
+      // via `brain.requireSubtype()` / `new Brainy({ requireSubtype })`
+      // remain available.
       requireSubtype: config?.requireSubtype ?? false,
       // Multi-process safety
       mode: config?.mode ?? 'writer',