diff --git a/apps/server/src/core/page/services/page.service.ts b/apps/server/src/core/page/services/page.service.ts
index c6ee150d..ae20d277 100644
--- a/apps/server/src/core/page/services/page.service.ts
+++ b/apps/server/src/core/page/services/page.service.ts
@@ -52,7 +52,9 @@ import {
   INTERNAL_LINK_REGEX,
   extractPageSlugId,
 } from '../../../integrations/export/utils';
-import { markdownToHtml, canonicalizeFootnotes } from '@docmost/editor-ext';
+import { canonicalizeFootnotes } from '@docmost/editor-ext';
+import { markdownToProseMirror } from '@docmost/prosemirror-markdown';
+import { normalizeForeignMarkdown } from '../../../integrations/import/utils/foreign-markdown';
 import { WatcherService } from '../../watcher/watcher.service';
 import { sql } from 'kysely';
 import { TransclusionService } from '../transclusion/transclusion.service';
@@ -1301,8 +1303,14 @@ export class PageService {
 
     switch (format) {
       case 'markdown': {
-        const html = await markdownToHtml(content as string);
-        prosemirrorJson = htmlToJson(html as string);
+        // Canonical markdown -> ProseMirror JSON directly via
+        // `@docmost/prosemirror-markdown` (issue #345) — no HTML intermediate,
+        // no editor-ext markdown layer. Foreign markdown surfaces the strict
+        // parser rejects (GFM `[^id]` reference footnotes) are normalized to the
+        // canonical inline form first.
+        prosemirrorJson = await markdownToProseMirror(
+          normalizeForeignMarkdown(content as string),
+        );
         break;
       }
       case 'html': {
diff --git a/apps/server/src/integrations/import/services/file-import-task.service.footnote-canonicalize.spec.ts b/apps/server/src/integrations/import/services/file-import-task.service.footnote-canonicalize.spec.ts
index 08ecce15..10d36902 100644
--- a/apps/server/src/integrations/import/services/file-import-task.service.footnote-canonicalize.spec.ts
+++ b/apps/server/src/integrations/import/services/file-import-task.service.footnote-canonicalize.spec.ts
@@ -17,6 +17,22 @@ jest.mock('image-dimensions', () => ({
   __esModule: true,
   imageDimensionsFromData: () => undefined,
 }));
+// FileImportTaskService -> PageService -> collaboration.gateway ->
+// metrics.registry imports `prom-client`, which is not resolvable in this
+// workspace's node_modules (types-only stub, no runtime entry). Metrics are
+// disabled on this path, so a virtual no-op mock keeps the module graph loadable.
+jest.mock(
+  'prom-client',
+  () => ({
+    collectDefaultMetrics: () => undefined,
+    Registry: class {},
+    Histogram: class {},
+    Gauge: class {},
+    Counter: class {},
+    Summary: class {},
+  }),
+  { virtual: true },
+);
 
 import { promises as fs } from 'fs';
 import * as os from 'os';
@@ -26,14 +42,17 @@ import { ImportService } from './import.service';
 
 /**
  * Binding test for issue #228 / review #5: FileImportTaskService.processGenericImport
- * is a NON-editor write path (markdownToHtml -> processHTML -> JSON, never runs
- * footnoteSyncPlugin), so it canonicalizes footnotes before persisting. This pins
- * that binding — the same one import.service has a spec for — which previously had
- * NO spec at all.
+ * is a NON-editor write path, so a zip-imported `.md` page ends up with canonical
+ * footnotes before persisting: ordered by first reference, reused refs deduped,
+ * orphan definitions dropped.
  *
- * The markdown -> HTML -> ProseMirror conversion is REAL (a real ImportService,
- * its createYdoc stubbed); the filesystem is a real temp dir with one .md file;
- * the DB transaction is stubbed to capture the persisted page content.
+ * Since #345 the `.md` parse runs `normalizeForeignMarkdown` ->
+ * `markdownToProseMirror` -> `jsonToHtml` (feeding the shared HTML attachment /
+ * link pipeline) -> `processHTML` -> `canonicalizeFootnotes`. The parser assigns
+ * fresh `fn-*` ids, so we assert by definition BODY order rather than the source
+ * labels. The conversion is REAL (a real ImportService, its createYdoc stubbed);
+ * the filesystem is a real temp dir with one .md file; the DB transaction is
+ * stubbed to capture the persisted page content.
  */
 
