diff --git a/docs/native-kanban-sot/P0-MAP-CURRENCY-2026-08-29.md b/docs/native-kanban-sot/P0-MAP-CURRENCY-2026-08-29.md
index b06f5746..c50b4f30 100644
--- a/docs/native-kanban-sot/P0-MAP-CURRENCY-2026-08-29.md
+++ b/docs/native-kanban-sot/P0-MAP-CURRENCY-2026-08-29.md
@@ -73,12 +73,22 @@ SHARED-CONTRACT.md §5.1 phase 1 requires an N-1 patch that stops
 `mission_tasks.status` as a write source, plus a writer inventory, before any
 expand DDL.
 
-- **Sole status write path:** `packages/brain/src/mission-tasks.ts`
+- **Sole authoring write path:** `packages/brain/src/mission-tasks.ts`
   `create`/`update` (Drizzle insert/update on `mission_tasks`), invoked by
   `apps/gateway/src/missions/missions.controller.ts`. `update` accepts
   `Partial<NewMissionTask>`, so `status` is writable through both DTOs today.
   The same module also exposes `remove`/`removeByMission` DELETE paths —
   immaterial to `status` writes, listed for inventory completeness.
+- **Storage-layer surfaces that touch the column without authoring it**
+  (added 2026-08-29 after independent review of the phase-1 patch):
+  `packages/storage/src/migrate-tier.ts` copies whole `mission_tasks` rows
+  between storage tiers and must preserve the stored `status` verbatim — row
+  transport, exempt from the write prohibition (stripping there would corrupt
+  data inside the N-1 window). The generic table-keyed storage adapters
+  (`adapters/postgres.ts`, `adapters/pglite.ts`) register `mission_tasks` in
+  their table maps but have no caller that targets it: measured at this head,
+  every runtime adapter caller passes a fixed collection constant
+  (preferences/insights). Neither surface authors a new `status` value.
 - **Read-only consumers of `mission_tasks`:** federation verb services
   (`get-query.service.ts`, `list-query.service.ts`) select only. The MCP
   `brain_*` tools do not touch `mission_tasks` at all; `brain_create_task` /
diff --git a/packages/brain/src/mission-tasks.spec.ts b/packages/brain/src/mission-tasks.spec.ts
index fb1ab0f4..805207c7 100644
--- a/packages/brain/src/mission-tasks.spec.ts
+++ b/packages/brain/src/mission-tasks.spec.ts
@@ -2,11 +2,13 @@ import { describe, it, expect, vi } from 'vitest';
 import { createMissionTasksRepo } from './mission-tasks.js';
 
 /**
- * SHARED-CONTRACT §5.5 "mission_tasks.status write prohibition": the repo is
- * the sole write path, and it must never forward a caller-supplied status to
- * the database on create or update. Callers keep working (the field is
- * accepted and ignored), so these tests assert on what reaches the Drizzle
- * chain, not on rejection.
+ * SHARED-CONTRACT §5.5 "mission_tasks.status write prohibition": this repo is
+ * the sole path that authors mission_tasks.status from caller input (storage
+ * tier migration is row transport and preserves stored values; the generic
+ * storage adapters have no mission_tasks caller), and it must never forward a
+ * caller-supplied status to the database on create or update. Callers keep
+ * working (the field is accepted and ignored), so these tests assert on what
+ * reaches the Drizzle chain, not on rejection.
  */
 
 function makeInsertDb(returned: unknown[]) {
diff --git a/packages/brain/src/mission-tasks.ts b/packages/brain/src/mission-tasks.ts
index d08baeed..22b21ba2 100644
--- a/packages/brain/src/mission-tasks.ts
+++ b/packages/brain/src/mission-tasks.ts
@@ -4,11 +4,17 @@ export type MissionTask = typeof missionTasks.$inferSelect;
 export type NewMissionTask = typeof missionTasks.$inferInsert;
 
 // SHARED-CONTRACT §5.1 phase 1 / §5.4: mission_tasks.status is prohibited as a
-// write source through the N-1 window. This repo is the sole write path, so the
-// field is stripped here — accepted and ignored rather than rejected, because
-// the legacy surface is frozen with existing consumers kept working
-// (tool-gateway-mapping.md §3.2). The column keeps its DB default, stays
-// declared and readable, and is retired only after no readers remain.
+// write source through the N-1 window. This repo is the sole path that authors
+// status from caller input, so the field is stripped here — accepted and
+// ignored rather than rejected, because the legacy surface is frozen with
+// existing consumers kept working (tool-gateway-mapping.md §3.2). Two other
+// surfaces touch the column and are deliberately NOT stripped:
+// packages/storage/migrate-tier.ts copies whole rows between storage tiers and
+// must preserve the stored value verbatim, and the generic table-keyed storage
+// adapters register mission_tasks but have no caller that targets it (runtime
+// callers use fixed collection constants). Neither authors a new status. The
+// column keeps its DB default, stays declared and readable, and is retired
+// only after no readers remain.
 function stripStatus<T extends { status?: unknown }>(data: T): Omit<T, 'status'> {
   const rest = { ...data };
   delete rest.status;