diff --git a/test/filters.test.ts b/test/filters.test.ts
new file mode 100644
index 0000000..020dc9d
--- /dev/null
+++ b/test/filters.test.ts
@@ -0,0 +1,234 @@
+import { describe, expect, it } from 'vitest';
+import {
+  filterComment,
+  filterGroup,
+  filterPage,
+  filterSearchResult,
+  filterSpace,
+  filterWorkspace,
+} from '../packages/docmost-client/src/lib/filters.js';
+
+describe('filterPage', () => {
+  const basePage = {
+    id: 'pg1',
+    slugId: 'slug-1',
+    title: 'Title',
+    parentPageId: 'parent-1',
+    spaceId: 'space-1',
+    isLocked: false,
+    createdAt: '2024-01-01',
+    updatedAt: '2024-01-02',
+    deletedAt: null,
+    // Extra fields that must be dropped by the filter.
+    secret: 'should-not-leak',
+  };
+
+  it('omits the content key when no content arg is given', () => {
+    const result = filterPage(basePage);
+    expect(result).not.toHaveProperty('content');
+    expect(result).not.toHaveProperty('secret');
+    expect(result.id).toBe('pg1');
+  });
+
+  it('includes an empty-string content (truthiness trap: empty string is kept)', () => {
+    const result = filterPage(basePage, '');
+    expect(result).toHaveProperty('content');
+    expect(result.content).toBe('');
+  });
+
+  it('includes a non-empty content string', () => {
+    const result = filterPage(basePage, '# Markdown');
+    expect(result.content).toBe('# Markdown');
+  });
+
+  it('omits content when it is not a string', () => {
+    // A non-string (e.g. an object passed by mistake) must be dropped.
+    const result = filterPage(basePage, { junk: true } as unknown as string);
+    expect(result).not.toHaveProperty('content');
+  });
+
+  it('omits subpages when undefined', () => {
+    const result = filterPage(basePage);
+    expect(result).not.toHaveProperty('subpages');
+  });
+
+  it('omits subpages when empty array', () => {
+    const result = filterPage(basePage, undefined, []);
+    expect(result).not.toHaveProperty('subpages');
+  });
+
+  it('maps non-empty subpages to { id, title } only', () => {
+    const result = filterPage(basePage, undefined, [
+      { id: 's1', title: 'Sub 1', extra: 'drop-me' },
+      { id: 's2', title: 'Sub 2' },
+    ]);
+    expect(result.subpages).toEqual([
+      { id: 's1', title: 'Sub 1' },
+      { id: 's2', title: 'Sub 2' },
+    ]);
+  });
+});
+
+describe('filterComment', () => {
+  const baseComment = {
+    id: 'c1',
+    pageId: 'pg1',
+    content: 'original content',
+    creatorId: 'u1',
+    createdAt: '2024-01-01',
+  };
+
+  it('overrides comment.content with markdownContent when provided', () => {
+    const result = filterComment(baseComment, 'markdown version');
+    expect(result.content).toBe('markdown version');
+  });
+
+  it('falls back to comment.content when markdownContent is undefined', () => {
+    const result = filterComment(baseComment, undefined);
+    expect(result.content).toBe('original content');
+  });
+
+  it('keeps an empty-string markdownContent (uses ?? not ||)', () => {
+    // `??` only falls back on null/undefined, so "" must be preserved.
+    const result = filterComment(baseComment, '');
+    expect(result.content).toBe('');
+  });
+
+  it('applies defaults for selection/type/parentCommentId/editedAt/resolvedAt/resolvedById', () => {
+    const result = filterComment(baseComment);
+    expect(result.selection).toBeNull();
+    expect(result.type).toBe('page');
+    expect(result.parentCommentId).toBeNull();
+    expect(result.editedAt).toBeNull();
+    expect(result.resolvedAt).toBeNull();
+    expect(result.resolvedById).toBeNull();
+  });
+
+  it('passes through provided optional values', () => {
+    const result = filterComment({
+      ...baseComment,
+      selection: 'some text',
+      type: 'inline',
+      parentCommentId: 'c0',
+      editedAt: '2024-02-01',
+      resolvedAt: '2024-03-01',
+      resolvedById: 'u9',
+    });
+    expect(result.selection).toBe('some text');
+    expect(result.type).toBe('inline');
+    expect(result.parentCommentId).toBe('c0');
+    expect(result.editedAt).toBe('2024-02-01');
+    expect(result.resolvedAt).toBe('2024-03-01');
+    expect(result.resolvedById).toBe('u9');
+  });
+
+  it('returns null for creatorName when creator is absent', () => {
+    const result = filterComment(baseComment);
+    expect(result.creatorName).toBeNull();
+  });
+
+  it('reads the nested creator?.name when present', () => {
+    const result = filterComment({
+      ...baseComment,
+      creator: { name: 'Alice' },
+    });
+    expect(result.creatorName).toBe('Alice');
+  });
+});
+
+describe('filterSearchResult', () => {
+  const baseResult = {
+    id: 'r1',
+    title: 'Result',
+    parentPageId: 'p0',
+    createdAt: '2024-01-01',
+    updatedAt: '2024-01-02',
+    rank: 0.9,
+    highlight: '<em>Result</em>',
+  };
+
+  it('reads nested space?.id and space?.name when space is present', () => {
+    const result = filterSearchResult({
+      ...baseResult,
+      space: { id: 'sp1', name: 'Space One' },
+    });
+    expect(result.spaceId).toBe('sp1');
+    expect(result.spaceName).toBe('Space One');
+  });
+
+  it('returns undefined for space fields when space is absent (no throw)', () => {
+    const result = filterSearchResult(baseResult);
+    expect(result.spaceId).toBeUndefined();
+    expect(result.spaceName).toBeUndefined();
+  });
+});
+
+describe('flat pluckers (no branching)', () => {
+  it('filterWorkspace plucks the expected shape', () => {
+    const result = filterWorkspace({
+      id: 'w1',
+      name: 'WS',
+      description: 'desc',
+      defaultSpaceId: 'sp1',
+      createdAt: '2024-01-01',
+      updatedAt: '2024-01-02',
+      deletedAt: null,
+      extra: 'drop',
+    });
+    expect(result).toEqual({
+      id: 'w1',
+      name: 'WS',
+      description: 'desc',
+      defaultSpaceId: 'sp1',
+      createdAt: '2024-01-01',
+      updatedAt: '2024-01-02',
+      deletedAt: null,
+    });
+  });
+
+  it('filterSpace plucks the expected shape', () => {
+    const result = filterSpace({
+      id: 'sp1',
+      name: 'Space',
+      description: 'desc',
+      slug: 'space',
+      visibility: 'open',
+      createdAt: '2024-01-01',
+      updatedAt: '2024-01-02',
+      deletedAt: null,
+      extra: 'drop',
+    });
+    expect(result).toEqual({
+      id: 'sp1',
+      name: 'Space',
+      description: 'desc',
+      slug: 'space',
+      visibility: 'open',
+      createdAt: '2024-01-01',
+      updatedAt: '2024-01-02',
+      deletedAt: null,
+    });
+  });
+
+  it('filterGroup plucks the expected shape', () => {
+    const result = filterGroup({
+      id: 'g1',
+      name: 'Group',
+      description: 'desc',
+      workspaceId: 'w1',
+      createdAt: '2024-01-01',
+      updatedAt: '2024-01-02',
+      deletedAt: null,
+      extra: 'drop',
+    });
+    expect(result).toEqual({
+      id: 'g1',
+      name: 'Group',
+      description: 'desc',
+      workspaceId: 'w1',
+      createdAt: '2024-01-01',
+      updatedAt: '2024-01-02',
+      deletedAt: null,
+    });
+  });
+});
diff --git a/test/json-edit.test.ts b/test/json-edit.test.ts
new file mode 100644
index 0000000..95a1383
--- /dev/null
+++ b/test/json-edit.test.ts
@@ -0,0 +1,288 @@
+import { describe, expect, it } from 'vitest';
+import { applyTextEdits } from '../packages/docmost-client/src/lib/json-edit.js';
+
+// Helper: build a ProseMirror text node.
+function text(value: string, extra: Record<string, unknown> = {}) {
+  return { type: 'text', text: value, ...extra };
+}
+
+// Helper: a simple doc with a single paragraph containing one text node.
+function singleParagraph(value: string) {
+  return {
+    type: 'doc',
+    content: [{ type: 'paragraph', content: [text(value)] }],
+  };
+}
+
+describe('applyTextEdits', () => {
+  describe('single match', () => {
+    it('replaces an exact single match and reports one replacement', () => {
+      const doc = singleParagraph('hello world');
+      const { doc: result, results } = applyTextEdits(doc, [
+        { find: 'world', replace: 'there' },
+      ]);
+
+      expect(result.content[0].content[0].text).toBe('hello there');
+      expect(results).toEqual([{ find: 'world', replacements: 1 }]);
+    });
+
+    it('preserves node id/marks around the edited text', () => {
+      const doc = {
+        type: 'doc',
+        content: [
+          {
+            type: 'paragraph',
+            attrs: { id: 'p1' },
+            content: [
+              text('old value', { marks: [{ type: 'bold' }], custom: 42 }),
+            ],
+          },
+        ],
+      };
+      const { doc: result } = applyTextEdits(doc, [
+        { find: 'old', replace: 'new' },
+      ]);
+
+      const node = result.content[0].content[0];
+      expect(node.text).toBe('new value');
+      expect(node.marks).toEqual([{ type: 'bold' }]);
+      expect(node.custom).toBe(42);
+      expect(result.content[0].attrs).toEqual({ id: 'p1' });
+    });
+  });
+
+  describe('replaceAll', () => {
+    it('replaces every occurrence inside a single node when replaceAll is set', () => {
+      const doc = singleParagraph('a a a');
+      const { doc: result, results } = applyTextEdits(doc, [
+        { find: 'a', replace: 'b', replaceAll: true },
+      ]);
+
+      expect(result.content[0].content[0].text).toBe('b b b');
+      expect(results).toEqual([{ find: 'a', replacements: 3 }]);
+    });
+
+    it('replaces occurrences across multiple separate text nodes', () => {
+      const doc = {
+        type: 'doc',
+        content: [
+          { type: 'paragraph', content: [text('foo and foo')] },
+          { type: 'paragraph', content: [text('also foo')] },
+        ],
+      };
+      const { doc: result, results } = applyTextEdits(doc, [
+        { find: 'foo', replace: 'bar', replaceAll: true },
+      ]);
+
+      expect(result.content[0].content[0].text).toBe('bar and bar');
+      expect(result.content[1].content[0].text).toBe('also bar');
+      // 2 + 1 occurrences counted.
+      expect(results).toEqual([{ find: 'foo', replacements: 3 }]);
+    });
+  });
+
+  describe('multi-match without replaceAll', () => {
+    it('throws reporting the match count', () => {
+      const doc = singleParagraph('x x x');
+      expect(() => applyTextEdits(doc, [{ find: 'x', replace: 'y' }])).toThrow(
+        /matches 3 times/,
+      );
+    });
+
+    it('counts matches across nodes when deciding to throw', () => {
+      const doc = {
+        type: 'doc',
+        content: [
+          { type: 'paragraph', content: [text('dup')] },
+          { type: 'paragraph', content: [text('dup')] },
+        ],
+      };
+      expect(() => applyTextEdits(doc, [{ find: 'dup', replace: 'z' }])).toThrow(
+        /matches 2 times/,
+      );
+    });
+  });
+
+  describe('zero match', () => {
+    it('throws "text not found" when text is absent entirely', () => {
+      const doc = singleParagraph('hello world');
+      expect(() =>
+        applyTextEdits(doc, [{ find: 'absent', replace: 'x' }]),
+      ).toThrow(/text not found in the document/);
+    });
+  });
+
+  describe('text split across formatting runs', () => {
+    it('throws a distinct "spans multiple formatting runs" error', () => {
+      // "hello world" exists in the concatenated text but no single text node
+      // contains it: it is split across a bold run and a plain run.
+      const doc = {
+        type: 'doc',
+        content: [
+          {
+            type: 'paragraph',
+            content: [
+              text('hello ', { marks: [{ type: 'bold' }] }),
+              text('world'),
+            ],
+          },
+        ],
+      };
+      expect(() =>
+        applyTextEdits(doc, [{ find: 'hello world', replace: 'x' }]),
+      ).toThrow(/spans multiple formatting runs/);
+    });
+
+    it('does not raise the spans error when text is genuinely missing', () => {
+      const doc = {
+        type: 'doc',
+        content: [
+          {
+            type: 'paragraph',
+            content: [text('hello ', { marks: [{ type: 'bold' }] }), text('world')],
+          },
+        ],
+      };
+      // "nope" is in neither the runs nor the concatenated text.
+      expect(() =>
+        applyTextEdits(doc, [{ find: 'nope', replace: 'x' }]),
+      ).toThrow(/text not found in the document/);
+    });
+  });
+
+  describe('empty find', () => {
+    it('throws on an empty find string', () => {
+      const doc = singleParagraph('hello');
+      expect(() => applyTextEdits(doc, [{ find: '', replace: 'x' }])).toThrow(
+        /edit\.find must be a non-empty string/,
+      );
+    });
+  });
+
+  describe('literal replacement (regex foot-gun)', () => {
+    it('inserts $& literally without regex expansion', () => {
+      const doc = singleParagraph('price NUM here');
+      const { doc: result } = applyTextEdits(doc, [
+        { find: 'NUM', replace: '$&100' },
+      ]);
+      // If String.replace were used, "$&" would expand to the matched "NUM".
