fix: an index lists the levels it declares, not all five

The TOC node regenerated over every heading level and minted a title of its
own. A file asking for level 1 only (text:outline-level, Word's TOC \o range)
got a 43-entry index instead of 12 — a full page where LibreOffice needs a
quarter, plus a second "Table of Contents" under the file's own heading.

maxLevel and an empty title now round-trip through both formats.

src/lib/editor/extensions/CLAUDE.md

@@ -30,7 +30,7 @@ Five topics are large enough to have their own deep-dive — read the file befor
 - **`bookmark.ts`** / **`crossReference.ts`** — a named range of text (a mark) and the live references to it (`REF`/`PAGEREF`). `ToolbarExpanded.svelte` owns both dialogs, as it does the link one.
 - **`searchReplace.ts`** — Find & Replace: decorations highlight all matches, commands navigate/replace. Touches the document only for actual replacements.
 - **`spellCheck.ts`** — decorations from `spell/controller.ts`; `spellErrorAt` feeds the context menu.
-- **`tableOfContents.ts`** — a generated TOC: block atom listing every heading (levels 1–5).
+- **`tableOfContents.ts`** — a generated TOC: block atom listing every heading down to `maxLevel` (ODF `text:outline-level`, Word's `TOC \o` range, default 5 — listing deeper than the file asks inflates the block by pages). `title: ''` is an index that deliberately has none (its heading is a separate paragraph, as Word and LibreOffice write it); only a missing title falls back to "Table of Contents".
 - **`trailingNode.ts`** — keeps an empty paragraph after a trailing table, text box or columns section (they are isolating, so the caret would otherwise have nowhere to go).
 - **`headerFooter.ts`** (`hfExtensions`) — the header/footer schema: `Document` constrained to one paragraph, the body's marks, `HardBreak`, `TextAlign`, and the two `pageField.ts` atoms. No image, no date field, no table.
 - **`pageField.ts`** — inline atoms `pageNumber`/`pageCount`, rendered as `<span data-page-field>`; `HeaderFooterLayer.svelte` patches each span's text to the real per-page value.

src/lib/editor/extensions/tableOfContents.ts

@@ -11,7 +11,8 @@ import { readVerticalMargins, pageOfElement } from './pageBreaks';
 export type TocEntry = { text: string; level: number; page: number };
 
 // The heading above the entries. An imported TOC keeps the one its file used
-// ("Inhalt", "Sommaire", …); a freshly inserted one takes this.
+// ("Inhalt", "Sommaire", …), or none at all where the file put its heading in a
+// separate paragraph (`''`); a freshly inserted one takes this.
 const TITLE = 'Table of Contents';
 // Enough leader dots to cross the widest gap a page can offer; the row clips the rest.
 const LEADER_DOTS = 200;
@@ -35,8 +36,15 @@ export const TableOfContents = Node.create({
     return {
       title: {
         default: null as string | null,
-        parseHTML: el => (el as HTMLElement).getAttribute('data-toc-title') || null,
-        renderHTML: attrs => (attrs.title ? { 'data-toc-title': String(attrs.title) } : {}),
+        parseHTML: el => (el as HTMLElement).getAttribute('data-toc-title'),
+        renderHTML: attrs => (attrs.title != null ? { 'data-toc-title': String(attrs.title) } : {}),
+      },
+      // Deepest heading level the index lists (ODF text:outline-level, Word's TOC \o
+      // range): listing more than the file asks for inflates the block by pages.
+      maxLevel: {
+        default: MAX_HEADING_LEVEL,
+        parseHTML: el => Number((el as HTMLElement).getAttribute('data-toc-levels')) || MAX_HEADING_LEVEL,
+        renderHTML: attrs => ({ 'data-toc-levels': String(attrs.maxLevel ?? MAX_HEADING_LEVEL) }),
       },
       entries: {
         default: [] as TocEntry[],
@@ -71,7 +79,8 @@ export const TableOfContents = Node.create({
   },
 });
 
-const tocTitle = (title: unknown): string => (typeof title === 'string' && title ? title : TITLE);
+// `''` is a title the file deliberately doesn't have, so only a missing one defaults.
+const tocTitle = (title: unknown): string => (typeof title === 'string' ? title : TITLE);
 
 type HeadingRef = { text: string; level: number; pos: number };
 
