@@ -0,0 +1,20 @@
+---
+'@objectstack/mcp': patch
+---
+
+fix(mcp)!: the stdio data bridge reads objects from the protocol's merged view, so `list_objects` and `describe_object` see every object `GET /api/v1/meta/object` lists, a package object declared `apiEnabled: false` is refused by every data verb, and so is every object of a disabled package (`404 OBJECT_PACKAGE_DISABLED`)
+
+Clause-②: no (narrowing)
+Metadata-protocol: none
+
+<!-- adr-0087: not-required (no-migration-prescription) No metadata moves: no spec key, authorable spelling, object definition or stored shape is added, removed, renamed or re-shaped, and no exported declaration is removed or narrowed, so there is nothing for `objectstack migrate meta` to rewrite. What changes is which definition the stdio MCP transport consults: its object discovery and its API-exposure gate now read the protocol's merged view, the definition REST and the `/mcp` HTTP bridge already serve and enforce, instead of the metadata service's copy. An object's own `enable.apiEnabled` / `enable.apiMethods` declaration is now enforced where it was not read; the remedy is the declaration the author already wrote, never a rewrite of a package source or a stored row. The other categories are closed on facts: the package publishes (not unpublished); no ADR-0087 id is named or touched (not registered or already-registered); and nothing exported is removed or narrowed (not runtime-interface-only, type-surface-only or runtime-export-retired). -->
+
+**BREAKING** (the stdio data verbs' accept set narrows to the object's own declaration), shipped as `patch`: it changes which requests the stdio transport serves, not what a metadata author can write.
+
+The long-lived stdio MCP server (`objectstack mcp`, `OS_MCP_STDIO_ENABLED`) answered `list_objects` and `describe_object` from the `metadata` service, and gated its data verbs and its record resource on the same service's copy of the object. That service holds a copy of an object only where something put one there. On a kernel with an `environmentId` (`os dev`, `os serve`, `os start`, and the cloud single-environment runtime) nothing copies the objects a package registers during the boot. So `list_objects` answered `{ objects: [], totalCount: 0 }` for such a package, `describe_object` answered "not found" for each of its objects, and the gate read the missing copy as "no declaration" and served them. REST and the `/mcp` HTTP bridge listed and refused the same objects.
+
+- **Before.** On that kernel, an object a package registered during the boot was missing from `list_objects` and answered `Object "NAME" not found` by `describe_object` and `validate_expression`. Declared `apiEnabled: false`, it was served by `query_records`, `get_record`, `aggregate_records` and the `objectstack://objects/NAME/records/ID` resource, and `create_record`, `update_record` and `delete_record` reached the store. Its `internal: true` fields were echoed in the `create_record` and `update_record` responses.
+- **Now.** `list_objects` and `describe_object` answer from the listing `GET /api/v1/meta/object` serves. Every data verb and the record resource refuse such an object `404 OBJECT_API_DISABLED`, or `405 OBJECT_API_METHOD_NOT_ALLOWED` for a verb its `apiMethods` leaves out, as `RestServer` and the HTTP bridge do. Its `internal: true` fields are omitted from the write responses, and its nested-relation conditions are gated on their targets.
+- **Also changed.** A disabled package's objects, where the `metadata` service still held a copy, were listed and described; they are now omitted, as REST omits them. Every data verb and the record resource now refuse a disabled package's object `404 OBJECT_PACKAGE_DISABLED`, whatever the object declares: before, the stdio transport served it on every verb, because each verb asks the engine and never the protocol. When the metadata store cannot be read, `list_objects` and `describe_object` answer the store's `503 SERVICE_UNAVAILABLE`, as `GET /api/v1/meta/object` does, instead of the `metadata` service's listing.
+- **Unchanged.** Objects that already had a copy (every object on a kernel without an `environmentId`, a marketplace install on any kernel, and a runtime-authored object) are listed and gated as before. A host with no `protocol` service, or one without the merged reads, keeps reading the `metadata` service. If the protocol's by-name read fails, the gate judges the `metadata` service's copy, as it did before.
+- **What to do.** Nothing, if the declarations say what you mean. A stdio client that relied on reaching an object declared `apiEnabled: false` was relying on the defect: set `enable.apiEnabled` (or `enable.apiMethods`) on the object to the exposure you want. A stdio client that read a disabled package's objects was relying on the same kind of defect: re-enable the package to restore access, as REST says.
@@ -526,8 +526,13 @@ export interface McpMergedMetadataRead {
  * the reason `packages/rest` reads it defensively at every one of its own call
  * sites: this is a duck-typed seam across a package boundary, and a host may
  * hand back the bare array.
+ *
+ * [#25138] Exported within the package for the stdio data bridge's object
+ * listing (`stdio-data-bridge.ts`), so the two merged reads on this transport
+ * cannot disagree about which answers they accept. `index.ts` does not
+ * publish it.
  */
-function metaItemsArray(answer: unknown): unknown[] {
+export function metaItemsArray(answer: unknown): unknown[] {
   if (Array.isArray(answer)) return answer;
   const items = (answer as { items?: unknown } | null | undefined)?.items;
   return Array.isArray(items) ? items : [];
 