+      expect(result.content[0].content[0].text).toBe('price $&100 here');
+    });
+
+    it('inserts $1 literally without regex expansion', () => {
+      const doc = singleParagraph('token TKN end');
+      const { doc: result } = applyTextEdits(doc, [
+        { find: 'TKN', replace: 'a$1b$$c' },
+      ]);
+      expect(result.content[0].content[0].text).toBe('token a$1b$$c end');
+    });
+
+    it('inserts $& literally for replaceAll as well', () => {
+      const doc = singleParagraph('K K');
+      const { doc: result } = applyTextEdits(doc, [
+        { find: 'K', replace: '[$&]', replaceAll: true },
+      ]);
+      expect(result.content[0].content[0].text).toBe('[$&] [$&]');
+    });
+  });
+
+  describe('pruning emptied nodes', () => {
+    it('removes a text node that becomes empty after the edit', () => {
+      const doc = {
+        type: 'doc',
+        content: [
+          {
+            type: 'paragraph',
+            content: [text('REMOVE'), text(' keep')],
+          },
+        ],
+      };
+      const { doc: result } = applyTextEdits(doc, [
+        { find: 'REMOVE', replace: '' },
+      ]);
+
+      // The emptied node is pruned, leaving only the surviving node.
+      expect(result.content[0].content).toHaveLength(1);
+      expect(result.content[0].content[0].text).toBe(' keep');
+    });
+  });
+
+  describe('immutability', () => {
+    it('does not mutate the input document', () => {
+      const doc = {
+        type: 'doc',
+        content: [
+          {
+            type: 'paragraph',
+            attrs: { id: 'p1' },
+            content: [text('hello world', { marks: [{ type: 'bold' }] })],
+          },
+        ],
+      };
+      const snapshot = structuredClone(doc);
+
+      applyTextEdits(doc, [{ find: 'world', replace: 'there' }]);
+
+      expect(doc).toEqual(snapshot);
+    });
+  });
+
+  describe('deeply nested recursion', () => {
+    it('finds and replaces text several levels deep', () => {
+      const doc = {
+        type: 'doc',
+        content: [
+          {
+            type: 'bulletList',
+            content: [
+              {
+                type: 'listItem',
+                content: [
+                  {
+                    type: 'paragraph',
+                    content: [
+                      {
+                        type: 'blockquote',
+                        content: [
+                          {
+                            type: 'paragraph',
+                            content: [text('deep target value')],
+                          },
+                        ],
+                      },
+                    ],
+                  },
+                ],
+              },
+            ],
+          },
+        ],
+      };
+      const { doc: result, results } = applyTextEdits(doc, [
+        { find: 'target', replace: 'goal' },
+      ]);
+
+      const leaf =
+        result.content[0].content[0].content[0].content[0].content[0]
+          .content[0];
+      expect(leaf.text).toBe('deep goal value');
+      expect(results).toEqual([{ find: 'target', replacements: 1 }]);
+    });
+  });
+
+  describe('multiple edits in sequence', () => {
+    it('applies each edit and returns a result per edit in order', () => {
+      const doc = singleParagraph('alpha beta gamma');
+      const { doc: result, results } = applyTextEdits(doc, [
+        { find: 'alpha', replace: 'A' },
+        { find: 'gamma', replace: 'G' },
+      ]);
+
+      expect(result.content[0].content[0].text).toBe('A beta G');
+      expect(results).toEqual([
+        { find: 'alpha', replacements: 1 },
+        { find: 'gamma', replacements: 1 },
+      ]);
+    });
+  });
+});
diff --git a/test/markdown-converter.test.ts b/test/markdown-converter.test.ts
new file mode 100644
index 0000000..51c34b1
--- /dev/null
+++ b/test/markdown-converter.test.ts
@@ -0,0 +1,507 @@
+import { describe, expect, it } from 'vitest';
+// Import DIRECTLY from src (NOT the docmost-client barrel, which pulls in
+// collaboration.ts and mutates global DOM at import time).
+import { convertProseMirrorToMarkdown } from '../packages/docmost-client/src/lib/markdown-converter.js';
+
+// Wrap a single node in a minimal ProseMirror doc. The top-level converter
+// joins doc children with "\n\n" and then .trim()s the whole output, so a
+// single-node doc yields exactly that node's rendered (and trimmed) string.
+const doc = (...nodes: any[]) => ({ type: 'doc', content: nodes });
+// Convenience: a text node, optionally with marks.
+const text = (t: string, marks?: any[]) =>
+  marks ? { type: 'text', text: t, marks } : { type: 'text', text: t };
+// Convenience: a paragraph wrapping inline children.
+const para = (...inline: any[]) => ({ type: 'paragraph', content: inline });
+
+describe('convertProseMirrorToMarkdown', () => {
+  // ---------------------------------------------------------------------------
+  describe('headings', () => {
+    it('emits the right number of "#" for levels 1-6', () => {
+      for (let level = 1; level <= 6; level++) {
+        const out = convertProseMirrorToMarkdown(
+          doc({ type: 'heading', attrs: { level }, content: [text('H')] }),
+        );
+        expect(out).toBe('#'.repeat(level) + ' H');
+      }
+    });
+
+    it('defaults to level 1 when level is missing', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc({ type: 'heading', content: [text('NoLevel')] }),
+      );
+      expect(out).toBe('# NoLevel');
+    });
+  });
+
+  // ---------------------------------------------------------------------------
+  describe('text marks', () => {
+    it('bold', () => {
+      expect(
+        convertProseMirrorToMarkdown(doc(para(text('x', [{ type: 'bold' }])))),
+      ).toBe('**x**');
+    });
+
+    it('italic', () => {
+      expect(
+        convertProseMirrorToMarkdown(doc(para(text('x', [{ type: 'italic' }])))),
+      ).toBe('*x*');
+    });
+
+    it('strike', () => {
+      expect(
+        convertProseMirrorToMarkdown(doc(para(text('x', [{ type: 'strike' }])))),
+      ).toBe('~~x~~');
+    });
+
+    it('inline code (sole mark) uses backtick span', () => {
+      expect(
+        convertProseMirrorToMarkdown(doc(para(text('x', [{ type: 'code' }])))),
+      ).toBe('`x`');
+    });
+
+    it('code + another mark switches to nested HTML (no backtick form)', () => {
+      // marks array order drives nesting: bold first wraps, then code wraps that.
+      const out = convertProseMirrorToMarkdown(
+        doc(para(text('x', [{ type: 'bold' }, { type: 'code' }]))),
+      );
+      expect(out).toBe('<code><strong>x</strong></code>');
+    });
+
+    it('code + strike combo emits <code> wrapping <s>', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc(para(text('x', [{ type: 'strike' }, { type: 'code' }]))),
+      );
+      expect(out).toBe('<code><s>x</s></code>');
+    });
+  });
+
+  // ---------------------------------------------------------------------------
+  describe('links', () => {
+    it('href only', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc(para(text('site', [{ type: 'link', attrs: { href: 'https://e.com' } }]))),
+      );
+      expect(out).toBe('[site](https://e.com)');
+    });
+
+    it('href + title with an embedded double quote is escaped', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc(
+          para(
+            text('site', [
+              { type: 'link', attrs: { href: 'https://e.com', title: 'a "b" c' } },
+            ]),
+          ),
+        ),
+      );
+      // The markdown link-title form escapes the inner " as \".
+      expect(out).toBe('[site](https://e.com "a \\"b\\" c")');
+    });
+  });
+
+  // ---------------------------------------------------------------------------
+  describe('image', () => {
+    it('percent-encodes spaces and parentheses in src', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc({
+          type: 'image',
+          attrs: { alt: 'cap', src: '/files/my pic (1).png' },
+        }),
+      );
+      // space -> %20, ( -> %28, ) -> %29
+      expect(out).toBe('![cap](/files/my%20pic%20%281%29.png)');
+    });
+
+    it('empty alt and missing src render harmlessly', () => {
+      const out = convertProseMirrorToMarkdown(doc({ type: 'image', attrs: {} }));
+      expect(out).toBe('![]()');
+    });
+  });
+
+  // ---------------------------------------------------------------------------
+  describe('codeBlock', () => {
+    it('with language', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc({
+          type: 'codeBlock',
+          attrs: { language: 'ts' },
+          content: [text('const a = 1;')],
+        }),
+      );
+      expect(out).toBe('```ts\nconst a = 1;\n```');
+    });
+
+    it('without language emits empty info string', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc({ type: 'codeBlock', content: [text('plain')] }),
+      );
+      expect(out).toBe('```\nplain\n```');
+    });
+
+    it('strips ALL trailing newlines for idempotency', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc({ type: 'codeBlock', content: [text('a\n\n\n')] }),
+      );
+      // Every trailing "\n" is removed, then exactly one is re-added by the fence.
+      expect(out).toBe('```\na\n```');
+    });
+  });
+
+  // ---------------------------------------------------------------------------
+  describe('lists', () => {
+    it('bullet list', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc({
+          type: 'bulletList',
+          content: [
+            { type: 'listItem', content: [para(text('one'))] },
+            { type: 'listItem', content: [para(text('two'))] },
+          ],
+        }),
+      );
+      expect(out).toBe('- one\n- two');
+    });
+
+    it('ordered list numbers items sequentially', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc({
+          type: 'orderedList',
+          content: [
+            { type: 'listItem', content: [para(text('a'))] },
+            { type: 'listItem', content: [para(text('b'))] },
+            { type: 'listItem', content: [para(text('c'))] },
+          ],
+        }),
+      );
+      expect(out).toBe('1. a\n2. b\n3. c');
+    });
+
+    it('nested bullet list indents the child by the 2-col marker width', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc({
+          type: 'bulletList',
+          content: [
+            {
+              type: 'listItem',
+              content: [
+                para(text('parent')),
+                {
+                  type: 'bulletList',
+                  content: [{ type: 'listItem', content: [para(text('child'))] }],
+                },
+              ],
+            },
+          ],
+        }),
+      );
+      // First line carries the marker; the nested list is indented 2 columns.
+      expect(out).toBe('- parent\n  - child');
+    });
+
+    it('nested ordered list indents by the wider 3-col marker width', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc({
+          type: 'orderedList',
+          content: [
+            {
+              type: 'listItem',
+              content: [
+                para(text('parent')),
+                {
+                  type: 'orderedList',
+                  content: [{ type: 'listItem', content: [para(text('child'))] }],
+                },
+              ],
+            },
+          ],
+        }),
+      );
+      // "1. " is 3 columns wide, so the continuation indent is 3 spaces.
+      expect(out).toBe('1. parent\n   1. child');
+    });
+  });
+
+  // ---------------------------------------------------------------------------
+  describe('task list', () => {
+    it('unchecked and checked items', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc({
+          type: 'taskList',
+          content: [
+            { type: 'taskItem', attrs: { checked: false }, content: [para(text('todo'))] },
+            { type: 'taskItem', attrs: { checked: true }, content: [para(text('done'))] },
+          ],
+        }),
+      );
+      expect(out).toBe('- [ ] todo\n- [x] done');
+    });
+
+    it('empty task item keeps its marker', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc({
+          type: 'taskList',
+          content: [{ type: 'taskItem', attrs: { checked: false }, content: [] }],
+        }),
+      );
+      expect(out).toBe('- [ ]');
+    });
+  });
+
+  // ---------------------------------------------------------------------------
+  describe('blockquote', () => {
+    it('single paragraph quote prefixes the line', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc({ type: 'blockquote', content: [para(text('quoted'))] }),
+      );
+      expect(out).toBe('> quoted');
+    });
+
+    it('multi-paragraph quote separates blocks with a bare ">" line', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc({
+          type: 'blockquote',
+          content: [para(text('first')), para(text('second'))],
+        }),
+      );
+      expect(out).toBe('> first\n>\n> second');
+    });
+  });
+
+  // ---------------------------------------------------------------------------
+  describe('breaks and rules', () => {
+    it('horizontal rule', () => {
+      expect(
+        convertProseMirrorToMarkdown(doc({ type: 'horizontalRule' })),
+      ).toBe('---');
+    });
+
+    it('hard break emits two trailing spaces then newline', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc(para(text('a'), { type: 'hardBreak' }, text('b'))),
+      );
+      expect(out).toBe('a  \nb');
+    });
+  });
+
+  // ---------------------------------------------------------------------------
+  describe('tables', () => {
+    it('GFM table emits alignment markers derived from header cells', () => {
+      const headerRow = {
+        type: 'tableRow',
+        content: [
+          { type: 'tableHeader', attrs: { align: 'left' }, content: [para(text('L'))] },
+          { type: 'tableHeader', attrs: { align: 'center' }, content: [para(text('C'))] },
+          { type: 'tableHeader', attrs: { align: 'right' }, content: [para(text('R'))] },
+          { type: 'tableHeader', content: [para(text('N'))] },
+        ],
+      };
+      const bodyRow = {
+        type: 'tableRow',
+        content: [
+          { type: 'tableCell', content: [para(text('1'))] },
+          { type: 'tableCell', content: [para(text('2'))] },
+          { type: 'tableCell', content: [para(text('3'))] },
+          { type: 'tableCell', content: [para(text('4'))] },
+        ],
+      };
+      const out = convertProseMirrorToMarkdown(
+        doc({ type: 'table', content: [headerRow, bodyRow] }),
+      );
+      expect(out).toBe(
+        [
+          '| L | C | R | N |',
+          '| :-- | :-: | --: | --- |',
+          '| 1 | 2 | 3 | 4 |',
+        ].join('\n'),
+      );
+    });
+
+    it('spanned table (colspan/rowspan) emits raw <table> HTML', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc({
+          type: 'table',
+          content: [
+            {
+              type: 'tableRow',
+              content: [
+                {
+                  type: 'tableHeader',
+                  attrs: { colspan: 2 },
+                  content: [para(text('wide'))],
+                },
+              ],
+            },
+            {
+              type: 'tableRow',
+              content: [
+                { type: 'tableCell', content: [para(text('a'))] },
+                { type: 'tableCell', content: [para(text('b'))] },
+              ],
+            },
+          ],
+        }),
+      );
+      expect(out).toBe(
+        '<table><tbody>' +
+          '<tr><th colspan="2"><p>wide</p></th></tr>' +
+          '<tr><td><p>a</p></td><td><p>b</p></td></tr>' +
+          '</tbody></table>',
+      );
+    });
+  });
+
+  // ---------------------------------------------------------------------------
+  describe('callout and details', () => {
+    it('callout uses lowercased type fence', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc({
+          type: 'callout',
+          attrs: { type: 'WARNING' },
+          content: [para(text('beware'))],
+        }),
+      );
+      expect(out).toBe(':::warning\nbeware\n:::');
+    });
+
+    it('callout defaults to info', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc({ type: 'callout', content: [para(text('hi'))] }),
+      );
+      expect(out).toBe(':::info\nhi\n:::');
+    });
+
+    it('details emits summary + content wrapped in <details>', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc({
+          type: 'details',
+          content: [
+            { type: 'detailsSummary', content: [text('Title')] },
+            { type: 'detailsContent', content: [para(text('Body'))] },
+          ],
+        }),
+      );
+      // details joins its children with "\n"; summary opens, content closes.