@@ -113,13 +122,15 @@ class TocView {
     });
   }
 
-  // Every heading (level ≤ MAX_HEADING_LEVEL) with non-empty text, in document order.
+  // Every heading with non-empty text down to the index's own level, in document order.
   private headings(): HeadingRef[] {
+    const max = Math.min(MAX_HEADING_LEVEL, Number(this.node()?.attrs?.maxLevel) || MAX_HEADING_LEVEL);
     const out: HeadingRef[] = [];
     this.editor.state.doc.descendants((node, pos) => {
       if (node.type.name === 'heading') {
         const text = node.textContent.trim();
-        if (text) out.push({ text, level: Math.min(MAX_HEADING_LEVEL, (node.attrs.level as number) ?? 1), pos });
+        const level = Math.min(MAX_HEADING_LEVEL, (node.attrs.level as number) ?? 1);
+        if (text && level <= max) out.push({ text, level, pos });
       }
     });
     return out;
@@ -149,10 +160,13 @@ class TocView {
 
   private paint(entries: TocEntry[], heads: HeadingRef[]): void {
     this.dom.textContent = '';
-    const title = document.createElement('div');
-    title.className = 'toc-title';
-    title.textContent = tocTitle(this.node()?.attrs?.title);
-    this.dom.appendChild(title);
+    const titleText = tocTitle(this.node()?.attrs?.title);
+    if (titleText) {
+      const title = document.createElement('div');
+      title.className = 'toc-title';
+      title.textContent = titleText;
+      this.dom.appendChild(title);
+    }
 
     if (entries.length === 0) {
       const empty = document.createElement('div');

src/lib/export/docx.ts

@@ -984,12 +984,16 @@ function blocksToDocx(content: TiptapNode[], num: Numbering, contentWidthCm: num
       textBoxes.push(textBoxDocxDescriptor(node));
       out.push(new Paragraph({ children: [new TextRun({ text: `${TBX}${i}${TBX}` })] }));
     } else if (node.type === 'tableOfContents') {
-      // A real, recognized TOC field (levels 1–3, hyperlinked); Word/LibreOffice populate
-      // + link it on field update (features.updateFields does this on open). Title is a
-      // plain bold paragraph so it isn't itself listed; our importer regenerates the node.
-      const tocTitle = typeof node.attrs?.title === 'string' && node.attrs.title ? node.attrs.title : 'Table of Contents';
-      out.push(new Paragraph({ children: [new TextRun({ text: tocTitle, bold: true, size: 32 })], spacing: { after: cmToTwip(0.3) } }));
-      out.push(new TableOfContents(tocTitle, { hyperlink: true, headingStyleRange: `1-${MAX_HEADING_LEVEL}` }));
+      // A real, recognized TOC field (hyperlinked, over the index's own heading levels);
+      // Word/LibreOffice populate + link it on field update (features.updateFields does
+      // this on open). Title is a plain bold paragraph so it isn't itself listed, and is
+      // omitted where the index has none; our importer regenerates the node.
+      const rawTitle = node.attrs?.title;
+      const tocTitle = typeof rawTitle === 'string' ? rawTitle : 'Table of Contents';
+      const depth = Number(node.attrs?.maxLevel);
+      const maxLevel = depth >= 1 ? Math.min(MAX_HEADING_LEVEL, depth) : MAX_HEADING_LEVEL;
+      if (tocTitle) out.push(new Paragraph({ children: [new TextRun({ text: tocTitle, bold: true, size: 32 })], spacing: { after: cmToTwip(0.3) } }));
+      out.push(new TableOfContents(tocTitle, { hyperlink: true, headingStyleRange: `1-${maxLevel}` }));
     }
   }
   return out;

src/lib/export/odt.ts

@@ -673,7 +673,7 @@ function replaceColumns(doc: TiptapNode, cols: ColumnsExport[]): TiptapNode {
 // One generated table of contents, collected by replaceTableOfContents and emitted by
 // applyToc. Entries are the cached heading→page rows (the node view keeps them current).
 type TocEntry = { text: string; level: number; page: number };
-type TocExport = { entries: TocEntry[]; title: string | null };
+type TocExport = { entries: TocEntry[]; title: string | null; maxLevel: number };
 
