diff --git a/packages/content/README.md b/packages/content/README.md
index 8a10544..f777539 100644
--- a/packages/content/README.md
+++ b/packages/content/README.md
@@ -66,7 +66,7 @@ rm -rf packages/content/.objectstack
 | Business objects | 9 (`piece`, `topic`, `signal`, `competitor`, `channel`, `publication`, `metric`, `cta`, `template`) |
 | State machines | 2 (`piece.status` 8-state, `signal.status` 3-state) |
 | Approvals | 1 (`publish_approval`: gates `in_review → approved`) |
-| Flows | 4 (signal → topic, default CTA, publication rollup placeholder, lifecycle timestamps) |
+| Flows | 4 (signal → topic, default CTA, publish approval, lifecycle notifications) |
 | Dashboards | 3 (Today's Workbench / Editorial Calendar / Channel ROI) |
 | App | 1 (Content Ops, 7 nav items) |
 | Views | 7 (incl. kanban on `piece.status`, calendar by `publish_at`) |
@@ -135,12 +135,12 @@ the charter.
 
 ## Known v0 caveats
 
-- The `publication_rollup` flow uses a `script` node placeholder (flow `aggregate`
-  nodes aren't in v6 spec yet). Live rollups happen via **`metricRollupHook`
-  + `publicationRollupHook`** in `src/objects/content_rollup.hook.ts`: every
-  metric insert/update deltas into `publication.total_*`, then up into
-  `piece.total_*`. Seed values are pre-populated so dashboards have data
-  before any metric is recorded.
+- Performance rollups are native **`Field.summary`** fields (#1870), not a flow
+  or hook: the engine recomputes `publication.total_*` from the child
+  `content_metric` rows on every metric write, and those cascade one level up into
+  `piece.total_*`. A piece with no publications yet has no child to trigger a
+  recompute, so its `total_*` read `null` (not `0`) until its first publication
+  exists — cosmetic, and the seeded published pieces all have publications.
 - Today's Workbench KPI tiles filter on `assignee == {current_user_id} OR
   assignee == null`, so unassigned seed pieces show up immediately. Newly
   created pieces auto-assign to the creator (see `content_piece.hook.ts`).
diff --git a/packages/content/SPEC.md b/packages/content/SPEC.md
index da31952..2c0beee 100644
--- a/packages/content/SPEC.md
+++ b/packages/content/SPEC.md
@@ -155,8 +155,12 @@ action on the record page instead of a background flow.
 
 1. `signal_to_topic_promotion` — on `signal.status → promoted`, create a `content_topic` linked back.
 2. `cta_creation_default` — on `content_piece` create, if `cta_count = 0`, create one default CTA from the channel's default goal.
-3. `publication_rollup` — on `content_metric` insert/update, refresh `publication.total_views / total_clicks / total_signups / total_revenue` denormalized fields.
-4. `stamp_lifecycle_timestamps` — on `piece.status` transitions, stamp `submitted_at / approved_at / published_at / archived_at` (todo template's pattern).
+3. `publish_approval` — gates the `in_review → approved` transition through an approval.
+4. `stamp_lifecycle_timestamps` — on `piece.status` transitions, notify the editor/writer/owner at the right moment.
+
+> `publication.total_*` / `piece.total_*` are native `Field.summary` roll-ups
+> (#1870), recomputed server-side from child `content_metric` rows and cascaded
+> one level up to the piece — not a flow.
 
 **Manual actions (button on record page):**
 
diff --git a/packages/content/src/objects/content_publication.object.ts b/packages/content/src/objects/content_publication.object.ts
index 9c3462a..53ec4e9 100644
--- a/packages/content/src/objects/content_publication.object.ts
+++ b/packages/content/src/objects/content_publication.object.ts
@@ -9,9 +9,13 @@ import { tmpl } from '@objectstack/spec';
  * entry in `piece.target_channels`).
  *
  * Metric snapshots are recorded against this row, not the piece — so a
- * blog post + LinkedIn cross-post are measured independently. The
- * `total_*` numbers are STORED fields (seed/client-maintained); cross-object
- * rollups via hook are unsupported in the standalone runtime — see
+ * blog post + LinkedIn cross-post are measured independently. The `total_*`
+ * numbers are native `Field.summary` roll-ups (#1870): the engine recomputes
+ * them server-side from the child `content_metric` rows, and they cascade one
+ * level up to the parent `content_piece`'s own `total_*` summaries. (A piece
+ * with no publications yet has no child to trigger a recompute, so its rollups
+ * read `null` until its first publication exists.) A hook can't maintain these —
+ * a nested cross-object write is unsupported in the standalone runtime; see
  * content/src/hooks/index.ts.
  */
 export const Publication = ObjectSchema.create({