+      expect(out).toBe('<details>\n<summary>Title</summary>\n\nBody\n</details>');
+    });
+  });
+
+  // ---------------------------------------------------------------------------
+  describe('math', () => {
+    it('inline math carries LaTeX in a text attr WITHOUT escaping < or >', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc(para({ type: 'mathInline', attrs: { text: 'a < b' } })),
+      );
+      // < and > must NOT be HTML-escaped (idempotency); only & and " would be.
+      expect(out).toBe(
+        '<span data-type="mathInline" data-katex="true" text="a < b"></span>',
+      );
+      expect(out).not.toContain('&lt;');
+    });
+
+    it('block math carries LaTeX in a text attr WITHOUT escaping < or >', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc({ type: 'mathBlock', attrs: { text: 'x > y & z' } }),
+      );
+      // & IS escaped (entity-significant), but < and > are NOT.
+      expect(out).toBe(
+        '<div data-type="mathBlock" data-katex="true" text="x > y &amp; z"></div>',
+      );
+      expect(out).not.toContain('&lt;');
+      expect(out).not.toContain('&gt;');
+    });
+  });
+
+  // ---------------------------------------------------------------------------
+  describe('inline atoms and media', () => {
+    it('mention emits schema span with data-* attrs and visible label', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc(
+          para({
+            type: 'mention',
+            attrs: { id: 'u1', label: 'Alice', entityType: 'user' },
+          }),
+        ),
+      );
+      expect(out).toBe(
+        '<span data-type="mention" data-id="u1" data-label="Alice" data-entity-type="user">@Alice</span>',
+      );
+    });
+
+    it('attachment emits div with schema data-attachment-* attrs', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc({
+          type: 'attachment',
+          attrs: { url: '/files/x.zip', name: 'x.zip', mime: 'application/zip', size: 99 },
+        }),
+      );
+      expect(out).toBe(
+        '<div data-type="attachment" data-attachment-url="/files/x.zip" ' +
+          'data-attachment-name="x.zip" data-attachment-mime="application/zip" ' +
+          'data-attachment-size="99"></div>',
+      );
+    });
+
+    it('video emits a <div>-wrapped <video> with schema attrs', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc({
+          type: 'video',
+          attrs: { src: '/v.mp4', alt: 'clip', width: 640 },
+        }),
+      );
+      expect(out).toBe(
+        '<div><video src="/v.mp4" aria-label="clip" width="640"></video></div>',
+      );
+    });
+
+    it('youtube emits a div[data-type="youtube"] with data-src', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc({
+          type: 'youtube',
+          attrs: { src: 'https://youtu.be/abc', width: 560, height: 315 },
+        }),
+      );
+      expect(out).toBe(
+        '<div data-type="youtube" data-src="https://youtu.be/abc" ' +
+          'data-width="560" data-height="315"></div>',
+      );
+    });
+  });
+
+  // ---------------------------------------------------------------------------
+  describe('edge cases', () => {
+    it('null content returns ""', () => {
+      expect(convertProseMirrorToMarkdown(null)).toBe('');
+    });
+
+    it('empty object returns ""', () => {
+      expect(convertProseMirrorToMarkdown({})).toBe('');
+    });
+
+    it('doc with no content returns ""', () => {
+      expect(convertProseMirrorToMarkdown({ type: 'doc' })).toBe('');
+    });
+
+    it('unknown node type falls back to children-only (no throw, text preserved)', () => {
+      const out = convertProseMirrorToMarkdown(
+        doc({ type: 'totallyUnknownType', content: [text('kept')] }),
+      );
+      expect(out).toBe('kept');
+    });
+
+    it('deeply nested structure does not stack-overflow', () => {
+      // Build a deeply nested bullet list (each level holds one nested list).
+      let node: any = { type: 'listItem', content: [para(text('leaf'))] };
+      for (let i = 0; i < 200; i++) {
+        node = {
+          type: 'listItem',
+          content: [para(text('lvl')), { type: 'bulletList', content: [node] }],
+        };
+      }
+      const root = doc({ type: 'bulletList', content: [node] });
+      expect(() => convertProseMirrorToMarkdown(root)).not.toThrow();
+      const out = convertProseMirrorToMarkdown(root);
+      expect(out).toContain('leaf');
+      expect(out.startsWith('- lvl')).toBe(true);
+    });
+  });
+});
diff --git a/test/markdown-document-envelope.test.ts b/test/markdown-document-envelope.test.ts
new file mode 100644
index 0000000..4e8d34b
--- /dev/null
+++ b/test/markdown-document-envelope.test.ts
@@ -0,0 +1,199 @@
+import { describe, expect, it } from 'vitest';
+// Import DIRECTLY from src (NOT the docmost-client barrel, which pulls in
+// collaboration.ts and mutates global DOM at import time).
+import {
+  serializeDocmostMarkdown,
+  parseDocmostMarkdown,
+  serializeDocmostMarkdownBody,
+  type DocmostMdMeta,
+} from '../packages/docmost-client/src/lib/markdown-document.js';
+
+const meta: DocmostMdMeta = {
+  version: 1,
+  pageId: 'p1',
+  slugId: 's1',
+  title: 'Hello',
+  spaceId: 'sp1',
+  parentPageId: null,
+};
+
+describe('serializeDocmostMarkdown / parseDocmostMarkdown', () => {
+  // ---------------------------------------------------------------------------
+  describe('round-trip', () => {
+    it('round-trips meta, body, and comments', () => {
+      const body = '# Title\n\nSome **body** text.';
+      const comments = [{ id: 'c1', text: 'a note' }];
+      const full = serializeDocmostMarkdown(meta, body, comments);
+      const parsed = parseDocmostMarkdown(full);
+      expect(parsed.meta).toEqual(meta);
+      expect(parsed.body).toBe(body);
+      expect(parsed.comments).toEqual(comments);
+    });
+
+    it('emits a comments block with [] even when there are no comments', () => {
+      const full = serializeDocmostMarkdown(meta, 'body', []);
+      expect(full).toContain('<!-- docmost:comments\n[]\n-->');
+      const parsed = parseDocmostMarkdown(full);
+      expect(parsed.comments).toEqual([]);
+      expect(parsed.body).toBe('body');
+    });
+
+    it('non-array comments arg is normalized to [] in the serialized output', () => {
+      const full = serializeDocmostMarkdown(meta, 'body', null as any);
+      expect(full).toContain('<!-- docmost:comments\n[]\n-->');
+    });
+
+    it('trims surrounding whitespace from the body on serialize', () => {
+      const full = serializeDocmostMarkdown(meta, '\n\n  body  \n\n', []);
+      const parsed = parseDocmostMarkdown(full);
+      expect(parsed.body).toBe('body');
+    });
+  });
+
+  // ---------------------------------------------------------------------------
+  describe('missing blocks (tolerant parsing)', () => {
+    it('missing meta block yields meta:null', () => {
+      const input = 'Just a body.\n\n<!-- docmost:comments\n[]\n-->\n';
+      const parsed = parseDocmostMarkdown(input);
+      expect(parsed.meta).toBeNull();
+      expect(parsed.body).toBe('Just a body.');
+      expect(parsed.comments).toEqual([]);
+    });
+
+    it('missing comments block yields comments:null and treats all as body', () => {
+      const input =
+        '<!-- docmost:meta\n' + JSON.stringify(meta) + '\n-->\n\nbody only';
+      const parsed = parseDocmostMarkdown(input);
+      expect(parsed.meta).toEqual(meta);
+      expect(parsed.comments).toBeNull();
+      expect(parsed.body).toBe('body only');
+    });
+
+    it('plain markdown with neither block: meta and comments null, whole input is body', () => {
+      const input = '# Plain\n\nNo envelope here.';
+      const parsed = parseDocmostMarkdown(input);
+      expect(parsed.meta).toBeNull();
+      expect(parsed.comments).toBeNull();
+      expect(parsed.body).toBe(input);
+    });
+  });
+
+  // ---------------------------------------------------------------------------
+  describe('CRLF normalization', () => {
+    it('parses a CRLF-encoded document the same as LF', () => {
+      const lf = serializeDocmostMarkdown(meta, 'line one\nline two', [
+        { id: 'c1' },
+      ]);
+      const crlf = lf.replace(/\n/g, '\r\n');
+      const parsed = parseDocmostMarkdown(crlf);
+      expect(parsed.meta).toEqual(meta);
+      expect(parsed.body).toBe('line one\nline two');
+      expect(parsed.comments).toEqual([{ id: 'c1' }]);
+    });
+  });
+
+  // ---------------------------------------------------------------------------
+  describe('only the final document-ending comments block is captured', () => {
+    it('an earlier literal docmost:comments opener inside the body stays in the body', () => {
+      // The body documents the format and contains a literal opener that does
+      // NOT end the document. Only the trailing block is treated as metadata.
+      const bodyWithLiteral =
+        'Here is how the format looks:\n\n<!-- docmost:comments\n[{"fake":true}]\n-->\n\nand more prose after it.';
+      const full = serializeDocmostMarkdown(meta, bodyWithLiteral, [
+        { id: 'real' },
+      ]);
+      const parsed = parseDocmostMarkdown(full);
+      // The real (final) block parses into the comments...
+      expect(parsed.comments).toEqual([{ id: 'real' }]);
+      // ...and the earlier literal opener is preserved verbatim in the body.
+      expect(parsed.body).toContain(
+        '<!-- docmost:comments\n[{"fake":true}]\n-->',
+      );
+      expect(parsed.body).toContain('and more prose after it.');
+    });
+
+    it('a literal opener whose closer does NOT end the doc is left entirely in the body', () => {
+      // No real trailing block: the opener is not document-ending, so comments
+      // stays null and nothing is stripped.
+      const input =
+        '<!-- docmost:meta\n' +
+        JSON.stringify(meta) +
+        '\n-->\n\nbody start\n\n<!-- docmost:comments\n[]\n-->\n\ntrailing text not ending the doc';
+      const parsed = parseDocmostMarkdown(input);
+      expect(parsed.comments).toBeNull();
+      expect(parsed.body).toContain('<!-- docmost:comments');
+      expect(parsed.body).toContain('trailing text not ending the doc');
+    });
+  });
+
+  // ---------------------------------------------------------------------------
+  describe('malformed JSON throws a clear error', () => {
+    it('throws on malformed meta JSON', () => {
+      const input = '<!-- docmost:meta\n{not valid json}\n-->\n\nbody';
+      expect(() => parseDocmostMarkdown(input)).toThrow(/docmost:meta JSON/);
+    });
+
+    it('throws on malformed comments JSON', () => {
+      const input = 'body\n\n<!-- docmost:comments\n[not, valid]\n-->\n';
+      expect(() => parseDocmostMarkdown(input)).toThrow(/docmost:comments JSON/);
+    });
+  });
+});
+
+describe('serializeDocmostMarkdownBody', () => {
+  it('emits NO comments block', () => {
+    const out = serializeDocmostMarkdownBody(meta, 'just the body');
+    expect(out).not.toContain('docmost:comments');
+    expect(out).toContain('<!-- docmost:meta');
+  });
+
+  it('serialize -> parse preserves meta and the trimmed body, comments null (SPEC §3)', () => {
+    const fullMeta: DocmostMdMeta = {
+      version: 1,
+      pageId: 'page-123',
+      slugId: 'slug-abc',
+      title: 'My Page',
+      spaceId: 'space-1',
+      parentPageId: 'parent-9',
+    };
+    const body = 'Hello\n\nWorld';
+    const out = serializeDocmostMarkdownBody(fullMeta, body);
+    const parsed = parseDocmostMarkdown(out);
+    expect(parsed.meta).toEqual(fullMeta);
+    expect(parsed.body).toBe(body);
+    expect(parsed.comments).toBeNull();
+  });
+
+  it('preserves a null parentPageId for a root page', () => {
+    const out = serializeDocmostMarkdownBody(meta, 'body text');
+    const parsed = parseDocmostMarkdown(out);
+    expect(parsed.meta).toEqual(meta);
+    expect(parsed.comments).toBeNull();
+  });
+
+  it('produces a parseable file for an empty or missing body', () => {
+    const minimal: DocmostMdMeta = { version: 1, pageId: 'p-empty' };
+
+    const emptyFile = serializeDocmostMarkdownBody(minimal, '');
+    const parsedEmpty = parseDocmostMarkdown(emptyFile);
+    expect(parsedEmpty.meta).toEqual(minimal);
+    expect(parsedEmpty.body).toBe('');
+    expect(parsedEmpty.comments).toBeNull();
+
+    // Missing body (undefined) — serializer coalesces to "".
