docs(converter): correct #515 mark-order comment — imported order depends on extension, not fixed

The inlineToHtml comment falsely claimed import ALWAYS yields the code mark
last; import yields code last for bold/italic/strike but code FIRST for the
==-highlight extension. Reworded to state the real invariant (wrap <code>
innermost regardless of imported order) and de-universalized the parallel
phrase in text-arbitraries.ts. Comment-only, no behavior change.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

AGENTS.md

@@ -334,7 +334,7 @@ pnpm workspace (`pnpm@10.4.0`) orchestrated by **Nx**. Four workspace packages:
 | `apps/client` | `client` | React 18 + Vite + Mantine 8 + TanStack Query + Jotai | SPA frontend |
 | `packages/editor-ext` | `@docmost/editor-ext` | Tiptap/ProseMirror | Shared Tiptap node/mark extensions, imported by both the client and the server |
 | `packages/mcp` | `@docmost/mcp` | MCP SDK, Tiptap, Yjs | Standalone MCP server, also bundled into the server at `/mcp`. Consumes the shared converter/schema from `@docmost/prosemirror-markdown` (#293) — it no longer carries its own vendored converter/schema copy |
-| `packages/prosemirror-markdown` | `@docmost/prosemirror-markdown` | Tiptap, marked, jsdom | The single, canonical ProseMirror↔Markdown converter + Docmost schema mirror (#293). Consumed by `mcp`, `git-sync`, AND `apps/server` (server-side markdown import/export, #345); there is exactly ONE copy of the converter now |
+| `packages/prosemirror-markdown` | `@docmost/prosemirror-markdown` | Tiptap, marked; jsdom (Node only) | The single, canonical ProseMirror↔Markdown converter + Docmost schema mirror (#293). Consumed by `mcp`, `git-sync`, `apps/server` (server-side markdown import/export, #345), AND `apps/client` (markdown paste/copy + AI-chat render, via the `browser` entry — native `DOMParser`, no jsdom in the client bundle, #347); there is exactly ONE copy of the converter now |
 
 `build` targets are Nx-cached and dependency-ordered (`dependsOn: ["^build"]`), so `editor-ext` builds before the apps. `nx.json` sets `affected.defaultBase: main`.
 
@@ -460,7 +460,7 @@ The API server is a Fastify app with a global `/api` prefix (`main.ts` excludes
 ### Client structure
 Vite SPA. Code is organized by feature under `apps/client/src/features/*` (mirrors the server domains: `page`, `space`, `comment`, `ai-chat`, `editor`, …). Conventions:
 - **TanStack Query** for server state (one `queries/` file per feature), **Jotai** atoms for local/shared UI state, **Mantine 8** + CSS modules (`*.module.css`) + `postcss-preset-mantine` for UI.
-- The editor is Tiptap; shared node/mark extensions live in `packages/editor-ext` and are imported by **both the client and the server** (collaboration, schema, `canonicalizeFootnotes`) — editor schema changes often need to be made in `editor-ext`, not just the client. Server-side markdown import/export no longer lives in `editor-ext`: it goes through the canonical converter (#345, see below). The ProseMirror↔Markdown converter and its Docmost schema mirror now live in a SINGLE package, `@docmost/prosemirror-markdown` (#293), consumed by `mcp`, `git-sync`, and `apps/server` (#345) — do NOT reintroduce a per-package copy. `editor-ext` is the upstream source of the Tiptap schema; the package's `docmost-schema.ts` mirrors it and a serializer-contract test (`packages/prosemirror-markdown/test/serializer-contract.test.ts`) guards the boundary (every schema node must have a converter case), so a drift surfaces as a failing test rather than silent divergence. For the converter's property-testing and counterexample→fixture process (P1–P4 invariants, the `PROPERTY_SEED`/`PROPERTY_NUM_RUNS` knobs, and the nightly fuzz workflow), see `packages/prosemirror-markdown/README.md`.
+- The editor is Tiptap; shared node/mark extensions live in `packages/editor-ext` and are imported by **both the client and the server** (collaboration, schema, `canonicalizeFootnotes`) — editor schema changes often need to be made in `editor-ext`, not just the client. Server-side markdown import/export no longer lives in `editor-ext`: it goes through the canonical converter (#345, see below). The ProseMirror↔Markdown converter and its Docmost schema mirror now live in a SINGLE package, `@docmost/prosemirror-markdown` (#293), consumed by `mcp`, `git-sync`, `apps/server` (#345), and `apps/client` (#347) — do NOT reintroduce a per-package copy. The client uses the package's `browser` entry (`@docmost/prosemirror-markdown/browser`): markdown paste (`markdown-clipboard.ts`), copy-as-markdown, and AI-chat rendering now all go through the canonical converter, so the hand-written `marked`/`turndown` markdown layer that used to live in `editor-ext` was deleted (#347). The browser entry runs the HTML→DOM stage on the native `DOMParser`, so jsdom stays out of the client bundle. `editor-ext` is the upstream source of the Tiptap schema; the package's `docmost-schema.ts` mirrors it and a serializer-contract test (`packages/prosemirror-markdown/test/serializer-contract.test.ts`) guards the boundary (every schema node must have a converter case), so a drift surfaces as a failing test rather than silent divergence. For the converter's property-testing and counterexample→fixture process (P1–P4 invariants, the `PROPERTY_SEED`/`PROPERTY_NUM_RUNS` knobs, and the nightly fuzz workflow), see `packages/prosemirror-markdown/README.md`.
 - API access goes through `apps/client/src/lib/api-client.ts` (axios). The `@` alias maps to `apps/client/src`.
 - Runtime config is injected at build time by `vite.config.ts` via `define` (`APP_URL`, `COLLAB_URL`, `APP_VERSION`, …) — these come from the root `.env`, not from `import.meta.env`.
 

CHANGELOG.md

@@ -270,6 +270,18 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+- **Client markdown paste/copy and AI-chat rendering now go through the canonical
+  converter.** Pasting markdown into the editor, "Copy as markdown", the AI title
+  generator, and the AI-chat markdown renderer all now use
+  `@docmost/prosemirror-markdown` (via its new `browser` entry — native
+  `DOMParser`, no jsdom in the client bundle) instead of the hand-written
+  `marked`/`turndown` markdown layer in `editor-ext`, which was **deleted**. As a
+  result, pasting canonical markdown (`^[…]` footnotes, `<!--img …-->`,
+  `> [!type]` callouts, `$…$` math, `==…==` highlight, standalone `<!--subpages-->`
+  comments) now produces the SAME nodes the server import produces for the same
+  text. Chat/reasoning markdown now renders through the editor schema (list items
+  are wrapped in `<p>`; CSS keeps them tight). (#347)
+
 - **Enabling a public share no longer auto-shares the whole sub-tree.** Turning
   a page "Shared to web" now defaults to the page alone; descendant pages become
   public only when you explicitly turn on the dedicated "Include sub-pages"
@@ -290,6 +302,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- **Markdown round-trips no longer silently drop a line that opens with a block
+  trigger.** When a document is exported to Markdown and re-imported (git-sync
+  stabilize, agent writes), a paragraph or continuation line (after a hard break)
+  that begins with a block marker — an ATX heading `#`, a blockquote/callout `>`,
+  a list marker (`-`/`*`/`+`/`N.`/`N)`), a code fence, a table `|`, a thematic
+  break (`---`), or a setext underline (`--`, `----`, or a lone `=`) — is now
+  backslash-escaped so it round-trips as text instead of being re-parsed into a
+  heading/list/quote/rule and losing its content. Front-matter stripping is
+  scoped to the import path only. (#493)
 - **The server no longer runs out of heap during long autonomous agent runs.** A
   new pnpm patch on `ai@6.0.134` stops the SDK from building a cumulative
   snapshot of the ENTIRE turn text on every streamed text-delta when no output

apps/client/package.json

@@ -21,6 +21,7 @@
     "@atlaskit/pragmatic-drag-and-drop-live-region": "1.3.4",
     "@casl/react": "5.0.1",
     "@docmost/editor-ext": "workspace:*",
+    "@docmost/prosemirror-markdown": "workspace:*",
     "@excalidraw/excalidraw": "0.18.0-3a5ef40",
     "@mantine/core": "8.3.18",
     "@mantine/dates": "8.3.18",

apps/client/src/features/ai-chat/components/ai-chat.module.css

@@ -55,6 +55,15 @@
     padding-inline-start: 1.4em;
 }
 
+/* The canonical converter renders list items through the editor schema, which
+   wraps each item's content in a <p> (listItem content is `paragraph+`). Drop
+   that paragraph's block margin so list items render TIGHT (no extra vertical
+   gap), matching the previous marked output — same rule already applied to
+   table cells above (issue #347). */
+.markdown li p {
+    margin: 0;
+}
+
 /* GFM tables in assistant markdown. The chat lives in a NARROW side panel, so a
    wide LLM table must scroll horizontally instead of collapsing its columns:
    `.markdown` sets `word-break: break-word`, which (with the default table
@@ -172,6 +181,14 @@
     margin: 0 0 4px;
 }
 
+/* Same as `.markdown li p` above: the canonical converter wraps every list
+   item's content in a <p>, so without this each reasoning-panel list item would
+   pick up `.reasoningText p`'s 4px bottom margin and render too loose. Drop it
+   so Reasoning-panel lists stay tight, mirroring the pre-#347 marked output. */
+.reasoningText li p {
+    margin: 0;
+}
+
 .inputWrapper {
     flex: 0 0 auto;
     padding-top: var(--mantine-spacing-xs);

apps/client/src/features/ai-chat/utils/collapse-blank-lines.test.ts

@@ -33,29 +33,44 @@ describe("collapseBlankLines", () => {
   });
 });
 
-describe("collapseBlankLines + renderChatMarkdown (tight reasoning rendering)", () => {
-  it("renders a blank-line-separated list as a TIGHT list (no <li><p>)", () => {
+describe("collapseBlankLines + renderChatMarkdown (canonical converter)", () => {
+  // Chat markdown now renders through @docmost/prosemirror-markdown (issue #347):
+  // the SAME converter the editor/import use. Its list items are schema-shaped —
+  // each <li>'s content is wrapped in a <p> (listItem content is `paragraph+`) —
+  // so the HTML always carries `<li><p>…</p></li>` regardless of blank-line
+  // looseness in the source (the converter has no tight/loose distinction). The
+  // visual tightness that `collapseBlankLines` used to buy is now provided by
+  // CSS (`.markdown li p { margin: 0 }`), not the HTML shape.
+  it("renders a blank-line-separated bullet list as a real <ul> list", () => {
     const loose =
       "Intro paragraph.\n\n- item one\n\n- item two\n\n- item three";
     const html = renderChatMarkdown(collapseBlankLines(loose), {});
-    // Tight list: each <li> holds the text directly, not wrapped in a <p>.
-    expect(html).toContain("<li>item one</li>");
-    expect(html).not.toContain("<li><p>");
-    // The list still parses as a list after the paragraph (not a paragraph+<br>).
+    // Clean, un-namespaced HTML (DOMSerializer, not XMLSerializer) — no xmlns.
     expect(html).toContain("<ul>");
+    expect(html).not.toMatch(/<ul[^>]*xmlns/);
+    // The item text is present (inside the schema's <li><p> wrapper).
+    expect(html).toContain("item one");
+    // The intro paragraph renders as its own paragraph before the list.
     expect(html).toContain("<p>Intro paragraph.</p>");
   });
 