 // Out-of-order references (c, a, b), a REUSED reference ([^a] twice), and an
@@ -49,13 +68,14 @@ const MARKDOWN = [
   '[^z]: orphan note',
 ].join('\n');
 
-function footnoteListIds(content: any): string[] {
+/** Definition body texts of the (single) footnotesList, in list order. */
+function footnoteListBodies(content: any): string[] {
   const list = (content?.content ?? []).find(
     (n: any) => n.type === 'footnotesList',
   );
   return (list?.content ?? [])
     .filter((n: any) => n.type === 'footnoteDefinition')
-    .map((n: any) => n.attrs?.id);
+    .map((n: any) => n.content?.[0]?.content?.[0]?.text);
 }
 
 // A permissive chainable stub for the spaces lookup (selectFrom(...).select(...)
@@ -134,15 +154,23 @@ describe('FileImportTaskService.processGenericImport — footnote canonicalizati
 
       expect(captured).toBeTruthy();
       const content = captured.content;
-      // Reference order is c, a, b (NOT the markdown definition order a, b, c).
-      expect(footnoteListIds(content)).toEqual(['c', 'a', 'b']);
+      // Definitions ordered by FIRST REFERENCE (C, A, B), NOT the markdown
+      // definition order (A, B, C). Ids are the parser's fresh `fn-*`, so pin
+      // the BODIES.
+      expect(footnoteListBodies(content)).toEqual([
+        'note C',
+        'note A',
+        'note B',
+      ]);
       // Orphan [^z] dropped; reused [^a] collapses to one definition; one list.
-      expect(footnoteListIds(content)).not.toContain('z');
+      expect(footnoteListBodies(content)).not.toContain('orphan note');
       const lists = (content.content ?? []).filter(
         (n: any) => n.type === 'footnotesList',
       );
       expect(lists).toHaveLength(1);
-      expect(footnoteListIds(content).filter((id) => id === 'a')).toHaveLength(1);
+      expect(
+        footnoteListBodies(content).filter((b) => b === 'note A'),
+      ).toHaveLength(1);
     } finally {
       await fs.rm(extractDir, { recursive: true, force: true });
     }
diff --git a/apps/server/src/integrations/import/services/file-import-task.service.ts b/apps/server/src/integrations/import/services/file-import-task.service.ts
index 5ec2fe8d..a5115c43 100644
--- a/apps/server/src/integrations/import/services/file-import-task.service.ts
+++ b/apps/server/src/integrations/import/services/file-import-task.service.ts
@@ -1,6 +1,9 @@
 import { Inject, Injectable, Logger } from '@nestjs/common';
 import * as path from 'path';
-import { jsonToText } from '../../../collaboration/collaboration.util';
+import {
+  jsonToHtml,
+  jsonToText,
+} from '../../../collaboration/collaboration.util';
 import { InjectKysely } from 'nestjs-kysely';
 import { KyselyDB } from '@docmost/db/types/kysely.types';
 import {
@@ -18,9 +21,11 @@ import { generateSlugId } from '../../../common/helpers';
 import { v7 } from 'uuid';
 import { generateJitteredKeyBetween } from 'fractional-indexing-jittered';
 import { FileTask, InsertablePage } from '@docmost/db/types/entity.types';
-import { markdownToHtml, canonicalizeFootnotes } from '@docmost/editor-ext';
+import { canonicalizeFootnotes } from '@docmost/editor-ext';
+import { markdownToProseMirror } from '@docmost/prosemirror-markdown';
 import { getProsemirrorContent } from '../../../common/helpers/prosemirror/utils';
 import { formatImportHtml } from '../utils/import-formatter';
+import { normalizeForeignMarkdown } from '../utils/foreign-markdown';
 import {
   buildAttachmentCandidates,
   collectMarkdownAndHtmlFiles,
@@ -461,7 +466,18 @@ export class FileImportTaskService {
               content = await fs.readFile(absPath, 'utf-8');
 
