diff --git a/app/frontend/package.json b/app/frontend/package.json
index ced45a4..ef55250 100644
--- a/app/frontend/package.json
+++ b/app/frontend/package.json
@@ -41,6 +41,7 @@
     "@tiptap/extension-node-range": "3.31.4",
     "@tiptap/extension-table": "3.31.4",
     "@tiptap/extension-text-style": "3.31.4",
+    "@tiptap/extension-unique-id": "3.31.4",
     "@tiptap/extensions": "3.31.4",
     "@tiptap/pm": "3.31.4",
     "@tiptap/react": "3.31.4",
diff --git a/app/frontend/src/components/NoteComments.tsx b/app/frontend/src/components/NoteComments.tsx
index 5ab053f..7954d76 100644
--- a/app/frontend/src/components/NoteComments.tsx
+++ b/app/frontend/src/components/NoteComments.tsx
@@ -1,4 +1,4 @@
-import { useState } from 'react';
+import { useEffect, useState } from 'react';
 import { timeAgo } from '@project-graphite/ui';
 import { useAuth } from '../auth';
 import { useAction } from '../useAction';
@@ -8,6 +8,7 @@ import { LoadError } from './LoadError';
 interface NoteComment {
   id: string;
   parentId: string | null;
+  blockId: string | null;
   body: string;
   resolvedAt: string | null;
   editedAt: string | null;
@@ -15,7 +16,26 @@ interface NoteComment {
   author: { id: string; displayName: string } | null;
 }
 
-function CommentForm({ label, onSave, initial = '', onCancel }: { label: string; onSave: (body: string) => Promise<boolean>; initial?: string; onCancel?: () => void }) {
+export interface QuotedBlock {
+  id: string;
+  excerpt: string;
+}
+
+const blockElement = (blockId: string) => document.querySelector<HTMLElement>(`.note-content [data-id="${CSS.escape(blockId)}"]`);
+
+function CommentForm({
+  label,
+  onSave,
+  initial = '',
+  onCancel,
+  autoFocus,
+}: {
+  label: string;
+  onSave: (body: string) => Promise<boolean>;
+  initial?: string;
+  onCancel?: () => void;
+  autoFocus?: boolean;
+}) {
   const [body, setBody] = useState(initial);
   const [busy, setBusy] = useState(false);
   return (
@@ -30,7 +50,7 @@ function CommentForm({ label, onSave, initial = '', onCancel }: { label: string;
         });
       }}
     >
-      <textarea aria-label={label} maxLength={2_000} onChange={(event) => setBody(event.currentTarget.value)} placeholder={label} rows={2} value={body} />
+      <textarea aria-label={label} autoFocus={autoFocus} maxLength={2_000} onChange={(event) => setBody(event.currentTarget.value)} placeholder={label} rows={2} value={body} />
       <div className="flex gap-2">
         <button className="secondary-button px-3 py-1.5 text-sm" disabled={!body.trim() || busy} type="submit">
           {label}
@@ -45,13 +65,33 @@ function CommentForm({ label, onSave, initial = '', onCancel }: { label: string;
   );
 }
 
-export function NoteComments({ noteId, editable, owner }: { noteId: string; editable: boolean; owner: boolean }) {
+export function NoteComments({
+  noteId,
+  editable,
+  owner,
+  quoting,
+  onQuoteDone,
+  onBlocks,
+}: {
+  noteId: string;
+  editable: boolean;
+  owner: boolean;
+  quoting?: QuotedBlock;
+  onQuoteDone: () => void;
+  onBlocks: (blockIds: string[]) => void;
+}) {
   const auth = useAuth();
   const comments = useResource<NoteComment[]>(`/notes/${noteId}/comments`, true);
   const action = useAction();
   const [replying, setReplying] = useState<string>();
   const [editing, setEditing] = useState<string>();
   const [showResolved, setShowResolved] = useState(false);
+  const commented = (comments.data ?? [])
+    .filter((comment) => comment.blockId && !comment.parentId && !comment.resolvedAt)
+    .map((comment) => comment.blockId!)
+    .join(' ');
+
+  useEffect(() => onBlocks(commented ? commented.split(' ') : []), [commented, onBlocks]);
 
