diff --git a/.changeset/21886-add-member-platform-admin-visibility.md b/.changeset/21886-add-member-platform-admin-visibility.md
new file mode 100644
index 0000000000..4bf3beef56
--- /dev/null
+++ b/.changeset/21886-add-member-platform-admin-visibility.md
@@ -0,0 +1,11 @@
+---
+"@objectstack/platform-objects": patch
+---
+
+"Add Member" is offered only to a platform administrator, the one standing its endpoint admits.
+
+Clause-②: no
+
+- `sys_member`'s `add_member` toolbar action now declares `visible: 'current_user.isPlatformAdmin == true'`. `requiresFeature: 'organization'` composes onto it at parse time, so the served predicate reads `(current_user.isPlatformAdmin == true) && features.organization != false`.
+- Its endpoint, `POST /api/v1/auth/organization/add-member`, has always admitted a platform administrator alone (ADR-0068) and answered every other caller, org owners and admins included, with 403 `PERMISSION_DENIED`. Before this change the button was still shown to every member of the organization.
+- ⛔ Nothing you author changes. The endpoint and the callers it admits are unchanged, and no key, export or parameter is added. The action's label is unchanged.
diff --git a/packages/platform-objects/src/identity/sys-member.object.ts b/packages/platform-objects/src/identity/sys-member.object.ts
index 05fc308d0e..9beac68ce1 100644
--- a/packages/platform-objects/src/identity/sys-member.object.ts
+++ b/packages/platform-objects/src/identity/sys-member.object.ts
@@ -151,6 +151,17 @@ export const SysMember = ObjectSchema.create({
       locations: ['list_toolbar'],
       type: 'api',
       target: '/api/v1/auth/organization/add-member',
+      // Offered only to the one standing the door admits (ADR-0068 D4):
+      // `current_user.isPlatformAdmin` is the ADR-0095 D3 PLATFORM_ADMIN
+      // posture rung — what the session payload emits and what the mount's
+      // platform-admin gate judges. Gated on the feature alone, the button was
+      // offered to every member, owners and admins included, and the door
+      // refused each with 403 `PERMISSION_DENIED`. ⛔ Never
+      // `'platform_admin' in current_user.positions`: `EvalUserSchema` rules
+      // that standing is read from this key, never from the array.
+      // `requiresFeature` below composes onto it at parse time:
+      // `(current_user.isPlatformAdmin == true) && features.organization != false`.
+      visible: 'current_user.isPlatformAdmin == true',
       // Gated on the org CAPABILITY, not multi-org (ADR-0093 D9): the
       // better-auth endpoints resolve the session's active org, which
       // single-org mode now guarantees via plugin-auth's default-org
diff --git a/packages/platform-objects/src/platform-objects.test.ts b/packages/platform-objects/src/platform-objects.test.ts
index 7264b48660..ead40140fe 100644
--- a/packages/platform-objects/src/platform-objects.test.ts
+++ b/packages/platform-objects/src/platform-objects.test.ts
@@ -590,7 +590,10 @@ describe('feature-gate lowering matrix (#2874)', () => {
     ['SysMember', SysMember, 'invite_user', `${INVITE} && ${ORG}`],
     // No grade term: add-member is gated on platform-admin standing, not on a
     // membership grade, so the action carries no `requiresMembershipReach`.
-    ['SysMember', SysMember, 'add_member', ORG],
+    // The standing term is the authored `visible` — the ADR-0095 D3
+    // PLATFORM_ADMIN rung the door's gate judges (ADR-0068 D4) — composed
+    // ahead of the feature gate. ⛔ Never a `current_user.positions` read.
+    ['SysMember', SysMember, 'add_member', `(current_user.isPlatformAdmin == true) && ${ORG}`],
     ['SysMember', SysMember, 'update_member_role', `${ADMINS} && ${ORG}`],
     ['SysMember', SysMember, 'remove_member', `${ADMINS} && ${ORG}`],
     ['SysMember', SysMember, 'transfer_ownership', `((has(record.role) && record.role != 'owner') && ${OWNER}) && ${ORG}`],
diff --git a/packages/qa/dogfood/test/org-admin-affordance-reach.dogfood.test.ts b/packages/qa/dogfood/test/org-admin-affordance-reach.dogfood.test.ts
index cb4d5ca959..9df2b5d9ec 100644
--- a/packages/qa/dogfood/test/org-admin-affordance-reach.dogfood.test.ts
+++ b/packages/qa/dogfood/test/org-admin-affordance-reach.dogfood.test.ts
@@ -42,6 +42,20 @@
  * mints the organization and sets membership roles in system context — the
  * shape `delegated-admin-invite.dogfood.test.ts` uses, and the only writer
  * better-auth-managed tables accept (ADR-0092).
