@@ -0,0 +1,11 @@
+---
+'@objectstack/skills': patch
+---
+
+docs(skills): the field-types guide names the backfill for an amount switched to record mode; the dashboards guide says a record-mode amount aggregate is served only grouped by its code field
+
+Clause-②: no
+Metadata-protocol: none
+
+- **`objectstack-data/rules/field-types.md`**: an amount field with stored rows that is switched to `currencyMode: 'record'` is backfilled with `os migrate record-currency-codes`. The derived-measure sentence moves out of this guide; it already sits in the dashboards guide, which the line now points to.
+- **`objectstack-ui/rules/dashboards.md`**: a record-mode amount refuses `sum` / `avg` / `min` / `max` unless grouped by its code field. The old "ungrouped" read as if any grouping would do.
@@ -353,6 +353,12 @@ Where a source leans one way, the lean is quoted here, not adopted. This record
     `packages/platform-objects/src`. ADR-0029 D1, D3 and D6 give a first-party capability ownership of its `sys_*`
     objects and decompose `platform-objects`, and ADR-0028 (Deferred) records the `sys` namespace design. #27185
     settles the owner against them.
+    *Note (2026-10-30):* settled: `@objectstack/platform-objects` owns it (D3's one owner per object), landed in PR
+    #27246 (`194e66c0`). The table's one reader is the ObjectQL engine's write path, present in every composition that
+    can write a record, so it has no on/off capability boundary of its own (ADR-0029 D2) and no service or plugin
+    package would own it; it registers with the engine-facing infrastructure objects `sys_migration` and `sys_secret`,
+    and workload row M1-1 names the same package. Settlement:
+    [`6511509227`](https://github.com/objectstack-ai/objectstack/issues/27185#issuecomment-6511509227) on #27185.
 12. **Whether today's cross-currency arithmetic between `fixed` fields of different codes is refused** (epic #8345).
     Two shapes: a measure `currency` that contradicts a `fixed` field's code, and a derived measure over two different
     `fixed` codes, which Context §1 counts among today's silently wrong numbers. The ruling on #27119 did not decide
@@ -362,6 +368,32 @@ Where a source leans one way, the lean is quoted here, not adopted. This record
     the tree evidence. The general `fixed`-versus-`fixed` guard stays undecided. The authority is the maintainer's, and
     epic #8345 carries the question
     ([`6485374827`](https://github.com/objectstack-ai/objectstack/issues/8345#issuecomment-6485374827)).
+    *Note (2026-10-30):* settled: the maintainer ruled both shapes refused at dataset compile, letter A
+    ([`6486427200`](https://github.com/objectstack-ai/objectstack/issues/8345#issuecomment-6486427200) on #8345).
+    Card #27579 landed it in PR #27991 (`6dc06b2e`): a measure `currency` that differs from its `fixed` field's code,
+    and a derived measure, whatever its op, over two different `fixed` codes answer `DATASET_INVALID`; a `count`
+    operand is not compared. A `fixed` code is not judged against `localization.currency`, and `currency` over a
+    `dynamic` field still wins.
+13. **An amount field switched to `currencyMode: 'record'` on an object that already holds rows** (#27577). A
+    `dynamic` or `fixed` field that turns `record` leaves its stored rows with an amount beside a blank code. No row is
+    refused for resting (ADR-0113 D1): the D8 rule 4 write guard refuses the next write that touches the pair
+    (`ERR_CURRENCY_CODE_REQUIRED`), and until the code is written the row shows a plain number, falls into the null
+    group of a grouped aggregate and sits outside every currency-paired filter. PR #27339's contract review
+    ([`6490309706`](https://github.com/objectstack-ai/objectstack/pull/27339#issuecomment-6490309706), item ③)
+    escalated whether the switch is refused while such rows exist or a backfill is owed; this record decided neither.
+    *Note (2026-10-30):* settled: the maintainer ruled letter B
+    ([`6492000994`](https://github.com/objectstack-ai/objectstack/issues/8345#issuecomment-6492000994) on #8345): the
+    switch is allowed and owes an explicit backfill. PR #28128 implements it. The operator runs
+    `os migrate record-currency-codes --object <object> --field <amount> --code <ISO 4217>`, which writes the given
+    code into every row that holds an amount beside a blank code (dry run by default, `--apply` writes; the code is
+    never derived, D8 rule 4), and the metadata save that makes the switch answers the existing 409
+    `destructive_change` with the finding `currency_mode_to_record`, lifted by the existing `force`. The finding reads
+    no row and fires only where a previous version exists, so a package registered at boot is not refused. The ruling
+    left open how a cloud-managed tenant without a CLI reaches the backfill; open beside it: the run walks every
+    organization under the unscoped system context and writes the one `--code` into each one's codeless rows (no
+    organization-scope flag, no per-organization count), so on a multi-organization deployment, where `dynamic`
+    amounts displayed in each organization's own `localization.currency`, that code can be wrong for some of them
+    (PR #28128's review should-fix S1, escalated to the epic PM).
 
 ## Verification notes
 
 
@@ -183,9 +183,9 @@ Stored as JSON on the parent row — no separate table / FK:
 `$`); `'record'`, each record's code in the `text` field `currencyField`
 names (by convention `currency_code`), with `valueDomain: 'iso_4217_currency'`. A
 dataset measure's own `currency` wins over a `'dynamic'` field; over a `'fixed'` one
-it may only restate the code, else `DATASET_INVALID` (delete it), as is a derived
-measure over two different `'fixed'` codes (derive from one currency or drop an
-operand). A `'fixed'` code is not judged against the tenant's.
+it may only restate the code, else `DATASET_INVALID` (objectstack-ui →
+Dashboards). A `'fixed'` code is not judged against the tenant's. Switched a
+stored field to `'record'`? Backfill: `os migrate record-currency-codes`.
 
 ### Select with Default
 
 
@@ -295,12 +295,12 @@ defineDataset({
   dimensions: [{ name: 'signed_date', field: 'signed_date', type: 'date', dateGranularity: 'month' }],
   measures: [{ name: 'signed_count', aggregate: 'count' }],
 });
-// A money measure may set `currency` (ISO 4217), e.g. `currency: 'USD'`.
-// Chain: measure `currency` → the field's `defaultCurrency` (`fixed`
-// only) → tenant `localization.currency`; omit it for counts. A
-// `currencyMode: 'record'` amount refuses `currency` and ungrouped
-// sum/avg/min/max; grouped by its code field, the column carries
-// `currencyField` (per-row code column); a `count` never does. A `fixed`
+// A money measure may set `currency` (ISO 4217, e.g. `'USD'`). Chain:
+// measure `currency` → the field's `defaultCurrency` (`fixed` only) →
+// tenant `localization.currency`; omit it for counts. A
+// `currencyMode: 'record'` amount refuses `currency`, and sum/avg/min/max
+// unless grouped by its code field; then the column carries
+// `currencyField` (the per-row code column); a `count` never does. A `fixed`
 // field refuses a different `currency` (delete it; restating is fine), and
 // a derived measure refuses operands in two `fixed` codes (derive from one
 // currency or drop one). Not judged: `currency` over a `dynamic` field, a