   if (comments.error) return <LoadError compact error={comments.error} onRetry={comments.reload} />;
   if (!comments.data) return null;
@@ -61,11 +101,12 @@ export function NoteComments({ noteId, editable, owner }: { noteId: string; edit
   const shown = threads.filter((thread) => showResolved || !thread.resolvedAt);
 
   const replace = (saved: NoteComment) => comments.mutate((current) => current.map((comment) => (comment.id === saved.id ? saved : comment)));
-  const add = (body: string, parentId?: string) =>
+  const add = (body: string, parentId?: string, blockId?: string) =>
     action.run(async () => {
-      const saved = await auth.request<NoteComment>(`/notes/${noteId}/comments`, { method: 'POST', body: JSON.stringify({ body, parentId }) });
+      const saved = await auth.request<NoteComment>(`/notes/${noteId}/comments`, { method: 'POST', body: JSON.stringify({ body, parentId, blockId }) });
       comments.mutate((current) => [...current, saved]);
       setReplying(undefined);
+      if (blockId) onQuoteDone();
       return '';
     }, 'The comment could not be saved.');
   const edit = (id: string, body: string) =>
@@ -97,6 +138,20 @@ export function NoteComments({ noteId, editable, owner }: { noteId: string; edit
           {comment.author?.displayName ?? 'Former member'} · {timeAgo(comment.createdAt)}
           {comment.editedAt ? ' · edited' : ''}
         </p>
+        {comment.blockId && (
+          <button
+            className="comment-block-quote"
+            onClick={() => {
+              const block = blockElement(comment.blockId!);
+              block?.scrollIntoView({ behavior: 'smooth', block: 'center' });
+              block?.classList.add('is-flashing');
+              window.setTimeout(() => block?.classList.remove('is-flashing'), 1600);
+            }}
+            type="button"
+          >
+            {blockElement(comment.blockId)?.textContent?.trim().slice(0, 80) || 'A block that was removed'}
+          </button>
+        )}
         <p className="m-0 whitespace-pre-wrap text-sm text-ink">{comment.body}</p>
         <div className="flex flex-wrap gap-3 text-sm">
           {!comment.parentId && !comment.resolvedAt && (
@@ -143,7 +198,14 @@ export function NoteComments({ noteId, editable, owner }: { noteId: string; edit
           </div>
         </article>
       ))}
-      <CommentForm label="Comment" onSave={(body) => add(body)} />
+      {quoting ? (
+        <div className="grid gap-2">
+          <p className="comment-block-quote m-0">{quoting.excerpt || 'An empty block'}</p>
+          <CommentForm autoFocus key={quoting.id} label="Comment on this block" onCancel={onQuoteDone} onSave={(body) => add(body, undefined, quoting.id)} />
+        </div>
+      ) : (
+        <CommentForm label="Comment" onSave={(body) => add(body)} />
+      )}
     </section>
   );
 }
diff --git a/app/frontend/src/components/NoteEditor.tsx b/app/frontend/src/components/NoteEditor.tsx
index 7d8a946..8659aaf 100644
--- a/app/frontend/src/components/NoteEditor.tsx
+++ b/app/frontend/src/components/NoteEditor.tsx
@@ -13,7 +13,8 @@ import { useAuth } from '../auth';
 import { maxUploadBytes, preparedUpload } from '../files';
 import type { Item } from '../spaces';
 import { colorFor, useLiveDocument, useLiveStatus, type Connection } from './live-document';
-import { blockChoices, blockMenuExtension, internalPath, pageContent, type BlockActions } from './note-extensions';
+import type { QuotedBlock } from './NoteComments';
+import { blockChoices, blockMenuExtension, CommentedBlocks, commentedBlocksKey, internalPath, pageContent, type BlockActions } from './note-extensions';
 
 const turnInto = new Set(['text', 'heading', 'subheading', 'bullets', 'numbers', 'checklist', 'quote', 'code', 'callout', 'toggle']);
 