+ *
+ * ## The one affordance no grade reaches: "Add Member"
+ *
+ * `sys_member.add_member` targets a door gated on PLATFORM-admin standing
+ * (ADR-0068), not on a grade, so an org owner is refused it too. Its `visible`
+ * reads that standing, `current_user.isPlatformAdmin == true` (ADR-0068 D4,
+ * the ADR-0095 D3 rung). That case binds `current_user` the way the CONSOLE
+ * does — the whole scope handed to the engine as `extra`, one subject built
+ * from the served session — and ⛔ not through `user:`, under which
+ * `@objectstack/formula` re-derives `isPlatformAdmin` from `positions` and so
+ * measures the name instead of the rung the session carries. The grade cases
+ * above keep their `user:` binding: their predicates read `positions` only.
+ * The platform admin is the seeded dev admin (the harness's signed-in
+ * principal); a second org owner who is NOT one is minted for the case.
  */
 
 import { describe, it, expect, beforeAll, afterAll } from 'vitest';
@@ -122,6 +136,8 @@ describe('org-admin affordances follow the membership grade (served metadata ×
   const rowOf = {} as Record<string, Record<string, unknown>>;
   let plainMemberRowId: string;
   let pendingInvitationId: string;
+  /** An org owner who is NOT a platform admin — the principal "Add Member" must not be offered to. */
+  const standingOwner = {} as { token: string; userId: string; session: Record<string, unknown>; served: Map<string, ServedAction> };
 
   beforeAll(async () => {
     stack = await bootStack(showcaseStack, {});
@@ -155,6 +171,16 @@ describe('org-admin affordances follow the membership grade (served metadata ×
       }
     }
 
+    // A second owner of the same org, signed up rather than seeded, so the
+    // owner grade is measured apart from platform-admin standing.
+    standingOwner.token = await stack.signUp('reach.owner@example.com', 'Reach!Pass123', 'Reach second owner');
+    {
+      const [user] = await findRows(ql, 'sys_user', { email: 'reach.owner@example.com' }, 1);
+      standingOwner.userId = String(user.id);
+      const membership = await waitForMembership(ql, standingOwner.userId);
+      await ql.update('sys_member', { id: membership.id, role: 'owner' }, { context: SYSTEM_CTX });
+    }
+
     // Rows for the row actions to bind against: a pending invitation, a team,
     // and a team membership — created through the doors, as the owner.
     const invite = await stack.apiAs(tokens.owner, 'POST', '/auth/organization/invite-member', {
@@ -192,6 +218,16 @@ describe('org-admin affordances follow the membership grade (served metadata ×
         servedFields[grade][object] = Object.keys(body.item?.fields ?? {});
       }
     }
+
+    {
+      const session = await stack.apiAs(standingOwner.token, 'GET', '/auth/get-session');
+      expect(session.status).toBe(200);
+      standingOwner.session = ((await session.json()) as { user: Record<string, unknown> }).user;
+      const meta = await stack.apiAs(standingOwner.token, 'GET', '/meta/object/sys_member');
+      expect(meta.status, 'the second owner reads /meta/object/sys_member').toBe(200);
+      const body = (await meta.json()) as { item?: { actions?: ServedAction[] } };
+      standingOwner.served = new Map((body.item?.actions ?? []).map((a) => [`sys_member.${a.name}`, a]));
+    }
   }, 240_000);
 
   afterAll(async () => {
@@ -324,4 +360,74 @@ describe('org-admin affordances follow the membership grade (served metadata ×
       memberId: plainMemberRowId, role: 'owner', organizationId: orgId,
     }), 'YOU_ARE_NOT_ALLOWED_TO_UPDATE_THIS_MEMBER');
   }, 60_000);
+
+  it('Add Member is offered to a platform admin alone — current_user bound as the console binds it — and the door agrees', async () => {
+    const servedAddMember = served.owner.get('sys_member.add_member')?.visible;
+    expect(servedAddMember, 'add_member is served with a predicate').toBeDefined();
+
+    /**
+     * The console's evaluation, not this file's `user:` one: objectui hands
+     * its whole scope to the engine as `extra`, ONE subject built from the
+     * served session under `current_user` / `user` / `ctx.user` / `os.user`,
+     * with `features` beside it — so `isPlatformAdmin` is the session's own
+     * value, the rung the door's gate judges.