+    const missingFile = serializeDocmostMarkdownBody(
+      minimal,
+      undefined as unknown as string,
+    );
+    const parsedMissing = parseDocmostMarkdown(missingFile);
+    expect(parsedMissing.meta).toEqual(minimal);
+    expect(parsedMissing.body).toBe('');
+    expect(parsedMissing.comments).toBeNull();
+  });
+
+  it('trims the body', () => {
+    const out = serializeDocmostMarkdownBody(meta, '\n\n  hi  \n');
+    const parsed = parseDocmostMarkdown(out);
+    expect(parsed.body).toBe('hi');
+  });
+});
diff --git a/test/node-ops.test.ts b/test/node-ops.test.ts
new file mode 100644
index 0000000..2707367
--- /dev/null
+++ b/test/node-ops.test.ts
@@ -0,0 +1,908 @@
+import { describe, expect, it } from 'vitest';
+import {
+  blockPlainText,
+  buildOutline,
+  getNodeByRef,
+  replaceNodeById,
+  deleteNodeById,
+  sanitizeForYjs,
+  findUnstorableAttr,
+  insertNodeRelative,
+  readTable,
+  insertTableRow,
+  deleteTableRow,
+  updateTableCell,
+} from '../packages/docmost-client/src/lib/node-ops.js';
+
+// ---------------------------------------------------------------------------
+// Tiny ProseMirror/TipTap JSON fixture builders. These produce the exact plain
+// JSON shape Docmost uses: { type, attrs?, content?, text?, marks? }.
+// ---------------------------------------------------------------------------
+
+/** A text leaf node, optionally carrying marks. */
+function text(value: string, marks?: any[]): any {
+  const node: any = { type: 'text', text: value };
+  if (marks) node.marks = marks;
+  return node;
+}
+
+/** A paragraph block with an id and a single text child (or empty). */
+function para(id: string, value = ''): any {
+  return {
+    type: 'paragraph',
+    attrs: { id, indent: 0 },
+    content: value ? [text(value)] : [],
+  };
+}
+
+/** A heading block. */
+function heading(id: string, level: number, value: string): any {
+  return {
+    type: 'heading',
+    attrs: { id, level },
+    content: [text(value)],
+  };
+}
+
+/** A table cell (or header) wrapping a single paragraph; extra attrs merged in. */
+function cell(
+  type: 'tableCell' | 'tableHeader',
+  paraId: string | null,
+  value = '',
+  extraAttrs: Record<string, any> = {},
+): any {
+  const attrs = { colspan: 1, rowspan: 1, ...extraAttrs };
+  return {
+    type,
+    attrs,
+    content: paraId == null ? [] : [para(paraId, value)],
+  };
+}
+
+/** A table row. */
+function row(cells: any[]): any {
+  return { type: 'tableRow', content: cells };
+}
+
+/** A doc root with the given top-level blocks. */
+function doc(...content: any[]): any {
+  return { type: 'doc', content };
+}
+
+// ===========================================================================
+// blockPlainText
+// ===========================================================================
+describe('blockPlainText', () => {
+  it('returns the text of a plain text node', () => {
+    expect(blockPlainText(text('hello'))).toBe('hello');
+  });
+
+  it('concatenates text from nested containers', () => {
+    const node = {
+      type: 'paragraph',
+      content: [text('foo'), text('bar'), { type: 'span', content: [text('baz')] }],
+    };
+    expect(blockPlainText(node)).toBe('foobarbaz');
+  });
+
+  it('returns "" for nullish or non-object inputs', () => {
+    expect(blockPlainText(null)).toBe('');
+    expect(blockPlainText(undefined)).toBe('');
+    expect(blockPlainText('a string')).toBe('');
+    expect(blockPlainText(42)).toBe('');
+    expect(blockPlainText([text('x')])).toBe(''); // arrays are not objects here
+  });
+
+  it('uses BOTH text and nested content of a node, text first', () => {
+    const node = { type: 'weird', text: 'A', content: [text('B'), text('C')] };
+    expect(blockPlainText(node)).toBe('ABC');
+  });
+});
+
+// ===========================================================================
+// buildOutline
+// ===========================================================================
+describe('buildOutline', () => {
+  it('captures heading level, id and firstText', () => {
+    const outline = buildOutline(doc(heading('h1', 2, 'Title')));
+    expect(outline).toEqual([
+      { index: 0, type: 'heading', id: 'h1', firstText: 'Title', level: 2 },
+    ]);
+  });
+
+  it('reports table rows/cols and header texts (cols from row 0)', () => {
+    const table = {
+      type: 'table',
+      content: [
+        row([cell('tableHeader', 'a', 'H1'), cell('tableHeader', 'b', 'H2')]),
+        row([cell('tableCell', 'c', 'x'), cell('tableCell', 'd', 'y')]),
+      ],
+    };
+    const [entry] = buildOutline(doc(table));
+    expect(entry.type).toBe('table');
+    expect(entry.rows).toBe(2);
+    expect(entry.cols).toBe(2);
+    expect(entry.header).toEqual(['H1', 'H2']);
+  });
+
+  it('derives cols from row 0 for a ragged table', () => {
+    const table = {
+      type: 'table',
+      content: [
+        row([cell('tableHeader', 'a', 'H1')]), // row 0 has 1 col
+        row([cell('tableCell', 'b', 'x'), cell('tableCell', 'c', 'y')]), // 2 cols
+      ],
+    };
+    const [entry] = buildOutline(doc(table));
+    expect(entry.rows).toBe(2);
+    expect(entry.cols).toBe(1); // cols reflect ONLY row 0
+    expect(entry.header).toEqual(['H1']);
+  });
+
+  it('reports item count for any *List block', () => {
+    const list = {
+      type: 'bulletList',
+      attrs: { id: 'l1' },
+      content: [{ type: 'listItem' }, { type: 'listItem' }, { type: 'listItem' }],
+    };
+    const [entry] = buildOutline(doc(list));
+    expect(entry.type).toBe('bulletList');
+    expect(entry.items).toBe(3);
+  });
+
+  it('returns [] for an empty or non-object doc', () => {
+    expect(buildOutline(null)).toEqual([]);
+    expect(buildOutline({ type: 'doc' })).toEqual([]); // no content array
+    expect(buildOutline({ type: 'doc', content: [] })).toEqual([]);
+    expect(buildOutline('nope')).toEqual([]);
+  });
+
+  it('falls back to null id when a block has no attrs.id', () => {
+    const [entry] = buildOutline(doc({ type: 'paragraph', content: [text('hi')] }));
+    expect(entry.id).toBeNull();
+    expect(entry.firstText).toBe('hi');
+  });
+
+  it('truncates firstText to 100 chars with an ellipsis', () => {
+    const long = 'x'.repeat(150);
+    const [entry] = buildOutline(doc(para('p', long)));
+    expect(entry.firstText).toBe('x'.repeat(100) + '…');
+    expect(entry.firstText.length).toBe(101); // 100 chars + ellipsis
+  });
+
+  it('truncates table header cell text to 40 chars', () => {
+    const long = 'y'.repeat(60);
+    const table = {
+      type: 'table',
+      content: [row([cell('tableHeader', 'a', long)])],
+    };
+    const [entry] = buildOutline(doc(table));
+    expect(entry.header).toEqual(['y'.repeat(40) + '…']);
+  });
+});
+
+// ===========================================================================
+// getNodeByRef
+// ===========================================================================
+describe('getNodeByRef', () => {
+  it('resolves a top-level block by #n', () => {
+    const d = doc(para('p0', 'zero'), para('p1', 'one'));
+    const hit = getNodeByRef(d, '#1');
+    expect(hit).not.toBeNull();
+    expect(hit!.path).toEqual([1]);
+    expect(hit!.type).toBe('paragraph');
+    expect(hit!.node.attrs.id).toBe('p1');
+  });
+
+  it('returns null for #n out of range', () => {
+    const d = doc(para('p0'));
+    expect(getNodeByRef(d, '#5')).toBeNull();
+    expect(getNodeByRef(d, '#1')).toBeNull();
+  });
+
+  it('finds a nested node by id with the correct path', () => {
+    const table = {
+      type: 'table',
+      content: [row([cell('tableCell', 'deep', 'found me')])],
+    };
+    const d = doc(para('p0'), table);
+    const hit = getNodeByRef(d, 'deep');
+    expect(hit).not.toBeNull();
+    // doc.content[1] -> table.content[0] -> row.content[0] -> cell.content[0]
+    expect(hit!.path).toEqual([1, 0, 0, 0]);
+    expect(hit!.type).toBe('paragraph');
+  });
+
+  it('returns null when the id is not found', () => {
+    const d = doc(para('p0'));
+    expect(getNodeByRef(d, 'missing')).toBeNull();
+  });
+
+  it('returns the FIRST node for a duplicate id', () => {
+    const d = doc(para('dup', 'first'), para('dup', 'second'));
+    const hit = getNodeByRef(d, 'dup');
+    expect(hit!.path).toEqual([0]);
+    expect(blockPlainText(hit!.node)).toBe('first');
+  });
+
+  it('returns null for a non-object doc', () => {
+    expect(getNodeByRef(null, '#0')).toBeNull();
+    expect(getNodeByRef('x', 'id')).toBeNull();
+  });
+
+  it('returns a CLONE — mutating it does not touch the input doc', () => {
+    const d = doc(para('p0', 'orig'));
+    const snapshot = structuredClone(d);
+    const hit = getNodeByRef(d, 'p0');
+    hit!.node.attrs.id = 'mutated';
+    hit!.node.content.push(text('extra'));
+    expect(d).toEqual(snapshot);
+  });
+});
+
+// ===========================================================================
+// replaceNodeById
+// ===========================================================================
+describe('replaceNodeById', () => {
+  const newNode = () => ({ type: 'paragraph', attrs: { id: 'new' }, content: [text('NEW')] });
+
+  it('reports replaced:0 when nothing matches', () => {
+    const d = doc(para('p0'));
+    const res = replaceNodeById(d, 'missing', newNode());
+    expect(res.replaced).toBe(0);
+    expect(res.doc).toEqual(d);
+  });
+
+  it('replaces a single match', () => {
+    const d = doc(para('p0', 'old'), para('p1'));
+    const res = replaceNodeById(d, 'p0', newNode());
+    expect(res.replaced).toBe(1);
+    expect(res.doc.content[0]).toEqual(newNode());
+    expect(res.doc.content[1].attrs.id).toBe('p1');
+  });
+
+  it('replaces N matches', () => {
+    const d = doc(para('dup', 'a'), para('keep'), para('dup', 'b'));
+    const res = replaceNodeById(d, 'dup', newNode());
+    expect(res.replaced).toBe(2);
+    expect(res.doc.content[0]).toEqual(newNode());
+    expect(res.doc.content[1].attrs.id).toBe('keep');
+    expect(res.doc.content[2]).toEqual(newNode());
+  });
+
+  it('replaces a nested match inside a table cell', () => {
+    const table = {
+      type: 'table',
+      content: [row([cell('tableCell', 'inner', 'x')])],
+    };
+    const d = doc(table);
+    const res = replaceNodeById(d, 'inner', newNode());
+    expect(res.replaced).toBe(1);
+    expect(res.doc.content[0].content[0].content[0].content[0]).toEqual(newNode());
+  });
+
+  it('does NOT recurse into the substituted node', () => {
+    // The replacement itself carries the same id; it must not be re-replaced.
+    const d = doc(para('target'));
+    const replacement = { type: 'paragraph', attrs: { id: 'target' }, content: [text('R')] };
+    const res = replaceNodeById(d, 'target', replacement);
+    expect(res.replaced).toBe(1); // not 2 — no recursion into the new node
+  });
+
+  it('gives each match a SEPARATE clone', () => {
+    const d = doc(para('dup'), para('dup'));
+    const res = replaceNodeById(d, 'dup', newNode());
+    res.doc.content[0].content.push(text('mutated'));
+    // The second replacement must be untouched.
+    expect(res.doc.content[1]).toEqual(newNode());
+  });
+
+  it('does not mutate the input doc', () => {
+    const d = doc(para('p0', 'old'));
+    const snapshot = structuredClone(d);
+    replaceNodeById(d, 'p0', newNode());
+    expect(d).toEqual(snapshot);
+  });
+});
+
+// ===========================================================================
+// deleteNodeById
+// ===========================================================================
+describe('deleteNodeById', () => {
+  it('reports deleted:0 when nothing matches', () => {
+    const d = doc(para('p0'));
+    const res = deleteNodeById(d, 'missing');
+    expect(res.deleted).toBe(0);
+    expect(res.doc).toEqual(d);
+  });
+
+  it('deletes a single match', () => {
+    const d = doc(para('p0'), para('p1'), para('p2'));
+    const res = deleteNodeById(d, 'p1');
+    expect(res.deleted).toBe(1);
+    expect(res.doc.content.map((c: any) => c.attrs.id)).toEqual(['p0', 'p2']);
+  });
+
+  it('deletes N matches', () => {
+    const d = doc(para('dup'), para('keep'), para('dup'));
+    const res = deleteNodeById(d, 'dup');
+    expect(res.deleted).toBe(2);
+    expect(res.doc.content.map((c: any) => c.attrs.id)).toEqual(['keep']);
+  });
+
+  it('deletes a nested node and preserves sibling order', () => {
+    // A callout-style container holding three paragraph children; deleting the
+    // middle one must leave the outer siblings in order.
