diff --git a/.changeset/7443-datetime-compact-style.md b/.changeset/7443-datetime-compact-style.md
index c7190f6f2..70900b838 100644
--- a/.changeset/7443-datetime-compact-style.md
+++ b/.changeset/7443-datetime-compact-style.md
@@ -13,8 +13,22 @@ The cell now reads `field.format` (it destructured `value` only, so a
 `datetime` field could not reach the style vocabulary a `date` field has) and
 renders through the shared function, and `data-table`'s `formatCellValue`
 calls `formatDateTime` instead of a third, independently authored option bag.
-Every existing cell renders byte-identically; `'compact'` is today's face
-named and rehoused, not a new one.
+Every existing cell without an authored `format`, and every cell authoring
+`'compact'`, renders byte-identically; `'compact'` is today's face named and
+rehoused, not a new one. A `datetime` field that authors any OTHER non-empty
+`format` does change: the cell previously ignored `field` altogether and always
+painted the compact face, and now anything other than `'compact'` selects the
+verbose `formatDateTime` default — measured as `Jul 4, 2024, 07:00 AM` in
+`en-US` for the instant whose compact face is `7/4/2024 7:00 am`. An
+unrecognised value is neither rejected nor passed through; it silently lands on
+that verbose face. No `datetime` field in this repository authors a `format`, so
+no cell here moves — a consumer that authored one is the case this sentence is
+for. Note that `format` has no declared value vocabulary to check a value
+against: `@object-ui/types` types it `format?: string`, and `@objectstack/spec`
+carries one free-form `format?: string` on its shared field schema, described
+"Format string (e.g. email, phone)" and accepting any string. `'compact'` is
+therefore the only value with a defined `datetime` meaning, and every other
+value means "the verbose face" by fallthrough rather than by design.
 
 Additive, no signature change: `formatDateTime(value, options?)` is unchanged
 and `formatDateTime(v, { locale })` keeps meaning what it meant.
diff --git a/.changeset/7747-datetime-format-cast-narrowing.md b/.changeset/7747-datetime-format-cast-narrowing.md
new file mode 100644
index 000000000..b9f09b92e
--- /dev/null
+++ b/.changeset/7747-datetime-format-cast-narrowing.md
@@ -0,0 +1,19 @@
+---
+---
+
+Narrow the `DateTimeCellRenderer` style cast from `as any` to the subtype that
+actually declares the property (objectui#7747).
+
+`const style = (field as any)?.format || 'compact'` becomes
+`(field as DateTimeFieldMetadata | undefined)?.format`. Some cast is
+load-bearing — `FieldMetadata` is a 37-member union and `BaseFieldMetadata`
+carries no `format`, so the bare read is `TS2339` — but `as any` was wider than
+the job: `DateTimeFieldMetadata` is exported from `@object-ui/types`, which this
+file already imports from, so the narrow cast was available at zero cost. The
+difference that buys: `as any` would also have silenced a typo in the property
+name, and the narrow cast will not.
+
+Type-level only; no package is released by this change. The emitted expression
+is identical, so every cell renders exactly what it rendered before —
+`'compact'` and an absent or empty `format` keep the compact face, and any
+other value keeps selecting the verbose `formatDateTime` default.
diff --git a/packages/fields/src/index.tsx b/packages/fields/src/index.tsx
index bb0974998..c16ba226e 100644
--- a/packages/fields/src/index.tsx
+++ b/packages/fields/src/index.tsx
@@ -7,7 +7,7 @@
  */
 
 import React from 'react';
-import type { FieldMetadata, SelectOptionMetadata } from '@object-ui/types';
+import type { DateTimeFieldMetadata, FieldMetadata, SelectOptionMetadata } from '@object-ui/types';
 import { ComponentRegistry, percentDisplayValue, getRecordDisplayName, humanizeLabel, isMissingForRequired, formatDate, formatDateTime, formatDateTimeCompactParts, formatRelativeDate, type ComponentMeta, type DateDisplayOptions } from '@object-ui/core';
 // The platform's own value-shape contract, asked rather than restated
 // (objectui#6744). See `locationStoredValueSchemaFor` below for why this is a
@@ -882,7 +882,11 @@ export function DateTimeCellRenderer({ value, field }: CellRendererProps): React
   // (objectui#7443). `||`, not `??`, matches the `date` cell and keeps an
   // authored empty string on the compact face rather than dropping it into
   // the verbose default.
-  const style = (field as any)?.format || 'compact';
+  // `FieldMetadata` is a 37-member union and `BaseFieldMetadata` carries no
+  // `format`, so the bare property read is `TS2339` — SOME cast is load-bearing.
+  // `DateTimeFieldMetadata` is the narrowest one that carries it (objectui#7747);
+  // `as any` would also silence a typo in the property name, this does not.
+  const style = (field as DateTimeFieldMetadata | undefined)?.format || 'compact';
 
   // The compact face is painted in two halves — the time is muted and offset
   // — so this branch asks the shared module for the halves rather than the