-  it("renders an ordered list (1. 2.) as tight after collapsing", () => {
+  it("renders an ordered list (1. 2.) as a real <ol> list", () => {
     const loose = "Intro.\n\n1. first\n\n2. second";
     const html = renderChatMarkdown(collapseBlankLines(loose), {});
     expect(html).toContain("<ol>");
-    expect(html).toContain("<li>first</li>");
-    expect(html).not.toContain("<li><p>");
+    expect(html).not.toMatch(/<ol[^>]*xmlns/);
+    expect(html).toContain("first");
+    expect(html).toContain("second");
   });
 
-  it("the loose source WOULD render <li><p> without collapsing (control)", () => {
+  it("wraps list-item content in <p> (schema shape; tightness is CSS)", () => {
+    // The canonical converter always wraps a list item's content in a paragraph,
+    // whether or not the source had blank lines between items.
     const loose = "- a\n\n- b";
     expect(renderChatMarkdown(loose, {})).toContain("<li><p>");
+    // And a "tight" source produces the identical wrapping (no distinction).
+    expect(renderChatMarkdown(collapseBlankLines(loose), {})).toContain(
+      "<li><p>",
+    );
   });
 });

apps/client/src/features/ai-chat/utils/markdown.ts

@@ -1,6 +1,37 @@
-import { markdownToHtml } from "@docmost/editor-ext";
+import {
+  markdownToProseMirrorSync,
+  docmostExtensions,
+} from "@docmost/prosemirror-markdown/browser";
+import { getSchema } from "@tiptap/core";
+import { Node as PMNode, DOMSerializer } from "@tiptap/pm/model";
 import DOMPurify from "dompurify";
 
+// The Docmost editor schema, built once. Chat markdown is rendered through the
+// SAME schema the editor/import use (issue #347), so chat output matches how the
+// page would render the same markdown.
+const chatSchema = getSchema(docmostExtensions);
+
+/**
+ * Markdown -> HTML for chat display, via the canonical converter. We serialize
+ * the ProseMirror doc with `DOMSerializer` into a real element and read its
+ * `innerHTML` (rather than `@tiptap/html`'s `generateHTML`, whose browser path
+ * uses `XMLSerializer` and stamps a `xmlns` on every block) so the markup is
+ * clean HTML. `li > p` wrapping is inherent to the schema (listItem content is
+ * `paragraph+`); the chat CSS zeroes those paragraph margins so lists still
+ * render tight.
+ */
+function markdownToChatHtml(markdown: string): string {
+  const doc = markdownToProseMirrorSync(markdown);
+  const node = PMNode.fromJSON(chatSchema, doc);
+  const div = document.createElement("div");
+  DOMSerializer.fromSchema(chatSchema).serializeFragment(
+    node.content,
+    { document },
+    div,
+  );
+  return div.innerHTML;
+}
+
 export interface RenderChatMarkdownOptions {
   /**
    * Neutralize INTERNAL links so they render as inert text (no `href`/`target`).
@@ -63,22 +94,32 @@ function neutralizeInternalLinksHook(node: Element): void {
 
 /**
  * Render AI markdown to sanitized HTML for read-only display. We reuse the
- * app's `markdownToHtml` (the same `marked` pipeline used for paste/import) so
- * chat output matches the editor's markdown flavor, then sanitize with
- * DOMPurify — LLM output is untrusted, so it must never reach the DOM unsanitized.
+ * canonical converter (issue #347): markdown -> ProseMirror JSON (the SAME
+ * `markdownToProseMirrorSync` the editor paste/import path uses, so chat output
+ * matches the editor's markdown flavor) -> HTML via `markdownToChatHtml`
+ * (DOMSerializer), then sanitize with DOMPurify — LLM output is untrusted, so it
+ * must never reach the DOM unsanitized.
  *
- * `markdownToHtml` can return `string | Promise<string>` (it has async marked
- * extensions registered). In practice plain chat markdown resolves
- * synchronously, but we guard the Promise case by returning a safe empty string
- * for that branch (the caller renders the raw text fallback instead).
+ * Stays SYNCHRONOUS: both callers render inside React (a memo and a useMemo),
+ * so the whole pipeline must resolve without awaiting. The converter's sync
+ * entry makes that possible; on any conversion error we return "" so the caller
+ * falls back to raw text (the same fallback the old Promise-guard produced).
  */
 export function renderChatMarkdown(
   markdown: string,
   options: RenderChatMarkdownOptions = {},
 ): string {
   if (!markdown) return "";
-  const html = markdownToHtml(markdown);
-  if (typeof html !== "string") return "";
+  let html: string;
+  try {
+    // markdown -> canonical PM JSON -> HTML (native DOMParser in the browser;
+    // jsdom is never bundled — see @docmost/prosemirror-markdown/browser).
+    html = markdownToChatHtml(markdown);
+  } catch {
+    // Malformed/unsupported markdown must not crash the chat render; fall back
+    // to raw text (empty return -> caller shows the plain-text branch).
+    return "";
+  }
 
   if (!options.neutralizeInternalLinks) {
     // Internal chat: unchanged behavior, no hook registered.

apps/client/src/features/comment/components/comment-editor.tsx

@@ -1,7 +1,7 @@
 import { EditorContent, ReactNodeViewRenderer, useEditor } from "@tiptap/react";
 import { Placeholder } from "@tiptap/extension-placeholder";
 import { StarterKit } from "@tiptap/starter-kit";
-import { Mention, LinkExtension } from "@docmost/editor-ext";
+import { Mention, LinkExtension, Code } from "@docmost/editor-ext";
 import classes from "./comment.module.css";
 import { useFocusWithin } from "@mantine/hooks";
 import clsx from "clsx";
@@ -44,7 +44,12 @@ const CommentEditor = forwardRef(
           gapcursor: false,
           dropcursor: false,
           link: false,
+          // #515: use the shared editor-ext `Code` (excludes: "") instead of
+          // StarterKit's excluding one, so inline code in a comment can carry
+          // other marks and does not drop them when the comment is edited.
+          code: false,
         }),
+        Code,
         Placeholder.configure({
           placeholder: placeholder || t("Reply..."),
         }),

apps/client/src/features/editor/extensions/extensions.ts

@@ -1,6 +1,5 @@
 import { markInputRule } from "@tiptap/core";
 import { StarterKit } from "@tiptap/starter-kit";
-import { Code } from "@tiptap/extension-code";
 import { TextAlign } from "@tiptap/extension-text-align";
 import { TaskList, TaskItem } from "@tiptap/extension-list";
 import { Placeholder, CharacterCount, UndoRedo } from "@tiptap/extensions";
@@ -67,6 +66,7 @@ import {
   FootnoteReference,
   FootnotesList,
   FootnoteDefinition,
+  Code,
 } from "@docmost/editor-ext";
 import {
   randomElement,
@@ -153,6 +153,10 @@ export const mainExtensions = [
     codeBlock: false,
     code: false,
   }),
+  // Base `Code` comes from @docmost/editor-ext, which overrides `excludes: ""`
+  // (#515) so inline code can co-occur with bold/italic/… — the SINGLE shared
+  // source also used by the collab server and comment editor. Here we keep the
+  // existing client-only behavior on top of it:
   // Override TipTap's Code extension to fix the inline code input rule.
   // The upstream regex /(^|[^`])`([^`]+)`(?!`)$/ captures the character
   // before the opening backtick as part of the match, causing markInputRule