+    const callout = {
+      type: 'callout',
+      attrs: { id: 'cal' },
+      content: [para('a', 'A'), para('b', 'B'), para('c', 'C')],
+    };
+    const d = doc(para('outer0'), callout, para('outer1'));
+    const res = deleteNodeById(d, 'b');
+    expect(res.deleted).toBe(1);
+    // Inner siblings keep their order.
+    const innerIds = res.doc.content[1].content.map((cl: any) => cl.attrs.id);
+    expect(innerIds).toEqual(['a', 'c']);
+    // Outer siblings are untouched and in order.
+    const outerIds = res.doc.content.map((cl: any) => cl.attrs.id);
+    expect(outerIds).toEqual(['outer0', 'cal', 'outer1']);
+  });
+
+  it('does not mutate the input doc (deep-equal before/after)', () => {
+    const d = doc(para('p0'), para('p1'));
+    const snapshot = structuredClone(d);
+    deleteNodeById(d, 'p0');
+    expect(d).toEqual(snapshot);
+  });
+});
+
+// ===========================================================================
+// sanitizeForYjs
+// ===========================================================================
+describe('sanitizeForYjs', () => {
+  it('strips undefined keys from node.attrs', () => {
+    const d = doc({ type: 'paragraph', attrs: { id: 'p', gone: undefined, kept: 1 } });
+    const res = sanitizeForYjs(d);
+    expect('gone' in res.content[0].attrs).toBe(false);
+    expect(res.content[0].attrs).toEqual({ id: 'p', kept: 1 });
+  });
+
+  it('strips undefined keys from mark.attrs', () => {
+    const d = doc({
+      type: 'paragraph',
+      attrs: { id: 'p' },
+      content: [text('hi', [{ type: 'link', attrs: { href: 'u', gone: undefined } }])],
+    });
+    const res = sanitizeForYjs(d);
+    expect('gone' in res.content[0].content[0].marks[0].attrs).toBe(false);
+    expect(res.content[0].content[0].marks[0].attrs).toEqual({ href: 'u' });
+  });
+
+  it('PRESERVES null, false, 0 and "" (only undefined is dropped)', () => {
+    const d = doc({
+      type: 'paragraph',
+      attrs: { a: null, b: false, c: 0, d: '', e: undefined },
+    });
+    const res = sanitizeForYjs(d);
+    expect(res.content[0].attrs).toEqual({ a: null, b: false, c: 0, d: '' });
+  });
+
+  it('recurses into nested content', () => {
+    const d = doc({
+      type: 'table',
+      content: [row([cell('tableCell', null, '', { gone: undefined, colwidth: null })])],
+    });
+    const res = sanitizeForYjs(d);
+    const cellAttrs = res.content[0].content[0].content[0].attrs;
+    expect('gone' in cellAttrs).toBe(false);
+    expect(cellAttrs.colwidth).toBeNull();
+  });
+
+  it('does not mutate the input doc', () => {
+    const d = doc({ type: 'paragraph', attrs: { id: 'p', gone: undefined } });
+    // structuredClone preserves an explicit `undefined` value key, so snapshot it.
+    const snapshot = structuredClone(d);
+    sanitizeForYjs(d);
+    expect(d).toEqual(snapshot);
+    expect('gone' in d.content[0].attrs).toBe(true); // still present on the input
+  });
+});
+
+// ===========================================================================
+// findUnstorableAttr
+// ===========================================================================
+describe('findUnstorableAttr', () => {
+  it('returns null for a fully storable doc', () => {
+    const d = doc(para('p0', 'clean'));
+    expect(findUnstorableAttr(d)).toBeNull();
+  });
+
+  it('detects an undefined node attr with its path and kind', () => {
+    const d = doc(para('a'), para('b'), { type: 'paragraph', attrs: { id: 'c', x: undefined } });
+    expect(findUnstorableAttr(d)).toBe('content[2].attrs.x (undefined)');
+  });
+
+  it('detects a function attr', () => {
+    const d = doc({ type: 'paragraph', attrs: { fn: () => 1 } });
+    expect(findUnstorableAttr(d)).toBe('content[0].attrs.fn (function)');
+  });
+
+  it('detects a symbol attr', () => {
+    const d = doc({ type: 'paragraph', attrs: { s: Symbol('x') } });
+    expect(findUnstorableAttr(d)).toBe('content[0].attrs.s (symbol)');
+  });
+
+  it('detects a bigint attr', () => {
+    const d = doc({ type: 'paragraph', attrs: { big: 10n } });
+    expect(findUnstorableAttr(d)).toBe('content[0].attrs.big (bigint)');
+  });
+
+  it('detects an unstorable mark attr with the marks[i] path', () => {
+    const d = doc({
+      type: 'paragraph',
+      attrs: { id: 'p' },
+      content: [text('hi'), text('yo', [{ type: 'link', attrs: { x: undefined } }])],
+    });
+    expect(findUnstorableAttr(d)).toBe('content[0].content[1].marks[0].attrs.x (undefined)');
+  });
+
+  it('returns the FIRST hit only', () => {
+    const d = doc(
+      { type: 'paragraph', attrs: { first: undefined } },
+      { type: 'paragraph', attrs: { second: undefined } },
+    );
+    expect(findUnstorableAttr(d)).toBe('content[0].attrs.first (undefined)');
+  });
+
+  it('returns null for a non-object doc', () => {
+    expect(findUnstorableAttr(null)).toBeNull();
+    expect(findUnstorableAttr('x')).toBeNull();
+  });
+});
+
+// ===========================================================================
+// insertNodeRelative
+// ===========================================================================
+describe('insertNodeRelative', () => {
+  const block = (id: string, value = '') => para(id, value);
+
+  it('appends a node to top-level content', () => {
+    const d = doc(para('p0'));
+    const res = insertNodeRelative(d, block('new', 'N'), { position: 'append' });
+    expect(res.inserted).toBe(true);
+    expect(res.doc.content.map((c: any) => c.attrs.id)).toEqual(['p0', 'new']);
+  });
+
+  it('creates a content array when appending to a doc without one', () => {
+    const res = insertNodeRelative({ type: 'doc' }, block('new'), { position: 'append' });
+    expect(res.inserted).toBe(true);
+    expect(res.doc.content.map((c: any) => c.attrs.id)).toEqual(['new']);
+  });
+
+  it('inserts before a node by id (top level)', () => {
+    const d = doc(para('p0'), para('p1'));
+    const res = insertNodeRelative(d, block('new'), { position: 'before', anchorNodeId: 'p1' });
+    expect(res.inserted).toBe(true);
+    expect(res.doc.content.map((c: any) => c.attrs.id)).toEqual(['p0', 'new', 'p1']);
+  });
+
+  it('inserts after a node by id (top level)', () => {
+    const d = doc(para('p0'), para('p1'));
+    const res = insertNodeRelative(d, block('new'), { position: 'after', anchorNodeId: 'p0' });
+    expect(res.inserted).toBe(true);
+    expect(res.doc.content.map((c: any) => c.attrs.id)).toEqual(['p0', 'new', 'p1']);
+  });
+
+  it('inserts before a NESTED anchor by id, into its own parent content', () => {
+    const table = {
+      type: 'table',
+      content: [row([cell('tableCell', 'inner', 'x')])],
+    };
+    const d = doc(table);
+    const res = insertNodeRelative(d, block('new'), { position: 'before', anchorNodeId: 'inner' });
+    expect(res.inserted).toBe(true);
+    // The new (non-structural) node is spliced into the cell's content before the paragraph.
+    const cellContent = res.doc.content[0].content[0].content[0].content;
+    expect(cellContent.map((c: any) => c.attrs.id)).toEqual(['new', 'inner']);
+  });
+
+  it('inserts by anchorText against top-level blocks (substring match)', () => {
+    const d = doc(para('p0', 'hello world'), para('p1', 'other'));
+    const res = insertNodeRelative(d, block('new'), { position: 'after', anchorText: 'world' });
+    expect(res.inserted).toBe(true);
+    expect(res.doc.content.map((c: any) => c.attrs.id)).toEqual(['p0', 'new', 'p1']);
+  });
+
+  it('returns inserted:false when the anchor cannot be resolved', () => {
+    const d = doc(para('p0'));
+    const byId = insertNodeRelative(d, block('new'), { position: 'after', anchorNodeId: 'nope' });
+    expect(byId.inserted).toBe(false);
+    expect(byId.doc).toEqual(d);
+
+    const byText = insertNodeRelative(d, block('new'), { position: 'before', anchorText: 'zzz' });
+    expect(byText.inserted).toBe(false);
+    expect(byText.doc).toEqual(d);
+  });
+
+  it('routes a structural tableRow to the nearest table container', () => {
+    const table = {
+      type: 'table',
+      content: [
+        row([cell('tableCell', 'r0c0', 'A')]),
+        row([cell('tableCell', 'r1c0', 'B')]),
+      ],
+    };
+    const d = doc(table);
+    const newRow = row([cell('tableCell', 'rNew', 'NEW')]);
+    // Anchor on a cell paragraph inside row 0; "after" should put the row after row 0.
+    const res = insertNodeRelative(d, newRow, { position: 'after', anchorNodeId: 'r0c0' });
+    expect(res.inserted).toBe(true);
+    const rowFirstCellId = (r: any) => r.content[0].content[0].attrs.id;
+    expect(res.doc.content[0].content.map(rowFirstCellId)).toEqual(['r0c0', 'rNew', 'r1c0']);
+  });
+
+  it('throws when appending a structural node at the top level', () => {
+    const d = doc(para('p0'));
+    const newRow = row([cell('tableCell', 'x', 'X')]);
+    expect(() => insertNodeRelative(d, newRow, { position: 'append' })).toThrow(
+      /cannot append a tableRow at the top level/,
+    );
+  });
+
+  it('throws when a structural anchor is not inside the required container', () => {
+    // Anchor resolves to a top-level paragraph that is not inside any table.
