@@ -0,0 +1,15 @@
+---
+'@objectstack/plugin-security': minor
+---
+
+feat(plugin-security): organization administrators assign positions and permission sets to their own members, inside the organization boundary
+
+Clause-②: no
+
+ADR-0090 D12 (as amended for ADR-0131 D3) names three kinds of administrator. This release enforces the second one, the organization administrator: a holder of `organization_admin` or `organization_admin_no_bypass` for the active organization who is not a platform administrator.
+
+- **What an organization administrator may now do.** Create and remove `sys_user_position` and `sys_user_permission_set` rows of its own organization, for that organization's members. Every permission set the row distributes must be inside the organization boundary: the granted set, or each set the assigned position carries (including the set of the position's own name). A set is inside when its `objects['*']` entry carries neither `viewAllRecords` nor `modifyAllRecords`, it has no `adminScope`, and every name in its `systemPermissions` is a capability declared `scope: 'org'`. `admin_full_access`, both organization-administrator sets and the three MCP agent ceilings are outside by name. An assignment row is never edited in place: remove it and create the one you mean. A row inserted with no organization lands in the caller's organization.
+- **What is refused, and how.** An out-of-boundary write answers `403 PERMISSION_DENIED`, and the message names the set and the condition it failed. The same refusal covers a row of another organization, removal of an organization-less row, a business unit of another organization, an edit in place and a filter delete. Assigning a user who is not a member of the organization is refused `400 VALIDATION_FAILED` as before, for every writer. So is assigning a built-in identity position (`platform_admin`, `org_owner`, `org_admin`, `org_member`). Organization membership rows stay platform-administrator-only.
+- **Overrides.** `organization_admin`, and so `organization_admin_no_bypass`, now carries `allowCreate` and `allowDelete` on both assignment tables. `allowEdit` stays `false`.
+- **The two doors.** `GET /security/my-delegable-scope` reports an organization administrator with `isTenantAdmin: false`, every unit of its organization as placeable, and only in-boundary positions as assignable. The walled `organization_admin` was reported as tenant-level before. Explaining another user's access now admits an organization administrator explaining a member of its own organization.
+- **Unchanged.** Platform administrators keep today's behaviour. Delegated (`adminScope`) administrators keep D12's subtree, allowlist and strict containment. Everyone else is denied as before. No spec key, no endpoint and no membership-model change.
@@ -3997,6 +3997,82 @@
           "ref": "#24632"
         }
       ]
+    },
+    {
+      "id": "access-security.org-admin-assignment-boundary",
+      "title": "An organization administrator creates and removes its own members' position and permission-set assignments inside the organization boundary, in all three tenancy postures; an out-of-boundary set answers 403 naming the set and the condition",
+      "since": "v18",
+      "status": "active",
+      "revision": 1,
+      "priority": "P1",
+      "surface": "api",
+      "personas": [
+        "a platform administrator (admin_full_access)",
+        "an organization administrator under a walled posture (organization_admin)",
+        "an organization administrator under a wall-less posture (organization_admin_no_bypass)",
+        "a member (member_default)"
+      ],
+      "fixtures": {
+        "app": "none — the real-stack pin boots ObjectQL over SQLite with the SecurityPlugin per posture",
+        "requires": [
+          "an in-boundary permission set (no objects['*'] superuser bit, no adminScope, only scope 'org' capabilities) and a position carrying it",
+          "a position carrying a mixed bundle (an in-boundary set plus admin_full_access)",
+          "two organizations, with the target user a member of the administrator's organization only"
+        ]
+      },
+      "steps": [
+        "for each posture (single, group, isolated) and each persona, insert a sys_user_position and a sys_user_permission_set row for a member, with an in-boundary and an out-of-boundary set",
+        "for the same cells, delete a system-seeded row of the administrator's organization by id",
+        "read GET /security/my-delegable-scope and explain another member's access as each organization administrator"
+      ],
+      "acceptance": [
+        {
+          "clause": "the three-posture matrix passes at the run subject sha (RUNNER rule 6: cite the pin's output, never re-derive by hand)",
+          "oracle": "test",
+          "verify": "run each file named in automated.ref with its package's vitest (`pnpm --filter @objectstack/plugin-security exec vitest run --maxWorkers=2 FILE`, never through a bare `--`); every named file reports ≥1 test and 0 failed. A file that reports 0 tests or is not found is NOT a pass — it is a stale ref, fix the item",
+          "evidence": "the vitest summary line per pin file, with the package name and the subject sha"
+        },
+        {
+          "clause": "both organization-administrator variants: in-boundary insert and delete on both tables succeed (the inserted row is stored in the administrator's organization); out-of-boundary insert and delete answer 403 PERMISSION_DENIED and the message names the set and the failed condition",
+          "oracle": "test",
+          "verify": "the per-cell cases of org-admin-assignment-boundary.posture.test.ts, three postures",
+          "evidence": "the case names and their pass lines"
+        },
+        {
+          "clause": "the platform administrator is admitted in every cell (unchanged); the member is refused 403 in every cell (unchanged)",
+          "oracle": "test",
+          "verify": "the platform and member cells of the same file",
+          "evidence": "the case names and their pass lines"
+        },
+        {
+          "clause": "the delegable-scope report gives an organization administrator isTenantAdmin false and offers only in-boundary positions; explain admits it for a member of its organization and refuses it for anyone else",
+          "oracle": "test",
+          "verify": "the report/explain case of the same file, per posture",
+          "evidence": "the case names and their pass lines"
+        }
+      ],
+      "negative": [
+        "an organization administrator's assignment of a member of another organization lands — FAIL (expected 400 VALIDATION_FAILED from the grant-holder membership hooks)",
+        "an organization administrator edits an assignment row in place — FAIL (expected 403)",
+        "an organization administrator assigns admin_full_access, an adminScope set, a platform-capability set, either organization-administrator set or an agent ceiling, to anyone including itself — FAIL (expected 403 naming the set)"
+      ],
+      "automated": {
+        "kind": "e2e",
+        "ref": "packages/plugins/plugin-security/src/org-admin-assignment-boundary.posture.test.ts + packages/plugins/plugin-security/src/delegated-admin-gate.test.ts (the organization-administrator describe) + packages/plugins/plugin-security/src/objects/rbac-objects.test.ts (the boundary pin over the shipped sets)"
+      },
+      "source": [
+        "packages/plugins/plugin-security/src/delegated-admin-gate.ts#organizationAdminFailure",
+        "packages/plugins/plugin-security/src/objects/default-permission-sets.ts",
+        "docs/adr/0090-permission-model-v2-concept-convergence.md (D12, amended 2026-10-17)"
+      ],
+      "history": [
+        {
+          "revision": 1,
+          "date": "2026-10-20",
+          "change": "initial — the organization administrator's assignment boundary (ADR-0090 D12 as amended 2026-10-17), run once on the PR head through the automated pins",
+          "ref": "#24136"
+        }
+      ]
     }
   ]
 }