@@ -0,0 +1,27 @@
+---
+'@objectstack/lint': minor
+---
+
+fix(lint)!: `os build`, `os validate`, `os lint` and the page save door refuse a page component props CEL slot over the platform's parse bounds (#25002)
+
+Clause-②: no (narrowing: a page component props CEL slot over the platform parse bounds is refused at `os build` and the page door; it ships now under the amended 「甲」, #6015 `6303865025`)
+
+A CEL source over `DEFAULT_LIMITS` (`maxAstNodes` 256, `maxDepth`, `maxListElements`) does not parse anywhere on the platform. It faults on every evaluation, and the console fails open, so the element it was written to gate draws for everyone. `page-predicate-over-budget` (`validatePagePredicateBounds`) finds such a source in the CEL slots declared inside a page component's `properties` bag: a `page:tabs` item `visibleWhen`, an `object-form` section or inline field `visibleWhen` / `readonlyWhen` / `requiredWhen`, `record:alert` `visible`, and the `visible` / `disabled` of the `action:*` blocks. The finding was a warning. It is now an error, and its authoring-rules entry moves from the advisory tier to the gating tier. This supersedes the warning-only behaviour described for the same rule earlier in this release line; its message no longer says "A future major release refuses it."
+
+**BREAKING — what moves for consumers.**
+
+- FROM: a warning at `os validate`, `os build` and `os lint`, and an entry on the page save door's `advisories` channel while the page saved. TO: an error. The three commands fail, and an active page write answers `422 INVALID_METADATA` with a `page-predicate-over-budget` issue located at the slot and naming the bound it overruns. The page is not stored. This covers `saveMetaItem` in publish mode (Studio, REST `/meta`, MCP) and the promotion of a draft (`publishMetaItem`).
+- The page door answers `INVALID_METADATA`, its existing author-time refusal envelope, not `VALIDATION_ERROR`.
+
+**Fix (one line).** Shrink the predicate (collapse an `||` chain into one `in ['a', 'b', …]` test), or precompute the heavy part into a formula or roll-up field on the object and test that one field.
+
+**Unchanged.**
+
+- A within-bounds source draws nothing at any door.
+- The component node's own `visibleWhen` keeps its existing verdict (`visibility-predicate-over-budget`), and this rule does not report it twice.
+- Stored pages are not migrated and are not refused on read. A stored page with such a slot keeps loading and serving until it is next saved, and that save is judged. Saving a page as a draft is still allowed; publishing the draft is judged.
+- `OS_ALLOW_UNLINTED_METADATA_WRITES=1` still turns a refusal into a logged write.
+- No public export or signature moves; `PagePredicateBoundsFinding.severity` is now `'error'`.
+- Measured before crossing, through the built `@objectstack/lint`: 0 in-repo producers carry such a slot. Every page module under `examples/` and `packages/` (30 files, 65 page values) draws 0 findings, and so do the `app-crm`, `app-multi-package` and `app-todo` composed stacks. A literal scan of 9,919 tracked source files (13,840 string literals of 120+ characters) finds 0 sources over the bounds, and HotCRM at `c8a7a70` (611 files) finds 0. A planted 78-term control is found by both instruments.
+
+<!-- adr-0087: not-required (no-migration-prescription) a refusal at `os build`, `os validate`, `os lint` and the page save door of a page component props CEL slot whose source overruns the platform's parse bounds: no authorable key, spelling, export or stored shape moves, and no stored row is read, rewritten or converted. A stored page whose slot is refused keeps loading until it is next saved, and the repair is the author's rewrite of the predicate (shrinking it, or precomputing it into a formula or roll-up field), which no ledger entry can derive. The other categories are closed on facts: the package publishes (not unpublished); no ADR-0087 id covers this verdict (not already-registered); and the change is a build and door verdict, not a declaration (not runtime-interface-only or type-surface-only). -->
@@ -1710,14 +1710,16 @@ export const AUTHORING_RULES: readonly AuthoringRule[] = [
   // `record:alert` / `action:*` `visible` and `disabled`), judged for the
   // platform's parse bounds with `validateExpression`'s verdict. The component
   // node's own `visibleWhen` is the visibility family's above, an error; these
-  // slots were judged by no rule at any door. `advisory` in 18.x: refusing a
-  // page that saves today is a narrowing no ADR-0087 conversion can carry, so
-  // under the standing ruling for post-GA narrowings (「甲」, record
-  // 6292005854) only the warning ships now and the refusal waits for the next
-  // major. Page-local, so the per-write snapshot is the whole input.
+  // slots were judged by no rule at any door. `gating` since #25002: the
+  // finding is an `error`, so a page carrying such a slot fails all three
+  // commands and its next save is refused at the page door. It first shipped
+  // as an advisory; the amended standing ruling for post-GA narrowings
+  // (「甲」, record 6303865025) ships a narrowing no ADR-0087 conversion can
+  // carry now, as a BREAKING minor. Page-local, so the per-write snapshot is
+  // the whole input.
   {
     name: 'validatePagePredicateBounds',
-    tier: 'advisory',
+    tier: 'gating',
     input: 'normalized',
     commands: ALL,
     source: 'packages/lint/src/validate-page-predicate-bounds.ts',
 