@@ -457,7 +457,7 @@ describe('#8266 the refusal carries the ADR-0112 envelope', () => {
   async function refusalFor(def: unknown, action: string): Promise<McpExposureError> {
     const metadataService = fakeMetadata(def) as unknown as IMetadataService;
     const context = { userId: 'u1', isSystem: false } as unknown as ExecutionContext;
-    const err = (await enforceApiExposure(metadataService, 'task', action, context).then(
+    const err = (await enforceApiExposure({ metadataService }, 'task', action, context).then(
       () => null,
       (e: unknown) => e,
     )) as McpExposureError | null;
 
@@ -42,6 +42,8 @@ import {
   GATED_ACTIONS,
   serveStoredMetadataHashes,
   serveStoredMetadataRow,
+  type StdioObjectReads,
+  type StdioProtocolObjectReads,
   type StoredHashDigest,
 } from './stdio-data-bridge.js';
 import type { McpDataBridge } from './mcp-http-tools.js';
@@ -703,10 +705,24 @@ export class MCPServerPlugin implements Plugin {
         if (gate) throw stdioAuthGateRefusal(gate);
         return ec;
       };
+      // [#25138] The protocol's object reads — the merged listing behind
+      // `list_objects` / `describe_object` and the by-name read behind the
+      // exposure gate — resolved at each use, never captured here: an absence
+      // read in `start()` is a verdict the rest of the boot can still
+      // contradict. `undefined` when this host registers no protocol, and the
+      // bridge then reads the metadata service, as before.
+      const protocolReads = (): StdioProtocolObjectReads | undefined => {
+        try {
+          return ctx.getService<StdioProtocolObjectReads>('protocol') ?? undefined;
+        } catch {
+          return undefined;
+        }
+      };
       if (metadataService) {
         dataBridge = createStdioDataBridge({
           engine: scopedQl,
           metadataService,
+          protocol: protocolReads,
           resolvePrincipal,
           keyedDigest: storedHashDigest,
         });
@@ -725,7 +741,11 @@ export class MCPServerPlugin implements Plugin {
       // from, captured once rather than re-read off the outer `let` inside the
       // closure — the reader must not be able to see a different service from
       // the one `bridgeResources` was registered with.
-      const gateMetadata = metadataService;
+      // [#25138] …beside the protocol's by-name read, which the gate asks
+      // first, as `bridge.get` asks it.
+      const gateReads: StdioObjectReads | undefined = metadataService
+        ? { metadataService, protocol: protocolReads }
+        : undefined;
       getRecord = async (objectName, recordId) => {
         const ec = await resolvePrincipal();
         // [#8266] The ADR-0049 exposure gate, applied BEFORE the read: the same
@@ -740,12 +760,12 @@ export class MCPServerPlugin implements Plugin {
         // leaking is the author's exposure DECLARATION.
         //
         // No metadata service ⇒ no declaration to read ⇒ open, exactly as
-        // `enforceApiExposure` itself falls open when `getObject` throws or
-        // resolves nothing. Unreachable in practice: `bridgeResources` — the
+        // `enforceApiExposure` itself falls open when the definition cannot be
+        // read or resolves nothing. Unreachable in practice: `bridgeResources` — the
         // only consumer of this reader — is called under `if (metadataService)`
         // below, so the resource is never registered without one.
-        if (gateMetadata) {
-          await enforceApiExposure(gateMetadata, objectName, GATED_ACTIONS.get, ec);
+        if (gateReads) {
+          await enforceApiExposure(gateReads, objectName, GATED_ACTIONS.get, ec);
         }
         const res = (await scopedQl.find(objectName, {
           where: { id: recordId },
 
@@ -159,8 +159,9 @@ const ALL_GATED = Object.keys(GATED_ACTIONS) as Array<keyof typeof GATED_ACTIONS
 describe('#8083 the gated verb set is the HTTP one', () => {
   it('gates exactly the six methods `buildMcpBridge` routes through callData', () => {
     // `listObjects` / `describeObject` are absent BY DESIGN: the HTTP bridge
-    // answers both straight off the metadata service, so gating them here
-    // would be a fresh divergence in the opposite direction.
+    // answers both without `callData` (from the protocol's merged listing
+    // since #25120), so gating them here would be a fresh divergence in the
+    // opposite direction.
     expect(ALL_GATED.sort()).toEqual(
       ['aggregate', 'create', 'get', 'query', 'remove', 'update'].sort(),
     );
@@ -420,7 +421,7 @@ describe('#15416 the stdio refusal never names an operation it also allows', ()
       for (const action of Object.values(GATED_ACTIONS)) {
         let err: McpExposureError | undefined;
         try {
-          await enforceApiExposure(metadataFor(apiMethods), 'task', action, {} as ExecutionContext);
+          await enforceApiExposure({ metadataService: metadataFor(apiMethods) }, 'task', action, {} as ExecutionContext);
         } catch (e) {
           err = e as McpExposureError;
         }