+     */
+    const consoleOffers = (session: Record<string, unknown>, own: Map<string, ServedAction>): boolean => {
+      const action = own.get('sys_member.add_member');
+      if (!action) throw new Error('sys_member.add_member is not served to this principal');
+      expect(action.visible, 'one predicate is served to every principal').toEqual(servedAddMember);
+      const subject = {
+        id: session.id,
+        name: session.name,
+        email: session.email,
+        isPlatformAdmin: session.isPlatformAdmin,
+        positions: session.positions,
+      };
+      const result = celEngine.evaluate(action.visible as never, {
+        extra: { current_user: subject, user: subject, ctx: { user: subject }, os: { user: subject }, features },
+      });
+      if (!result.ok) throw new Error(`sys_member.add_member faulted: ${JSON.stringify(result)}`);
+      return result.value === true;
+    };
+
+    // The standing each principal's served session carries — measured, not
+    // assumed: the seeded admin holds the rung, and no org grade does.
+    const principals: Array<[string, Record<string, unknown>, Map<string, ServedAction>, boolean]> = [
+      ['platform admin (the seeded admin)', sessionUser.owner, served.owner, true],
+      ['org owner, not a platform admin', standingOwner.session, standingOwner.served, false],
+      ['org admin', sessionUser.admin, served.admin, false],
+      ['delegated admin', sessionUser.delegated_admin, served.delegated_admin, false],
+      ['plain member', sessionUser.member, served.member, false],
+    ];
+    for (const [who, session, , platformAdmin] of principals) {
+      expect(session.isPlatformAdmin, `${who}: the session's standing`).toBe(platformAdmin);
+    }
+    // The second owner really is an owner on the session face, so its hidden
+    // verdict is about standing and not about a missing grade.
+    expect(standingOwner.session.positions as string[]).toContain('org_owner');
+
+    // Both halves at once, every principal named: who IS offered it, and so
+    // who is not.
+    const offeredTo = principals.filter(([, session, own]) => consoleOffers(session, own)).map(([who]) => who);
+    expect(offeredTo).toEqual(['platform admin (the seeded admin)']);
+
+    // The door's own verdicts on the same boot: the owner and the plain member
+    // are refused before anything is written; the platform admin is admitted.
+    const org2 = await ql.insert('sys_organization', { name: 'Reach Org Two', slug: 'reach-org-two' }, { context: SYSTEM_CTX });
+    const attach = { userId: standingOwner.userId, role: 'member', organizationId: String(org2.id) };
+    for (const [who, token] of [['org owner', standingOwner.token], ['plain member', tokens.member]] as const) {
+      const res = await stack.apiAs(token, 'POST', '/auth/organization/add-member', attach);
+      const body = (await res.clone().json()) as { success?: boolean; error?: { code?: string } };
+      expect(res.status, `${who}: ${JSON.stringify(body)}`).toBe(403);
+      expect(body.error?.code, who).toBe('PERMISSION_DENIED');
+    }
+    expect(await findRows(ql, 'sys_member', { user_id: standingOwner.userId, organization_id: String(org2.id) }, 5)).toEqual([]);
+
+    const admitted = await stack.apiAs(tokens.owner, 'POST', '/auth/organization/add-member', attach);
+    const admittedBody = (await admitted.clone().json()) as { success?: boolean };
+    expect(admitted.status, JSON.stringify(admittedBody)).toBe(200);
+    expect(admittedBody.success).toBe(true);
+    const attached = await findRows(ql, 'sys_member', { user_id: standingOwner.userId, organization_id: String(org2.id) }, 5);
+    expect(attached.map((m) => m.role)).toEqual(['member']);
+  }, 60_000);
 });