               if (page.fileExtension.toLowerCase() === '.md') {
-                content = await markdownToHtml(content);
+                // Parse markdown with the single canonical converter
+                // (`@docmost/prosemirror-markdown`), after normalizing foreign
+                // reference footnotes, then serialize to HTML so the shared HTML
+                // pipeline below (processAttachments + formatImportHtml +
+                // processHTML) keeps handling `.md` and `.html` imports
+                // uniformly. The markdown PARSE no longer goes through the
+                // editor-ext markdown layer (issue #345) — the drift source is
+                // gone. The PM -> HTML -> PM hop that follows is lossless
+                // plumbing for attachment/link resolution, NOT a second parse.
+                content = jsonToHtml(
+                  await markdownToProseMirror(normalizeForeignMarkdown(content)),
+                );
               }
             } catch (err: any) {
               if (err?.code === 'ENOENT') {
@@ -500,10 +516,12 @@ export class FileImportTaskService {
               this.importService.extractTitleAndRemoveHeading(pmState);
 
             // Canonicalize footnote topology on this non-editor write path
-            // (markdownToHtml/processHTML never runs footnoteSyncPlugin), so a
-            // zip-imported page's footnotes are reference-ordered, deduped, and
+            // (the HTML pipeline's processHTML never runs footnoteSyncPlugin), so
+            // a zip-imported page's footnotes are reference-ordered, deduped, and
             // orphan-free like the editor's invariant (issue #228). Pure +
-            // idempotent + shape-safe; a footnote-free doc is unchanged.
+            // idempotent + shape-safe; a footnote-free doc is unchanged. (For a
+            // `.md` file the package parser already yields canonical footnotes,
+            // so this is a no-op there.)
             // (Future consolidation, architecture B: like import.service, this
             // path persists directly rather than via PageService — a shared
             // "prepare JSON for persist" helper would centralize this call.)
diff --git a/apps/server/src/integrations/import/services/import.service.footnote-canonicalize.spec.ts b/apps/server/src/integrations/import/services/import.service.footnote-canonicalize.spec.ts
index e53b17a1..40972b10 100644
--- a/apps/server/src/integrations/import/services/import.service.footnote-canonicalize.spec.ts
+++ b/apps/server/src/integrations/import/services/import.service.footnote-canonicalize.spec.ts
@@ -12,13 +12,19 @@ import { canonicalizeFootnotes } from '@docmost/editor-ext';
 
 /**
  * Integration-ish test for the USER-FACING markdown import path
- * (`ImportService.importPage`). It exercises the REAL markdown -> HTML -> JSON
- * conversion and asserts that the stored page content has its footnotes
- * canonicalized — the gap that issue #228 fixes: the import path builds
- * ProseMirror JSON directly (never running the editor's footnoteSyncPlugin), so
- * before this wiring the stored footnotes kept the markdown's physical
- * definition order (out of order vs. references), retained orphan definitions,
- * and did not collapse reused references.
+ * (`ImportService.importPage`). It exercises the REAL markdown -> ProseMirror
+ * conversion and asserts the stored page's footnotes are canonical: ordered by
+ * FIRST REFERENCE (not markdown definition order), reused references deduped to a
+ * single definition, and orphan definitions dropped.
+ *
+ * Since #345 the markdown parse runs through the canonical package
+ * (`normalizeForeignMarkdown` -> `markdownToProseMirror`), which owns this
+ * canonicalization: the input's GFM `[^id]` reference footnotes are normalized to
+ * inline `^[…]`, and the parser assigns fresh sequential ids (`fn-*`) in
+ * reference order while merging identical bodies — so we assert by definition
+ * BODY order, not by the source labels. `canonicalizeFootnotes` remains wired as
+ * an idempotent safety net (issue #228) and is a no-op on this already-canonical
+ * output.
  *
  * The DB/ydoc side-effects are stubbed: `getNewPagePosition` (DB query) and
  * `createYdoc` (Yjs encode) are spied, and `pageRepo.insertPage` captures the
@@ -67,24 +73,14 @@ function makeService() {
 }
 