apps/client/src/features/editor/extensions/markdown-clipboard.paste.test.ts

@@ -0,0 +1,206 @@
+import { describe, it, expect } from "vitest";
+import { Editor } from "@tiptap/core";
+import { Document } from "@tiptap/extension-document";
+import { Paragraph } from "@tiptap/extension-paragraph";
+import { Text } from "@tiptap/extension-text";
+import { Bold } from "@tiptap/extension-bold";
+import { Italic } from "@tiptap/extension-italic";
+import { MarkdownClipboard } from "./markdown-clipboard";
+
+/**
+ * Integration coverage for the async `handlePaste` seam (issue #347). The paste
+ * conversion moved to `@docmost/prosemirror-markdown`'s browser entry, whose
+ * `markdownToProseMirror` is async — so `handlePaste` captures the range, claims
+ * the event (returns true), and dispatches the insert on the next microtask.
+ * These tests drive that path end to end on a minimal schema (a plain-markdown
+ * paste whose converted nodes fit paragraph/text/bold/italic), asserting the
+ * text lands with the right marks and that the raw markdown syntax is consumed
+ * (recognized as markdown, not inserted literally).
+ */
+
+function makeEditor() {
+  const element = document.createElement("div");
+  document.body.appendChild(element);
+  return new Editor({
+    element,
+    extensions: [
+      Document,
+      Paragraph,
+      Text,
+      Bold,
+      Italic,
+      MarkdownClipboard.configure({ transformPastedText: true }),
+    ],
+    content: { type: "doc", content: [{ type: "paragraph" }] },
+  });
+}
+
+// Locate the markdownClipboard plugin and invoke its handlePaste directly with a
+// synthetic clipboard event (jsdom has no real paste pipeline). The plugin's
+// handlePaste closes over the extension `this`, so calling it off the plugin
+// props preserves `this.editor`/`this.options`.
+function paste(editor: Editor, text: string): boolean {
+  const view = editor.view;
+  const plugin = view.state.plugins.find(
+    (p: any) => p.props && p.spec?.key,
+  ) as any;
+  const event = {
+    clipboardData: {
+      getData: (type: string) => (type === "text/plain" ? text : ""),
+    },
+  } as unknown as ClipboardEvent;
+  // Find the specific handlePaste that belongs to the markdown clipboard plugin.
+  const md = view.state.plugins.find(
+    (p: any) => typeof p.props?.handlePaste === "function",
+  ) as any;
+  return md.props.handlePaste(view, event, view.state.selection.content());
+}
+
+// Flush the microtask queue so the async .then() dispatch runs.
+const flush = () => new Promise((r) => setTimeout(r, 0));
+
+describe("MarkdownClipboard handlePaste (async md -> PM)", () => {
+  it("converts a plain-markdown paste with bold/italic into marked text", async () => {
+    const editor = makeEditor();
+    const claimed = paste(editor, "hello **bold** and *italic*");
+    // The paste is claimed synchronously (async insert follows).
+    expect(claimed).toBe(true);
+    await flush();
+
+    const json = editor.getJSON();
+    const text = JSON.stringify(json);
+    // The raw markdown asterisks are consumed (recognized), not inserted literally.
+    expect(editor.getText()).not.toContain("**");
+    expect(editor.getText()).toContain("bold");
+    expect(editor.getText()).toContain("italic");
+    // The bold/italic marks materialized.
+    expect(text).toContain('"bold"');
+    expect(text).toContain('"italic"');
+    editor.destroy();
+  });
+
+  it("recognizes a bullet list paste as list structure (not literal '-')", async () => {
+    // A bullet list is not representable in this minimal schema, so the converter
+    // output would fail PMNode.fromJSON and the catch inserts raw text. Use a
+    // paste whose nodes DO fit the schema to assert the happy path instead: two
+    // paragraphs separated by a blank line.
+    const editor = makeEditor();
+    paste(editor, "first para\n\nsecond para");
+    await flush();
+    const json = editor.getJSON() as any;
+    const paras = (json.content || []).filter(
+      (n: any) => n.type === "paragraph",
+    );
+    // Two paragraphs materialized from the blank-line-separated markdown.
+    expect(paras.length).toBeGreaterThanOrEqual(2);
+    expect(editor.getText()).toContain("first para");
+    expect(editor.getText()).toContain("second para");
+    editor.destroy();
+  });
+
+  it("falls back to raw text when conversion yields nodes the schema lacks", async () => {
+    // `# heading` converts to a `heading` node absent from this minimal schema,
+    // so PMNode.fromJSON throws and the catch re-inserts the raw text — the user
+    // never loses their clipboard content.
+    const editor = makeEditor();
+    paste(editor, "# a heading line");
+    await flush();
+    // Content is preserved (either as heading text or literal), never dropped.
+    expect(editor.getText()).toContain("a heading line");
+    editor.destroy();
+  });
+});
+
+// The async seam captures the target range synchronously, then replaces on the
+// next microtask. If the document changed under it between capture and resolve
+// (impossible in prod — same microtask — but pinned here), BOTH the success
+// (replaceRange) and the fail-open (insertText) branches must fall back to the
+// LIVE selection rather than a stale absolute range, so neither clobbers content
+// nor throws a RangeError. We force the mid-flight change by dispatching a
+// doc-mutating transaction AFTER the synchronous claim but BEFORE flushing the
+// microtask that runs the `.then`/`.catch`.
+describe("MarkdownClipboard handlePaste — doc-changed-mid-flight guard", () => {
+  // Replace the whole doc with one paragraph of `text` (synchronous dispatch).
+  // An empty string yields an empty paragraph (a text node may not be empty).
+  function seedContent(editor: Editor, text: string) {
+    editor.commands.setContent({
+      type: "doc",
+      content: [
+        text
+          ? { type: "paragraph", content: [{ type: "text", text }] }
+          : { type: "paragraph" },
+      ],
+    });
+  }
+
+  it("success branch: mid-flight doc change routes the paste to the LIVE selection, never the stale range (clobber-proving)", async () => {
+    // The paste captures a NON-EMPTY range {1,5} (over "AAAA"). Then, before the
+    // async resolve, the doc GROWS ("MARKER" inserted at the start) and the cursor
+    // is parked at the doc END. The captured {1,5} is now stale and points INTO
+    // "MARKER". A WORKING guard replaces at the live (end) selection → MARKER is
+    // untouched. A BROKEN guard replaces the stale {1,5} → it erases the first
+    // characters of MARKER (this is what a zero-width `from==to` range could never
+    // reveal, which is why the earlier version was vacuous).
+    const editor = makeEditor();
+    seedContent(editor, "AAAABBBB");
+    editor.commands.setTextSelection({ from: 1, to: 5 }); // captured range = {1,5}
+    const claimed = paste(editor, "hello **bold**");
+    expect(claimed).toBe(true);
+
+    // Mid-flight: grow the doc and move the cursor to a KNOWN-safe end position.
+    editor.view.dispatch(editor.view.state.tr.insertText("MARKER", 1));
+    const end = editor.state.doc.content.size;
+    editor.commands.setTextSelection({ from: end, to: end });
+    await flush();
+
+    const text = editor.getText();
+    // MARKER intact only if the guard used the live selection, not the stale range.
+    expect(text).toContain("MARKER");
+    expect(text).toContain("bold");
+    expect(text).not.toContain("**");
+    editor.destroy();
+  });
+
+  it("fail-open branch: a mid-flight doc SHRINK makes the stale `to` out of bounds — the guard must avoid a RangeError (throw-proving)", async () => {
+    // The paste captures a range {1,9} over an 8-char paragraph, then the
+    // conversion FAILS (`# heading` -> a heading node the minimal schema lacks,
+    // so PMNode.fromJSON throws -> the fail-open catch runs). Before the reject,
+    // the doc is SHRUNK to an empty paragraph, so the captured `to` (9) is now far
+    // past the doc's end. A WORKING guard inserts the raw text at the live (valid)
+    // selection → "raw heading" lands. A BROKEN guard does insertText(md, 1, 9) on
+    // a size-2 doc → RangeError, so the dispatch never runs and "raw heading" is
+    // absent (the assertion reddens). A zero-width/growing-doc setup could never
+    // push `to` out of bounds, which is why the earlier version was vacuous.
+    const editor = makeEditor();
+    seedContent(editor, "AAAABBBB");
+    editor.commands.setTextSelection({ from: 1, to: 9 }); // captured range = {1,9}
+    paste(editor, "# raw heading");
+
+    // Mid-flight: shrink the doc so the captured `to` = 9 is now out of bounds.
+    seedContent(editor, "");
+    await flush();
+
+    const text = editor.getText();
+    // Raw text lands (via the live selection) only if the guard avoided the
+    // stale, now-out-of-bounds range.
+    expect(text).toContain("raw heading");
+    editor.destroy();
+  });
+
+  it("two pastes in flight: neither payload is lost (no data loss)", async () => {
+    // Prod-unreachable (two paste events are separate macrotasks, and each
+    // conversion resolves on a microtask before the next), but pinned here: when
+    // both resolve back-to-back, the second sees the changed doc and inserts at
+    // the live selection the first left — so the two payloads may INTERLEAVE, but
+    // neither is dropped. We assert no data loss, not contiguity.
+    const editor = makeEditor();
+    paste(editor, "alphaword");
+    paste(editor, "betaword");
+    await flush();
+    const text = editor.getText();
+    // Neither payload fully dropped (interleaving may split one of them).
+    expect(text).toContain("alpha");
+    expect(text).toContain("beta");
+    editor.destroy();
+  });
+});

apps/client/src/features/editor/extensions/markdown-clipboard.test.ts

@@ -1,5 +1,12 @@
 import { describe, it, expect } from "vitest";
-import { htmlToMarkdown } from "@docmost/editor-ext";
+// Markdown conversion now goes through the canonical package's BROWSER entry
+// (issue #347): the same converter the server import/export uses, resolved via
+// the `browser` exports condition so it runs on the native `DOMParser` (the
+// client jsdom vitest env provides one) with jsdom never bundled.
+import {
+  convertProseMirrorToMarkdown,
+  markdownToProseMirrorSync,
+} from "@docmost/prosemirror-markdown/browser";
 import {
   normalizeTableColumnWidths,
   classifyClipboardSelection,
@@ -175,10 +182,13 @@ describe("classifyClipboardSelection", () => {
 
 // Output-level tests for the table clipboard regression: copying a table must
 // yield a real GFM pipe table, NOT one-value-per-line concatenated cells.
-// These exercise the actual markdown produced by htmlToMarkdown (the same
-// serializer step the clipboardTextSerializer runs), so they pin the OUTPUT
-// shape that the classifier-flag tests above do not cover.
-describe("table clipboard markdown output (htmlToMarkdown)", () => {
+// These exercise the actual markdown produced by convertProseMirrorToMarkdown —
+// the same serializer step the clipboardTextSerializer now runs (issue #347) —
+// so they pin the OUTPUT shape that the classifier-flag tests above do not cover.
+// Input is ProseMirror JSON (what the copied slice serializes to), matching the
+// clipboardTextSerializer's new call: it wraps the slice content in a synthetic
+// `doc` (and the bare-rows case in a `table`) and calls the converter.
+describe("table clipboard markdown output (convertProseMirrorToMarkdown)", () => {
   // Trim each line and drop blanks so structural assertions are whitespace-robust.
   function lines(md: string): string[] {
     return md
@@ -188,10 +198,10 @@ describe("table clipboard markdown output (htmlToMarkdown)", () => {
   }
 
   // A GFM separator row like "| --- | --- |" (any number of columns), tolerant
-  // of the padding turndown emits.
+  // of the padding the serializer emits.
   function isSeparatorRow(line: string): boolean {
     const compact = line.replace(/\s+/g, "");
-    return /^\|(?:-{3,}\|)+$/.test(compact);
+    return /^\|(?::?-{2,}:?\|)+$/.test(compact);
   }
 
   // Split a pipe-delimited row into trimmed cell values.
@@ -203,42 +213,33 @@ describe("table clipboard markdown output (htmlToMarkdown)", () => {
       .map((c) => c.trim());
   }
 
-  it("serializes a header-less partial cell selection (bare rows) as a valid GFM pipe table", () => {
-    // Mirror the serializer's `wrapBareRows` branch exactly: bare <tr> nodes are
-    // wrapped in <table><tbody> and htmlToMarkdown(div.innerHTML) is called.
-    // See markdown-clipboard.ts clipboardTextSerializer:
-    //   const table = document.createElement("table");
-    //   const tbody = document.createElement("tbody");
-    //   tbody.appendChild(fragment); table.appendChild(tbody);
-    //   div.appendChild(table);
-    //   return htmlToMarkdown(div.innerHTML);
-    const div = document.createElement("div");
-    const table = document.createElement("table");
-    const tbody = document.createElement("tbody");
-    for (const [c1, c2] of [
-      ["a", "b"],
-      ["c", "d"],
-    ]) {
-      const tr = document.createElement("tr");
-      const td1 = document.createElement("td");
-      td1.textContent = c1;
-      const td2 = document.createElement("td");
-      td2.textContent = c2;
-      tr.appendChild(td1);
-      tr.appendChild(td2);
-      tbody.appendChild(tr);
-    }
-    table.appendChild(tbody);
-    div.appendChild(table);
+  const cell = (t: string) => ({
+    type: "tableCell",
+    content: [{ type: "paragraph", content: [{ type: "text", text: t }] }],
+  });
+  const headerCell = (t: string) => ({
+    type: "tableHeader",
+    content: [{ type: "paragraph", content: [{ type: "text", text: t }] }],
+  });
+  const row = (nodes: any[]) => ({ type: "tableRow", content: nodes });
 
-    const md = htmlToMarkdown(div.innerHTML);
+  it("serializes a header-less partial cell selection (bare rows) as a valid GFM pipe table", () => {
+    // Mirror the serializer's `wrapBareRows` branch: bare tableRow nodes are
+    // wrapped in a synthetic `table` and convertProseMirrorToMarkdown is called
+    // (see markdown-clipboard.ts clipboardTextSerializer).
+    const rows = [
+      row([cell("a"), cell("b")]),
+      row([cell("c"), cell("d")]),
+    ];
+    const md = convertProseMirrorToMarkdown({
+      type: "doc",
+      content: [{ type: "table", content: rows }],
+    });
     const ls = lines(md);
 
