diff --git a/apps/api/src/authorization-middleware.ts b/apps/api/src/authorization-middleware.ts
index 813d184..9b88124 100644
--- a/apps/api/src/authorization-middleware.ts
+++ b/apps/api/src/authorization-middleware.ts
@@ -17,9 +17,11 @@ function sanitizedDenial(c: Context, status: 403 | 503, code: string): Response
 }
 
 /**
- * Builds a Hono middleware that enforces `permissionId`, resolved exclusively from Core's own
- * trusted, server-side permission registry — a route never supplies its own baseline, and no
- * request input can influence which baseline is checked. The principal is resolved exclusively
+ * Builds a Hono middleware that enforces `permissionId`, resolved exclusively from the injected,
+ * trusted, server-side `PermissionRegistry` — in production, the complete platform registry
+ * `startApi` composes from Core's own declarations plus every installed module's, never a
+ * Core-only fallback. A route never supplies its own baseline, and no request input can influence
+ * which baseline is checked. The principal is resolved exclusively
  * through the injected identity runtime (`resolvePrincipal`), the same one `/api/v1/principal`
  * already uses; nothing here ever trusts a client-supplied claim about identity, ownership, or
  * grants. A permission id that is not registered fails closed (403) exactly like a denied
diff --git a/apps/api/tests/api-http.integration.ts b/apps/api/tests/api-http.integration.ts
index 812d963..902ae1b 100644
--- a/apps/api/tests/api-http.integration.ts
+++ b/apps/api/tests/api-http.integration.ts
@@ -891,9 +891,11 @@ describe.sequential("live API — platform owner and delegated grant management"
   const ownerEmail = "authz-owner@example.test";
   const managerEmail = "authz-manager@example.test";
   const password = "correct horse battery staple";
-  // Module permission registration does not exist yet, so `core.authorization.grants.manage` —
-  // the one permission `CORE_PERMISSION_REGISTRY` actually declares — stands in for "some
-  // registered permission" throughout this scenario's explicit-grant lifecycle.
+  // This scenario intentionally proves out the explicit-grant lifecycle (create, list, use,
+  // revoke) against Core's own grant-management permission rather than a module's — a module
+  // permission would exercise the exact same route and evaluator code, adding coverage breadth
+  // without coverage depth. The "live API — installed module permission end-to-end" scenario
+  // below is where a real installed module's declared permission is proven end-to-end instead.
   const testPermission = "core.authorization.grants.manage";
   // Well-formed (passes `PermissionId` shape validation) but never registered — used to prove the
   // live route rejects it even for a caller who otherwise has full grant-management authority.
diff --git a/apps/api/tests/grants-routes.test.ts b/apps/api/tests/grants-routes.test.ts
index 0b1b37c..07012a5 100644
--- a/apps/api/tests/grants-routes.test.ts
+++ b/apps/api/tests/grants-routes.test.ts
@@ -25,8 +25,13 @@ const subjectUserId = parseEkklesiaUserId("subject_1");
 // (or, for listing, still return) an unregistered permission id rather than assuming registration.
 const permission = parsePermissionId("calendar.events.read");
 // A permission `CORE_PERMISSION_REGISTRY` actually declares, so tests that must reach
-// `store.createGrant`/`store.revokeGrant` can do so without also depending on module permission
-// registration, which does not exist yet.
+// `store.createGrant`/`store.revokeGrant` can do so. This suite exercises `createGrantsRoutes` in
+// isolation and intentionally injects `CORE_PERMISSION_REGISTRY` directly rather than a composed
+// platform registry — the routes have no notion of "Core" versus "module" permissions, they only
+// ever consult whichever registry they are given. Coverage proving a module-declared permission
+// works through the exact same route code lives in
+// `apps/api/tests/authorization-middleware.test.ts` (unit) and the "installed module permission
+// end-to-end" scenario in `apps/api/tests/api-http.integration.ts` (live).
 const registeredPermission = CORE_AUTHORIZATION_GRANTS_MANAGE;
 const grantId = parseGrantId("11111111-1111-1111-1111-111111111111");
 
diff --git a/core/src/authorization/permissions.ts b/core/src/authorization/permissions.ts
index f5242c1..e81e56f 100644
--- a/core/src/authorization/permissions.ts
+++ b/core/src/authorization/permissions.ts
@@ -46,9 +46,10 @@ export class PermissionRegistryError extends Error {
  * Builds an immutable permission registry from a fixed list of declarations, rejecting any
  * duplicate permission id outright at composition time. Deliberately the smallest mechanism that
  * distinguishes "registered" from "well-formed": no module discovery, no dynamic registration, no
- * network or filesystem I/O — a future module registration mechanism can merge its own
- * declarations into a combined list and still call this same constructor, inheriting duplicate
- * detection for free instead of reimplementing it.
+ * network or filesystem I/O. The module integration layer's composer
+ * (`composePlatformPermissionRegistry`, `core/src/modules/permissions.ts`) merges Core's own
+ * declarations with every discovered module's into one combined list and calls this same
+ * constructor, inheriting duplicate detection for free rather than reimplementing it.
  */
 export function createPermissionRegistry(
   declarations: readonly PermissionDeclaration[],
@@ -98,11 +99,12 @@ export const CORE_PERMISSION_DECLARATIONS: readonly PermissionDeclaration[] = Ob
 ]);
 
 /**
- * Core's own permission registry — the trusted source of truth `apps/api`'s authorization
- * enforcement consults so an HTTP route can never supply its own baseline. Contains exactly the
- * one Core-owned permission this slice needs; a future module registration mechanism is
- * deliberately out of scope here and will compose its own declarations through
- * `createPermissionRegistry` rather than through this constant.
+ * Core's own permission registry, containing exactly the Core-owned permissions declared above.
+ * Production `apps/api` does not consult this constant directly: it enforces requests against the
+ * composed platform registry (`composePlatformPermissionRegistry`,
+ * `core/src/modules/permissions.ts`), which merges these same declarations with every installed
+ * module's. `CORE_PERMISSION_REGISTRY` remains for Core-only callers and tests that need Core's
+ * permissions in isolation, without composing in any module.
  */
 export const CORE_PERMISSION_REGISTRY: PermissionRegistry = createPermissionRegistry(
   CORE_PERMISSION_DECLARATIONS,