 /** List the footnote-definition ids of the (single) footnotesList, in order. */
-function footnoteListIds(content: any): string[] {
+/** Definition body texts of the (single) footnotesList, in list order. */
+function footnoteListBodies(content: any): string[] {
   const list = (content.content ?? []).find(
     (n: any) => n.type === 'footnotesList',
   );
-  if (!list) return [];
-  return (list.content ?? [])
+  return (list?.content ?? [])
     .filter((n: any) => n.type === 'footnoteDefinition')
-    .map((n: any) => n.attrs?.id);
-}
-
-function definitionText(content: any, id: string): string | undefined {
-  const list = (content.content ?? []).find(
-    (n: any) => n.type === 'footnotesList',
-  );
-  const def = (list?.content ?? []).find(
-    (n: any) => n.type === 'footnoteDefinition' && n.attrs?.id === id,
-  );
-  return def?.content?.[0]?.content?.[0]?.text;
+    .map((n: any) => n.content?.[0]?.content?.[0]?.text);
 }
 
 describe('ImportService.importPage — footnote canonicalization (#228)', () => {
@@ -101,23 +97,23 @@ describe('ImportService.importPage — footnote canonicalization (#228)', () =>
     const content = getCaptured().content;
     expect(content).toBeTruthy();
 
-    // Reference order is c, a, b (NOT the markdown definition order a, b, c).
-    expect(footnoteListIds(content)).toEqual(['c', 'a', 'b']);
-
-    // Definitions preserved and attached to the right ids.
-    expect(definitionText(content, 'c')).toBe('note C');
-    expect(definitionText(content, 'a')).toBe('note A');
-    expect(definitionText(content, 'b')).toBe('note B');
+    // Definitions ordered by FIRST REFERENCE (C, A, B) — NOT the markdown
+    // definition order (A, B, C) — with the orphan [^z] dropped and the reused
+    // [^a] collapsed to a single definition. (Ids are the parser's fresh `fn-*`,
+    // so we pin the BODIES.)
+    expect(footnoteListBodies(content)).toEqual(['note C', 'note A', 'note B']);
 
     // Orphan definition [^z] is dropped.
-    expect(footnoteListIds(content)).not.toContain('z');
+    expect(footnoteListBodies(content)).not.toContain('orphan note');
 
     // Reused [^a] yields exactly ONE definition, and exactly one list.
     const lists = (content.content ?? []).filter(
       (n: any) => n.type === 'footnotesList',
     );
     expect(lists).toHaveLength(1);
-    expect(footnoteListIds(content).filter((id) => id === 'a')).toHaveLength(1);
+    expect(
+      footnoteListBodies(content).filter((b) => b === 'note A'),
+    ).toHaveLength(1);
   });
 
   it('is idempotent: canonicalizing the stored output again is a no-op', async () => {
@@ -134,6 +130,6 @@ describe('ImportService.importPage — footnote canonicalization (#228)', () =>
     // time must not change it (safe to wire into every write path).
     const second = canonicalizeFootnotes(stored);
     expect(second).toEqual(stored);
-    expect(footnoteListIds(second)).toEqual(['c', 'a', 'b']);
+    expect(footnoteListBodies(second)).toEqual(['note C', 'note A', 'note B']);
   });
 });
diff --git a/apps/server/src/integrations/import/services/import.service.ts b/apps/server/src/integrations/import/services/import.service.ts
index 75418e55..dd86d71e 100644
--- a/apps/server/src/integrations/import/services/import.service.ts
+++ b/apps/server/src/integrations/import/services/import.service.ts
@@ -17,7 +17,9 @@ import {
 import { generateJitteredKeyBetween } from 'fractional-indexing-jittered';
 import { TiptapTransformer } from '@hocuspocus/transformer';
 import * as Y from 'yjs';
-import { markdownToHtml, canonicalizeFootnotes } from '@docmost/editor-ext';
+import { canonicalizeFootnotes } from '@docmost/editor-ext';
+import { markdownToProseMirror } from '@docmost/prosemirror-markdown';
+import { normalizeForeignMarkdown } from '../utils/foreign-markdown';
 import {
   FileTaskStatus,
   FileTaskType,
@@ -85,11 +87,13 @@ export class ImportService {
 