-    // Valid GFM: a header/data separator row is present (an empty header is
-    // synthesized by the GFM turndown plugin for a header-less table — fine).
+    // Valid GFM: a header/data separator row is present.
     expect(ls.some(isSeparatorRow)).toBe(true);
-    // NOT the old broken "one value per line" shape: every line is pipe-delimited
-    // and no line is a bare cell value on its own.
+    // NOT the old broken "one value per line" shape: every line is pipe-delimited.
     expect(ls.every((l) => l.includes("|"))).toBe(true);
     expect(md).not.toMatch(/^\s*(a|b|c|d)\s*$/m);
     // The cell values land in real pipe-delimited data rows.
@@ -248,39 +249,21 @@ describe("table clipboard markdown output (htmlToMarkdown)", () => {
   });
 
   it("serializes a whole table with a header row as a proper GFM table (headline regression)", () => {
-    // Mirror the serializer's non-wrap branch: the full <table> node is appended
-    // directly (div.appendChild(fragment)) and htmlToMarkdown(div.innerHTML) runs.
-    const div = document.createElement("div");
-    const table = document.createElement("table");
-
-    const thead = document.createElement("thead");
-    const headerRow = document.createElement("tr");
-    for (const h of ["Name", "Age"]) {
-      const th = document.createElement("th");
-      th.textContent = h;
-      headerRow.appendChild(th);
-    }
-    thead.appendChild(headerRow);
-    table.appendChild(thead);
-
-    const tbody = document.createElement("tbody");
-    for (const [name, age] of [
-      ["Alice", "30"],
-      ["Bob", "25"],
-    ]) {
-      const tr = document.createElement("tr");
-      const td1 = document.createElement("td");
-      td1.textContent = name;
-      const td2 = document.createElement("td");
-      td2.textContent = age;
-      tr.appendChild(td1);
-      tr.appendChild(td2);
-      tbody.appendChild(tr);
-    }
-    table.appendChild(tbody);
-    div.appendChild(table);
-
-    const md = htmlToMarkdown(div.innerHTML);
+    // Mirror the serializer's non-wrap branch: the full `table` node is the
+    // slice content and convertProseMirrorToMarkdown runs on it.
+    const md = convertProseMirrorToMarkdown({
+      type: "doc",
+      content: [
+        {
+          type: "table",
+          content: [
+            row([headerCell("Name"), headerCell("Age")]),
+            row([cell("Alice"), cell("30")]),
+            row([cell("Bob"), cell("25")]),
+          ],
+        },
+      ],
+    });
     const ls = lines(md);
 
     // Proper GFM structure: separator row + all rows pipe-delimited.
@@ -296,3 +279,146 @@ describe("table clipboard markdown output (htmlToMarkdown)", () => {
     expect(md).not.toMatch(/^\s*(Name|Age|Alice|Bob|30|25)\s*$/m);
   });
 });
+
+// #347 acceptance: pasting CANONICAL markdown yields the SAME nodes the server
+// import produces for the same text. The paste path calls markdownToProseMirror
+// (the package browser entry) — the identical converter the server import uses —
+// so asserting the converter (via the browser entry, on the native DOMParser)
+// recognizes each canon form pins the paste-parity guarantee. These forms were
+// NOT recognized by the old editor-ext marked layer the paste used before.
+describe("canonical markdown paste recognition (browser entry parity)", () => {
+  // Collect every node type present in a doc (recursively).
+  const collectTypes = (n: any, set = new Set<string>()): Set<string> => {
+    if (!n || typeof n !== "object") return set;
+    if (n.type) set.add(n.type);
+    if (Array.isArray(n.content)) n.content.forEach((c) => collectTypes(c, set));
+    return set;
+  };
+  const findNode = (n: any, type: string): any => {
+    if (!n || typeof n !== "object") return undefined;
+    if (n.type === type) return n;
+    if (Array.isArray(n.content)) {
+      for (const c of n.content) {
+        const hit = findNode(c, type);
+        if (hit) return hit;
+      }
+    }
+    return undefined;
+  };
+  const allText = (n: any): string => {
+    if (!n || typeof n !== "object") return "";
+    if (typeof n.text === "string") return n.text;
+    if (Array.isArray(n.content)) return n.content.map(allText).join("");
+    return "";
+  };
+
+  it("^[…] inline footnote -> footnoteReference + footnotesList", () => {
+    const doc = markdownToProseMirrorSync("Body^[a note here].");
+    const types = collectTypes(doc);
+    expect(types.has("footnoteReference")).toBe(true);
+    expect(types.has("footnotesList")).toBe(true);
+    expect(types.has("footnoteDefinition")).toBe(true);
+  });
+
+  it('<!--img {…}--> attached image comment -> image with align', () => {
+    const doc = markdownToProseMirrorSync(
+      '![alt](/files/x.png) <!--img {"align":"left"}-->',
+    );
+    const img = findNode(doc, "image");
+    expect(img).toBeTruthy();
+    expect(img.attrs?.align).toBe("left");
+    expect(img.attrs?.src).toBe("/files/x.png");
+  });
+
+  it("> [!type] Obsidian callout -> callout node with type", () => {
+    const doc = markdownToProseMirrorSync("> [!warning]\n> be careful");
+    const callout = findNode(doc, "callout");
+    expect(callout).toBeTruthy();
+    expect(callout.attrs?.type).toBe("warning");
+    expect(allText(callout)).toContain("be careful");
+  });
+
+  it("$…$ inline math -> mathInline node", () => {
+    const doc = markdownToProseMirrorSync("Euler: $e^{i\\pi}+1=0$ done");
+    const math = findNode(doc, "mathInline");
+    expect(math).toBeTruthy();
+    expect(math.attrs?.text).toContain("e^{i\\pi}");
+  });
+
+  it("==…== highlight -> highlight mark", () => {
+    const doc = markdownToProseMirrorSync("A ==marked== word");
+    const marked = findNode(doc, "text");
+    // The highlighted run carries a `highlight` mark somewhere in the doc.
+    const hasHighlight = (n: any): boolean => {
+      if (!n || typeof n !== "object") return false;
+      if (
+        n.type === "text" &&
+        (n.marks || []).some((m: any) => m.type === "highlight")
+      )
+        return true;
+      return Array.isArray(n.content) ? n.content.some(hasHighlight) : false;
+    };
+    expect(marked).toBeTruthy();
+    expect(hasHighlight(doc)).toBe(true);
+  });
+
+  it("<!--subpages--> standalone comment -> subpages node", () => {
+    const doc = markdownToProseMirrorSync("intro\n\n<!--subpages-->\n\nafter");
+    expect(collectTypes(doc).has("subpages")).toBe(true);
+  });
+});
+
+// #347 negatives: plain text carrying markdown-LIKE punctuation must NOT be
+// silently converted/mangled (currency, bare `==`, a `[^1]` reference form).
+describe("plain-text paste negatives (no phantom conversion)", () => {
+  const findNode = (n: any, type: string): any => {
+    if (!n || typeof n !== "object") return undefined;
+    if (n.type === type) return n;
+    if (Array.isArray(n.content)) {
+      for (const c of n.content) {
+        const hit = findNode(c, type);
+        if (hit) return hit;
+      }
+    }
+    return undefined;
+  };
+  const collectTypes = (n: any, set = new Set<string>()): Set<string> => {
+    if (!n || typeof n !== "object") return set;
+    if (n.type) set.add(n.type);
+    if (Array.isArray(n.content)) n.content.forEach((c) => collectTypes(c, set));
+    return set;
+  };
+  const allText = (n: any): string => {
+    if (!n || typeof n !== "object") return "";
+    if (typeof n.text === "string") return n.text;
+    if (Array.isArray(n.content)) return n.content.map(allText).join("");
+    return "";
+  };
+
+  it("currency `$5 and $10` is NOT turned into math", () => {
+    const doc = markdownToProseMirrorSync("It costs $5 and $10 total");
+    expect(findNode(doc, "mathInline")).toBeFalsy();
+    expect(allText(doc)).toContain("$5 and $10");
+  });
+
+  it("a lone `==` is NOT turned into a highlight", () => {
+    const doc = markdownToProseMirrorSync("compare a == b in code");
+    const hasHighlight = (n: any): boolean => {
+      if (!n || typeof n !== "object") return false;
+      if (
+        n.type === "text" &&
+        (n.marks || []).some((m: any) => m.type === "highlight")
+      )
+        return true;
+      return Array.isArray(n.content) ? n.content.some(hasHighlight) : false;
+    };
+    expect(hasHighlight(doc)).toBe(false);
+    expect(allText(doc)).toContain("== b");
+  });
+
+  it("a `[^1]` reference form (no `^[`) is NOT turned into a footnote", () => {
+    const doc = markdownToProseMirrorSync("see note [^1] for details");
+    expect(collectTypes(doc).has("footnoteReference")).toBe(false);
+    expect(allText(doc)).toContain("[^1]");
+  });
+});

apps/client/src/features/editor/extensions/markdown-clipboard.ts

@@ -1,15 +1,23 @@
 // adapted from: https://github.com/aguingand/tiptap-markdown/blob/main/src/extensions/tiptap/clipboard.js - MIT
 import { Extension } from "@tiptap/core";
 import { Plugin, PluginKey, TextSelection } from "@tiptap/pm/state";
-import { DOMParser, DOMSerializer, Fragment, Slice } from "@tiptap/pm/model";
+import { DOMParser, DOMSerializer, Fragment, Slice, Node as PMNode } from "@tiptap/pm/model";
 import { find } from "linkifyjs";
 import {
-  markdownToHtml,
-  htmlToMarkdown,
   canonicalizeFootnotes,
   FOOTNOTES_LIST_NAME,
   FOOTNOTE_REFERENCE_NAME,
 } from "@docmost/editor-ext";
+// Markdown <-> ProseMirror conversion now lives ONLY in the canonical
+// `@docmost/prosemirror-markdown` package (issue #347). The BROWSER entry uses
+// the native `DOMParser` for its HTML->DOM stage (jsdom stays out of the client
+// bundle) while producing the SAME nodes the server import does — so a paste of
+// canonical markdown (`^[…]`, `<!--img …-->`, `> [!type]`, `$…$`, `==…==`,
+// standalone comments) is recognized identically to import.
+import {
+  markdownToProseMirror,
+  convertProseMirrorToMarkdown,
+} from "@docmost/prosemirror-markdown/browser";
 import type { Schema } from "@tiptap/pm/model";
 
 export const MarkdownClipboard = Extension.create({
@@ -39,25 +47,24 @@ export const MarkdownClipboard = Extension.create({
               classifyClipboardSelection(topLevelNodes);
             if (!asMarkdown) return null;
 