@@ -56,7 +57,19 @@ function Toolbar({ editor }: { editor: Editor }) {
   );
 }
 
-function CollaborativeEditor({ connection, editable, noteId, spaceId }: { connection: Connection; editable: boolean; noteId: string; spaceId: string }) {
+interface CommentHooks {
+  onComment?: (block: QuotedBlock) => void;
+  commentedBlocks?: string[];
+}
+
+function CollaborativeEditor({
+  connection,
+  editable,
+  noteId,
+  spaceId,
+  onComment,
+  commentedBlocks,
+}: { connection: Connection; editable: boolean; noteId: string; spaceId: string } & CommentHooks) {
   const auth = useAuth();
   const show = useSnackbar();
   const navigate = useNavigate();
@@ -74,6 +87,7 @@ function CollaborativeEditor({ connection, editable, noteId, spaceId }: { connec
         Collaboration.configure({ document: connection.document }),
         CollaborationCaret.configure({ provider: connection.provider, user: { name: user.displayName, color: colorFor(user.id) } }),
         blockMenuExtension(actions),
+        CommentedBlocks,
       ],
       editorProps: {
         attributes: { 'aria-label': 'Page content', class: 'note-content' },
@@ -128,6 +142,11 @@ function CollaborativeEditor({ connection, editable, noteId, spaceId }: { connec
     if (outdated) editor?.setEditable(false);
   }, [editor, outdated]);
 
+  const commented = (commentedBlocks ?? []).join(' ');
+  useEffect(() => {
+    if (editor) editor.view.dispatch(editor.state.tr.setMeta(commentedBlocksKey, new Set(commented ? commented.split(' ') : [])).setMeta('addToHistory', false));
+  }, [editor, commented]);
+
   if (!editor) return <LinesSkeleton label="Loading the editor" lines={6} />;
   return (
     <div className="note-editor grid gap-3">
@@ -146,7 +165,7 @@ function CollaborativeEditor({ connection, editable, noteId, spaceId }: { connec
           </span>
         </div>
       </div>
-      {editable && !outdated && <BlockHandle actions={actions} editor={editor} />}
+      {editable && !outdated && <BlockHandle actions={actions} editor={editor} onComment={onComment} />}
       <EditorContent editor={editor} />
     </div>
   );
@@ -162,7 +181,7 @@ function HoldHandle({ editor }: { editor: Editor }) {
   return null;
 }
 
-function BlockHandle({ actions, editor }: { actions: BlockActions; editor: Editor }) {
+function BlockHandle({ actions, editor, onComment }: { actions: BlockActions; editor: Editor; onComment?: (block: QuotedBlock) => void }) {
   const [block, setBlock] = useState<{ node: BlockNode; pos: number }>();
   const at = (pos: number, bias: 1 | -1 = 1) =>
     editor.chain().focus().command(({ tr }) => {
@@ -173,6 +192,9 @@ function BlockHandle({ actions, editor }: { actions: BlockActions; editor: Edito
     ? [
         { label: 'Duplicate', onSelect: () => editor.chain().focus().insertContentAt(block.pos + block.node.nodeSize, block.node.toJSON()).run() },
         { label: 'Delete', onSelect: () => editor.chain().focus().deleteRange({ from: block.pos, to: block.pos + block.node.nodeSize }).run() },
+        ...(onComment && typeof block.node.attrs.id === 'string'
+          ? [{ label: 'Comment', onSelect: () => onComment({ id: block.node.attrs.id as string, excerpt: block.node.textContent.trim().slice(0, 80) }) }]
+          : []),
         ...(block.node.type.name === 'table'
           ? [
               { label: 'Add a row', onSelect: () => at(block.pos + block.node.nodeSize - 2, -1).addRowAfter().run(), separated: true },
@@ -197,8 +219,8 @@ function BlockHandle({ actions, editor }: { actions: BlockActions; editor: Edito
   );
 }
 