     const extracted = this.extractTitleAndRemoveHeading(prosemirrorState);
     const title = extracted.title;
-    // Imported markdown/HTML is built via markdownToHtml -> htmlToJson, which
-    // never runs the editor's footnoteSyncPlugin, so the footnote topology keeps
-    // the source's PHYSICAL definition order (out of order vs. references),
-    // retains orphan definitions, and is not deduped. Canonicalize before
-    // persisting so the stored page matches the editor's invariant (issue #228).
+    // The markdown path now canonicalizes footnotes itself (the package parser),
+    // but the HTML path (processHTML -> htmlToJson) does NOT run the editor's
+    // footnoteSyncPlugin, so an imported HTML doc can keep its source's PHYSICAL
+    // definition order (out of order vs. references), retain orphan definitions,
+    // and not be deduped. Canonicalize before persisting so the stored page
+    // matches the editor's invariant (issue #228); it is an idempotent no-op on
+    // the already-canonical markdown output.
     // Pure + idempotent + shape-safe: a doc with no footnotes is unchanged.
     // (Future consolidation, architecture B: this import path persists directly
     // via pageRepo.insertPage rather than through PageService.createPage, so the
@@ -133,12 +137,15 @@ export class ImportService {
   }
 
   async processMarkdown(markdownInput: string): Promise<any> {
-    try {
-      const html = await markdownToHtml(markdownInput);
-      return this.processHTML(html);
-    } catch (err) {
-      throw err;
-    }
+    // Canonical markdown -> ProseMirror JSON directly via
+    // `@docmost/prosemirror-markdown` (issue #345) — no HTML intermediate and no
+    // second editor-ext markdown layer. Foreign markdown surfaces the strict
+    // canonical parser does not accept (GFM `[^id]` reference footnotes) are
+    // rewritten to the canonical inline form by `normalizeForeignMarkdown` first.
+    // The HTML-cleanup pass (`normalizeImportHtml`) is intentionally skipped here:
+    // it targets foreign *HTML* (Notion/XWiki), which only ever arrives on the
+    // `.html` path (`processHTML`), never as canonical markdown.
+    return markdownToProseMirror(normalizeForeignMarkdown(markdownInput));
   }
 