-            const div = document.createElement("div");
-            const serializer = DOMSerializer.fromSchema(this.editor.schema);
-            const fragment = serializer.serializeFragment(slice.content);
-
+            // Convert the copied selection to Markdown through the canonical
+            // package (issue #347), the SAME serializer the server export uses,
+            // so a copied table/list matches the on-disk markdown form. The
+            // converter takes a ProseMirror `doc` JSON, so wrap the slice's
+            // top-level content in a synthetic doc.
+            const content = slice.content.toJSON() as any[];
             if (wrapBareRows) {
-              // A partial table cell-selection serializes to bare <tr> nodes
-              // (prosemirror-tables returns the whole `table` node only when the
-              // entire table is selected). Bare <tr> would be foster-parented
-              // away by the HTML parser inside htmlToMarkdown, so wrap them in
-              // <table><tbody> first for the GFM turndown rule to detect them.
-              const table = document.createElement("table");
-              const tbody = document.createElement("tbody");
-              tbody.appendChild(fragment);
-              table.appendChild(tbody);
-              div.appendChild(table);
-            } else {
-              div.appendChild(fragment);
+              // A partial table cell-selection serializes to bare `tableRow`
+              // nodes (prosemirror-tables yields the whole `table` node only for
+              // a full-table selection). The converter's table case expects a
+              // `table` wrapper, so wrap the bare rows in one — mirroring the old
+              // <table><tbody> wrap that the HTML->markdown step needed.
+              return convertProseMirrorToMarkdown({
+                type: "doc",
+                content: [{ type: "table", content }],
+              });
             }
-            return htmlToMarkdown(div.innerHTML);
+            return convertProseMirrorToMarkdown({ type: "doc", content });
           },
           handlePaste: (view, event, slice) => {
             if (!event.clipboardData) {
@@ -95,37 +102,115 @@ export const MarkdownClipboard = Extension.create({
               }
             }
 
-            const { tr } = view.state;
-            const { from, to } = view.state.selection;
+            const schema = this.editor.schema;
+            // Capture the target range NOW. markdownToProseMirror RETURNS A
+            // PROMISE (kept async only for the Node consumers' contract; the
+            // conversion pipeline itself is synchronous), so the actual replace
+            // happens on the next microtask. No user input can interleave a
+            // microtask, so the state is unchanged when we dispatch — but we
+            // still re-read the live state before replacing and, if the doc did
+            // change under us, fall back to the live selection rather than the
+            // captured (now-stale) range.
+            const from = view.state.selection.from;
+            const to = view.state.selection.to;
+            const startDoc = view.state.doc;
+            const md = text.replace(/\n+$/, "");
 
-            const parsed = markdownToHtml(text.replace(/\n+$/, ""));
-            const body = elementFromString(parsed);
-            normalizeTableColumnWidths(body);
+            void markdownToProseMirror(md)
+              .then((doc) => {
+                if (view.isDestroyed) return;
+                // Canonical PM-JSON -> HTML via the LIVE editor schema, then
+                // reuse the UNCHANGED downstream seam (normalizeTableColumnWidths
+                // + parseSlice + canonicalizePastedFootnotes). The JSON->HTML->
+                // JSON hop is lossless (same schema both directions); it lets the
+                // existing paste-insertion logic stay byte-identical — only the
+                // SOURCE of the markdown conversion changed (issue #347 guardrail:
+                // no converter logic in the client, only a call into the package).
+                const node = PMNode.fromJSON(schema, doc);
+                const div = document.createElement("div");
+                DOMSerializer.fromSchema(schema).serializeFragment(
+                  node.content,
+                  { document },
+                  div,
+                );
 
-            const parsedSlice = DOMParser.fromSchema(
-              this.editor.schema,
-            ).parseSlice(body, {
-              preserveWhitespace: true,
-            });
+                const body = elementFromString(div.innerHTML);
+                normalizeTableColumnWidths(body);
 
-            // A markdown paste builds its ProseMirror fragment directly (DOM ->
-            // parseSlice), bypassing the editor's footnoteSyncPlugin, which never
-            // reorders an existing list. So a pasted markdown block whose footnote
-            // definitions are out of order (or contains orphan defs) would be
-            // stored out of order. Canonicalize the self-contained pasted block so
-            // its footnotes come out reference-ordered, deduped and orphan-free
-            // (issue #228). See canonicalizePastedFootnotes for why this is scoped
-            // to whole-block pastes that carry their own footnotesList.
-            const contentNodes = canonicalizePastedFootnotes(
-              parsedSlice,
-              this.editor.schema,
-            );
+                const parsedSlice = DOMParser.fromSchema(schema).parseSlice(
+                  body,
+                  { preserveWhitespace: true },
+                );
 
-            tr.replaceRange(from, to, contentNodes);
-            const insertEnd = tr.mapping.map(from, 1);
-            tr.setSelection(TextSelection.near(tr.doc.resolve(Math.max(from, insertEnd - 2)), -1));
-            tr.setMeta('paste', true)
-            view.dispatch(tr);
+                // A markdown paste builds its ProseMirror fragment directly (DOM
+                // -> parseSlice), bypassing the editor's footnoteSyncPlugin, which
+                // never reorders an existing list. So a pasted markdown block whose
+                // footnote definitions are out of order (or contains orphan defs)
+                // would be stored out of order. Canonicalize the self-contained
+                // pasted block so its footnotes come out reference-ordered, deduped
+                // and orphan-free (issue #228). See canonicalizePastedFootnotes for
+                // why this is scoped to whole-block pastes that carry their own
+                // footnotesList.
+                const contentNodes = canonicalizePastedFootnotes(
+                  parsedSlice,
+                  schema,
+                );
+
+                // Target the captured range (normally still valid — same
+                // microtask). If the doc changed under us since capture, the
+                // captured absolute from/to are stale, so fall back to the live
+                // selection rather than StepMap-mapping the old range.
+                const tr = view.state.tr;
+                let mappedFrom = from;
+                let mappedTo = to;
+                if (view.state.doc !== startDoc) {
+                  // Defensive: if the doc changed under us, fall back to the
+                  // current selection rather than a stale absolute range.
+                  mappedFrom = view.state.selection.from;
+                  mappedTo = view.state.selection.to;
+                }
+                tr.replaceRange(mappedFrom, mappedTo, contentNodes);
+                const insertEnd = tr.mapping.map(mappedFrom, 1);
+                tr.setSelection(
+                  TextSelection.near(
+                    tr.doc.resolve(Math.max(mappedFrom, insertEnd - 2)),
+                    -1,
+                  ),
+                );
+                tr.setMeta("paste", true);
+                view.dispatch(tr);
+              })
+              .catch((err) => {
+                // Fail-open: a conversion error must not swallow the paste
+                // silently in a way that loses the text. We already claimed the
+                // event (returned true), so re-insert the raw text as a plain
+                // paragraph so the user never loses their clipboard content.
+                // Log it: this catch covers BOTH the converter and the success
+                // `.then` body (e.g. PMNode.fromJSON throwing on a schema drift
+                // between the canonical package and the live editor schema), so a
+                // silent degrade to raw text would otherwise be an invisible,
+                // non-reproducible regression ("my table pasted as text").
+                console.error(
+                  "markdown paste conversion failed, inserting raw text",
+                  err,
+                );
+                if (view.isDestroyed) return;
+                const tr = view.state.tr;
+                // Same guard the success path uses: if the doc changed under us
+                // since the range was captured (normally never — same microtask),
+                // the captured absolute from/to are stale and would throw a
+                // RangeError here (an unhandled rejection on a hot paste path).
+                // Fall back to the live selection instead of a stale range.
+                if (view.state.doc !== startDoc) {
+                  const sel = view.state.selection;
+                  tr.insertText(md, sel.from, sel.to);
+                } else {
+                  tr.insertText(md, from, to);
+                }
+                tr.setMeta("paste", true);
+                view.dispatch(tr);
+              });
+            // Claim the paste: we insert asynchronously above.
             return true;
           },
           // Strip trailing whitespace-only paragraphs from pasted content.

apps/client/src/features/editor/gitmost/gitmost-recording.test.ts

@@ -9,7 +9,7 @@ import { Italic } from "@tiptap/extension-italic";
 import { Link } from "@tiptap/extension-link";
 import { gitmostInsertTranscriptIntoEditor } from "./gitmost-recording.ts";
 
-const ZWSP = "​"; // U+200B, the helper's block-trigger neutralizer
+const ZWSP = "​"; // U+200B — asserted ABSENT (the block-escape lives in the serializer now)
 
 /**
  * #377 — the web-side bridge must append the native host's transcript below the
@@ -18,8 +18,9 @@ const ZWSP = "​"; // U+200B, the helper's block-trigger neutralizer
  * regression would be caught), asserting the resulting document rather than
  * mocking the editor: transcript present -> "Transcript" heading + one paragraph
  * per non-empty line; content is inserted as LITERAL TEXT (no HTML/markdown
- * parsing); col-0 markdown block triggers are neutralized so git-sync keeps them
- * paragraphs; absent/empty/non-string -> no-op.
+ * parsing); col-0 markdown block triggers are stored verbatim (the git-sync
+ * serializer block-escapes them, so no client-side ZWSP is needed);
+ * absent/empty/non-string -> no-op.
  */
 describe("gitmostInsertTranscriptIntoEditor", () => {
   const makeEditor = () =>
@@ -91,19 +92,22 @@ describe("gitmostInsertTranscriptIntoEditor", () => {
     editor.destroy();
   });
 
-  it("neutralizes col-0 markdown block triggers with a leading ZWSP (git-sync safety)", () => {
+  it("inserts col-0 markdown block triggers as verbatim paragraph text (no ZWSP workaround)", () => {
     const editor = makeEditor();
-    // Trigger lines (some with a leaked indent) + a normal prefixed line.
+    // Trigger lines (some with a leaked indent) + a normal prefixed line. The
+    // git-sync serializer now block-escapes a leading trigger itself, so the
+    // bridge inserts each line's TEXT byte-exact (only the leaked indent is
+    // trimmed) — no invisible ZWSP is prepended anymore.
     const inserted = gitmostInsertTranscriptIntoEditor(
       editor,
       [
         "- dash",
-        "  > quote", // leading indent must be trimmed then neutralized
+        "  > quote", // leading indent is trimmed, text otherwise verbatim
         "# hash",
         "1. one",
         "> [!info] note",
         "```js",
-        "---", // solid thematic break -> horizontalRule (text-losing) if unneutralized
+        "---",
         "***",
         "___",
         "You: normal line",
@@ -116,20 +120,23 @@ describe("gitmostInsertTranscriptIntoEditor", () => {
       .map((n: any) => n.content?.[0]?.text)
       .filter((t: any) => typeof t === "string") as string[];
 