-export default function NoteEditor({ editable, noteId, spaceId }: { editable: boolean; noteId: string; spaceId: string }) {
+export default function NoteEditor({ editable, noteId, spaceId, ...hooks }: { editable: boolean; noteId: string; spaceId: string } & CommentHooks) {
   const connection = useLiveDocument(noteId);
   if (!connection) return <LinesSkeleton label="Loading the editor" lines={6} />;
-  return <CollaborativeEditor connection={connection} editable={editable} noteId={noteId} spaceId={spaceId} />;
+  return <CollaborativeEditor connection={connection} editable={editable} noteId={noteId} spaceId={spaceId} {...hooks} />;
 }
diff --git a/app/frontend/src/components/live-document.ts b/app/frontend/src/components/live-document.ts
index b7921c3..0a77076 100644
--- a/app/frontend/src/components/live-document.ts
+++ b/app/frontend/src/components/live-document.ts
@@ -17,7 +17,7 @@ export interface Person {
   color: string;
 }
 
-export const editorFormat = 3;
+export const editorFormat = 4;
 
 const colors = ['#e5736b', '#e0915a', '#d7b24a', '#5fbf7f', '#4fb3c4', '#6b8fe5', '#a07be5', '#e57bb5'];
 
diff --git a/app/frontend/src/components/note-extensions.tsx b/app/frontend/src/components/note-extensions.tsx
index 5cccf96..87cf5b0 100644
--- a/app/frontend/src/components/note-extensions.tsx
+++ b/app/frontend/src/components/note-extensions.tsx
@@ -1,10 +1,14 @@
 import { forwardRef, useEffect, useImperativeHandle, useState } from 'react';
 import { Extension, mergeAttributes, Node, type ChainedCommands, type Editor } from '@tiptap/core';
+import { isChangeOrigin } from '@tiptap/extension-collaboration';
 import { Details, DetailsContent, DetailsSummary } from '@tiptap/extension-details';
 import Highlight from '@tiptap/extension-highlight';
 import { TaskItem, TaskList } from '@tiptap/extension-list';
 import { TableKit } from '@tiptap/extension-table';
+import UniqueID from '@tiptap/extension-unique-id';
 import StarterKit from '@tiptap/starter-kit';
+import { Plugin, PluginKey } from '@tiptap/pm/state';
+import { Decoration, DecorationSet } from '@tiptap/pm/view';
 import Image from '@tiptap/extension-image';
 import Mention from '@tiptap/extension-mention';
 import { NodeViewWrapper, ReactNodeViewRenderer, ReactRenderer, type NodeViewProps } from '@tiptap/react';
@@ -319,6 +323,34 @@ export const BoardEmbedExtension = Node.create({
   addNodeView: () => ReactNodeViewRenderer(BoardEmbed),
 });
 