   async processHTML(htmlInput: string): Promise<any> {
diff --git a/apps/server/src/integrations/import/utils/foreign-markdown.spec.ts b/apps/server/src/integrations/import/utils/foreign-markdown.spec.ts
new file mode 100644
index 00000000..fb22f1dd
--- /dev/null
+++ b/apps/server/src/integrations/import/utils/foreign-markdown.spec.ts
@@ -0,0 +1,113 @@
+import {
+  convertProseMirrorToMarkdown,
+  markdownToProseMirror,
+} from '@docmost/prosemirror-markdown';
+import { normalizeForeignMarkdown } from './foreign-markdown';
+
+/**
+ * STEP 2 goldens for issue #345: the foreign-markdown normalizer that runs at the
+ * import boundary BEFORE the strict canonical parser (`markdownToProseMirror`).
+ *
+ * Two layers:
+ *  1. PURE string→string cases pinning the normalizer's own behavior (GFM
+ *     reference footnotes → inline `^[…]`).
+ *  2. END-TO-END acceptance: for a foreign corpus, `normalizeForeignMarkdown`
+ *     then `markdownToProseMirror` then `convertProseMirrorToMarkdown` must leave
+ *     NO literal `[^id]` / `:::` garbage in the document and must re-export in the
+ *     canonical forms.
+ */
+
+describe('normalizeForeignMarkdown — GFM reference footnotes', () => {
+  it('inlines a single-line reference footnote and drops its definition', () => {
+    const out = normalizeForeignMarkdown(
+      'A note[^1] here.\n\n[^1]: The definition.',
+    );
+    expect(out).toBe('A note^[The definition.] here.\n');
+  });
+
+  it('inlines every reference to a reused id (downstream dedups)', () => {
+    const out = normalizeForeignMarkdown(
+      'X[^a] and Y[^a].\n\n[^a]: shared.',
+    );
+    expect(out).toBe('X^[shared.] and Y^[shared.].\n');
+  });
+
+  it('joins indented continuation lines of a definition with a space', () => {
+    const out = normalizeForeignMarkdown(
+      'See[^n].\n\n[^n]: line one\n    line two',
+    );
+    expect(out).toBe('See^[line one line two].\n');
+  });
+
+  it('never rewrites a reference inside a fenced code block', () => {
+    const out = normalizeForeignMarkdown(
+      '```\ncode[^1] here\n```\n\n[^1]: def.',
+    );
+    expect(out).toContain('code[^1] here');
+    // The (now orphaned) definition line is still removed.
+    expect(out).not.toContain('[^1]: def.');
+  });
+
+  it('leaves a reference with no matching definition literal (no body to inline)', () => {
+    const out = normalizeForeignMarkdown('Dangling[^x] ref.');
+    expect(out).toBe('Dangling[^x] ref.');
+  });
+
+  it('returns the input unchanged when there are no reference footnotes', () => {
+    const md = '# Title\n\nJust text with `inline code` and a [link](/x).';
+    expect(normalizeForeignMarkdown(md)).toBe(md);
+  });
+
+  it('does NOT touch callout surfaces — the canonical parser handles them', () => {
+    const callouts = ':::info\nHi\n:::\n\n> [!warning]\n> Careful';
+    expect(normalizeForeignMarkdown(callouts)).toBe(callouts);
+  });
+});
+
+describe('foreign markdown import acceptance (normalizer + canonical parser)', () => {
+  const FOREIGN = [
+    '# Doc',
+    '',
+    'Body refs [^c] and [^a] and [^b] and again [^a].',
+    '',
+    ':::info',
+    'A legacy callout.',
+    ':::',
+    '',
+    '| h1 | h2 |',
+    '| --- | --- |',
+    '| 1 | 2 |',
+    '',
+    '[^a]: note A',
+    '[^b]: note B',
+    '[^c]: note C',
+    '[^z]: orphan note',
+  ].join('\n');
+
+  it('leaves no literal [^id] or ::: in the imported doc and re-exports canonically', async () => {
+    const normalized = normalizeForeignMarkdown(FOREIGN);
+    const doc = await markdownToProseMirror(normalized);
+    const reexport = convertProseMirrorToMarkdown(doc);
+
+    // No foreign garbage leaks into the document.
+    expect(reexport).not.toMatch(/\[\^/); // no reference footnote refs/defs
+    expect(reexport).not.toContain(':::'); // no legacy callout fences
+
+    // Canonical forms are present.
+    expect(reexport).toContain('^[note C]');
+    expect(reexport).toContain('> [!info]');
+    expect(reexport).toContain('| h1 | h2 |');
+
+    // Footnotes: ordered by first reference (C, A, B), reused [^a] deduped to one,
+    // orphan [^z] dropped (it had no reference after normalization).
+    const list = doc.content.find((n: any) => n.type === 'footnotesList');
+    const bodies = list.content.map(
