diff --git a/.changeset/8114-detail-tab-activity-timeline.md b/.changeset/8114-detail-tab-activity-timeline.md
new file mode 100644
index 0000000000..7b059643bf
--- /dev/null
+++ b/.changeset/8114-detail-tab-activity-timeline.md
@@ -0,0 +1,54 @@
+---
+'@object-ui/plugin-detail': patch
+---
+
+The README's Activity tab example names `record:activity`, a block this package
+registers, instead of `activity-timeline`, which nothing registers
+(objectui#8114).
+
+`README.md` ships in this package's `files`, so the example went out in every
+tarball. `DetailTabs` renders a tab's `content` through
+`<SchemaRenderer schema={toRenderableSchema(tab.content)} />`, which makes
+`content.type` an SDUI node position judged by the component registry — so a
+reader copying the tab got the registry's `Unknown component type` panel
+(OBJUI-001) where the timeline should be. Same shape as the `line-chart` widget
+in `plugin-dashboard/README.md` (objectui#7896's census; fixed by objectui#7951)
+and the fourth known instance.
+
+Which type replaces it was read off the registry rather than guessed, using the
+repository's own derivation — `deriveRegistryKeys()` from
+`scripts/check-doc-component-types.mjs`, the 649-key universe that gate judges
+against:
+
+| key | reading |
+|---|---|
+| `record:activity` | REGISTERED — `packages/plugin-detail/src/index.tsx:673` |
+| `activity-timeline` | absent |
+| `activity` (bare) | absent — the `skipFallback: true` half |
+| `related-list`, `detail-section`, `record:details` | REGISTERED (lit controls) |
+
+Two keys move, because naming the type alone would leave the block fed through a
+key it never reads:
+
+- **`type: 'record:activity'`**, namespace spelled out. The registration passes
+  the bare name under `{ namespace: 'record', skipFallback: true }`, and
+  `skipFallback` is what keeps the bare name unclaimed — `record:activity`
+  resolves, `activity` does not. That `activity` is also the tab's own `key` is
+  a coincidence of spelling, and the card that filed this read the key as
+  evidence there was no such component type.
+- **`items`, not `data`.** `RecordActivityRenderer` takes its feed from `items`
+  on the node, a mounted discussion context, or a self-fetch from `sys_activity`
+  scoped off `useRecordContext`. The last two need a record host and a bare
+  `<DetailView>` mounts neither, so the example's own intent — a caller handing
+  over a feed it already owns — is the first source. `data` is read on no path.
+
+`activityData` is retyped from `Record<string, unknown>[]` to the exported
+`FeedItem`, which puts the block under `check:doc-snippets`. No package source
+and no runtime behaviour changes.
+
+**Still ungated, stated so this is not mistaken for coverage.**
+`check:doc-types` is the gate that judges `type` literals and it deliberately
+does not walk `packages/NAME/README.md` — that widening is objectui#7896's, and
+objectui#7896 is blocked by this card. Measured rather than assumed: with an
+unregistered type substituted back into this very block, `check:doc-snippets`
+and `check:doc-types` both still exit 0.
diff --git a/packages/plugin-detail/README.md b/packages/plugin-detail/README.md
index 2e83f658c0..99e8728a1e 100644
--- a/packages/plugin-detail/README.md
+++ b/packages/plugin-detail/README.md
@@ -134,8 +134,9 @@ const accountDetail = <DetailView
 
 ```tsx
 import { DetailView } from '@object-ui/plugin-detail';
+import type { FeedItem } from '@object-ui/types';
 
-declare const activityData: Record<string, unknown>[];
+declare const activityData: FeedItem[];
 declare const navigate: (url: string) => void;
 declare const deleteAccount: (id: string) => void;
 
@@ -166,9 +167,11 @@ const accountDetail = <DetailView
         key: 'activity',
         label: 'Activity',
         badge: '12',
+        // `record:activity` — the registered Activity Timeline block. Reachable
+        // under that exact key and no other; see the note below the block.
         content: {
-          type: 'activity-timeline',
-          data: activityData,
+          type: 'record:activity',
+          items: activityData,
         },
       },
     ],
@@ -181,6 +184,33 @@ const accountDetail = <DetailView
 />;
 ```
 
+A tab's `content` is an **SDUI node**, not a private vocabulary: `DetailTabs`
+renders it with `<SchemaRenderer schema={toRenderableSchema(tab.content)} />`,
+so `content.type` is resolved by the component registry and an unregistered
+name paints the `Unknown component type` panel (**OBJUI-001**) instead of a
+component. Author only types this repository registers.
+
+Two things about the Activity tab above are worth copying rather than guessing
+(objectui#8114 — it previously taught `type: 'activity-timeline'`, which
+nothing registers):
+
+- **The key is `record:activity`, with the namespace spelled out.** The
+  registration in `src/index.tsx` passes the bare name under
+  `{ namespace: 'record', skipFallback: true }`, and `skipFallback` is what
+  stops the bare name from also being claimed globally — so `record:activity`
+  resolves and `activity` resolves to nothing. `activity` is additionally a tab
+  **key** in the example above; the two are unrelated.
+- **The feed arrives as `items`, not `data`.** `record:activity` takes its feed
+  from three sources, in precedence order: `items` on the node, a mounted
+  discussion context, or a self-fetch from `sys_activity` scoped off
+  `useRecordContext`. The last two need a record host; a bare `<DetailView>`
+  like the one above mounts neither, so a caller that already owns the feed
+  passes it in as `items` (the convention `record:history` uses for `entries`).
+  `data` is not a key this block reads.
+
+See **The `record:activity` block** in the plugin-detail guide for its declared
+inputs (`types`, `limit`, `filterMode`, `showCompleted`, …).
+
 ## Schema
 
 The DetailView component accepts a `DetailViewSchema`, declared in