@@ -127,7 +127,7 @@ describe('#24491 — the page door gives the build\'s visibility-predicate verdi
       'validateComponentTypes',
       'validatePrintPageBlocks',
       ...FAMILY,
-      // #24953 — the props-bag CEL slots' bounds warning, after the family.
+      // #24953 / #25002 — the props-bag CEL slots' bounds refusal, after the family.
       'validatePagePredicateBounds',
     ]);
   });
 
@@ -3,11 +3,15 @@
 /**
  * #24953 — a CEL slot inside a page component's `properties` over the
  * platform's parse bounds is reported, with `validateExpression`'s bounds
- * verdict, at every door that accepts a page; a WARNING in 18.x (「甲」).
+ * verdict, at every door that accepts a page. #25002 — the finding is an
+ * ERROR: `os validate` / `os build` / `os lint` fail and the page door refuses
+ * the write (the amended 「甲」, record 6303865025).
  *
  * The card's shape is a `page:tabs` item `visibleWhen` of ~390 AST nodes,
  * which parsed through `PageSchema` and drew no finding anywhere while the
  * console faulted on it at every evaluation and drew the tab for everyone.
+ * The door's real save path (422, nothing stored) is pinned in
+ * `@objectstack/metadata-protocol`'s `protocol.runtime-authoring-gate.test.ts`.
  */
 import { validateExpression } from '@objectstack/formula';
 import { PageSchema } from '@objectstack/spec/ui';
@@ -66,38 +70,40 @@ describe('#24953 — the card\'s shape: a `page:tabs` item `visibleWhen` over `m
     const verdict = validateExpression('predicate', OVER_AST_NODES);
     expect(verdict.errors.map((e) => e.code)).toEqual(['cel-too-large']);
     expect(verdict.errors[0]!.params).toMatchObject({ limit: 'maxAstNodes', limitValue: 256 });
-    // Parse acceptance is unchanged by this rule — it is a finding, not a refusal.
+    // Parse acceptance is unchanged by this rule — the refusal is the lint finding's, not the schema's.
     expect(PageSchema.safeParse(tabsPage(OVER_AST_NODES)).success).toBe(true);
   });
 