-    // Every block-trigger line is prefixed with the invisible ZWSP (indent
-    // trimmed first); the normal `You:` line is left byte-exact.
+    // Each trigger line is stored as its own byte-exact text (indent trimmed);
+    // the git-sync round-trip keeps it a paragraph via the serializer's
+    // block-escape, so no ZWSP is needed here.
     expect(texts).toEqual([
-      ZWSP + "- dash",
-      ZWSP + "> quote",
-      ZWSP + "# hash",
-      ZWSP + "1. one",
-      ZWSP + "> [!info] note",
-      ZWSP + "```js",
-      ZWSP + "---",
-      ZWSP + "***",
-      ZWSP + "___",
+      "- dash",
+      "> quote",
+      "# hash",
+      "1. one",
+      "> [!info] note",
+      "```js",
+      "---",
+      "***",
+      "___",
       "You: normal line",
     ]);
+    // Guard: no invisible ZWSP leaked into any inserted line.
+    for (const t of texts) expect(t).not.toContain(ZWSP);
 
     editor.destroy();
   });

apps/client/src/features/editor/gitmost/gitmost-recording.ts

@@ -240,45 +240,22 @@ export async function gitmostUploadFileToEditor(
   }
 }
 
-// Zero-width space (U+200B). Prepended to a transcript line that begins with a
-// markdown BLOCK trigger: it is invisible in the rendered doc but shifts the
-// trigger off column 0, so the git-sync doc->markdown->doc round-trip keeps the
-// line a plain paragraph (see GITMOST_MD_BLOCK_TRIGGER_RE).
-const GITMOST_ZWSP = "​";
-
-// A markdown BLOCK-level construct that, sitting at column 0 of a paragraph
-// line, the git-sync markdown serializer (packages/prosemirror-markdown
-// markdown-converter.ts, `case "paragraph"`) would re-parse into a NON-paragraph
-// block on the doc->markdown->doc cycle. That serializer emits paragraph text
-// verbatim with NO block-escape (the pre-existing root cause), so a leading
-// `#`/`-`/`*`/`+`/`>`, an ordered-list `N.`/`N)`, a code fence ```/~~~, a table
-// `|`, or a `> [!info]` callout opener would silently become a heading / list /
-// quote / code block / table / callout. The final alternative matches a WHOLE-
-// LINE thematic break — solid `---`/`***`/`___` or spaced `- - -`/`_ _ _` (3+ of
-// the same `-`/`*`/`_`) — which round-trips into a `horizontalRule`; because
-// that node carries NO text, an un-neutralized separator line would LOSE its
-// text entirely (worse than the list/quote case). This matches a TRIMMED line's
-// start; the transcript's own `You:` / `Speaker N:` prefix begins with a letter
-// and never matches, so prefixed lines are left byte-exact.
-const GITMOST_MD_BLOCK_TRIGGER_RE =
-  /^(?:#{1,6}(?:\s|$)|[-*+](?:\s|$)|>|\d+[.)](?:\s|$)|```|~~~|\||([-*_])(?:\s*\1){2,}\s*$)/;
-
 // Append a transcript block BELOW the recording's audio node in a live editor:
 // a "Transcript" heading followed by one paragraph per non-empty transcript
 // line. The transcript is plain text, `\n`-separated, each line already
 // formatted as `You: ...` / `Speaker N: ...` by the native host — line text is
 // inserted as a TEXT node (never HTML/markdown), so there is no injection or
 // mark-parsing surface. Each kept line is trimmed (drops an indent that would
-// both leak into the display and, at col 0, form a markdown block trigger) and,
-// if it still begins with a col-0 markdown block trigger, gets an invisible
-// zero-width space prepended so the git-sync round-trip cannot turn it into a
-// list/quote/heading/callout/code/table (defensive boundary against the
-// serializer's missing block-escape). This is best-effort and meant to run
-// AFTER the audio has already been inserted; the caller must guard against a
-// throw so a transcript failure never fails the (already successful) recording.
-// Returns true when a block was inserted, false when there was nothing to
-// insert (transcript undefined/empty/not-a-string). A non-string value is a
-// no-op, not an error.
+// leak into the display). A line that begins with a col-0 markdown block
+// trigger (`#`/`-`/`>`/`1.`/fence/`---`/…) needs no client-side workaround: the
+// git-sync serializer (packages/prosemirror-markdown, `case "paragraph"`) now
+// block-escapes such a leading trigger, so the doc->markdown->doc round-trip
+// keeps the line a paragraph on its own — the former invisible-ZWSP defense is
+// gone. This is best-effort and meant to run AFTER the audio has already been
+// inserted; the caller must guard against a throw so a transcript failure never
+// fails the (already successful) recording. Returns true when a block was
+// inserted, false when there was nothing to insert (transcript
+// undefined/empty/not-a-string). A non-string value is a no-op, not an error.
 export function gitmostInsertTranscriptIntoEditor(
   editor: Editor,
   transcript: unknown,
@@ -288,13 +265,7 @@ export function gitmostInsertTranscriptIntoEditor(
     .split("\n")
     // Trim each line and drop blank (whitespace-only) ones.
     .map((line) => line.trim())
-    .filter((line) => line.length > 0)
-    // Neutralize a col-0 markdown block trigger with an invisible ZWSP so the
-    // git-sync round-trip keeps the line a paragraph. Host lines (`You:` /
-    // `Speaker N:`) never match and stay byte-exact.
-    .map((line) =>
-      GITMOST_MD_BLOCK_TRIGGER_RE.test(line) ? GITMOST_ZWSP + line : line,
-    );
+    .filter((line) => line.length > 0);
   if (lines.length === 0) return false;
 
   const content = [

apps/client/src/features/editor/hooks/use-generate-page-title.test.tsx

@@ -33,10 +33,11 @@ vi.mock("@/lib/local-emitter.ts", () => ({
   default: { emit: (...args: unknown[]) => localEmitMock(...args) },
 }));
 
-// htmlToMarkdown just echoes the editor HTML so each test controls the markdown
-// purely via the fake page editor's getHTML().
-vi.mock("@docmost/editor-ext", () => ({
-  htmlToMarkdown: (html: string) => html,
+// convertProseMirrorToMarkdown echoes a marker carried on the fake editor's
+// getJSON() doc, so each test controls the markdown purely via the fake page
+// editor (issue #347: the hook now serializes editor JSON through the package).
+vi.mock("@docmost/prosemirror-markdown/browser", () => ({
+  convertProseMirrorToMarkdown: (doc: { __md?: string }) => doc?.__md ?? "",
 }));
 
 const notificationsShowMock = vi.fn();
@@ -53,10 +54,12 @@ import { useGeneratePageTitle } from "./use-generate-page-title.ts";
 
 // --- Test helpers -------------------------------------------------------------
 
-function makePageEditor(pageId: string, html = "<p>content</p>"): Editor {
+function makePageEditor(pageId: string, md = "content"): Editor {
   return {
     isDestroyed: false,
-    getHTML: () => html,
+    // The mocked convertProseMirrorToMarkdown reads `__md` back off this doc,
+    // so `md` is exactly the markdown the hook will send to the title service.
+    getJSON: () => ({ type: "doc", __md: md }),
     storage: { pageId },
   } as unknown as Editor;
 }

apps/client/src/features/editor/hooks/use-generate-page-title.ts

@@ -3,7 +3,7 @@ import { useMutation } from "@tanstack/react-query";
 import { useAtomValue } from "jotai";
 import { notifications } from "@mantine/notifications";
 import { useTranslation } from "react-i18next";
-import { htmlToMarkdown } from "@docmost/editor-ext";
+import { convertProseMirrorToMarkdown } from "@docmost/prosemirror-markdown/browser";
 import {
   pageEditorAtom,
   titleEditorAtom,
@@ -49,7 +49,9 @@ export function useGeneratePageTitle(pageId: string) {
     mutationFn: async () => {
       if (!pageEditor || pageEditor.isDestroyed) return;
 
-      const markdown = htmlToMarkdown(pageEditor.getHTML()).trim();
+      // Serialize the live editor content to markdown through the canonical
+      // converter (issue #347), matching the on-disk/export markdown form.
+      const markdown = convertProseMirrorToMarkdown(pageEditor.getJSON()).trim();
       if (!markdown) {
         notifications.show({ message: t("The note is empty"), color: "yellow" });
         return;

apps/client/src/features/page/components/header/page-header-menu.tsx

@@ -37,7 +37,7 @@ import { useTreeMutation } from "@/features/page/tree/hooks/use-tree-mutation.ts
 import { PageWidthToggle } from "@/features/user/components/page-width-pref.tsx";
 import { Trans, useTranslation } from "react-i18next";
 import ExportModal from "@/components/common/export-modal";
-import { htmlToMarkdown } from "@docmost/editor-ext";
+import { convertProseMirrorToMarkdown } from "@docmost/prosemirror-markdown/browser";
 import {
   pageEditorAtom,
   yjsConnectionStatusAtom,
@@ -199,8 +199,9 @@ function PageActionMenu({ readOnly }: PageActionMenuProps) {
 
   const handleCopyAsMarkdown = () => {
     if (!pageEditor) return;
-    const html = pageEditor.getHTML();
-    const markdown = htmlToMarkdown(html);
+    // Copy the page as canonical markdown through the shared converter (issue
+    // #347), so "Copy as markdown" matches the server export byte-for-byte.
+    const markdown = convertProseMirrorToMarkdown(pageEditor.getJSON());
     const title = page?.title ? `# ${page.title}\n\n` : "";
     clipboard.copy(`${title}${markdown}`);
     notifications.show({ message: t("Copied") });

apps/server/package.json

@@ -41,6 +41,7 @@
     "@aws-sdk/s3-request-presigner": "3.1050.0",
     "@azure/storage-blob": "12.31.0",
     "@clickhouse/client": "^1.18.2",
+    "@docmost/editor-ext": "workspace:*",
     "@docmost/mcp": "workspace:*",
     "@docmost/pdf-inspector": "1.9.6",
     "@docmost/prosemirror-markdown": "workspace:*",

apps/server/src/collaboration/collaboration.util.ts

@@ -49,6 +49,7 @@ import {
   FootnotesList,
   FootnoteDefinition,
   PageEmbed,
+  Code,
 } from '@docmost/editor-ext';
 import { convertProseMirrorToMarkdown } from '@docmost/prosemirror-markdown';
 import { generateText, getSchema, JSONContent } from '@tiptap/core';
@@ -67,7 +68,12 @@ export const tiptapExtensions = [
     link: false,
     trailingNode: false,
     heading: false,
+    // #515: replace StarterKit's bundled inline `code` (which inherits tiptap's
+    // `excludes: "_"`) with the shared editor-ext `Code` below, so the server's
+    // HTML->PM parse/export keeps code co-occurring with other marks.
+    code: false,
   }),
+  Code,
   Heading,
   UniqueID.configure({
     types: ['heading', 'paragraph', 'transclusionSource'],

apps/server/src/common/helpers/prosemirror/html-embed-import-detect.spec.ts

@@ -1,4 +1,5 @@
-import { markdownToHtml, encodeHtmlEmbedSource } from '@docmost/editor-ext';
+import { markdownToProseMirror } from '@docmost/prosemirror-markdown';
+import { encodeHtmlEmbedSource } from '@docmost/editor-ext';
 import { htmlToJson } from '../../../collaboration/collaboration.util';
 import { hasHtmlEmbedNode, stripHtmlEmbedNodes } from './html-embed.util';
 
@@ -10,13 +11,12 @@ import { hasHtmlEmbedNode, stripHtmlEmbedNodes } from './html-embed.util';
  *
  * The block renders inside a sandboxed iframe, so this is not an XSS surface;
  * this exercises the REAL server import conversion path that ImportService uses
- * (`markdownToHtml` then `htmlToJson`; `processHTML` adds only a cheerio
- * link/iframe normalize pass which does not touch htmlEmbed divs) and asserts
- * that such a node is DETECTED and STRIPPABLE — so the share read path's
+ * (`markdownToProseMirror`, the canonical converter — issue #345/#347) and
+ * asserts that such a node is DETECTED and STRIPPABLE — so the share read path's
  * master-toggle strip can remove it when the workspace toggle is OFF.
  */
 describe('htmlEmbed smuggled via the raw serialized div in imported markdown/HTML', () => {
-  it('round-trips through markdownToHtml -> htmlToJson and is DETECTED (base64 data-source)', async () => {
+  it('round-trips through markdownToProseMirror and is DETECTED (base64 data-source)', async () => {
     const source = '<script>steal()</script>';
     const encoded = encodeHtmlEmbedSource(source);
     const md = [
@@ -27,12 +27,9 @@ describe('htmlEmbed smuggled via the raw serialized div in imported markdown/HTM
       'World',
     ].join('\n');
 
