@@ -0,0 +1,13 @@
+---
+"@objectstack/platform-objects": patch
+---
+
+`sys_email.highlightFields` names the recipient column that exists, so the platform's own email log stops rendering one column short (#15629)
+
+The list read `['subject', 'to', 'status', 'sent_at']`. Three of those four resolve; `to` does not — `sys_email`'s recipient column is `to_addresses`. It now reads `['subject', 'to_addresses', 'status', 'sent_at']`, and nothing else about the object moved.
+
+`highlightFields` is the object's ordered "most important fields" pointer (ADR-0085): it drives the default list columns, record cards, previews and the detail highlight strip. Every consumer **silently skips** an entry it cannot resolve — nothing throws and nothing logs — so each of those surfaces rendered one field short, and the field missing from the platform's own outbound-email log was the recipient.
+
+There was a second, louder consequence that nobody could reach by accident. Since `object-field-ref-unknown` crossed onto the object write door (#15254), this body could not be republished through `PUT /api/v1/meta/object` or a package publish: the door answers `422 INVALID_METADATA`. `sys_email` reaches the runtime as a code-shipped registry object instead — `EmailServicePlugin` hands it to the manifest service, a path that runs no authoring gate — so boot was never affected and no deployment was failing. It was a trap laid for whoever next edited the object through a door rather than the file.
+
+`sys-email.highlight-fields-resolve.test.ts` pins it through that real door rather than by comparing the array against `Object.keys(fields)`: it runs `runRuntimeAuthoringRules({ type: 'object' })` over the shipped declaration with the audit module's other objects as resolution context, and a control case restores the old entry and requires the same call to refuse it — so a green result means the door read this object and accepted it, never that nothing looked.
@@ -0,0 +1,71 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+import { describe, expect, it } from 'vitest';
+import { runRuntimeAuthoringRules } from '@objectstack/lint';
+import * as audit from './index.js';
+import { SysEmail } from './sys-email.object.js';
+
+/**
+ * [#15629] `sys_email.highlightFields` names fields `sys_email` actually has.
+ *
+ * ## The state this pins, measured on `origin/main` (5f4f1f6e2)
+ *
+ * The list read `['subject', 'to', 'status', 'sent_at']`. Three of the four
+ * resolve; `to` does not — the recipient column on this object is
+ * `to_addresses`. So the shipped declaration carried a dangling field
+ * reference, and the two consequences are of different kinds:
+ *
+ *  - **Silent, on every render.** `highlightFields` is the object's ordered
+ *    "most important fields" pointer (`packages/spec/src/data/object.zod.ts`
+ *    — "Drives default columns, cards, previews, detail highlight strip"),
+ *    and every consumer of it SKIPS an entry it cannot resolve. Nothing
+ *    throws, nothing logs: the platform's own email log just renders one
+ *    column short, and the missing one is the recipient.
+ *  - **Loud, but only through a door nothing here walks.** Since #15254
+ *    crossed `object-field-ref-unknown` onto the object write door, this body
+ *    could not be republished through `PUT /api/v1/meta/object` or a package
+ *    publish — `runtime-authoring-gate.ts` turns any `error` finding into
+ *    `INVALID_METADATA` / 422. `sys_email` reaches the runtime as a
+ *    code-shipped registry object instead (`EmailServicePlugin` hands it to
+ *    the manifest service), and that path runs no authoring gate at all, so
+ *    boot was never affected. A live trap for whoever next edits it through a
+ *    door rather than the file — not an active failure, which is why the card
+ *    was p2.
+ *
+ * ## Why the pin is driven through the door and not by reading the array
+ *
+ * Comparing `highlightFields` against `Object.keys(fields)` here would pin a
+ * MIRROR of the rule, and a mirror is exactly what stops agreeing with the
+ * rule the moment either moves — the rule resolves injected system columns
+ * and semantic-role aliases that a naive key comparison does not. So this
+ * calls the real gate, with the audit module's other objects as resolution
+ * context, the same shape the finding was measured with.
+ *
+ * The second case is not decoration. A gate assertion that yields zero
+ * findings is indistinguishable from a gate that never ran, so the control
+ * restores the one bad entry and requires the SAME call to refuse it, at the
+ * same path. Green here therefore means "the door read this object and
+ * accepted it", never "nothing looked".
+ */
+describe('sys_email — highlightFields resolves at the object write door', () => {
+  /** The audit module's other shipped objects, as the live resolution context. */
+  const siblings: unknown[] = Object.values(audit as Record<string, unknown>).filter((o) => {
+    const name = (o as { name?: unknown } | null)?.name;
+    return typeof name === 'string' && name !== 'sys_email';
+  });
+
+  const gate = (item: unknown) =>
+    runRuntimeAuthoringRules({ type: 'object', item, context: { objects: siblings } });
+
+  it('publishes clean — the door adds no error to the shipped declaration', () => {
+    const result = gate(SysEmail);
+    expect(result.errors, JSON.stringify(result.errors, null, 2)).toEqual([]);
+  });
+
+  it('control: the pre-fix entry is still refused, so the case above is not vacuous', () => {
+    const result = gate({ ...SysEmail, highlightFields: ['subject', 'to', 'status', 'sent_at'] });
+    expect(result.errors.map((e) => `${e.rule} ${e.path}`)).toEqual([
+      'object-field-ref-unknown objects.sys_email.highlightFields[1]',
+    ]);
+  });
+});
@@ -29,7 +29,7 @@ export const SysEmail = ObjectSchema.create({
   displayNameField: 'subject',
   nameField: 'subject', // [ADR-0079] canonical primary-title pointer (mirrors deprecated displayNameField)
   titleFormat: '{subject}',
-  highlightFields: ['subject', 'to', 'status', 'sent_at'],
+  highlightFields: ['subject', 'to_addresses', 'status', 'sent_at'],
 
   fields: {
     id: Field.text({