-  it('is a WARNING naming the field and the bound, at the slot, without echoing the source', () => {
+  it('is an ERROR naming the field and the bound, at the slot, without echoing the source', () => {
     const findings = validatePagePredicateBounds({ pages: [tabsPage(OVER_AST_NODES)] });
     expect(findings).toHaveLength(1);
     expect(findings[0]).toMatchObject({
-      severity: 'warning',
+      severity: 'error',
       rule: PAGE_PREDICATE_OVER_BUDGET,
       where: 'page "deal_home" · page:tabs',
       path: TAB_PATH,
     });
     expect(findings[0]!.message).toContain('`visibleWhen`');
     expect(findings[0]!.message).toContain('`maxAstNodes` budget (platform limit 256)');
     expect(findings[0]!.message).not.toContain('record.f0');
+    // The 18.x warning's forward-looking sentence is gone: the refusal is now.
+    expect(findings[0]!.message).not.toContain('future major');
   });
 
   for (const command of ['validate', 'build', 'lint'] as const) {
-    it(`\`os ${command}\` reports it as a warning, never an error`, () => {
+    it(`\`os ${command}\` fails on it: an error, the only one the page draws`, () => {
       const stack = { pages: [tabsPage(OVER_AST_NODES)] };
       const findings = runAuthoringRules(command, { normalized: stack, parsed: stack });
-      expect(ours(findings).map((f) => [f.severity, f.path])).toEqual([['warning', TAB_PATH]]);
-      expect(findings.filter((f) => f.severity === 'error')).toEqual([]);
+      expect(ours(findings).map((f) => [f.severity, f.path])).toEqual([['error', TAB_PATH]]);
+      expect(findings.filter((f) => f.severity === 'error').map((f) => f.rule)).toEqual([PAGE_PREDICATE_OVER_BUDGET]);
     });
   }
 
-  it('the page publish door carries it on the advisories channel, the build\'s finding verbatim', () => {
+  it('the page publish door refuses it on the errors channel, the build\'s finding verbatim', () => {
     const result = gatePage(tabsPage(OVER_AST_NODES));
     expect(result.rulesRun).toContain('validatePagePredicateBounds');
-    expect(ours(result.errors)).toEqual([]);
-    const atDoor = ours(result.advisories);
+    expect(ours(result.advisories)).toEqual([]);
+    const atDoor = ours(result.errors);
     expect(atDoor.map((f) => f.rule)).toEqual([PAGE_PREDICATE_OVER_BUDGET]);
     const stack = { pages: [tabsPage(OVER_AST_NODES)] };
     const atBuild = ours(runAuthoringRules('build', { normalized: stack, parsed: stack }));
@@ -186,9 +192,9 @@ describe('#24953 — no double report with the visibility family', () => {
 });
 
 describe('#24953 — wiring', () => {
-  it('runs on all three commands as an advisory rule, and at the page door only', () => {
+  it('runs on all three commands as a gating rule, and at the page door only', () => {
     const entry = authoringRulesFor('validate').find((r) => r.name === 'validatePagePredicateBounds');
-    expect(entry?.tier).toBe('advisory');
+    expect(entry?.tier).toBe('gating');
     for (const command of ['build', 'lint'] as const) {
       expect(authoringRulesFor(command).map((r) => r.name)).toContain('validatePagePredicateBounds');
     }
 
@@ -58,14 +58,17 @@
  * budget by definition, and `validateExpression`'s own `detail` quotes the
  * author's line); the `path` locates it.
  *
- * ## Why a warning
+ * ## Why an error
  *
- * Refusing a page that saves today is a narrowing no ADR-0087 conversion can
- * carry — a predicate cannot be shrunk mechanically — so under the standing
- * ruling for breaking narrowings after the 18.0 GA (「甲」, record 6292005854)
- * the 18.x line ships the loud half only: a `warning` at `os validate`,
- * `os build`, `os lint` and the page publish door's `advisories` channel. The
- * refusal belongs to the next major, which promotes the finding to `error`.
+ * Such a source never gates what it was written to gate, at any door, so the
+ * finding is a refusal: `os validate`, `os build` and `os lint` fail, and the
+ * page publish door answers its structured 422 on the page's next save.
+ * Stored pages keep loading and serving — the gate judges writes, never the
+ * read path. The 18.x line first shipped this as a warning; under the amended
+ * standing ruling for breaking narrowings (「甲」, record 6303865025: a
+ * narrowing no ADR-0087 conversion can carry also ships now, as a BREAKING
+ * minor) the refusal ships in 18.x too. No conversion carries it: a predicate
+ * cannot be shrunk mechanically, so the author's fix is the hint below.
  */
 