-    const html = await markdownToHtml(md);
-    // marked preserves the raw block-level div verbatim.
-    expect(html).toContain('data-type="htmlEmbed"');
-
-    const json = htmlToJson(html);
-    // The div parses into a real htmlEmbed node carrying the decoded source.
+    // The canonical importer parses the raw block-level div into a real
+    // htmlEmbed node carrying the decoded source.
+    const json = await markdownToProseMirror(md);
     expect(hasHtmlEmbedNode(json)).toBe(true);
 
     // Because it is detected, the share master-toggle strip can remove it.
@@ -59,8 +56,7 @@ describe('htmlEmbed smuggled via the raw serialized div in imported markdown/HTM
     // therefore stripping) does not depend on the source being well-formed, so
     // the bypass cannot be hidden by sending a malformed data-source.
     const md = `<div data-type="htmlEmbed" data-source="&lt;script&gt;x&lt;/script&gt;"></div>`;
-    const html = await markdownToHtml(md);
-    const json = htmlToJson(html);
+    const json = await markdownToProseMirror(md);
     expect(hasHtmlEmbedNode(json)).toBe(true);
     expect(hasHtmlEmbedNode(stripHtmlEmbedNodes(json))).toBe(false);
   });

apps/server/src/core/page/services/page.service.ts

@@ -53,8 +53,10 @@ import {
   extractPageSlugId,
 } from '../../../integrations/export/utils';
 import { canonicalizeFootnotes } from '@docmost/editor-ext';
-import { markdownToProseMirror } from '@docmost/prosemirror-markdown';
-import { normalizeForeignMarkdown } from '../../../integrations/import/utils/foreign-markdown';
+import {
+  markdownToProseMirror,
+  normalizeForeignMarkdown,
+} from '@docmost/prosemirror-markdown';
 import { WatcherService } from '../../watcher/watcher.service';
 import { sql } from 'kysely';
 import { TransclusionService } from '../transclusion/transclusion.service';

apps/server/src/integrations/import/services/file-import-task.service.ts

@@ -22,10 +22,12 @@ import { v7 } from 'uuid';
 import { generateJitteredKeyBetween } from 'fractional-indexing-jittered';
 import { FileTask, InsertablePage } from '@docmost/db/types/entity.types';
 import { canonicalizeFootnotes } from '@docmost/editor-ext';
-import { markdownToProseMirror } from '@docmost/prosemirror-markdown';
+import {
+  markdownToProseMirror,
+  normalizeForeignMarkdown,
+} 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,

apps/server/src/integrations/import/services/import.service.ts

@@ -18,8 +18,10 @@ import { generateJitteredKeyBetween } from 'fractional-indexing-jittered';
 import { TiptapTransformer } from '@hocuspocus/transformer';
 import * as Y from 'yjs';
 import { canonicalizeFootnotes } from '@docmost/editor-ext';
-import { markdownToProseMirror } from '@docmost/prosemirror-markdown';
-import { normalizeForeignMarkdown } from '../utils/foreign-markdown';
+import {
+  markdownToProseMirror,
+  normalizeForeignMarkdown,
+} from '@docmost/prosemirror-markdown';
 import {
   FileTaskStatus,
   FileTaskType,

packages/editor-ext/package.json

@@ -11,9 +11,6 @@
   "main": "dist/index.js",
   "module": "./src/index.ts",
   "types": "dist/index.d.ts",
-  "dependencies": {
-    "marked": "17.0.5"
-  },
   "devDependencies": {
     "@vitest/coverage-v8": "4.1.6",
     "vitest": "4.1.6"

packages/editor-ext/src/index.ts

@@ -1,4 +1,5 @@
 export * from "./lib/trailing-node";
+export * from "./lib/code";
 export * from "./lib/comment/comment";
 export * from "./lib/utils";
 export * from "./lib/math";
@@ -18,7 +19,6 @@ export * from "./lib/excalidraw";
 export * from "./lib/embed";
 export * from "./lib/html-embed/html-embed";
 export * from "./lib/mention";
-export * from "./lib/markdown";
 export * from "./lib/search-and-replace";
 export * from "./lib/embed-provider";
 export * from "./lib/subpages";

packages/editor-ext/src/lib/code.ts

@@ -0,0 +1,20 @@
+import { Code as TiptapCode } from "@tiptap/extension-code";
+
+// #515: canonical inline `code` mark for Docmost.
+//
+// Tiptap's stock Code mark (via StarterKit) declares `excludes: "_"`, which
+// makes it exclude EVERY other inline mark: applying `code` drops any co-
+// occurring bold/italic/… on both the HTML->PM import and editor transactions.
+// That silently stripped emphasis adjacent to inline code (`` **`--flag`** ``
+// lost its bold on markdown import). CommonMark nests them (`<strong><code>`),
+// so Docmost lets `code` combine with all marks by overriding `excludes` to the
+// empty string (excludes nothing).
+//
+// This is the SINGLE shared source imported by the live editor, the collab
+// server and the comment editor schemas. The markdown-import mirror in
+// @docmost/prosemirror-markdown re-declares the same override locally (it must
+// not pull this React-aware package into its node runtime) and a parity test
+// keeps the two in lockstep.
+export const Code = TiptapCode.extend({
+  excludes: "",
+});

packages/editor-ext/src/lib/footnote/footnote-canonicalize.ts

@@ -14,7 +14,8 @@ import {
  * ProseMirror JSON directly (never running the editor's plugins), so the
  * canonical footnote topology was never enforced on those writes. The consumers
  * of this editor-ext copy are: the server markdown/HTML import
- * (`markdownToHtml -> htmlToJson` in import.service / file-import-task.service),
+ * (`markdownToProseMirror` from @docmost/prosemirror-markdown in import.service /
+ * file-import-task.service),
  * `PageService` create/update (`parseProsemirrorContent` for the JSON/markdown/
  * HTML REST write paths), and the client markdown PASTE path
  * (`markdown-clipboard.ts`). (The MCP package mirrors this canonicalizer in

packages/editor-ext/src/lib/footnote/footnote-markdown.test.ts

@@ -1,131 +0,0 @@
-import { describe, it, expect } from "vitest";
-import { htmlToMarkdown } from "../markdown/utils/turndown.utils";
-import { markdownToHtml } from "../markdown/utils/marked.utils";
-import { extractFootnoteDefinitions } from "../markdown/utils/footnote.marked";
-
-// HTML the editor-ext nodes render (sup[data-footnote-ref], section/div).
-const HTML =
-  `<p>Water<sup data-footnote-ref data-id="fn1"></sup> and clay<sup data-footnote-ref data-id="fn2"></sup>.</p>` +
-  `<section data-footnotes>` +
-  `<div data-footnote-def data-id="fn1"><p>First note.</p></div>` +
-  `<div data-footnote-def data-id="fn2"><p>Second note.</p></div>` +
-  `</section>`;
-
-describe("footnote markdown round-trip", () => {
-  it("HTML -> Markdown produces pandoc footnote syntax", () => {
-    const md = htmlToMarkdown(HTML);
-    expect(md).toContain("[^fn1]");
-    expect(md).toContain("[^fn2]");
-    expect(md).toContain("[^fn1]: First note.");
-    expect(md).toContain("[^fn2]: Second note.");
-  });
-
-  it("Markdown -> HTML rebuilds the footnote nodes' HTML", async () => {
-    const md = htmlToMarkdown(HTML);
-    const html = await markdownToHtml(md);
-    expect(html).toContain('data-footnote-ref data-id="fn1"');
-    expect(html).toContain('data-footnote-ref data-id="fn2"');
-    expect(html).toContain("data-footnotes");
-    expect(html).toContain('data-footnote-def data-id="fn1"');
-    expect(html).toContain("First note.");
-    expect(html).toContain("Second note.");
-  });
-
-  it("preserves a [^id]: line shown inside a fenced code block (not a definition)", async () => {
-    // A document that DOCUMENTS footnote syntax inside a code fence. The
-    // `[^demo]: ...` line is example text, not a real definition, and must
-    // survive the Markdown -> HTML conversion verbatim.
-    const md = [
-      "Here is how footnotes look:",
-      "",
-      "```markdown",
-      "Some text[^demo]",
-      "",
-      "[^demo]: this is the definition",
-      "```",
-      "",
-      "End of doc.",
-    ].join("\n");
-
-    const html = await markdownToHtml(md);
-    // The example definition line is kept inside the rendered code block.
-    expect(html).toContain("[^demo]: this is the definition");
-    // It did NOT get pulled out into a real footnotes section.
-    expect(html).not.toContain("data-footnotes");
-    expect(html).not.toContain("data-footnote-def");
-  });
-
-  it("extractFootnoteDefinitions keeps the FIRST duplicate definition and reuses markers", () => {
-    // Two definitions share id `d`, and the body has two `[^d]` markers. Under
-    // the import model (#166) duplicate definition ids are FIRST-WINS: only the
-    // first definition is kept; markers are NEVER rewritten, so the two `[^d]`
-    // references reuse the single footnote.
-    const md = [
-      "See here[^d] and there[^d].",
-      "",
-      "[^d]: first",
-      "[^d]: second",
-    ].join("\n");
-
-    const { body, section } = extractFootnoteDefinitions(md);
-
-    const defIds = Array.from(
-      section.matchAll(/data-footnote-def data-id="([^"]+)"/g),
-    ).map((m) => m[1]);
-    expect(defIds).toEqual(["d"]); // first-wins: one definition
-    expect(section).toContain("first");
-    expect(section).not.toContain("second"); // duplicate dropped
-
-    // Both markers stay `[^d]` (reuse) — no `d__2` minting.
-    const refIds = Array.from(body.matchAll(/\[\^([^\]\s]+)\]/g)).map(
-      (m) => m[1],
-    );
-    expect(refIds).toEqual(["d", "d"]);
-  });
-
-  it("extractFootnoteDefinitions is DETERMINISTIC and stable (same input -> same output)", () => {
-    // The output must be a pure function of the input markdown so importing the
-    // same source twice (or via the editor and the MCP mirror) is identical.
-    const md = [
-      "See[^d] one[^d] two[^d].",
-      "",
-      "[^d]: first",
-      "[^d]: second",
-      "[^d]: third",
-    ].join("\n");
-
-    const run = () => {
-      const { body, section } = extractFootnoteDefinitions(md);
-      const defIds = Array.from(
-        section.matchAll(/data-footnote-def data-id="([^"]+)"/g),
-      ).map((m) => m[1]);
-      const refIds = Array.from(body.matchAll(/\[\^([^\]\s]+)\]/g)).map(
-        (m) => m[1],
-      );
-      return { defIds, refIds };
-    };
-
-    const a = run();
-    const b = run();
-    expect(a).toEqual(b);
-    // First-wins: one kept definition `d`; all three reuse markers stay `d`.
-    expect(a.defIds).toEqual(["d"]);
-    expect(a.refIds).toEqual(["d", "d", "d"]);
-  });
-
-  it("markdownToHtml with a reused id renders ONE shared footnote def", async () => {
-    const md = [
-      "See here[^d] and there[^d].",
-      "",
-      "[^d]: first",
-      "[^d]: second",
-    ].join("\n");
-    const html = await markdownToHtml(md);
-    const defIds = Array.from(
-      html.matchAll(/data-footnote-def data-id="([^"]+)"/g),
-    ).map((m) => m[1]);
-    expect(defIds).toEqual(["d"]); // one shared definition
-    expect(html).toContain("first");
-    expect(html).not.toContain("second");
-  });
-});