+export const commentedBlocksKey = new PluginKey<Set<string>>('commentedBlocks');
+
+export const CommentedBlocks = Extension.create({
+  name: 'commentedBlocks',
+  addProseMirrorPlugins: () => [
+    new Plugin<Set<string>>({
+      key: commentedBlocksKey,
+      state: {
+        init: () => new Set(),
+        apply: (transaction, current) => (transaction.getMeta(commentedBlocksKey) as Set<string> | undefined) ?? current,
+      },
+      props: {
+        decorations(state) {
+          const commented = commentedBlocksKey.getState(state);
+          if (!commented?.size) return null;
+          const marks: Decoration[] = [];
+          state.doc.descendants((node, pos) => {
+            if (typeof node.attrs.id === 'string' && commented.has(node.attrs.id)) marks.push(Decoration.node(pos, pos + node.nodeSize, { class: 'has-comments' }));
+          });
+          return DecorationSet.create(state.doc, marks);
+        },
+      },
+    }),
+  ],
+});
+
+const blockTypes = ['paragraph', 'heading', 'blockquote', 'codeBlock', 'callout', 'details', 'table', 'bulletList', 'orderedList', 'taskList', 'listItem', 'taskItem', 'image', 'boardEmbed', 'horizontalRule'];
+
 export function pageContent(request: Request, noteId: string) {
   return [
     StarterKit.configure({ undoRedo: false, link: { openOnClick: true, autolink: true, protocols: ['https', 'http', 'mailto'] } }),
@@ -333,5 +365,7 @@ export function pageContent(request: Request, noteId: string) {
     mentionExtension(request, noteId),
     BoardEmbedExtension,
     StoredImageExtension,
+    UniqueID.configure({ types: blockTypes, filterTransaction: (transaction) => !isChangeOrigin(transaction) }),
   ];
 }
+
diff --git a/app/frontend/src/pages/NotePage.tsx b/app/frontend/src/pages/NotePage.tsx
index a46d8d8..3a08980 100644
--- a/app/frontend/src/pages/NotePage.tsx
+++ b/app/frontend/src/pages/NotePage.tsx
@@ -6,7 +6,7 @@ import { DatabaseView } from '../components/database/DatabaseView';
 import { IconPicker } from '../components/IconPicker';
 import { PropertyField } from '../components/database/PropertyField';
 import { LoadError } from '../components/LoadError';
-import { NoteComments } from '../components/NoteComments';
+import { NoteComments, type QuotedBlock } from '../components/NoteComments';
 import { NoteHistory } from '../components/NoteHistory';
 import { ShareLinks } from '../components/ShareLinks';
 import { announcePagesChanged, noteTitle, type Note, type NoteDetails, type PropertyValues } from '../notes';
@@ -35,6 +35,8 @@ export function NotePage() {
   const note = useResource<NoteDetails>(`/notes/${id}`, true);
   const [wide, setWide] = useState(() => widePages.has(id));
   if (wide !== widePages.has(id)) setWide(widePages.has(id));
+  const [quoting, setQuoting] = useState<QuotedBlock & { noteId: string }>();
+  const [commentedBlocks, setCommentedBlocks] = useState<string[]>([]);
   const pages = useResource<Note[]>(note.data ? `/spaces/${note.data.spaceId}/notes` : null, true);
   const links = useResource<{ backlinks: { id: string; kind: string; item: { id: string; spaceId: string; kind: string; title: string } }[] }>(
     note.data ? `/items/${note.data.id}/links` : null,
@@ -217,7 +219,17 @@ export function NotePage() {
         {details.kind === 'board' ? (
           <BoardCanvas editable={details.editable} key={details.id} noteId={details.id} spaceId={details.spaceId} />
         ) : (
-          <NoteEditor editable={details.editable} key={details.id} noteId={details.id} spaceId={details.spaceId} />
+          <NoteEditor
+            commentedBlocks={commentedBlocks}
+            editable={details.editable}
+            key={details.id}
+            noteId={details.id}
+            onComment={(block) => {
+              setQuoting({ ...block, noteId: details.id });
+              window.setTimeout(() => document.querySelector('section[aria-label="Comments"]')?.scrollIntoView({ behavior: 'smooth', block: 'center' }));
+            }}
+            spaceId={details.spaceId}
+          />
         )}
       </Suspense>
       {details.database && <DatabaseView editable={details.editable} key={details.id} noteId={details.id} spaceId={details.spaceId} />}
@@ -273,7 +285,15 @@ export function NotePage() {
           </ul>
         </section>
       )}
-      <NoteComments editable={details.editable} key={`comments-${details.id}`} noteId={details.id} owner={space?.role === 'owner'} />
+      <NoteComments
+        editable={details.editable}
+        key={`comments-${details.id}`}
+        noteId={details.id}
+        onBlocks={setCommentedBlocks}
+        onQuoteDone={() => setQuoting(undefined)}
+        owner={space?.role === 'owner'}
+        quoting={quoting?.noteId === details.id ? quoting : undefined}
+      />
       {unconverting && (
         <ConfirmDialog
           confirmLabel="Turn back into a page"
diff --git a/app/frontend/src/styles/global.css b/app/frontend/src/styles/global.css
index 966a0b4..c3c4824 100644
--- a/app/frontend/src/styles/global.css
+++ b/app/frontend/src/styles/global.css
@@ -629,3 +629,26 @@ button.habit-day {
   background: var(--color-line-soft);
 }
 