+    const d = doc(para('p0', 'loose'));
+    const newRow = row([cell('tableCell', 'x', 'X')]);
+    expect(() =>
+      insertNodeRelative(d, newRow, { position: 'after', anchorNodeId: 'p0' }),
+    ).toThrow(/the anchor is not inside a table/);
+  });
+
+  it('honours offset: before vs after place the node on the correct side', () => {
+    const d = doc(para('a'), para('b'), para('c'));
+    const before = insertNodeRelative(d, block('N'), { position: 'before', anchorNodeId: 'b' });
+    expect(before.doc.content.map((c: any) => c.attrs.id)).toEqual(['a', 'N', 'b', 'c']);
+    const after = insertNodeRelative(d, block('N'), { position: 'after', anchorNodeId: 'b' });
+    expect(after.doc.content.map((c: any) => c.attrs.id)).toEqual(['a', 'b', 'N', 'c']);
+  });
+
+  it('does not mutate the input doc or the node argument', () => {
+    const d = doc(para('p0'));
+    const dSnapshot = structuredClone(d);
+    const node = block('new', 'N');
+    const nodeSnapshot = structuredClone(node);
+    insertNodeRelative(d, node, { position: 'append' });
+    expect(d).toEqual(dSnapshot);
+    expect(node).toEqual(nodeSnapshot);
+  });
+});
+
+// ===========================================================================
+// readTable
+// ===========================================================================
+describe('readTable', () => {
+  const makeTable = () => ({
+    type: 'table',
+    content: [
+      row([cell('tableHeader', 'h0', 'H0'), cell('tableHeader', 'h1', 'H1')]),
+      row([cell('tableCell', 'c0', 'A'), cell('tableCell', 'c1', 'B')]),
+    ],
+  });
+
+  it('reads a table by #n', () => {
+    const d = doc(para('p0'), makeTable());
+    const res = readTable(d, '#1');
+    expect(res).not.toBeNull();
+    expect(res!.rows).toBe(2);
+    expect(res!.cols).toBe(2);
+    expect(res!.cells).toEqual([['H0', 'H1'], ['A', 'B']]);
+    expect(res!.cellIds).toEqual([['h0', 'h1'], ['c0', 'c1']]);
+    expect(res!.path).toEqual([1]);
+  });
+
+  it('climbs from an inner paragraph id up to the table', () => {
+    const d = doc(makeTable());
+    const res = readTable(d, 'c1'); // id of a paragraph inside a data cell
+    expect(res).not.toBeNull();
+    expect(res!.path).toEqual([0]);
+    expect(res!.cells).toEqual([['H0', 'H1'], ['A', 'B']]);
+  });
+
+  it('reports per-row widths via cells for a ragged table', () => {
+    const table = {
+      type: 'table',
+      content: [
+        row([cell('tableHeader', 'h0', 'H0')]),
+        row([cell('tableCell', 'c0', 'A'), cell('tableCell', 'c1', 'B')]),
+      ],
+    };
+    const res = readTable(doc(table), '#0');
+    expect(res!.cols).toBe(1); // cols comes from row 0
+    expect(res!.cells).toEqual([['H0'], ['A', 'B']]); // actual per-row widths preserved
+    expect(res!.cellIds).toEqual([['h0'], ['c0', 'c1']]);
+  });
+
+  it('reports null cellId for an empty cell with no paragraph', () => {
+    const table = {
+      type: 'table',
+      content: [row([cell('tableCell', null), cell('tableCell', 'c1', 'B')])],
+    };
+    const res = readTable(doc(table), '#0');
+    expect(res!.cells).toEqual([['', 'B']]);
+    expect(res!.cellIds).toEqual([[null, 'c1']]);
+  });
+
+  it('returns null when the ref matches no table', () => {
+    const d = doc(para('p0'));
+    expect(readTable(d, '#0')).toBeNull(); // #0 is a paragraph, not a table
+    expect(readTable(d, 'missing')).toBeNull();
+    expect(readTable(d, 'p0')).toBeNull(); // id found but no enclosing table
+  });
+});
+
+// ===========================================================================
+// insertTableRow
+// ===========================================================================
+describe('insertTableRow', () => {
+  const makeTable = () => ({
+    type: 'table',
+    content: [
+      row([
+        cell('tableHeader', 'h0', 'H0', { colwidth: [120] }),
+        cell('tableHeader', 'h1', 'H1', { colwidth: [240] }),
+      ]),
+      row([cell('tableCell', 'c0', 'A'), cell('tableCell', 'c1', 'B')]),
+    ],
+  });
+
+  /** First-paragraph ids of every cell in a row, for ordering assertions. */
+  const rowCellParaIds = (r: any): (string | undefined)[] =>
+    r.content.map((c: any) => c.content[0]?.attrs?.id);
+  /** Cell text of a row. */
+  const rowTexts = (r: any): string[] =>
+    r.content.map((c: any) => blockPlainText(c));
+
+  it('appends a row when index is omitted', () => {
+    const d = doc(makeTable());
+    const res = insertTableRow(d, '#0', ['X', 'Y']);
+    expect(res.inserted).toBe(true);
+    const rows = res.doc.content[0].content;
+    expect(rows.length).toBe(3);
+    expect(rowTexts(rows[2])).toEqual(['X', 'Y']);
+  });
+
+  it('splices at a middle index', () => {
+    const d = doc(makeTable());
+    const res = insertTableRow(d, '#0', ['X', 'Y'], 1);
+    const rows = res.doc.content[0].content;
+    expect(rows.length).toBe(3);
+    expect(rowTexts(rows[1])).toEqual(['X', 'Y']); // new row at index 1
+    expect(rowTexts(rows[2])).toEqual(['A', 'B']); // old data row pushed down
+  });
+
+  it('splices at the end index', () => {
+    const d = doc(makeTable());
+    const res = insertTableRow(d, '#0', ['X', 'Y'], 2); // rows == 2, valid end index
+    const rows = res.doc.content[0].content;
+    expect(rows.length).toBe(3);
+    expect(rowTexts(rows[2])).toEqual(['X', 'Y']);
+  });
+
+  it('APPENDS (does not throw) for an out-of-range index', () => {
+    const d = doc(makeTable());
+    const res = insertTableRow(d, '#0', ['X', 'Y'], 99);
+    const rows = res.doc.content[0].content;
+    expect(res.inserted).toBe(true);
+    expect(rows.length).toBe(3);
+    expect(rowTexts(rows[2])).toEqual(['X', 'Y']); // appended at the end
+  });
+
+  it('throws when given more cells than columns', () => {
+    const d = doc(makeTable());
+    expect(() => insertTableRow(d, '#0', ['X', 'Y', 'Z'])).toThrow(
+      /got 3 cell\(s\) but the table has 2 column\(s\)/,
+    );
+  });
+
+  it('pads a short row to the column count', () => {
+    const d = doc(makeTable());
+    const res = insertTableRow(d, '#0', ['only']);
+    const rows = res.doc.content[0].content;
+    expect(rowTexts(rows[2])).toEqual(['only', '']); // padded with empty cell
+  });
+
+  it('copies colwidth from the header row for each column', () => {
+    const d = doc(makeTable());
+    const res = insertTableRow(d, '#0', ['X', 'Y']);
+    const newRow = res.doc.content[0].content[2];
+    expect(newRow.content[0].attrs.colwidth).toEqual([120]);
+    expect(newRow.content[1].attrs.colwidth).toEqual([240]);
+    expect(newRow.content[0].attrs).toMatchObject({ colspan: 1, rowspan: 1 });
+  });
+
+  it('index 0 inherits the header cell TYPE', () => {
+    const d = doc(makeTable());
+    const res = insertTableRow(d, '#0', ['X', 'Y'], 0);
+    const newRow = res.doc.content[0].content[0];
+    expect(newRow.content.every((c: any) => c.type === 'tableHeader')).toBe(true);
+    // A non-zero index produces plain data cells instead.
+    const res2 = insertTableRow(d, '#0', ['X', 'Y'], 1);
+    const dataRow = res2.doc.content[0].content[1];
+    expect(dataRow.content.every((c: any) => c.type === 'tableCell')).toBe(true);
+  });
+
+  it('mints unique, well-formed paragraph ids for new cells', () => {
+    const d = doc(makeTable());
+    const existing = new Set(['h0', 'h1', 'c0', 'c1']);
+    const res = insertTableRow(d, '#0', ['X', 'Y']);
+    const newRow = res.doc.content[0].content[2];
+    const ids = rowCellParaIds(newRow) as string[];
+    for (const id of ids) {
+      expect(typeof id).toBe('string');
+      expect(id).toMatch(/^[a-z0-9]{12}$/); // Docmost-style 12-char id
+      expect(existing.has(id)).toBe(false); // unique vs pre-existing ids
+    }
+    expect(new Set(ids).size).toBe(ids.length); // unique within the row
+  });
+
+  it('returns inserted:false when the table cannot be located', () => {
+    const d = doc(para('p0'));
+    const res = insertTableRow(d, 'missing', ['X']);
+    expect(res.inserted).toBe(false);
+    expect(res.doc).toEqual(d);
+  });
+
+  it('does not mutate the input doc', () => {
+    const d = doc(makeTable());
+    const snapshot = structuredClone(d);
+    insertTableRow(d, '#0', ['X', 'Y'], 1);
+    expect(d).toEqual(snapshot);
+  });
+});
+
+// ===========================================================================
+// deleteTableRow
+// ===========================================================================
+describe('deleteTableRow', () => {
+  const makeTable = () => ({
+    type: 'table',
+    content: [
+      row([cell('tableHeader', 'h0', 'H')]),
+      row([cell('tableCell', 'c0', 'A')]),
+      row([cell('tableCell', 'c1', 'B')]),
+    ],
+  });
+  const firstId = (r: any) => r.content[0].content[0].attrs.id;
+
+  it('deletes a middle row and preserves siblings', () => {
+    const d = doc(makeTable());
+    const res = deleteTableRow(d, '#0', 1);
+    expect(res.deleted).toBe(true);
+    expect(res.doc.content[0].content.map(firstId)).toEqual(['h0', 'c1']);
+  });
+
+  it('deletes the first row', () => {
+    const d = doc(makeTable());
+    const res = deleteTableRow(d, '#0', 0);
+    expect(res.doc.content[0].content.map(firstId)).toEqual(['c0', 'c1']);
+  });
+
+  it('deletes the last row', () => {
+    const d = doc(makeTable());
+    const res = deleteTableRow(d, '#0', 2);
+    expect(res.doc.content[0].content.map(firstId)).toEqual(['h0', 'c0']);
+  });
+
+  it('throws on an out-of-range index', () => {
+    const d = doc(makeTable());
+    expect(() => deleteTableRow(d, '#0', 99)).toThrow(/out of range/);
+    expect(() => deleteTableRow(d, '#0', -1)).toThrow(/out of range/);
+  });
+
+  it('throws when asked to delete the only row', () => {
+    const single = {
+      type: 'table',
+      content: [row([cell('tableCell', 'c0', 'A')])],
+    };
+    expect(() => deleteTableRow(doc(single), '#0', 0)).toThrow(
+      /refusing to delete the only row/,
+    );
+  });
+
+  it('returns deleted:false when the table cannot be located', () => {
+    const d = doc(para('p0'));
+    const res = deleteTableRow(d, 'missing', 0);
+    expect(res.deleted).toBe(false);
+    expect(res.doc).toEqual(d);
+  });
+
+  it('does not mutate the input doc', () => {
+    const d = doc(makeTable());
+    const snapshot = structuredClone(d);
+    deleteTableRow(d, '#0', 1);
+    expect(d).toEqual(snapshot);
+  });
+});
+
+// ===========================================================================
+// updateTableCell
+// ===========================================================================
+describe('updateTableCell', () => {
+  const makeTable = () => ({
+    type: 'table',
+    content: [
+      row([cell('tableHeader', 'h0', 'H0'), cell('tableHeader', 'h1', 'H1')]),
+      row([
+        cell('tableCell', 'c0', 'A', { colspan: 2, rowspan: 3, colwidth: [200] }),
+        cell('tableCell', 'c1', 'B'),
+      ]),
+    ],
+  });
+
+  it('sets the cell text', () => {
+    const d = doc(makeTable());
+    const res = updateTableCell(d, '#0', 1, 1, 'NEW');
+    expect(res.updated).toBe(true);
+    expect(blockPlainText(res.doc.content[0].content[1].content[1])).toBe('NEW');
+  });
+
+  it('REUSES the existing first-paragraph id', () => {
+    const d = doc(makeTable());
+    const res = updateTableCell(d, '#0', 1, 0, 'changed');
+    const para0 = res.doc.content[0].content[1].content[0].content[0];
+    expect(para0.attrs.id).toBe('c0'); // critical: id reused, not regenerated
+    expect(para0.content[0].text).toBe('changed');
+  });
+
+  it('mints a fresh id when the cell had no paragraph', () => {
+    const table = {
+      type: 'table',
+      content: [row([cell('tableCell', null), cell('tableCell', 'c1', 'B')])],
+    };
+    const d = doc(table);
+    const res = updateTableCell(d, '#0', 0, 0, 'now has text');
+    const newPara = res.doc.content[0].content[0].content[0].content[0];
+    expect(typeof newPara.attrs.id).toBe('string');
+    expect(newPara.attrs.id).toMatch(/^[a-z0-9]{12}$/);
+    expect(newPara.attrs.id).not.toBe('c1'); // unique vs existing ids
+    expect(newPara.content[0].text).toBe('now has text');
+  });
+
+  it('PRESERVES the cell colspan/rowspan/colwidth (only content replaced)', () => {
+    const d = doc(makeTable());
+    const res = updateTableCell(d, '#0', 1, 0, 'x');
+    const cellNode = res.doc.content[0].content[1].content[0];
+    expect(cellNode.attrs).toEqual({ colspan: 2, rowspan: 3, colwidth: [200] });
+  });
+
+  it('throws when row or col is out of range', () => {
+    const d = doc(makeTable());
+    expect(() => updateTableCell(d, '#0', 5, 0, 'x')).toThrow(/out of range/);
+    expect(() => updateTableCell(d, '#0', 0, 5, 'x')).toThrow(/out of range/);
+    expect(() => updateTableCell(d, '#0', -1, 0, 'x')).toThrow(/out of range/);
+  });
+
+  it('an empty string yields an empty paragraph content array', () => {
+    const d = doc(makeTable());
+    const res = updateTableCell(d, '#0', 1, 1, '');
+    const cellPara = res.doc.content[0].content[1].content[1].content[0];
+    expect(cellPara.type).toBe('paragraph');
+    expect(cellPara.content).toEqual([]); // empty string -> empty content
+    expect(cellPara.attrs.id).toBe('c1'); // id still reused
+  });
+
+  it('returns updated:false when the table cannot be located', () => {
+    const d = doc(para('p0'));
+    const res = updateTableCell(d, 'missing', 0, 0, 'x');
+    expect(res.updated).toBe(false);
+    expect(res.doc).toEqual(d);
+  });
+
+  it('does not mutate the input doc', () => {
+    const d = doc(makeTable());
+    const snapshot = structuredClone(d);
+    updateTableCell(d, '#0', 1, 1, 'NEW');
+    expect(d).toEqual(snapshot);
+  });
+});
diff --git a/test/page-lock.test.ts b/test/page-lock.test.ts
new file mode 100644
index 0000000..20a60b0
--- /dev/null
+++ b/test/page-lock.test.ts
@@ -0,0 +1,170 @@
+import { describe, expect, it } from 'vitest';
+import { withPageLock } from '../packages/docmost-client/src/lib/page-lock.js';
+
+// A manually-resolvable promise so ordering is fully deterministic without
+// any timers. `resolve`/`reject` are pulled out of the executor.
+function deferred<T = void>() {
+  let resolve!: (value: T) => void;
+  let reject!: (reason?: unknown) => void;
+  const promise = new Promise<T>((res, rej) => {
+    resolve = res;
+    reject = rej;
+  });
+  return { promise, resolve, reject };
+}
+
+// A unique pageId per test: the module-level Map is process-global and shared
+// across every test in a worker, so reusing ids would couple tests together.
+let pageCounter = 0;
+function uniquePageId() {
+  return `page-${process.pid}-${Date.now()}-${pageCounter++}`;
+}
+
+// Drain the microtask queue several times. withPageLock chains through
+// `Promise.resolve().catch().then(fn)`, so `fn` only starts after a few
+// microtask hops — a single `await Promise.resolve()` is not enough. We never
+// use timers, so this stays fully deterministic.
+async function flushMicrotasks() {
+  for (let i = 0; i < 10; i++) await Promise.resolve();
+}
+
+describe('withPageLock', () => {
+  it('serializes two ops on the same pageId (second waits for the first to settle)', async () => {
+    const pageId = uniquePageId();
+    const order: string[] = [];
+
+    const gate1 = deferred();
+
+    const op1 = withPageLock(pageId, async () => {
+      order.push('op1-start');
+      await gate1.promise;
+      order.push('op1-end');
+      return 'one';
+    });
+
+    const op2 = withPageLock(pageId, async () => {
+      order.push('op2-start');
+      return 'two';
+    });
+
+    // Let microtasks flush: op1 has started, op2 must not have started yet.