+      (d: any) => d.content[0].content[0].text,
+    );
+    expect(bodies).toEqual(['note C', 'note A', 'note B']);
+    expect(bodies).not.toContain('orphan note');
+    expect(
+      doc.content.filter((n: any) => n.type === 'footnotesList'),
+    ).toHaveLength(1);
+  });
+});
diff --git a/apps/server/src/integrations/import/utils/foreign-markdown.ts b/apps/server/src/integrations/import/utils/foreign-markdown.ts
new file mode 100644
index 00000000..6c8e99f6
--- /dev/null
+++ b/apps/server/src/integrations/import/utils/foreign-markdown.ts
@@ -0,0 +1,167 @@
+/**
+ * Foreign-markdown normalizer — an input-liberal / output-canonical adapter that
+ * runs at the IMPORT boundary, BEFORE the canonical parser
+ * (`markdownToProseMirror` from `@docmost/prosemirror-markdown`).
+ *
+ * The canonical parser is deliberately STRICT: it only understands Docmost's
+ * canonical markdown surface (Obsidian-style `> [!type]` callouts, Pandoc/Obsidian
+ * inline footnotes `^[body]`, lossless `![alt](src) <!--img {...}-->` images, …).
+ * Import, however, ingests FOREIGN files (GitHub/GFM, Notion, old Docmost
+ * exports). Those use surfaces the canonical parser does not accept, most notably
+ * GitHub-flavoured *reference* footnotes:
+ *
+ *     Text with a note[^1] and another[^long].
+ *
+ *     [^1]: The first definition.
+ *     [^long]: A second one.
+ *
+ * Left untouched, the parser does NOT recognise `[^id]` (it only parses `^[body]`),
+ * so the reference leaks as literal text — and worse, the trailing `[^id]: def`
+ * line is a valid CommonMark *link-reference definition*, so `[^id]` is silently
+ * rendered as a bogus link. This normalizer rewrites reference footnotes into the
+ * canonical inline form so the parser materialises real footnote nodes.
+ *
+ * This is a TEXT pre-pass, NOT a second parser fork: it does not re-implement any
+ * converter logic. Callout surfaces (`:::type` and `> [!type]`) are intentionally
+ * NOT touched here — the canonical parser already accepts BOTH natively (its
+ * `preprocessCallouts` pass), so normalizing them would be redundant and would
+ * only risk degrading the parser's nesting/code-fence-aware handling.
+ */
+
+/** Matches a fenced code block delimiter (``` or ~~~), capturing the marker run. */
+const CODE_FENCE_RE = /^(\s*)(`{3,}|~{3,})/;
+
+/**
+ * Matches a GFM footnote DEFINITION line: `[^id]: body`. The id is any run of
+ * non-`]` characters; the body is the remainder of the line (possibly empty).
+ */
+const FOOTNOTE_DEF_RE = /^\[\^([^\]]+)\]:[ \t]?(.*)$/;
+
+/** True when a line is a code-fence delimiter that toggles fenced-code state. */
+function fenceMarker(line: string): string | null {
+  const m = line.match(CODE_FENCE_RE);
+  return m ? m[2] : null;
+}
+
+/** True when a line is indented (leading space/tab) and not blank — a continuation. */
+function isIndentedContinuation(line: string): boolean {
+  return /^[ \t]+\S/.test(line);
+}
+
+function escapeRegExp(value: string): string {
+  return value.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
+}
+
+/**
+ * Convert GFM reference footnotes (`[^id]` + `[^id]: def`) into canonical inline
+ * footnotes (`^[def]`).
+ *
+ * - Definitions are collected first (a leading `[^id]: text` line plus any
+ *   immediately-following indented continuation lines, joined with a space) and
+ *   removed from the output.
+ * - Each in-text reference `[^id]` for which a definition was found is replaced by
+ *   `^[def]`. References with no matching definition are left literal (there is no
+ *   body to inline; the parser fails them open the same way).
+ * - Code fences are respected on both passes: `[^id]` inside a ``` / ~~~ block is
+ *   never rewritten, and a `[^id]:` line inside a fence is never treated as a
+ *   definition.
+ *
+ * Deduplication / reference-ordering / orphan-dropping of the resulting footnotes
+ * is handled downstream by the canonical parser (`assembleFootnotes`); this pass
+ * only changes the surface syntax.
+ */
+function convertReferenceFootnotes(markdown: string): string {
+  const lines = markdown.split('\n');
+
+  // Pass 1: collect definitions and mark their lines for removal.
+  const defs = new Map<string, string>();
+  const dropped = new Array<boolean>(lines.length).fill(false);
+  let inFence = false;
+  let fence = '';
+