+.note-content .has-comments {
+  box-shadow: inset 3px 0 0 #d7b24a;
+  padding-left: 0.6rem;
+}
+
+.note-content .is-flashing {
+  background: var(--color-line-soft);
+  transition: background 400ms ease;
+}
+
+.comment-block-quote {
+  width: fit-content;
+  max-width: 100%;
+  overflow: hidden;
+  border-left: 3px solid #d7b24a;
+  padding-left: 0.6rem;
+  color: var(--color-muted);
+  font-size: 0.85rem;
+  text-align: left;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
diff --git a/app/frontend/test/notes.spec.tsx b/app/frontend/test/notes.spec.tsx
index 00a901f..4a0a04f 100644
--- a/app/frontend/test/notes.spec.tsx
+++ b/app/frontend/test/notes.spec.tsx
@@ -8,7 +8,13 @@ import { internalPath, storedFileId } from '../src/components/note-extensions';
 import { flattenTree, type Note } from '../src/notes';
 
 vi.mock('../src/components/NoteEditor', () => ({
-  default: ({ editable, noteId }: { editable: boolean; noteId: string }) => <div data-editable={editable} data-note={noteId} data-testid="editor" />,
+  default: ({ editable, noteId, onComment, commentedBlocks }: { editable: boolean; noteId: string; onComment?: (block: { id: string; excerpt: string }) => void; commentedBlocks?: string[] }) => (
+    <div data-commented={(commentedBlocks ?? []).join(' ')} data-editable={editable} data-note={noteId} data-testid="editor">
+      <button onClick={() => onComment?.({ id: 'block-1', excerpt: 'Buy milk' })} type="button">
+        Comment on a block
+      </button>
+    </div>
+  ),
 }));
 
 vi.mock('../src/components/BoardCanvas', () => ({
@@ -224,6 +230,38 @@ describe('Notes', () => {
     expect(JSON.parse(localStorage.getItem('strata-wide-pages')!)).toEqual(['trips']);
   });
 
