@@ -0,0 +1,12 @@
+---
+'@objectstack/skills': patch
+---
+
+docs(skills): objectstack-i18n teaches the `books` translation group, with an eval for a two-language doc book
+
+Clause-②: no
+Metadata-protocol: none
+
+- **Before.** The top-level group list in `skills/objectstack-i18n/SKILL.md` named fourteen of the bundle's fifteen groups and left out `books`, the group the spec added so a doc book's title and section titles follow the reader's locale. An agent writing a zh-CN bundle from the skill left the docs sidebar in one language or invented a key under `pages`.
+- **Now.** The list names `books` with its three keys — `books.{book}.label` / `.description` by `Book.name` and `books.{book}.groups.{group_key}.label` by each group's stable `key` — says the pages themselves localize through `doc.translations` and that a book's inline `translations` map stays retired; `os i18n extract --no-objects-only` seeds the group like every other. Eval 9 in `evals/bundles-locales-coverage.json` checks that an answer for a two-language manual spells the book label and a group label by key and never a `pages.*` key. Five eval sentences that restated a rule the skill already teaches were cut to pay for it.
+- No schema, key or behaviour changes.
@@ -989,7 +989,25 @@ export const CEILINGS = new Map([
   // pin duplicated case 5's (77 bytes cut, 20 tokens); the remainder is the new
   // case; pinned AT the measurement, zero headroom. The raising PR's body carries
   // the same arithmetic.
-  ['skills/objectstack-i18n/evals/bundles-locales-coverage.json', 1642],
+  // 1642 -> 1790 (2026-10-28, the owed Skills-docs follow-up of the spec PR that
+  // added the `books` translation group): one eval prompt for a doc book's
+  // spine copy — `books.<book>.label` / `.description` and
+  // `books.<book>.groups.<key>.label`. Same ruling as the rows above, tap label
+  // verbatim and untranslated: 「A:先削重复,余额按实测提高」. PAID DOWN FIRST: five
+  // sentences restated a rule whose home the reader already reads — case 1's
+  // "no ICU plural/select" (SKILL.md "No ICU MessageFormat" + its own
+  // `{count, plural` pin), case 3's "retired o.* dialect" (SKILL.md "The
+  // Retired o.* Shape" + its own `o: {` pin), case 5's "extract --check is the
+  // freshness gate" (SKILL.md "os i18n extract --check — freshness, not
+  // coverage"), case 6's "inherited by every field referencing the picklist"
+  // (SKILL.md's `picklists` entry in the top-level group list), case 8's
+  // "neither is a pages.*.components key" (its own `components.open_block`
+  // pin): 227 bytes = 57 units (6567 -> 6340 bytes, 1642 -> 1585); the new case
+  // adds 817 bytes = 205 units (6340 -> 7157 bytes, 1585 -> 1790):
+  //   ceil($(wc -c < skills/objectstack-i18n/evals/bundles-locales-coverage.json) / 4) == ceil(7157 / 4)
+  // pinned AT the measurement, zero headroom. The raising PR's body carries the
+  // same arithmetic.
+  ['skills/objectstack-i18n/evals/bundles-locales-coverage.json', 1790],
   // 1211 -> 1458 (card #26302): one eval for a demo whose seed names people —
   // expected: both in `demoStaff` with a declared `position` /
   // `permissionSets`, created by `os dev`; NO `role:` alias and NO platform
 
@@ -171,10 +171,13 @@ Top-level groups alongside `objects`: `apps` (label, description, navigation),
 an **error** whose message names the `objects.{owner}._actions.{action_name}` key to write
 instead), `picklists` (`label`, `options` by stored value — every field referencing the
 picklist inherits them), `dashboards`, `datasets`, `reports`, `pages`, `flows`, `positions`,
-`permissions` (permission sets, spelled as the stack's `permissions[]`), `metadataForms`,
-`settingsCommon`; `reports`, `positions` and `permissions` hold `label` + `description` by name,
-and a joined report's block headings sit at `reports.{report}.blocks.{block_name}.{label,description}`,
-keyed by the block's required `name`.
+`permissions` (permission sets, spelled as the stack's `permissions[]`), `books` (a doc book's
+spine, by `Book.name`: `books.{book}.label` / `.description`, and `groups.{group_key}.label` by
+each group's stable `key`, never its position — `books.crm_manual.groups.getting_started.label`;
+the pages themselves localize through `doc.translations`, and the inline `translations` map a
+book once carried stays retired), `metadataForms`, `settingsCommon`; `reports`, `positions` and
+`permissions` hold `label` + `description` by name, and a joined report's block headings sit at
+`reports.{report}.blocks.{block_name}.{label,description}`, keyed by the block's required `name`.
 Two keys sit deeper than their group's `label`: a `page:tabs` item at
 `pages.{page}.components.{tabs_id}.items.{value}.label` (by the item's `value`; an item without
 one has no key) and an approval step at `flows.{flow}.approvals.{node_id}.label`.