+  for (let i = 0; i < lines.length; i++) {
+    const line = lines[i];
+    const marker = fenceMarker(line);
+    if (inFence) {
+      if (marker && marker[0] === fence[0] && marker.length >= fence.length) {
+        inFence = false;
+        fence = '';
+      }
+      continue;
+    }
+    if (marker) {
+      inFence = true;
+      fence = marker;
+      continue;
+    }
+
+    const def = line.match(FOOTNOTE_DEF_RE);
+    if (!def) continue;
+
+    const id = def[1];
+    const body: string[] = [def[2].trim()];
+    dropped[i] = true;
+
+    // Consume immediately-following indented continuation lines (GFM lazy
+    // continuation is not supported by design — keep it simple and predictable).
+    let j = i + 1;
+    while (j < lines.length && isIndentedContinuation(lines[j])) {
+      body.push(lines[j].trim());
+      dropped[j] = true;
+      j++;
+    }
+    i = j - 1;
+
+    // Last definition wins for a duplicated id (matches CommonMark link-ref
+    // semantics closely enough for a foreign-input adapter).
+    defs.set(id, body.filter((s) => s.length > 0).join(' '));
+  }
+
+  if (defs.size === 0) {
+    return markdown;
+  }
+
+  // Pass 2: rewrite in-text references, skipping fenced code and dropped lines.
+  const out: string[] = [];
+  inFence = false;
+  fence = '';
+  for (let i = 0; i < lines.length; i++) {
+    if (dropped[i]) continue;
+    let line = lines[i];
+
+    const marker = fenceMarker(line);
+    if (inFence) {
+      out.push(line);
+      if (marker && marker[0] === fence[0] && marker.length >= fence.length) {
+        inFence = false;
+        fence = '';
+      }
+      continue;
+    }
+    if (marker) {
+      inFence = true;
+      fence = marker;
+      out.push(line);
+      continue;
+    }
+
+    for (const [id, body] of defs) {
+      const ref = new RegExp('\\[\\^' + escapeRegExp(id) + '\\]', 'g');
+      line = line.replace(ref, `^[${body}]`);
+    }
+    out.push(line);
+  }
+
+  return out.join('\n');
+}
+
+/**
+ * Normalize a foreign markdown string into Docmost's canonical markdown surface
+ * so the strict canonical parser accepts it losslessly. Currently this rewrites
+ * GFM reference footnotes into inline footnotes; add further fixture-driven
+ * foreign-surface cases here as they are found.
+ */
+export function normalizeForeignMarkdown(markdown: string): string {
+  if (!markdown) return markdown;
+  return convertReferenceFootnotes(markdown);
+}
diff --git a/apps/server/test/stubs/tiptap-react.js b/apps/server/test/stubs/tiptap-react.js
index e11ef884..edd98738 100644
--- a/apps/server/test/stubs/tiptap-react.js
+++ b/apps/server/test/stubs/tiptap-react.js
@@ -1,11 +1,21 @@
-// Jest stub for @tiptap/react. The server export/import code paths transitively
-// import editor-ext, whose node extensions reference `ReactNodeViewRenderer`
-// inside `addNodeView()` — code that only runs inside a live browser editor and
-// is NEVER invoked on the server. The real module eagerly pulls react-dom, which
-// throws `navigator is not defined` under jest's node environment. This stub
-// supplies the named exports the extensions bind at import time; if any were
-// actually called on the server that would (correctly) surface as a test error.
+// Jest stub for @tiptap/react.
+//
+// The server export/import code paths transitively import editor-ext, whose node
+// extensions import from `@tiptap/react`. The real module re-exports all of
+// `@tiptap/core` (headless, safe under node) AND adds React view helpers
+// (`ReactNodeViewRenderer`, …) that eagerly pull in react-dom — which throws
+// `navigator is not defined` under jest's node environment.
+//
+// So this stub DELEGATES to the real `@tiptap/core` (keeping `mergeAttributes`,
+// `Node`, `Mark`, `nodeInputRule`, … working — they are used by
+// `jsonToHtml`/`htmlToJson` on the server) and overrides ONLY the React view
+// helpers with no-ops. Those helpers are referenced solely inside `addNodeView()`
+// — code that runs only in a live browser editor, never on the server; if any
+// were actually invoked here it would (correctly) surface as a test failure.
+const core = require('@tiptap/core');
+
 module.exports = {
+  ...core,
   ReactNodeViewRenderer: () => () => ({}),
   NodeViewWrapper: () => null,
   NodeViewContent: () => null,