+  it('comments on a block and marks the block in the editor', async () => {
+    const sent: unknown[] = [];
+    let listed: unknown[] = [];
+    serve((path, init) => {
+      if (path === '/notes/trips/comments' && init?.method === 'POST') {
+        const body = JSON.parse(String(init.body));
+        sent.push(body);
+        const saved = { id: 'c1', parentId: null, blockId: body.blockId, body: body.body, resolvedAt: null, editedAt: null, createdAt: '2026-10-09T10:00:00Z', author: { id: 'me', displayName: 'Amr' } };
+        listed = [saved];
+        return json(saved, 201);
+      }
+      if (path === '/notes/trips/comments') return json(listed);
+      if (path === '/notes/trips') return json({ ...note('trips', 'Trips'), editable: true, path: [] });
+      return undefined;
+    });
+    await render('/notes/trips');
+
+    await act(async () => [...container.querySelectorAll('button')].find((button) => button.textContent === 'Comment on a block')!.click());
+    expect(container.querySelector('section[aria-label="Comments"]')?.textContent).toContain('Buy milk');
+    const box = container.querySelector<HTMLTextAreaElement>('textarea[aria-label="Comment on this block"]')!;
+    await act(async () => {
+      Object.getOwnPropertyDescriptor(HTMLTextAreaElement.prototype, 'value')!.set!.call(box, 'Oat or whole?');
+      box.dispatchEvent(new Event('input', { bubbles: true }));
+    });
+    await act(async () => box.form!.requestSubmit());
+
+    expect(sent).toEqual([{ body: 'Oat or whole?', blockId: 'block-1' }]);
+    expect(container.querySelector('[data-testid="editor"]')?.getAttribute('data-commented')).toBe('block-1');
+    expect(container.querySelector('textarea[aria-label="Comment on this block"]')).toBeNull();
+    expect(container.querySelector('.comment-block-quote')?.textContent).toBe('A block that was removed');
+  });
+
   it('creates a view link for a page and turns it off', async () => {
     const sent: { method: string; path: string }[] = [];
     serve((path, init) => {
diff --git a/app/package-lock.json b/app/package-lock.json
index 402696e..5b5e6ad 100644
--- a/app/package-lock.json
+++ b/app/package-lock.json
@@ -37,6 +37,7 @@
         "@tiptap/extension-node-range": "3.31.4",
         "@tiptap/extension-table": "3.31.4",
         "@tiptap/extension-text-style": "3.31.4",
+        "@tiptap/extension-unique-id": "3.31.4",
         "@tiptap/extensions": "3.31.4",
         "@tiptap/pm": "3.31.4",
         "@tiptap/react": "3.31.4",
@@ -4129,6 +4130,23 @@
         "@tiptap/core": "3.31.4"
       }
     },
+    "node_modules/@tiptap/extension-unique-id": {
+      "version": "3.31.4",
+      "resolved": "https://registry.npmjs.org/@tiptap/extension-unique-id/-/extension-unique-id-3.31.4.tgz",
+      "integrity": "sha512-UtdgDSWAMzxQ+fsu3ZFNmFPrYFS64ixyZr7GF08RHf3DyUXYPWqyhwRVmA4/Bh7DQPRerz1GTS7VwFGL+Wc1Ew==",
+      "license": "MIT",
+      "dependencies": {
+        "uuid": "^14.0.0"
+      },
+      "funding": {
+        "type": "github",
+        "url": "https://github.com/sponsors/ueberdosis"
+      },
+      "peerDependencies": {
+        "@tiptap/core": "3.31.4",
+        "@tiptap/pm": "3.31.4"
+      }
+    },
     "node_modules/@tiptap/extensions": {
       "version": "3.31.4",
       "resolved": "https://registry.npmjs.org/@tiptap/extensions/-/extensions-3.31.4.tgz",
diff --git a/app/server/prisma/migrations/20261009000000_comment_blocks/migration.sql b/app/server/prisma/migrations/20261009000000_comment_blocks/migration.sql
new file mode 100644
index 0000000..e54706f
--- /dev/null
+++ b/app/server/prisma/migrations/20261009000000_comment_blocks/migration.sql
@@ -0,0 +1 @@
+ALTER TABLE "note_comments" ADD COLUMN "block_id" TEXT;
diff --git a/app/server/prisma/schema.prisma b/app/server/prisma/schema.prisma
index 4cf8484..474a3ea 100644
--- a/app/server/prisma/schema.prisma
+++ b/app/server/prisma/schema.prisma
@@ -822,6 +822,7 @@ model NoteComment {
   itemId       String        @map("item_id") @db.Uuid
   parentId     String?       @map("parent_id") @db.Uuid
   authorId     String?       @map("author_id") @db.Uuid
+  blockId      String?       @map("block_id")
   body         String
   resolvedAt   DateTime?     @map("resolved_at")
   resolvedById String?       @map("resolved_by_id") @db.Uuid
diff --git a/app/server/src/notes/dto/notes.dto.ts b/app/server/src/notes/dto/notes.dto.ts
index 92875cf..3673a91 100644
--- a/app/server/src/notes/dto/notes.dto.ts
+++ b/app/server/src/notes/dto/notes.dto.ts
@@ -1,5 +1,5 @@
 import { Type } from 'class-transformer';
-import { ArrayMaxSize, IsArray, IsBoolean, IsIn, IsNumber, IsObject, IsOptional, IsString, IsUUID, Length, MaxLength, ValidateIf, ValidateNested } from 'class-validator';
+import { ArrayMaxSize, IsArray, IsBoolean, IsIn, IsNumber, IsObject, IsOptional, IsString, IsUUID, Length, Matches, MaxLength, ValidateIf, ValidateNested } from 'class-validator';
 import { databaseViews, propertyTypes } from '../database';
 import { builtInTemplates } from '../templates';
 import { IsColor } from '../../validation/color.decorator';
@@ -135,6 +135,10 @@ export class CreateCommentDto {
   @IsOptional()
   @IsUUID('all', { message: 'Reply to a comment on this page.' })
   parentId?: string;
+
+  @IsOptional()
+  @Matches(/^[\w-]{1,64}$/, { message: 'Choose a block on this page.' })
+  blockId?: string;
 }
 
