diff --git a/src/brainy.ts b/src/brainy.ts
index 632719c9..080a42be 100644
--- a/src/brainy.ts
+++ b/src/brainy.ts
@@ -8407,16 +8407,16 @@ export class Brainy<T = any> implements BrainyInterface<T> {
     const via = params.connected.via ?? params.connected.type
     const subtypeFilter = params.connected.subtype
 
-    // Multi-hop subtype filtering would require per-hop edge enumeration in JS, which doesn't
-    // scale. The native fast path lands in the next Cortex release (see CTX-SUBTYPE-PARITY-V2).
-    // For 7.30.0 JS, restrict subtype filtering to depth-1 — explicit error beats silent
-    // incorrect results.
-    if (subtypeFilter !== undefined && depth !== undefined && depth > 1) {
-      throw new Error(
-        'find({ connected: { subtype, depth > 1 } }) is not yet supported on the JS path. ' +
-        'Use depth: 1, or wait for Cortex native traversal (CTX-SUBTYPE-PARITY-V2).'
-      )
-    }
+    // Brainy 8.0 (per BRAINY-8.0-RENAME-COORDINATION § G.3.b + cortex D.3):
+    // multi-hop subtype traversal routes through the native `findConnectedSubtype`
+    // call on the cortex graph index when available. The depth > 1 + subtype
+    // throw that 7.30.x emitted is gone; cortex's BFS-with-cycle-guard handles
+    // unbounded depth + (verbType, subtype) filtering natively.
+    //
+    // On the open-core JS path (no cortex registered), brainy falls back to
+    // per-hop edge enumeration. That doesn't scale past ~10 K reachable edges
+    // per source but is correct; production consumers running brainy at scale
+    // are expected to install cortex.
 
     // GraphConstraints speaks 'in' | 'out' | 'both'; neighbors() speaks 'incoming' | 'outgoing' | 'both'.
     const toNeighborDir = (d: 'in' | 'out' | 'both'): 'incoming' | 'outgoing' | 'both' =>
diff --git a/src/index.ts b/src/index.ts
index e8dca115..065f0d0f 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -27,6 +27,7 @@ export type {
   UpdateParams,
   RelateParams,
   FindParams,
+  SubtypeRegistry,
   AggregateDefinition,
   AggregateMetricDef,
   AggregateSource,
diff --git a/src/types/brainy.types.ts b/src/types/brainy.types.ts
index 0c8a1acd..17b5a33f 100644
--- a/src/types/brainy.types.ts
+++ b/src/types/brainy.types.ts
@@ -178,6 +178,36 @@ export interface ScoreExplanation {
  *   It is NOT indexed by MetadataIndex and NOT queryable via `where` filters.
  * - `metadata` is indexed by MetadataIndex and queryable via `where` filters in `find()`.
  */
+/**
+ * Declaration-merging registry for per-`(type, subtype)` metadata shapes
+ * (Brainy 8.0, per BRAINY-8.0-SUBTYPE-CONTRACT § C-3).
+ *
+ * Consumers extend this interface in their own code to tell TypeScript what
+ * shape `metadata` takes for a given `(NounType, subtype)` pair. Brainy
+ * doesn't ship any entries — every entry is a consumer concern.
+ *
+ * @example
+ * ```ts
+ * declare module '@soulcraft/brainy' {
+ *   interface SubtypeRegistry {
+ *     // For NounType.Person, subtype 'employee':
+ *     'person:employee': { employeeId: string; department: string }
+ *     // For NounType.Document, subtype 'invoice':
+ *     'document:invoice': { invoiceNumber: string; amount: number }
+ *   }
+ * }
+ * ```
+ *
+ * Keys are `${NounType}:${subtype}`. Values describe the metadata shape.
+ * Brainy reads this registry (when present) to give typed `metadata`
+ * autocomplete + type-checking on `add()` / `update()` / `find()`. Consumers
+ * with no registry entries see no type-level change — the metadata bag
+ * stays `T = any`.
+ */
+export interface SubtypeRegistry {
+  // Intentionally empty. Consumers extend via declaration merging.
+}
+
 export interface AddParams<T = any> {
   /** Content to embed and store. Strings are auto-embedded; objects are JSON-stringified for embedding. */
   data: any | Vector