 import { validateExpression } from '@objectstack/formula';
@@ -78,7 +81,7 @@ import { recordsOf } from './object-graph.js';
 export const PAGE_PREDICATE_OVER_BUDGET = 'page-predicate-over-budget';
 
 export interface PagePredicateBoundsFinding {
-  severity: 'warning';
+  severity: 'error';
   rule: typeof PAGE_PREDICATE_OVER_BUDGET;
   /** e.g. `page "pipeline_home" · page:tabs`. */
   where: string;
@@ -202,14 +205,13 @@ export function validatePagePredicateBounds(stack: AnyRec): PagePredicateBoundsF
           ? `the \`${verdict.limit}\` budget (platform limit ${verdict.limitValue})`
           : "one of the platform's CEL parse budgets";
         findings.push({
-          severity: 'warning',
+          severity: 'error',
           rule: PAGE_PREDICATE_OVER_BUDGET,
           where: `page "${pageName}" · ${type}`,
           path: `${path}.properties${slot.rel}`,
           message:
             `\`${slot.key}\` is valid CEL that exceeds ${bound}, so it does not parse anywhere on the ` +
-            'platform: it faults on every evaluation and never gates what it was written to gate. ' +
-            'A future major release refuses it.',
+            'platform: it faults on every evaluation and never gates what it was written to gate.',
           hint:
             "Make the expression smaller: collapse an `||` chain into one `in ['a', 'b', …]` test, or " +
             'precompute the heavy part into a formula or roll-up field on the object and test that one field',
 
@@ -3471,6 +3471,116 @@ describe('runtime authoring gate on PAGE writes — the component visibleWhen ve
     });
 });
 