 
@@ -4,7 +4,7 @@
     {
       "id": 1,
       "prompt": "Add Simplified Chinese for the `support_case` object: its label and plural, the `status` field with options New / Open / Closed, the `close` action, and a welcome message that greets the user by name.",
-      "expected_output": "A `TranslationData` per locale under `objects.support_case` — `label`, `pluralLabel`, `fields.status.label`, `fields.status.options` keyed by the STORED option value (`new`, `open`, `closed`, never the display label), `_actions.close.label` — assembled with `defineTranslationBundle({ en, 'zh-CN': zhCN })` and registered under `defineStack({ translations })`. The message uses double-brace interpolation, `'welcome.user': '欢迎，{{userName}}！'`; there is no ICU plural/select.",
+      "expected_output": "A `TranslationData` per locale under `objects.support_case` — `label`, `pluralLabel`, `fields.status.label`, `fields.status.options` keyed by the STORED option value (`new`, `open`, `closed`, never the display label), `_actions.close.label` — assembled with `defineTranslationBundle({ en, 'zh-CN': zhCN })` and registered under `defineStack({ translations })`. The message uses double-brace interpolation, `'welcome.user': '欢迎，{{userName}}！'`.",
       "files": [],
       "assertions": {
         "must_contain": ["defineTranslationBundle", "objects", "pluralLabel", "options", "_actions", "{{"],
@@ -24,7 +24,7 @@
     {
       "id": 3,
       "prompt": "A customer admin wants to relabel `account` as 客户 in their Studio without waiting for a redeploy.",
-      "expected_output": "A `translation` metadata item (author with `defineTranslation`, shape `TranslationItemSchema`) carrying `locale: 'zh-CN'` and the same `objects.account.label` group as a file bundle; published items layer over the shipped bundles at boot and on every publish, and deleting the item restores the shipped value. One locale per item; the retired `o.*` dialect is rejected on this door too.",
+      "expected_output": "A `translation` metadata item (author with `defineTranslation`, shape `TranslationItemSchema`) carrying `locale: 'zh-CN'` and the same `objects.account.label` group as a file bundle; published items layer over the shipped bundles at boot and on every publish, and deleting the item restores the shipped value. One locale per item.",
       "files": [],
       "assertions": {
         "must_contain": ["translation", "locale", "objects", "defineTranslation"],
@@ -44,7 +44,7 @@
     {
       "id": 5,
       "prompt": "`os i18n check` reports zh-CN is missing app, navigation and dashboard keys even though we just ran `os i18n extract`. What is wrong?",
-      "expected_output": "Diagnoses that `--objects-only` is on by default, so extract wrote only the `objects` / `globalActions` subtree while check also demands `apps`, `navigation`, `dashboard`, `widget`, `page` and `flow` keys. Re-runs `os i18n extract --no-objects-only` (or hand-authors those groups), re-checks with `os i18n check --locales=zh-CN`, and adds `--strict` / `--threshold` in CI; `extract --check` is the separate freshness gate.",
+      "expected_output": "Diagnoses that `--objects-only` is on by default, so extract wrote only the `objects` / `globalActions` subtree while check also demands `apps`, `navigation`, `dashboard`, `widget`, `page` and `flow` keys. Re-runs `os i18n extract --no-objects-only` (or hand-authors those groups), re-checks with `os i18n check --locales=zh-CN`, and adds `--strict` / `--threshold` in CI.",
       "files": [],
       "assertions": {
         "must_contain": ["--no-objects-only", "os i18n check", "apps", "--strict"],
@@ -54,7 +54,7 @@
     {
       "id": 6,
       "prompt": "Add zh-CN for the `pipeline_by_stage` report, the `sales_manager` permission set, the `regional_lead` position and the `deal_stage` picklist's option labels.",
-      "expected_output": "Top-level groups keyed by name: `reports.pipeline_by_stage` and `positions.regional_lead` (`label`, `description`), `permissions.sales_manager` (the same, spelled as the stack's `permissions[]`, not the camelCase name), `picklists.deal_stage.options` by stored value, inherited by every field referencing the picklist.",
+      "expected_output": "Top-level groups keyed by name: `reports.pipeline_by_stage` and `positions.regional_lead` (`label`, `description`), `permissions.sales_manager` (the same, spelled as the stack's `permissions[]`, not the camelCase name), `picklists.deal_stage.options` by stored value.",
       "files": [],
       "assertions": {
         "must_contain": ["reports", "permissions", "positions", "picklists"],
@@ -74,12 +74,22 @@
     {
       "id": 8,
       "prompt": "In zh-CN the `Products` grid heading on the `crm_opportunity` form and the `Open Tasks` block heading of the joined `showcase_task_overview` report are still English.",
-      "expected_output": "`objects.crm_opportunity_line_item.fields.opportunity.inlineTitle` — the field lives on the child object, so the key is the child's, and an untranslated `inlineTitle` keeps its authored text (no fallback to the child's plural label); `reports.showcase_task_overview.blocks.open_block.label`, keyed by the block's required `name`. Neither is a `pages.*.components` key.",
+      "expected_output": "`objects.crm_opportunity_line_item.fields.opportunity.inlineTitle` — the field lives on the child object, so the key is the child's, and an untranslated `inlineTitle` keeps its authored text (no fallback to the child's plural label); `reports.showcase_task_overview.blocks.open_block.label`, keyed by the block's required `name`.",
       "files": [],
       "assertions": {
         "must_contain": ["inlineTitle", "crm_opportunity_line_item", "blocks", "open_block"],
         "must_not_contain": ["fields.opportunity_line_item", "components.open_block"]
       }
+    },
+    {
+      "id": 9,
+      "prompt": "Our `crm_manual` doc book ships in English and zh-CN, but the docs sidebar still shows the book title and its `getting_started` section title in English.",
+      "expected_output": "The `books` group, keyed by `Book.name`: `books.crm_manual.label` / `.description` and `books.crm_manual.groups.getting_started.label`, by the group's stable `key` (never its position); `os i18n extract --no-objects-only` seeds all three. The pages' own titles and bodies localize through `doc.translations`, and the inline `translations` map a book once carried stays retired.",
+      "files": [],
+      "assertions": {
+        "must_contain": ["books", "groups", "getting_started", "doc.translations"],
+        "must_not_contain": ["pages.crm_manual", "sections.getting_started"]
+      }
     }
   ]
 }