@@ -0,0 +1,20 @@
+---
+"@objectstack/spec": patch
+---
+
+fix(spec): correct `GanttConfig.timeZone`'s describe — persisted gantt drops on a `date` field are not "real instants" (#20466)
+
+Clause-②: no
+
+The `GanttConfig` `timeZone` member's `.describe()` said "persisted data stays real
+instants" for every field. That is false for a `Field.date` column: per the spec's own
+storage rule (`temporalStorageForm` / ADR-0053), a gantt drop on a `date` field writes the
+calendar day it landed on, as a timezone-naive `YYYY-MM-DD`, while a `datetime` field
+still writes the real instant. Only the false clause is replaced — "a datetime value is
+still written as the real instant, and a date value as the calendar day it was dropped on
+in this zone's calendar (`YYYY-MM-DD`)" — the rest of the describe, and every other
+member, is unchanged.
+
+No key moves and no verdict moves: this corrects a published describe's prose to match
+the contract it already had, it does not add, remove or re-scope anything authorable. The
+JSON Schema and reference docs regenerate from the corrected source.
@@ -1917,7 +1917,7 @@ export const GanttConfigSchema = lazySchema(() => strictObject({
   summaryExtent: z.enum(['children', 'self']).optional().describe("How a summary bar's span is computed. 'children' (renderer default) rolls the bar up from its children — min start, max end, duration-weighted progress — and ignores the record's own dates; 'self' renders the record's OWN start, end and progress and falls back to rollup only for records without dates (use it when the parent's schedule is authoritative, e.g. a shift plan whose work-order children are locked history)"),
   defaultCollapsedDepth: z.number().int().min(0).optional().describe('Auto-collapse tree nodes at or below this 0-indexed depth on first render (roots are depth 0): every node at that depth or deeper that has children starts folded; the user can still expand them. Omit to start fully expanded'),
   dependencyTypes: z.boolean().optional().describe('Whether the backing store persists dependency link TYPES (fs, ss, ff, sf); renderer default true. Set false when dependencies are bare predecessor ids: the link menu hides the type switcher (a switch would be silently reverted on refetch) and drag-created links are always finish-to-start'),
-  timeZone: z.string().optional().describe("Business time zone, an IANA name such as 'Asia/Shanghai': the chart's calendar — shift bands, day columns, snapping, the today line, date labels — renders in this zone's wall time for every viewer instead of the browser's zone; persisted data stays real instants. An invalid name falls back to the browser zone with a console warning"),
+  timeZone: z.string().optional().describe("Business time zone, an IANA name such as 'Asia/Shanghai': the chart's calendar — shift bands, day columns, snapping, the today line, date labels — renders in this zone's wall time for every viewer instead of the browser's zone; a datetime value is still written as the real instant, and a date value as the calendar day it was dropped on in this zone's calendar (YYYY-MM-DD). An invalid name falls back to the browser zone with a console warning"),
   exportFileName: z.string().optional().describe("Base name for exported PNG and PDF files (e.g. the view's display label — the host's view schema often reaches the renderer stripped of label); falls back to the object schema label, then the object API name. A timestamp suffix is always appended"),
   interactions: strictObject({
     surface: 'this gantt interactions block',