+    await flushMicrotasks();
+    expect(order).toEqual(['op1-start']);
+
+    // Release op1; op2 may only begin after op1 fully settles.
+    gate1.resolve();
+    await Promise.all([op1, op2]);
+
+    expect(order).toEqual(['op1-start', 'op1-end', 'op2-start']);
+  });
+
+  it('does not poison the queue when the first op rejects (second still runs)', async () => {
+    const pageId = uniquePageId();
+    const order: string[] = [];
+
+    const gate1 = deferred();
+
+    const op1 = withPageLock(pageId, async () => {
+      order.push('op1-start');
+      await gate1.promise;
+      throw new Error('boom');
+    });
+
+    const op2 = withPageLock(pageId, async () => {
+      order.push('op2-start');
+      return 'survived';
+    });
+
+    await flushMicrotasks();
+    expect(order).toEqual(['op1-start']);
+
+    gate1.resolve();
+
+    // op1 rejects, but op2 still runs afterwards.
+    await expect(op1).rejects.toThrow('boom');
+    await expect(op2).resolves.toBe('survived');
+    expect(order).toEqual(['op1-start', 'op2-start']);
+  });
+
+  it('runs ops on different pageIds concurrently (no cross-page blocking)', async () => {
+    const pageIdA = uniquePageId();
+    const pageIdB = uniquePageId();
+    const order: string[] = [];
+
+    const gateA = deferred();
+
+    const opA = withPageLock(pageIdA, async () => {
+      order.push('A-start');
+      await gateA.promise;
+      order.push('A-end');
+      return 'a';
+    });
+
+    const opB = withPageLock(pageIdB, async () => {
+      order.push('B-start');
+      return 'b';
+    });
+
+    // B is on a different page and must start without waiting for A.
+    await flushMicrotasks();
+    expect(order).toContain('A-start');
+    expect(order).toContain('B-start');
+
+    gateA.resolve();
+    await Promise.all([opA, opB]);
+
+    // B finished while A was still gated.
+    expect(order).toEqual(['A-start', 'B-start', 'A-end']);
+  });
+
+  it('returns the real resolved value to the caller', async () => {
+    const pageId = uniquePageId();
+    const value = { ok: true, n: 7 };
+
+    await expect(withPageLock(pageId, async () => value)).resolves.toBe(value);
+  });
+
+  it('propagates the real rejection to the caller (not swallowed)', async () => {
+    const pageId = uniquePageId();
+    const err = new Error('real failure');
+
+    await expect(
+      withPageLock(pageId, async () => {
+        throw err;
+      }),
+    ).rejects.toBe(err);
+  });
+
+  it('serializes a third op behind the chain even after a rejection mid-chain', async () => {
+    const pageId = uniquePageId();
+    const order: string[] = [];
+
+    const gate1 = deferred();
+
+    const op1 = withPageLock(pageId, async () => {
+      order.push('1-start');
+      await gate1.promise;
+      throw new Error('mid-fail');
+    });
+
+    const op2 = withPageLock(pageId, async () => {
+      order.push('2');
+      return 2;
+    });
+
+    const op3 = withPageLock(pageId, async () => {
+      order.push('3');
+      return 3;
+    });
+
+    await flushMicrotasks();
+    expect(order).toEqual(['1-start']);
+
+    gate1.resolve();
+
+    await expect(op1).rejects.toThrow('mid-fail');
+    await expect(op2).resolves.toBe(2);
+    await expect(op3).resolves.toBe(3);
+    expect(order).toEqual(['1-start', '2', '3']);
+  });
+});
diff --git a/test/transforms.test.ts b/test/transforms.test.ts
new file mode 100644
index 0000000..1b91462
--- /dev/null
+++ b/test/transforms.test.ts
@@ -0,0 +1,561 @@
+import { describe, expect, it } from 'vitest';
+import {
+  walk,
+  getList,
+  insertMarkerAfter,
+  setCalloutRange,
+  noteItem,
+  mdToInlineNodes,
+  commentsToFootnotes,
+} from '../packages/docmost-client/src/lib/transforms.js';
+
+// ---------------------------------------------------------------------------
+// Small inline fixture builders. A ProseMirror node is a plain JSON object of
+// shape { type, attrs?, content?, text?, marks? }.
+// ---------------------------------------------------------------------------
+
+/** A plain text run, optionally with marks. */
+function text(t: string, marks?: any[]): any {
+  return marks ? { type: 'text', text: t, marks } : { type: 'text', text: t };
+}
+
+/** A paragraph holding the given inline runs. */
+function para(...runs: any[]): any {
+  return { type: 'paragraph', attrs: { id: 'p' }, content: runs };
+}
+
+/** A callout holding the given child blocks. */
+function callout(...children: any[]): any {
+  return { type: 'callout', content: children };
+}
+
+/** A document with the given top-level blocks. */
+function doc(...blocks: any[]): any {
+  return { type: 'doc', content: blocks };
+}
+
+/**
+ * Recursively strip every `attrs.id` so docs containing freshId()-generated ids
+ * can be deep-compared structurally. Mutates a clone, returns it.
+ */
+function stripIds<T>(value: T): T {
+  const v: any = structuredClone(value);
+  const recur = (n: any): void => {
+    if (Array.isArray(n)) {
+      n.forEach(recur);
+      return;
+    }
+    if (n && typeof n === 'object') {
+      if (n.attrs && typeof n.attrs === 'object' && 'id' in n.attrs) {
+        delete n.attrs.id;
+      }
+      for (const k of Object.keys(n)) recur(n[k]);
+    }
+  };
+  recur(v);
+  return v;
+}
+
+// ===========================================================================
+describe('walk', () => {
+  it('is a no-op for a nullish or non-object root', () => {
+    const seen: any[] = [];
+    walk(null, (n) => seen.push(n));
+    walk(undefined, (n) => seen.push(n));
+    walk('string', (n) => seen.push(n));
+    walk(42, (n) => seen.push(n));
+    walk([1, 2, 3], (n) => seen.push(n)); // array is not an object root
+    expect(seen).toEqual([]);
+  });
+
+  it('visits the root itself and all nested nodes (callout/table/list)', () => {
+    const tree = {
+      type: 'doc',
+      content: [
+        callout(para(text('a'))),
+        {
+          type: 'table',
+          content: [
+            { type: 'tableRow', content: [{ type: 'tableCell', content: [para(text('b'))] }] },
+          ],
+        },
+        {
+          type: 'orderedList',
+          content: [{ type: 'listItem', content: [para(text('c'))] }],
+        },
+      ],
+    };
+    const types: string[] = [];
+    walk(tree, (n) => types.push(n.type));
+    // Root first, then DFS into every nested container.
+    expect(types[0]).toBe('doc');
+    expect(types).toContain('callout');
+    expect(types).toContain('table');
+    expect(types).toContain('tableRow');
+    expect(types).toContain('tableCell');
+    expect(types).toContain('orderedList');
+    expect(types).toContain('listItem');
+    expect(types).toContain('paragraph');
+    expect(types).toContain('text');
+  });
+
+  it('ignores a non-array content field', () => {
+    const node = { type: 'weird', content: { not: 'an array' } };
+    const seen: any[] = [];
+    walk(node, (n) => seen.push(n));
+    // Only the root is visited; the object content is never recursed into.
+    expect(seen).toEqual([node]);
+  });
+});
+
+// ===========================================================================
+describe('getList', () => {
+  it('returns the FIRST match in depth-first order', () => {
+    const first = { type: 'orderedList', attrs: { id: 'L1' }, content: [] };
+    const second = { type: 'orderedList', attrs: { id: 'L2' }, content: [] };
+    const tree = doc(callout(first), second);
+    const found = getList(tree, (n) => n.type === 'orderedList');
+    expect(found).toBe(first); // DFS reaches the callout's child before the sibling
+    expect(found.attrs.id).toBe('L1');
+  });
+
+  it('returns null when nothing matches', () => {
+    const tree = doc(para(text('x')));
+    expect(getList(tree, (n) => n.type === 'orderedList')).toBeNull();
+  });
+
+  it('returns a LIVE reference, not a clone', () => {
+    const list = { type: 'orderedList', content: [] };
+    const tree = doc(list);
+    const found = getList(tree, (n) => n.type === 'orderedList');
+    expect(found).toBe(list); // same object identity
+    found.marker = 'mutated';
+    expect(list.marker).toBe('mutated'); // mutation visible on the original
+  });
+
+  it('matches a node lacking attrs.id', () => {
+    const noId = { type: 'orderedList', content: [] }; // no attrs at all
+    const tree = doc(para(text('x')), noId);
+    const found = getList(tree, (n) => n.type === 'orderedList');
+    expect(found).toBe(noId);
+  });
+});
+
+// ===========================================================================
+describe('insertMarkerAfter', () => {
+  it('returns inserted:false when the anchor is not found', () => {
+    const d = doc(para(text('hello world')));
+    const r = insertMarkerAfter(d, 'absent text', '[1]');
+    expect(r.inserted).toBe(false);
+    // Returned doc is a clone of the unchanged input.
+    expect(r.doc).toEqual(d);
+    expect(r.doc).not.toBe(d);
+  });
+
+  it('inserts a plain marker run after the anchor in a single text run', () => {
+    const d = doc(para(text('see here for details')));
+    const r = insertMarkerAfter(d, 'see here', '[1]');
+    expect(r.inserted).toBe(true);
+    expect(r.doc.content[0].content).toEqual([
+      { type: 'text', text: 'see here', marks: [] },
+      { type: 'text', text: ' [1]' },
+      { type: 'text', text: ' for details', marks: [] },
+    ]);
+  });
+
+  it('preserves marks across runs and emits a PLAIN marker, no empty runs', () => {
+    // Anchor "foo bar" spans a plain run "foo " and a bold run "bar baz".
+    const d = doc(
+      para(
+        text('foo '),
+        text('bar baz', [{ type: 'bold' }]),
+      ),
+    );
+    const r = insertMarkerAfter(d, 'foo bar', '[1]');
+    expect(r.inserted).toBe(true);
+    // The bold run "bar baz" is split at the anchor end (after "bar"); the
+    // leading "foo " run is untouched, the marker is plain, surrounding marks
+    // are preserved verbatim, and no empty text run is emitted.
+    expect(r.doc.content[0].content).toEqual([
+      { type: 'text', text: 'foo ' },
+      { type: 'text', text: 'bar', marks: [{ type: 'bold' }] },
+      { type: 'text', text: ' [1]' },
+      { type: 'text', text: ' baz', marks: [{ type: 'bold' }] },
+    ]);
+  });
+
+  it('splits exactly at a run boundary without emitting an empty run', () => {
+    // Anchor ends exactly at the end of the first run "alpha".
+    const d = doc(para(text('alpha'), text('beta')));
+    const r = insertMarkerAfter(d, 'alpha', '[1]');
+    expect(r.inserted).toBe(true);
+    // "before" == whole first run, "after" is empty -> no empty run pushed.
+    expect(r.doc.content[0].content).toEqual([
+      { type: 'text', text: 'alpha', marks: [] },
+      { type: 'text', text: ' [1]' },
+      { type: 'text', text: 'beta' },
+    ]);
+  });
+
+  it('beforeBlock scope excludes blocks at/after the boundary', () => {
+    const d = doc(
+      para(text('body anchor')),     // index 0 (in scope when beforeBlock=1)
+      para(text('notes anchor')),    // index 1 (out of scope)
+    );
+    // Anchor only exists in the out-of-scope block -> not inserted.
+    const r = insertMarkerAfter(d, 'notes anchor', '[1]', { beforeBlock: 1 });
+    expect(r.inserted).toBe(false);
+    // The in-scope anchor still inserts when limited.
+    const r2 = insertMarkerAfter(d, 'body anchor', '[1]', { beforeBlock: 1 });
+    expect(r2.inserted).toBe(true);
+  });
+
+  it('does not mutate the input document', () => {
+    const d = doc(para(text('keep me intact please')));
+    const snapshot = structuredClone(d);
+    insertMarkerAfter(d, 'keep me', '[1]');
+    expect(d).toEqual(snapshot);
+  });
+
+  it('returns inserted:false for an empty anchor', () => {
+    const d = doc(para(text('anything')));
+    const r = insertMarkerAfter(d, '', '[1]');
+    expect(r.inserted).toBe(false);
+    expect(r.doc).toEqual(d);
+  });
+});
+
+// ===========================================================================
+describe('setCalloutRange', () => {
+  it('rewrites a Unicode-ellipsis [1]…[K] range inside a callout', () => {
+    const d = doc(callout(para(text('Footnotes [1]…[5] follow'))));
+    const r = setCalloutRange(d, 7);
+    expect(r.changed).toBe(1);
+    expect(r.doc.content[0].content[0].content[0].text).toBe('Footnotes [1]…[7] follow');
+  });
+
+  it('rewrites an ASCII-ellipsis [1]...[K] range inside a callout', () => {
+    const d = doc(callout(para(text('range [1]...[3] here'))));
+    const r = setCalloutRange(d, 9);
+    expect(r.changed).toBe(1);
+    expect(r.doc.content[0].content[0].content[0].text).toBe('range [1]...[9] here');
+  });
+
+  it('leaves a paragraph [1]…[K] (outside any callout) untouched', () => {
+    const d = doc(para(text('not a callout [1]…[5]')));
+    const r = setCalloutRange(d, 9);
+    expect(r.changed).toBe(0);
+    expect(r.doc.content[0].content[0].text).toBe('not a callout [1]…[5]');
+  });
+
+  it('rewrites across multiple callouts and reports the changed count', () => {
+    const d = doc(
+      callout(para(text('a [1]…[2] b'))),
+      para(text('skip [1]…[2]')),
+      callout(para(text('c [1]...[4] d'))),
+    );
+    const r = setCalloutRange(d, 10);
+    expect(r.changed).toBe(2);
+    expect(r.doc.content[0].content[0].content[0].text).toBe('a [1]…[10] b');
+    expect(r.doc.content[2].content[0].content[0].text).toBe('c [1]...[10] d');
+  });
+
+  it('reports changed:0 when no range matches', () => {
+    const d = doc(callout(para(text('no range here'))));
+    const r = setCalloutRange(d, 4);
+    expect(r.changed).toBe(0);
+  });
+
+  it('does not mutate the input document', () => {
+    const d = doc(callout(para(text('x [1]…[5] y'))));
+    const snapshot = structuredClone(d);
+    setCalloutRange(d, 99);
+    expect(d).toEqual(snapshot);
+  });
+
+  it('handles TWO matching text nodes in one callout (regex lastIndex reset)', () => {
+    // Two separate text nodes, each carrying a range, inside one callout.
