diff --git a/packages/prosemirror-markdown/src/lib/markdown-converter.ts b/packages/prosemirror-markdown/src/lib/markdown-converter.ts
index d19dadd4..63c39333 100644
--- a/packages/prosemirror-markdown/src/lib/markdown-converter.ts
+++ b/packages/prosemirror-markdown/src/lib/markdown-converter.ts
@@ -78,23 +78,26 @@ export function convertProseMirrorToMarkdown(content: any): string {
       .replace(/\(/g, "%28")
       .replace(/\)/g, "%29");
 
-  // Backslash-escape every character a markdown link's `[text]` label would
-  // otherwise INTERPRET, so a link-form media node's visible text (a filename or
-  // provider carried in `attrs.name`/`attrs.provider`) round-trips byte-exact
-  // (#293 canon #8 link-form). Escaping only `[ ] \` is NOT enough: the label is
-  // parsed as inline content, so emphasis (`* _`), code (`` ` ``), strikethrough
-  // (`~`), autolinks/raw-HTML (`<`), HTML entities (`&`), and image markers (`!`)
-  // would all be consumed and lost when the importer reads `a.textContent` back
-  // (e.g. `report *v2*.pdf` -> `report v2.pdf`). CommonMark treats a backslash
-  // before ANY ASCII punctuation as that literal char, so escaping this active
-  // set is always lossless on re-parse; the old `<div data-attachment-name>`
-  // form carried arbitrary strings via escapeAttr, so anything less is a
-  // data-loss regression on the git-sync data path. `( )` are escaped too: even
-  // with `[ ]` escaped, an unescaped `](x)` sequence inside the label (e.g. a
-  // name like `![shot](x).pdf`) forms a false nested-link destination and
-  // fragments the parse — escaping the parens removes that ambiguity entirely.
+  // Backslash-escape every character that would be INTERPRETED inside a markdown
+  // label re-parsed as inline content — used for a link-form media node's visible
+  // text (`attrs.name`/`attrs.provider`, #293 canon #8) AND for an image `![alt]`
+  // (canon #4) — so the value round-trips byte-exact. Two overlapping trigger
+  // sets must be escaped:
+  //   1. Stock CommonMark inline: emphasis (`* _`), code (`` ` ``), strikethrough
+  //      (`~`), autolinks/raw-HTML (`<`), HTML entities (`&`), image markers (`!`),
+  //      brackets (`[ ]`), and `( )` — even with `[ ]` escaped, an unescaped
+  //      `](x)` forms a false nested-link destination and fragments the parse.
+  //   2. The Docmost inline EXTENSIONS this package registers on its marked
+  //      instance: highlight `==x==` (canon #7), math `$x$` (canon #6), and
+  //      footnote `^[x]` (canon #2). Their triggers `= $ ^` are NOT CommonMark
+  //      punctuation the stock lexer would treat specially, but the extension
+  //      tokenizers fire on them — so an alt/name like `x $A$ y`, `use ==b==`, or
+  //      `^[fn]` would be silently turned into a math/highlight/footnote node on
+  //      import unless the trigger is escaped. `\= \$ \^` decode back to literals
+  //      (all ASCII punctuation) and, being escape tokens, stop the extension
+  //      tokenizer from matching — verified lossless round-trip.
   const escapeLinkText = (value: unknown): string =>
-    String(value ?? "").replace(/[\\`*_~[\]<&!()]/g, (c: string) => `\\${c}`);
+    String(value ?? "").replace(/[\\`*_~[\]<&!()=$^]/g, (c: string) => `\\${c}`);
 
   // #293 canon #6: the schema-HTML forms for math. These are the LOSSLESS forms
   // the raw-HTML path (columns/cells) and the mathInline fallback emit, and the
diff --git a/packages/prosemirror-markdown/test/image-comment.test.ts b/packages/prosemirror-markdown/test/image-comment.test.ts
index 6f4974cb..605e3e5b 100644
--- a/packages/prosemirror-markdown/test/image-comment.test.ts
+++ b/packages/prosemirror-markdown/test/image-comment.test.ts
@@ -62,7 +62,13 @@ describe('#293 canon #4 — image serialization + attached img-comment', () => {
     // import; without escaping, a bracket/emphasis in a realistic description
     // would make the image node VANISH or collapse emphasis. Assert the image
     // survives with the exact alt AND the markdown is byte-stable on re-export.
-    for (const alt of ['a]b[c', 'Figure [1]', 'the *new* logo', 'x_y_z', 'see ![img', 'a & b']) {
+    for (const alt of [
+      'a]b[c', 'Figure [1]', 'the *new* logo', 'x_y_z', 'see ![img', 'a & b',
+      // Canon inline-extension triggers this same package introduces (F5): math
+      // `$`, highlight `==`, footnote `^[` — an unescaped one turns the alt into
+      // a math/highlight/footnote node on import.
+      'x $A$ y', '5$ and 10$', 'use ==bold==', '^[fn]', 'cost $5 == price',
+    ]) {
       const md1 = convertProseMirrorToMarkdown(image({ alt }));
       const back = await markdownToProseMirror(md1);
       const img = findImage(back);
diff --git a/packages/prosemirror-markdown/test/media-comments.test.ts b/packages/prosemirror-markdown/test/media-comments.test.ts
index c8f8a2c5..35ccb783 100644
--- a/packages/prosemirror-markdown/test/media-comments.test.ts
+++ b/packages/prosemirror-markdown/test/media-comments.test.ts
@@ -249,6 +249,13 @@ describe('#293 #8 LINK-FORM: pdf', () => {
       'tag <x> & y.pdf',
       'amp &amp; here.pdf',
       '![shot](x).pdf',
+      // Canon inline-extension triggers (F5): math `$`, highlight `==`, footnote
+      // `^[` — a filename carrying these must not become a math/highlight/footnote
+      // node on import.
+      'data $A$.csv',
+      'q3 ==final==.pdf',
+      '5$ and 10$.pdf',
+      'note ^[x].pdf',
     ]) {
       const { md1, md2, doc2 } = await roundTrip(mkDoc([{ type: 'pdf', attrs: { src: '/x', name } }]));
       expect(md2).toBe(md1); // byte-stable, no churn