 // Swap each top-level tableOfContents node for a marker paragraph carrying the TOC
 // sentinel and collect its cached entries. Top-level only (like replacePageBreaks): a
@@ -692,7 +692,12 @@ function replaceTableOfContents(doc: TiptapNode, tocs: TocExport[]): TiptapNode
           page: Math.max(1, Number(e.page) || 1),
         }));
       const rawTitle = child.attrs?.title;
-      tocs.push({ entries, title: typeof rawTitle === 'string' && rawTitle ? rawTitle : null });
+      const depth = Number(child.attrs?.maxLevel);
+      tocs.push({
+        entries,
+        title: typeof rawTitle === 'string' ? rawTitle : null,
+        maxLevel: depth >= 1 ? Math.min(MAX_HEADING_LEVEL, depth) : MAX_HEADING_LEVEL,
+      });
       content.push({ type: 'paragraph', content: [{ type: 'text', text: `${TOC_SENT}${tocs.length - 1}${TOC_SENT}` }] });
       continue;
     }
@@ -3118,9 +3123,9 @@ function tocXml(toc: TocExport, index: number): string {
   const title = toc.title ?? 'Table of Contents';
   const name = `Table of Contents${index + 1}`;
   const source =
-    `<text:table-of-content-source text:outline-level="${MAX_HEADING_LEVEL}" text:use-index-marks="false" text:use-index-source-styles="false">` +
-    `<text:index-title-template text:style-name="Contents_20_Heading">${escapeXml(title)}</text:index-title-template>` +
-    HEADING_LEVELS
+    `<text:table-of-content-source text:outline-level="${toc.maxLevel}" text:use-index-marks="false" text:use-index-source-styles="false">` +
+    (title ? `<text:index-title-template text:style-name="Contents_20_Heading">${escapeXml(title)}</text:index-title-template>` : '') +
+    HEADING_LEVELS.filter(l => l <= toc.maxLevel)
       .map(
         l =>
           `<text:table-of-content-entry-template text:outline-level="${l}" text:style-name="Contents_20_${l}">` +
@@ -3135,9 +3140,11 @@ function tocXml(toc: TocExport, index: number): string {
     `</text:table-of-content-source>`;
   const body =
     `<text:index-body>` +
-    `<text:index-title text:name="${escapeXml(name)}_Head">` +
-    `<text:p text:style-name="Contents_20_Heading">${escapeXml(title)}</text:p>` +
-    `</text:index-title>` +
+    (title
+      ? `<text:index-title text:name="${escapeXml(name)}_Head">` +
+        `<text:p text:style-name="Contents_20_Heading">${escapeXml(title)}</text:p>` +
+        `</text:index-title>`
+      : '') +
     toc.entries
       .map(e => `<text:p text:style-name="Contents_20_${e.level}">${escapeXml(e.text)}<text:tab/>${e.page}</text:p>`)
       .join('') +

src/lib/import/docx.ts

@@ -262,6 +262,17 @@ function documentLanguage(stylesDoc: Document | null, warnings: Set<string>): Do
 // so field depth is tracked (across one convertBlocks call) to match the TOC's own end.
 type TocFieldState = { fieldDepth: number; tocDepth: number; instr: string[] };
 