 export class UpdateCommentDto {
diff --git a/app/server/src/notes/note-comments.service.ts b/app/server/src/notes/note-comments.service.ts
index 77e194e..1f32eac 100644
--- a/app/server/src/notes/note-comments.service.ts
+++ b/app/server/src/notes/note-comments.service.ts
@@ -11,6 +11,7 @@ const commentFields = {
   id: true,
   parentId: true,
   body: true,
+  blockId: true,
   resolvedAt: true,
   editedAt: true,
   createdAt: true,
@@ -41,7 +42,7 @@ export class NoteCommentsService {
     }
     return this.prisma.$transaction(async (transaction) => {
       const created = await transaction.noteComment.create({
-        data: { itemId: noteId, parentId: input.parentId ?? null, authorId: userId, body: input.body },
+        data: { itemId: noteId, parentId: input.parentId ?? null, authorId: userId, body: input.body, blockId: input.parentId ? null : (input.blockId ?? null) },
         select: commentFields,
       });
       const recipients = await this.recipients(transaction, noteId, found.spaceId, userId);
diff --git a/app/server/src/realtime/realtime.service.ts b/app/server/src/realtime/realtime.service.ts
index 2a80714..043c62b 100644
--- a/app/server/src/realtime/realtime.service.ts
+++ b/app/server/src/realtime/realtime.service.ts
@@ -22,7 +22,7 @@ const maxDocumentsPerUser = 40;
 const recheckMs = 60_000;
 const versionEveryMs = 15 * 60 * 1000;
 const maxLinksPerNote = 200;
-export const editorFormat = 3;
+export const editorFormat = 4;
 
 interface BoardVersion {
   version?: number;
diff --git a/app/server/test/integration/note-comments.spec.ts b/app/server/test/integration/note-comments.spec.ts
index 3e0527b..8ef2e47 100644
--- a/app/server/test/integration/note-comments.spec.ts
+++ b/app/server/test/integration/note-comments.spec.ts
@@ -49,4 +49,16 @@ describe('Page comments against Postgres', () => {
     expect((await owner.call('DELETE', `/comments/${question.body.id}`)).status).toBe(204);
     expect((await owner.call('GET', `/notes/${note.id}/comments`)).body).toEqual([]);
   });
+
+  it('ties a comment to a block, keeping replies in the thread', async () => {
+    const owner = await member('block-owner');
+    const space = (await owner.call('POST', '/spaces', { name: 'Allotment' })).body;
+    const note = (await owner.call('POST', `/spaces/${space.id}/notes`, { title: 'Beds' })).body;
+
+    const onBlock = (await owner.call('POST', `/notes/${note.id}/comments`, { body: 'Which variety?', blockId: 'block-1' })).body;
+    expect(onBlock.blockId).toBe('block-1');
+    expect((await owner.call('POST', `/notes/${note.id}/comments`, { body: 'Cherry ones.', parentId: onBlock.id, blockId: 'block-2' })).body.blockId).toBeNull();
+    expect((await owner.call('POST', `/notes/${note.id}/comments`, { body: 'Whole page' })).body.blockId).toBeNull();
+    expect((await owner.call('POST', `/notes/${note.id}/comments`, { body: 'Bad block', blockId: 'no spaces allowed' })).status).toBe(400);
+  });
 });