+// #25002 — a CEL slot INSIDE a page component's `properties` bag that overruns
+// the platform's parse bounds (`page-predicate-over-budget`,
+// `validatePagePredicateBounds`) is refused at the runtime save door, as
+// `os build` refuses it. #24953 shipped it as an advisory (the door admitted the
+// save and listed the finding); the amended 「甲」 (record 6303865025) ships
+// the refusal in 18.x. The card's shape: a `page:tabs` item `visibleWhen` of
+// ~390 AST nodes, over `maxAstNodes` (256). Pinned through the REAL
+// `saveMetaItem`:
+//
+//  (a) the active save is refused — 422 `INVALID_METADATA`, the door's own
+//      envelope — naming the slot and the bound, and nothing lands; the draft
+//      promotion is refused the same way;
+//  (b) the door's finding IS the build's;
+//  (c) control: a within-bounds tab predicate saves, and the row lands.
+//
+// ⚠️ As above: this package reaches `@objectstack/lint` through its built
+// `dist/`, so a registry or rule edit is invisible here until
+// `pnpm --filter @objectstack/lint build` has run.
+describe('runtime authoring gate on PAGE writes — a props-bag CEL slot over the parse bounds (#25002)', () => {
+    const RULE = 'page-predicate-over-budget';
+    const TAB_PATH = 'pages[0].regions[0].components[0].properties.items[1].visibleWhen';
+    /** 78 `||` terms, five AST nodes each — the card's ~390-node class. */
+    const OVER = Array.from({ length: 78 }, (_, i) => `record.f${i} == ${i}`).join(' || ');
+    const WITHIN = "record.stage == 'won' || page.tab != ''";
+    const page = (tabVisibleWhen: string) => ({
+        name: 'deal_home',
+        label: 'Deal',
+        type: 'app',
+        regions: [{
+            name: 'main',
+            components: [{
+                type: 'page:tabs',
+                properties: {
+                    items: [
+                        { label: 'Overview', value: 'overview', children: [] },
+                        { label: 'Finance', value: 'finance', visibleWhen: tabVisibleWhen, children: [] },
+                    ],
+                },
+            }],
+        }],
+    });
+
+    const savePage = (protocol: any, item: unknown, extra: Record<string, unknown> = {}) =>
+        protocol.saveMetaItem({ type: 'page', name: 'deal_home', item, ...extra });
+    const activePageRows = (rows: Map<string, Row>) =>
+        Array.from(rows.values()).filter((r) => r.type === 'page' && r.state === 'active');
+
+    let warn: ReturnType<typeof vi.spyOn>;
+    beforeEach(() => {
+        warn = vi.spyOn(console, 'warn').mockImplementation(() => {});
+        delete process.env.OS_ALLOW_UNLINTED_METADATA_WRITES;
+    });
+    afterEach(() => {
+        warn.mockRestore();
+        delete process.env.OS_ALLOW_UNLINTED_METADATA_WRITES;
+    });
+
+    it('(a) REFUSES an active save of the card\'s tab-item `visibleWhen`, naming the bound; nothing stored', async () => {
+        const { protocol, rows } = makeProtocol();
+
+        const err = await savePage(protocol, page(OVER)).catch((e: any) => e);
+
+        expect(err, 'the save resolved — the door still admits the over-budget slot').toBeInstanceOf(Error);
+        expect({ code: err.code, status: err.status }).toEqual({ code: 'INVALID_METADATA', status: 422 });
+        expect(err.rulesRun).toContain('validatePagePredicateBounds');
+        const issues = (err.issues ?? []).filter((i: any) => i.rule === RULE);
+        expect(issues, `issues: ${JSON.stringify(err.issues)}`).toHaveLength(1);
+        expect(issues[0]).toMatchObject({ severity: 'error', path: TAB_PATH });
+        expect(issues[0].message).toContain('`maxAstNodes` budget (platform limit 256)');
+        expect(activePageRows(rows)).toEqual([]);
+    });
+
+    it('(a) gates the draft → active promotion of the same page', async () => {
+        const { protocol, rows } = makeProtocol();
+        await expect(savePage(protocol, page(OVER), { mode: 'draft' })).resolves.toMatchObject({ success: true });
+
+        const err = await protocol.publishMetaItem({ type: 'page', name: 'deal_home' }).catch((e: any) => e);
+
+        expect({ code: err?.code, status: err?.status }).toEqual({ code: 'INVALID_METADATA', status: 422 });
+        expect((err.issues ?? []).map((i: any) => i.rule)).toContain(RULE);
+        expect(activePageRows(rows)).toEqual([]);
+    });
+
+    it('(b) the door and `os build` give the SAME finding', async () => {
+        const { protocol } = makeProtocol();
+        const err = await savePage(protocol, page(OVER)).catch((e: any) => e);
+        const atDoor = (err?.issues ?? []).filter((i: any) => i.rule === RULE);
+
+        const stack = { pages: [page(OVER)] };
+        const atBuild = runAuthoringRules('build', { normalized: stack, parsed: stack })
+            .filter((f) => f.severity === 'error');
+
+        expect(atBuild.map((f) => f.rule)).toEqual([RULE]);
+        expect(atDoor).toHaveLength(1);
+        for (const k of ['rule', 'where', 'path', 'message', 'hint'] as const) {
+            expect(atDoor[0][k], `door and build disagree on '${k}'`).toBe(atBuild[0]![k]);
+        }
+    });
+
+    it('(c) CONTROL — a within-bounds tab predicate saves, and the row lands', async () => {
+        const { protocol, rows } = makeProtocol();
+
+        await expect(savePage(protocol, page(WITHIN))).resolves.toMatchObject({ success: true });
+
+        expect(activePageRows(rows)).toHaveLength(1);
+        const stack = { pages: [page(WITHIN)] };
+        expect(runAuthoringRules('build', { normalized: stack, parsed: stack }).filter((f) => f.rule === RULE)).toEqual([]);
+    });
+});
+
 // A page component's `data` prop naming the retired view-level `api` provider,
 // at the runtime save door. `object-grid`, `object-map`, `object-gantt` and
 // `object-tree` take a view data source (`ViewDataSchema`) as `data`, so the