+// The deepest heading level a TOC field lists: the end of its `\o "1-3"` range (Word's
+// own default is 1-9). Anything deeper only inflates the block on screen.
+function tocMaxLevel(instr: string): number {
+  const m = /\\o\s+"?\s*\d+\s*-\s*(\d+)/.exec(instr);
+  const n = m ? Number(m[1]) : NaN;
+  return n >= 1 ? Math.min(MAX_HEADING_LEVEL, n) : MAX_HEADING_LEVEL;
+}
+
+const instrTextOf = (el: Element): string =>
+  Array.from(el.getElementsByTagNameNS(W, 'instrText')).map(i => i.textContent ?? '').join('');
+
 function scanTocField(p: Element, st: TocFieldState): { emit: boolean } {
   let emit = false;
   for (const r of Array.from(p.getElementsByTagNameNS(W, 'r'))) {
@@ -384,7 +395,11 @@ function convertBlocks(children: Element[], ctx: Ctx, kind: BlockKind, boldByDef
       // A paragraph owned by a TOC field is skipped; the field emits one node.
       const startedInToc = tocState.tocDepth >= 0;
       const { emit } = scanTocField(el, tocState);
-      if (emit && kind === 'body') { flush(); out.push({ type: 'tableOfContents', attrs: { entries: [] } }); }
+      if (emit && kind === 'body') {
+        flush();
+        // The field carries no heading of its own — Word's sits in a separate paragraph.
+        out.push({ type: 'tableOfContents', attrs: { entries: [], title: '', maxLevel: tocMaxLevel(instrTextOf(el)) } });
+      }
       if (startedInToc || emit) continue;
       const num = paragraphNum(el, ctx);
       if (num) {
@@ -429,8 +444,12 @@ function convertBlocks(children: Element[], ctx: Ctx, kind: BlockKind, boldByDef
       if (sdtIsToc(el)) {
         // A content-control-wrapped TOC → one node (regenerated live); skip its content.
         if (kind === 'body') {
-          const title = tocHeading(fc(el, 'sdtContent'));
-          out.push({ type: 'tableOfContents', attrs: { entries: [], ...(title ? { title } : {}) } });
+          const content = fc(el, 'sdtContent');
+          out.push({ type: 'tableOfContents', attrs: {
+            entries: [],
+            title: tocHeading(content) ?? '',
+            maxLevel: tocMaxLevel(content ? instrTextOf(content) : ''),
+          } });
         }
       } else {
         const content = fc(el, 'sdtContent');

src/lib/import/odt.ts

@@ -813,8 +813,13 @@ function convertToc(el: Element): Node {
     }
   }
   // The file's own heading ("Inhalt", "Sommaire", …), so a reopened index keeps its name.
-  const title = el.getElementsByTagNameNS(NS.text, 'index-title')[0]?.textContent?.trim();
-  return { type: 'tableOfContents', attrs: { entries, ...(title ? { title } : {}) } };
+  // No <text:index-title> means the index really has none — its heading is an ordinary
+  // paragraph above it, and adding ours would double it.
+  const title = el.getElementsByTagNameNS(NS.text, 'index-title')[0]?.textContent?.trim() ?? '';
+  const source = el.getElementsByTagNameNS(NS.text, 'table-of-content-source')[0];
+  const depth = Number(source?.getAttributeNS(NS.text, 'outline-level'));
+  const maxLevel = depth >= 1 ? Math.min(MAX_HEADING_LEVEL, depth) : MAX_HEADING_LEVEL;
+  return { type: 'tableOfContents', attrs: { entries, title, maxLevel } };
 }
 
 // Split a TOC entry paragraph around its last <text:tab/>: the text before it is the

tests/roundtrip.test.ts

@@ -1396,6 +1396,24 @@ describe('Leg 5: table of contents (text:table-of-content)', () => {
     check('headings after the TOC survive',
       blocks.some((n: N) => n.type === 'heading' && n.content?.[0]?.text === 'Introduction'));
   });
+
+  // Listing deeper than the index asks for inflates it by whole pages; a title the file
+  // doesn't have doubles the heading standing above it.
+  it('round-trips the index depth and a title-less index', async () => {
+    const shallow: N = { ...tocDoc, content: [
+      { type: 'tableOfContents', attrs: { entries: [], title: '', maxLevel: 1 } },
+      ...(tocDoc.content ?? []).slice(1),
+    ] };
+    const bytes = await buildOdt(shallow, margins, 'portrait');
+    const content = strFromU8(unzipSync(bytes)['content.xml']);
+    check('source stops at the index depth', content.includes('<text:table-of-content-source text:outline-level="1"'));
+    check('one entry template only', (content.match(/<text:table-of-content-entry-template/g) ?? []).length === 1);
+    check('no index title emitted', !content.includes('<text:index-title'));
+
+    const toc = (importOdt(bytes).content.content ?? []).find((n: N) => n.type === 'tableOfContents');
+    check('maxLevel survives', toc?.attrs?.maxLevel === 1, toc?.attrs);
+    check('title stays empty', toc?.attrs?.title === '', toc?.attrs);
+  });
 });
 
 describe('Leg 10: date/time fields (text:date / text:time)', () => {