diff --git a/.changeset/reconcile-system-append-only-api-methods.md b/.changeset/reconcile-system-append-only-api-methods.md
new file mode 100644
index 0000000000..3f664ef217
--- /dev/null
+++ b/.changeset/reconcile-system-append-only-api-methods.md
@@ -0,0 +1,33 @@
+---
+"@objectstack/service-realtime": patch
+"@objectstack/metadata-core": patch
+---
+
+fix(identity): close the generic-write apiMethods hole on sys_presence and sys_metadata (#3220)
+
+Follow-through on #1591/#3213 (better-auth apiMethods reconciliation) for two
+non-better-auth managed objects that shipped the same contradiction: their
+`enable.apiMethods` advertised generic `create`/`update`/`delete` while their
+`managedBy` bucket forbids user-context writes, leaving the generic `/data`
+route open to a write the bucket does not permit.
+
+- `sys_presence` (`managedBy: 'append-only'`) advertised `create`/`update`/`delete`
+  (update/delete on an append-only object at that) but is written only over the
+  realtime websocket/in-memory path, never through ObjectQL. Narrowed to
+  `['get', 'list']`.
+- `sys_metadata` (`managedBy: 'system'`) advertised full CRUD but customization
+  overlays are authored only through the metadata-protocol RPC (engine writes
+  carry a transaction context, not a user session); neither the framework nor
+  the Console (objectui) POSTs `/data/sys_metadata`. Narrowed to `['get', 'list']`.
+
+Reads stay open. The metadata-protocol / realtime write paths are engine-level
+and bypass the HTTP exposure gate, so they are unaffected — verified by the
+metadata-authoring dogfood and the objectql overlay tests.
+
+A blast-radius audit confirmed the broader `system`/`append-only` buckets are NOT
+safe to guard wholesale: several `system` objects (`sys_user_position`,
+`sys_user_permission_set`, `sys_position_permission_set`, `sys_user_preference`,
+`sys_import_job`) are legitimately user-writable by design (delegated
+administration, user preferences, imports). Generalizing the engine write guard
+to those buckets is intentionally NOT done here — see #3220 for the bucket-taxonomy
+root cause.
diff --git a/packages/metadata-core/src/objects/sys-metadata.object.ts b/packages/metadata-core/src/objects/sys-metadata.object.ts
index f24e88cb60..144274ab8a 100644
--- a/packages/metadata-core/src/objects/sys-metadata.object.ts
+++ b/packages/metadata-core/src/objects/sys-metadata.object.ts
@@ -227,7 +227,13 @@ export const SysMetadataObject = ObjectSchema.create({
     trackHistory: true,
     searchable: false,
     apiEnabled: true,
-    apiMethods: ['get', 'list', 'create', 'update', 'delete'],
+    // #3220 — sys_metadata is `managedBy: 'system'`: customization overlays are
+    // authored ONLY through the metadata-protocol RPC (its engine writes carry a
+    // transaction context, not a user session), never the generic /data route.
+    // Neither the framework nor the Console (objectui) POSTs /data/sys_metadata,
+    // so the generic write verbs were a latent hole for a user-context raw write
+    // the bucket forbids. Reads stay open for the Setup "Data Model" grids.
+    apiMethods: ['get', 'list'],
     trash: false,
   },
 
diff --git a/packages/services/service-realtime/src/objects/sys-presence.object.test.ts b/packages/services/service-realtime/src/objects/sys-presence.object.test.ts
index 029327f745..9f3e84e1b0 100644
--- a/packages/services/service-realtime/src/objects/sys-presence.object.test.ts
+++ b/packages/services/service-realtime/src/objects/sys-presence.object.test.ts
@@ -70,4 +70,12 @@ describe('SysPresence object definition', () => {
   it('should have API enabled', () => {
     expect(SysPresence.enable?.apiEnabled).toBe(true);
   });
+
+  it('exposes reads only — append-only, written over the realtime path, never /data (#3220)', () => {
+    expect(SysPresence.enable?.apiMethods).toEqual(['get', 'list']);
+    // Guard against re-introducing a generic write verb on an append-only object.
+    for (const verb of ['create', 'update', 'delete', 'upsert']) {
+      expect(SysPresence.enable?.apiMethods).not.toContain(verb);
+    }
+  });
 });
diff --git a/packages/services/service-realtime/src/objects/sys-presence.object.ts b/packages/services/service-realtime/src/objects/sys-presence.object.ts
index 26b1c458f8..562961a00f 100644
--- a/packages/services/service-realtime/src/objects/sys-presence.object.ts
+++ b/packages/services/service-realtime/src/objects/sys-presence.object.ts
@@ -113,7 +113,13 @@ export const SysPresence = ObjectSchema.create({
     trackHistory: false,
     searchable: false,
     apiEnabled: true,
-    apiMethods: ['get', 'list', 'create', 'update', 'delete'],
+    // #3220 — sys_presence is `managedBy: 'append-only'` and is written only
+    // over the realtime (websocket/in-memory) path, never through ObjectQL.
+    // Advertising create/update/delete here (and update/delete on an
+    // append-only object at that) was a latent hole: it left the generic
+    // /data route open for a user-context write the bucket forbids. Reads
+    // stay open for diagnostic list views.
+    apiMethods: ['get', 'list'],
     trash: false,
     mru: false,
   },