diff --git a/docs/repository-standards_v0.1.md b/docs/repository-standards_v0.1.md
index c6a1f7d..1b47fc0 100644
--- a/docs/repository-standards_v0.1.md
+++ b/docs/repository-standards_v0.1.md
@@ -33,3 +33,24 @@ rmgr prefix-uniqueness --root ..
 Registry: [`config/workplan-prefix-registry.yaml`](../config/workplan-prefix-registry.yaml).
 
 Work: `RMGR-WP-0004-T01`, `RMGR-WP-0004-T08`.
+
+## Identifier registrar (interim)
+
+Until UUIDv5 derivation lands (`RMGR-WP-0005-T03`), only the registrar
+instance may mint `state_hub_workstream_id` / `state_hub_task_id` into
+files (`ADR-007` decision 2). Other hubs may read and project; they must
+not write new hub primary keys into git.
+
+| Signal | Registrar? |
+| --- | --- |
+| `STATEHUB_REGISTRAR=1` / `true` / `yes` / `on` | yes |
+| `STATEHUB_REGISTRAR=0` / `false` / `no` / `off` | no |
+| env unset, hostname starts with `railiance` | yes |
+| env unset, any other hostname | no |
+
+Accepted cost: new workplan/task registration requires connectivity to
+the registrar. Disconnected work cannot register until T03. Implementation:
+`repo_manager.registrar.is_identifier_registrar`; consumed by
+`statehub fix-consistency` C-06 / C-11 / C-32.
+
+Work: `RMGR-WP-0005-T01`.
diff --git a/src/repo_manager/registrar.py b/src/repo_manager/registrar.py
new file mode 100644
index 0000000..0b21f77
--- /dev/null
+++ b/src/repo_manager/registrar.py
@@ -0,0 +1,30 @@
+"""Interim single-writer for hub identifiers (ADR-007 decision 2).
+
+Until deterministic derivation (RMGR-WP-0005-T03) ships, exactly one
+instance may mint ``state_hub_workstream_id`` / ``state_hub_task_id``
+into repository files. Other instances may read and project; they must
+not write new hub primary keys into git-tracked files.
+
+The registrar is the automated production instance (hostname prefix
+``railiance``). Override with ``STATEHUB_REGISTRAR=1`` or ``=0``.
+"""
+
+from __future__ import annotations
+
+import os
+import socket
+
+_TRUE = frozenset({"1", "true", "yes", "on"})
+_FALSE = frozenset({"0", "false", "no", "off"})
+REGISTRAR_HOST_PREFIX = "railiance"
+
+
+def is_identifier_registrar(*, hostname: str | None = None) -> bool:
+    """Return True if this process may mint hub IDs into repository files."""
+    raw = os.environ.get("STATEHUB_REGISTRAR", "").strip().lower()
+    if raw in _TRUE:
+        return True
+    if raw in _FALSE:
+        return False
+    host = (hostname if hostname is not None else socket.gethostname()).strip().lower()
+    return host.startswith(REGISTRAR_HOST_PREFIX)
diff --git a/tests/test_registrar.py b/tests/test_registrar.py
new file mode 100644
index 0000000..57c9c16
--- /dev/null
+++ b/tests/test_registrar.py
@@ -0,0 +1,25 @@
+from repo_manager.registrar import is_identifier_registrar
+
+
+def test_env_true_wins_over_hostname(monkeypatch):
+    monkeypatch.setenv("STATEHUB_REGISTRAR", "1")
+    assert is_identifier_registrar(hostname="bnt-lap001") is True
+
+
+def test_env_false_wins_over_production_hostname(monkeypatch):
+    monkeypatch.setenv("STATEHUB_REGISTRAR", "0")
+    assert is_identifier_registrar(hostname="railiance") is False
+
+
+def test_hostname_prefix_when_env_unset(monkeypatch):
+    monkeypatch.delenv("STATEHUB_REGISTRAR", raising=False)
+    assert is_identifier_registrar(hostname="railiance") is True
+    assert is_identifier_registrar(hostname="railiance-prod") is True
+    assert is_identifier_registrar(hostname="bnt-lap001") is False
+
+
+def test_env_aliases(monkeypatch):
+    monkeypatch.setenv("STATEHUB_REGISTRAR", "yes")
+    assert is_identifier_registrar(hostname="other") is True
+    monkeypatch.setenv("STATEHUB_REGISTRAR", "off")
+    assert is_identifier_registrar(hostname="railiance") is False
diff --git a/workplans/RMGR-WP-0004-repository-standards-conformance.md b/workplans/RMGR-WP-0004-repository-standards-conformance.md
index 8d49cbe..bd5cf4c 100644
--- a/workplans/RMGR-WP-0004-repository-standards-conformance.md
+++ b/workplans/RMGR-WP-0004-repository-standards-conformance.md
@@ -170,7 +170,7 @@ flavor-blind template silently re-breaks conformant repos.
 
 ```task
 id: RMGR-WP-0004-T05
-status: todo
+status: done
 priority: medium
 state_hub_task_id: "8402b8b6-2a1e-4236-b27d-d50b6161a176"
 ```
@@ -192,6 +192,12 @@ Follow the dual-run strangler pattern already proven in `RMGR-WP-0002` and
 points at `rmgr scaffold`. T03 is done. Cutover / inventory move can start
 alongside `STATE-WP-0080-T02`.
 
+**Result (2026-08-18):** Cutover is live via `STATE-WP-0080-T02`: project
+flavor delegates to `rmgr scaffold` (or registers only when `GOAL.md`
+exists); durable repos keep hub templating until `STATE-WP-0080-T04`
+deletes it. Inventory `caller:custodian-cli` is already `move` →
+`repo-manager`. Coordination remains `SHR-WP-0001`.
+
 ## Add compatibility and regression tests
 
 ```task
diff --git a/workplans/RMGR-WP-0005-registrar-consolidation-deterministic-ids.md b/workplans/RMGR-WP-0005-registrar-consolidation-deterministic-ids.md
index 7f2804e..e2f18fd 100644
--- a/workplans/RMGR-WP-0005-registrar-consolidation-deterministic-ids.md
+++ b/workplans/RMGR-WP-0005-registrar-consolidation-deterministic-ids.md
@@ -50,7 +50,7 @@ model; a file carrying a hub's private key is the file holding hub state.
 
 ```task
 id: RMGR-WP-0005-T01
-status: todo
+status: done
 priority: high
 state_hub_task_id: "b57a6882-280d-4f0a-9c73-899843dfc3d3"
 ```
@@ -69,6 +69,12 @@ workstation hubs are rebuildable caches (`ADR-010` decision 2).
 Interim, and deliberately so — it trades availability for correctness, and T03
 removes the need for the trade.
 
+**Result (2026-08-18):** `repo_manager.registrar.is_identifier_registrar`
+(`STATEHUB_REGISTRAR` env, else hostname prefix `railiance`).
+`statehub fix-consistency` skips C-06 / C-11 / C-32 mint+writeback when
+this instance is not the registrar. Read/project checks are unchanged.
+Cost documented in `docs/repository-standards_v0.1.md`.
+
 ## Re-register identifiers minted outside the registrar
 
 ```task