+    const d = doc(
+      callout(
+        para(text('first [1]…[2]')),
+        para(text('second [1]…[3]')),
+      ),
+    );
+    const r = setCalloutRange(d, 6);
+    expect(r.changed).toBe(2);
+    expect(r.doc.content[0].content[0].content[0].text).toBe('first [1]…[6]');
+    expect(r.doc.content[0].content[1].content[0].text).toBe('second [1]…[6]');
+  });
+});
+
+// ===========================================================================
+describe('noteItem', () => {
+  it('wraps inline nodes in listItem > paragraph', () => {
+    const inline = [text('hello')];
+    const item = noteItem(inline);
+    expect(item.type).toBe('listItem');
+    expect(item.content).toHaveLength(1);
+    const p = item.content[0];
+    expect(p.type).toBe('paragraph');
+    expect(p.content).toEqual([text('hello')]);
+    // The paragraph carries a string id from Math.random()-based freshId().
+    expect(typeof p.attrs.id).toBe('string');
+    expect(p.attrs.id.length).toBeGreaterThan(0);
+  });
+
+  it('produces empty content for non-array input', () => {
+    expect(noteItem(undefined as any).content[0].content).toEqual([]);
+    expect(noteItem(null as any).content[0].content).toEqual([]);
+    expect(noteItem('nope' as any).content[0].content).toEqual([]);
+  });
+
+  it('clones the input so the result shares no references', () => {
+    const inline = [text('mutable')];
+    const item = noteItem(inline);
+    inline[0].text = 'changed';
+    expect(item.content[0].content[0].text).toBe('mutable'); // unaffected
+    expect(item.content[0].content[0]).not.toBe(inline[0]);
+  });
+
+  it('matches the expected structure (ignoring the random id)', () => {
+    const item = noteItem([text('body', [{ type: 'bold' }])]);
+    expect(stripIds(item)).toEqual({
+      type: 'listItem',
+      content: [
+        {
+          type: 'paragraph',
+          attrs: {},
+          content: [{ type: 'text', text: 'body', marks: [{ type: 'bold' }] }],
+        },
+      ],
+    });
+  });
+});
+
+// ===========================================================================
+describe('mdToInlineNodes', () => {
+  it('returns [] for empty or non-string input', () => {
+    expect(mdToInlineNodes('')).toEqual([]);
+    expect(mdToInlineNodes('   ')).toEqual([]);
+    expect(mdToInlineNodes(undefined as any)).toEqual([]);
+    expect(mdToInlineNodes(null as any)).toEqual([]);
+    expect(mdToInlineNodes(123 as any)).toEqual([]);
+  });
+
+  it('strips a case-insensitive "комментарий:" prefix', () => {
+    expect(mdToInlineNodes('Комментарий: hello')).toEqual([{ type: 'text', text: 'hello' }]);
+    expect(mdToInlineNodes('комментарий : hi')).toEqual([{ type: 'text', text: 'hi' }]);
+  });
+
+  it('strips a leading "N. " numeric prefix', () => {
+    expect(mdToInlineNodes('3. some note')).toEqual([{ type: 'text', text: 'some note' }]);
+  });
+
+  it('turns a leading **bold lead** into a bold node + plain remainder, space preserved', () => {
+    const nodes = mdToInlineNodes('**Lead** rest of text');
+    expect(nodes).toEqual([
+      { type: 'text', text: 'Lead', marks: [{ type: 'bold' }] },
+      { type: 'text', text: ' rest of text' }, // separating space preserved
+    ]);
+  });
+
+  it('splits an inline **bold** mid-text', () => {
+    const nodes = mdToInlineNodes('start **mid** end');
+    expect(nodes).toEqual([
+      { type: 'text', text: 'start ' },
+      { type: 'text', text: 'mid', marks: [{ type: 'bold' }] },
+      { type: 'text', text: ' end' },
+    ]);
+  });
+
+  it('passes plain text through unchanged when there is no bold', () => {
+    expect(mdToInlineNodes('just plain text')).toEqual([{ type: 'text', text: 'just plain text' }]);
+  });
+
+  it('handles a bold-only string', () => {
+    // A bold-only string is treated as a leading bold lead with empty remainder.
+    expect(mdToInlineNodes('**only**')).toEqual([
+      { type: 'text', text: 'only', marks: [{ type: 'bold' }] },
+    ]);
+  });
+});
+
+// ===========================================================================
+describe('commentsToFootnotes', () => {
+  const HEADING = 'Примечания переводчика';
+
+  /**
+   * Build a realistic doc: body paragraphs, then the notes heading, then the
+   * notes orderedList. `notes` is an array of inline-text strings for existing
+   * list items.
+   */
+  function buildDoc(opts: {
+    body: any[];
+    notes?: string[];
+    omitHeading?: boolean;
+    omitList?: boolean;
+    disclaimer?: any;
+  }): any {
+    const blocks: any[] = [];
+    if (opts.disclaimer) blocks.push(opts.disclaimer);
+    blocks.push(...opts.body);
+    if (!opts.omitHeading) {
+      blocks.push({ type: 'heading', attrs: { id: 'h', level: 2 }, content: [text(HEADING)] });
+    }
+    if (!opts.omitList) {
+      const items = (opts.notes ?? []).map((t, i) => ({
+        type: 'listItem',
+        attrs: { id: `li${i}` },
+        content: [para(text(t))],
+      }));
+      blocks.push({ type: 'orderedList', attrs: { id: 'ol' }, content: items });
+    }
+    return doc(...blocks);
+  }
+
+  function findNotesList(d: any): any {
+    return d.content.find((n: any) => n.type === 'orderedList');
+  }
+
+  it('is identity (renumber pass only) when there are zero comments', () => {
+    const d = buildDoc({ body: [para(text('plain body'))], notes: [] });
+    const r = commentsToFootnotes(d, []);
+    expect(r.consumed).toEqual([]);
+    expect(r.doc.content[0]).toEqual(para(text('plain body')));
+  });
+
+  it('inserts a marker and appends one note for one comment with a selection', () => {
+    const d = buildDoc({ body: [para(text('the quick brown fox'))], notes: [] });
+    const r = commentsToFootnotes(d, [
+      { id: 'c1', content: 'A note', selection: 'quick brown' },
+    ]);
+    expect(r.consumed).toEqual(['c1']);
+    // Body now carries "[1]" right after the selection.
+    const bodyText = r.doc.content[0].content.map((n: any) => n.text).join('');
+    expect(bodyText).toBe('the quick brown [1] fox');
+    // The notes list holds exactly one note built from the comment content.
+    const list = findNotesList(r.doc);
+    expect(list.content).toHaveLength(1);
+    expect(stripIds(list.content[0])).toEqual(
+      stripIds(noteItem(mdToInlineNodes('A note'))),
+    );
+  });
+
+  it('numbers many comments by BODY reading order, not comment-array order', () => {
+    // Body order: "alpha" then "omega". Comments are given out of order.
+    const d = buildDoc({
+      body: [para(text('alpha then omega here'))],
+      notes: [],
+    });
+    const r = commentsToFootnotes(d, [
+      { id: 'cOmega', content: 'note for omega', selection: 'omega' },
+      { id: 'cAlpha', content: 'note for alpha', selection: 'alpha' },
+    ]);
+    // Both consumed, in comment-array processing order (NOT reading order, NOT sorted).
+    expect(r.consumed).toEqual(['cOmega', 'cAlpha']);
+    const bodyText = r.doc.content[0].content.map((n: any) => n.text).join('');
+    // "alpha" precedes "omega" in reading order => [1] then [2].
+    expect(bodyText).toBe('alpha [1] then omega [2] here');
+    const list = findNotesList(r.doc);
+    // Note list reordered to reading order: alpha-note first, omega-note second.
+    expect(list.content[0].content[0].content[0].text).toBe('note for alpha');
+    expect(list.content[1].content[0].content[0].text).toBe('note for omega');
+  });
+
+  it('skips a comment with no selection without consuming it', () => {
+    const d = buildDoc({ body: [para(text('body text here'))], notes: [] });
+    const r = commentsToFootnotes(d, [
+      { id: 'c1', content: 'no anchor', selection: null },
+      { id: 'c2', content: 'anchored', selection: 'body text' },
+    ]);
+    expect(r.consumed).toEqual(['c2']);
+    const list = findNotesList(r.doc);
+    expect(list.content).toHaveLength(1);
+  });
+
+  it('skips a comment whose selection is absent (no orphan note)', () => {
+    const d = buildDoc({ body: [para(text('present text'))], notes: [] });
+    const r = commentsToFootnotes(d, [
+      { id: 'c1', content: 'orphan', selection: 'this string is not in the body' },
+    ]);
+    expect(r.consumed).toEqual([]); // nothing anchored
+    const list = findNotesList(r.doc);
+    expect(list.content).toHaveLength(0); // no orphan note appended
+    const bodyText = r.doc.content[0].content.map((n: any) => n.text).join('');
+    expect(bodyText).toBe('present text'); // body unchanged
+  });
+
+  it('renumbers existing [N] markers mixed with new placeholders by reading order', () => {
+    // Body already has an existing "[1]" marker after "first"; a new comment
+    // anchors before it in reading order at "intro".
+    const d = buildDoc({
+      body: [para(text('intro and first [1] then more'))],
+      notes: ['existing note one'],
+    });
+    const r = commentsToFootnotes(d, [
+      { id: 'cNew', content: 'fresh note', selection: 'intro' },
+    ]);
+    expect(r.consumed).toEqual(['cNew']);
+    const bodyText = r.doc.content[0].content.map((n: any) => n.text).join('');
+    // Reading order: "intro" placeholder -> [1]; existing "[1]" -> [2].
+    expect(bodyText).toBe('intro [1] and first [2] then more');
+    const list = findNotesList(r.doc);
+    // Notes reordered: the new note (for "intro") first, the existing note second.
+    expect(list.content).toHaveLength(2);
+    expect(list.content[0].content[0].content[0].text).toBe('fresh note');
+    expect(list.content[1].content[0].content[0].text).toBe('existing note one');
+  });
+
+  it('throws "document is inconsistent" when a body [N] has no matching note', () => {
+    // Body references [9] but the notes list has only 3 items.
+    const d = buildDoc({
+      body: [para(text('see footnote [9] here'))],
+      notes: ['n1', 'n2', 'n3'],
+    });
+    expect(() => commentsToFootnotes(d, [])).toThrow(/document is inconsistent/);
+  });
+
+  it('throws when the notes heading is missing', () => {
+    const d = buildDoc({ body: [para(text('x'))], notes: [], omitHeading: true });
+    expect(() => commentsToFootnotes(d, [])).toThrow(/not found/);
+  });
+
+  it('throws when the notes orderedList is missing', () => {
+    const d = buildDoc({ body: [para(text('x'))], omitList: true });
+    expect(() => commentsToFootnotes(d, [])).toThrow(/orderedList not found/);
+  });
+
+  it('does not mutate the input document', () => {
+    const d = buildDoc({ body: [para(text('the quick brown fox'))], notes: [] });
+    const snapshot = structuredClone(d);
+    commentsToFootnotes(d, [{ id: 'c1', content: 'A note', selection: 'quick brown' }]);
+    expect(d).toEqual(snapshot);
+  });
+
+  it('does not renumber a top-level disclaimer callout but syncs its range', () => {
+    // A disclaimer callout carries "[1]…[K]"; it must be preserved (not consumed
+    // as a footnote marker) and its range synced to the final note count.
+    const disclaimer = callout(para(text('Notes range [1]…[1] applies')));
+    const d = buildDoc({
+      body: [para(text('alpha and beta here'))],
+      notes: [],
+      disclaimer,
+    });
+    const r = commentsToFootnotes(d, [
+      { id: 'c1', content: 'note a', selection: 'alpha' },
+      { id: 'c2', content: 'note b', selection: 'beta' },
+    ]);
+    expect(r.consumed.sort()).toEqual(['c1', 'c2']);
+    // Disclaimer callout is at index 0; its body must NOT have been renumbered
+    // into [1][2], it remains a "[1]…[n]" range synced to 2 notes.
+    const calloutText = r.doc.content[0].content[0].content
+      .map((n: any) => n.text)
+      .join('');
+    expect(calloutText).toBe('Notes range [1]…[2] applies');
+    // Body markers (index 1) are the real footnotes.
+    const bodyText = r.doc.content[1].content.map((n: any) => n.text).join('');
+    expect(bodyText).toBe('alpha [1] and beta [2] here');
+    const list = findNotesList(r.doc);
+    expect(list.content).toHaveLength(2);
+  });
+});