packages/editor-ext/src/lib/footnote/footnote-sync.ts

@@ -103,8 +103,9 @@ interface CollisionPlan {
  * `X__2`, `X__3`, collision-bumped) so it survives as a distinct footnote — which,
  * having no matching reference, then falls under the normal orphan policy. It is
  * only ever dropped for lacking a reference, never for colliding. The IMPORT
- * paths (footnote.marked.ts / MCP extractFootnotes) instead apply first-wins +
- * drop + warn for duplicate definitions; that divergence is intentional — import
+ * paths (@docmost/prosemirror-markdown / MCP extractFootnotes) instead apply
+ * first-wins + drop + warn for duplicate definitions; that divergence is
+ * intentional — import
  * is an agent-authored artifact we sanitize, the editor is live user data we must
  * not lose.
  *

packages/editor-ext/src/lib/footnote/footnote-util.derive-id.test.ts

@@ -6,8 +6,9 @@ import { deriveFootnoteId } from "./footnote-util";
  *
  * `deriveFootnoteId` lives ONLY in editor-ext now — it is used by
  * `resolveCollisions` (re-id of a duplicate definition) and `footnotePastePlugin`
- * (re-id of a pasted colliding definition). The MCP/marked import paths no longer
- * derive ids (duplicate definitions there are first-wins-dropped, #166), so there
+ * (re-id of a pasted colliding definition). The MCP / @docmost/prosemirror-markdown
+ * import paths no longer derive ids (duplicate definitions there are
+ * first-wins-dropped, #166), so there
  * is no cross-package copy and no parity test to keep in sync. This table pins the
  * deterministic scheme so a future change to it is a conscious one.
  */

packages/editor-ext/src/lib/footnote/footnote-util.ts

@@ -63,8 +63,9 @@ export function generateFootnoteId(): string {
  * its own seen-set before requesting the next derived id.
  *
  * Used only inside editor-ext now (resolveCollisions for a re-id'd duplicate
- * DEFINITION, and footnotePastePlugin). The MCP/marked import paths no longer
- * derive ids — duplicate definitions there are first-wins-dropped (#166) — so
+ * DEFINITION, and footnotePastePlugin). The MCP / @docmost/prosemirror-markdown
+ * import paths no longer derive ids — duplicate definitions there are
+ * first-wins-dropped (#166) — so
  * there is no cross-package copy to keep in sync. The golden table in
  * footnote-util.derive-id.test.ts pins the scheme.
  */

packages/editor-ext/src/lib/image/image-markdown.test.ts

@@ -1,68 +0,0 @@
-import { describe, it, expect } from "vitest";
-import { generateJSON } from "@tiptap/html";
-import { Document } from "@tiptap/extension-document";
-import { Paragraph } from "@tiptap/extension-paragraph";
-import { Text } from "@tiptap/extension-text";
-import { htmlToMarkdown } from "../markdown/utils/turndown.utils";
-import { markdownToHtml } from "../markdown/utils/marked.utils";
-import { TiptapImage } from "./image";
-
-// Minimal schema for parsing markdownToHtml output back to JSON (mirrors
-// image.spec.ts), so we can assert the recovered caption EXACTLY.
-const parseExtensions = [Document, Paragraph, Text, TiptapImage];
-
-// Lossless markdown round-trip for image captions (issue #221). An image WITH a
-// caption can't be expressed as `![alt](src)`, so it is emitted as a raw <img>
-// (carrying data-caption) wrapped in a block <div>, the same trick the <video>
-// rule uses. marked passes the raw HTML through, so markdownToHtml keeps the
-// data-caption, and the image extension's parseHTML restores the attribute.
-describe("image caption markdown round-trip", () => {
-  it("HTML -> Markdown emits a raw <img data-caption> for captioned images", () => {
-    const html = `<p><img src="/files/a.png" alt="cat" data-caption="A grey cat"></p>`;
-    const md = htmlToMarkdown(html);
-    expect(md).toContain("data-caption=\"A grey cat\"");
-    expect(md).toContain('src="/files/a.png"');
-    expect(md).toContain('alt="cat"');
-    // It must NOT degrade to the lossy ![]() form.
-    expect(md).not.toContain("![cat]");
-  });
-
-  it("Markdown -> HTML restores data-caption on the <img>", async () => {
-    const html = `<p><img src="/files/a.png" alt="cat" data-caption="A grey cat"></p>`;
-    const md = htmlToMarkdown(html);
-    const back = await markdownToHtml(md);
-    expect(back).toContain('data-caption="A grey cat"');
-    expect(back).toContain('src="/files/a.png"');
-  });
-
-  it("special characters in the caption survive the round-trip (escaped)", async () => {
-    // The source caption is the decoded string `Tom & "Jerry"` (both an `&` and
-    // a `"`). escapeHtmlAttr must encode `&` -> `&amp;` and `"` -> `&quot;`.
-    const html = `<p><img src="/files/a.png" data-caption='Tom &amp; &quot;Jerry&quot;'></p>`;
-    const md = htmlToMarkdown(html);
-
-    // (a) The intermediate Markdown must carry the EXACT escaped attribute. This
-    // fails if escapeHtmlAttr stopped escaping `"` (attribute break-out:
-    // data-caption="Tom & "Jerry"") or double-encoded `&` (`&amp;amp;`).
-    expect(md).toContain('data-caption="Tom &amp; &quot;Jerry&quot;"');
-
-    const back = await markdownToHtml(md);
-    expect(back).toContain("data-caption=");
-    expect(back).toContain("Jerry");
-    expect(back).toContain("Tom");
-
-    // (b) Re-parse the rendered HTML through the image extension's parseHTML and
-    // assert the recovered caption is EXACTLY the original (no corruption, loss,
-    // or double-encoding).
-    const json = generateJSON(back, parseExtensions);
-    expect(json.content?.[0]?.attrs?.caption).toBe('Tom & "Jerry"');
-  });
-
-  it("caption-less images stay a clean ![alt](src) with no raw HTML", () => {
-    const html = `<p><img src="/files/a.png" alt="cat"></p>`;
-    const md = htmlToMarkdown(html);
-    expect(md).toContain("![cat](/files/a.png)");
-    expect(md).not.toContain("data-caption");
-    expect(md).not.toContain("<img");
-  });
-});

packages/editor-ext/src/lib/markdown/html-embed-marked.spec.ts

@@ -1,105 +0,0 @@
-import { describe, expect, it } from "vitest";
-import { htmlEmbedExtension } from "./utils/html-embed.marked";
-import { markdownToHtml } from "./index";
-import { encodeHtmlEmbedSource } from "../html-embed/html-embed";
-
-// CONTRACT tests for the marked block tokenizer that rebuilds an htmlEmbed node
-// from the `<!--html-embed:BASE64-->` marker (html-embed.marked.ts), plus the
-// observable round-trip through markdownToHtml.
-//
-// These pin the REAL tokenizer behaviour the import path depends on:
-//   - the tokenizer rule is anchored (^) and only accepts the base64 alphabet
-//     [A-Za-z0-9+/=], so a marker with non-base64 chars is NOT tokenized and
-//     survives as a literal HTML comment (not silently turned into something the
-//     server's strip no longer recognizes);
-//   - start() reports the correct index of the next marker so marked invokes the
-//     tokenizer at the right offset when a marker sits mid-document / after text;
-//   - a marker with surrounding text on the SAME line is split out into its own
-//     embed div while the surrounding text becomes ordinary paragraphs.
-//
-// The contract is asserted against the actual exported extension and pipeline —
-// no behaviour is invented; the expectations were read off the real tokenizer.
-
-const SAMPLE = "<b>x</b>";
-const ENC = encodeHtmlEmbedSource(SAMPLE);
-
-describe("htmlEmbed marked tokenizer — start()", () => {
-  it("returns the index of a marker that sits mid-document", () => {
-    const src = `hello world <!--html-embed:${ENC}-->`;
-    expect(htmlEmbedExtension.start(src)).toBe(src.indexOf("<!--html-embed:"));
-  });
-
-  it("returns 0 when the marker is at the very start", () => {
-    expect(htmlEmbedExtension.start(`<!--html-embed:${ENC}-->`)).toBe(0);
-  });
-
-  it("returns -1 when there is no marker", () => {
-    expect(htmlEmbedExtension.start("no marker here")).toBe(-1);
-  });
-});
-
-describe("htmlEmbed marked tokenizer — tokenizer()", () => {
-  it("tokenizes a marker at the start of the input, capturing the base64 payload", () => {
-    const token = htmlEmbedExtension.tokenizer(`<!--html-embed:${ENC}-->`);
-    expect(token).toBeTruthy();
-    expect(token!.type).toBe("htmlEmbed");
-    expect(token!.raw).toBe(`<!--html-embed:${ENC}-->`);
-    expect(token!.encoded).toBe(ENC);
-  });
-
-  it("tokenizes an EMPTY marker (the [A-Za-z0-9+/=]* class allows zero chars)", () => {
-    const token = htmlEmbedExtension.tokenizer("<!--html-embed:-->");
-    expect(token).toBeTruthy();
-    expect(token!.encoded).toBe("");
-    expect(token!.raw).toBe("<!--html-embed:-->");
-  });
-
-  it("does NOT tokenize when text precedes the marker (rule is anchored ^)", () => {
-    // marked relies on start() to advance to the marker; the tokenizer itself
-    // only matches at offset 0, so a non-anchored call returns undefined.
-    expect(
-      htmlEmbedExtension.tokenizer(`hello <!--html-embed:${ENC}-->`),
-    ).toBeUndefined();
-  });
-
-  it("does NOT tokenize a marker containing a non-base64 char ('$')", () => {
-    expect(
-      htmlEmbedExtension.tokenizer("<!--html-embed:ab$cd-->"),
-    ).toBeUndefined();
-  });
-
-  it("does NOT tokenize a marker containing a space", () => {
-    expect(
-      htmlEmbedExtension.tokenizer("<!--html-embed:ab cd-->"),
-    ).toBeUndefined();
-  });
-
-  it("renderer emits the embed div the node's parseHTML recognizes", () => {
-    const token = htmlEmbedExtension.tokenizer(`<!--html-embed:${ENC}-->`)!;
-    const html = htmlEmbedExtension.renderer(token as any);
-    expect(html).toBe(
-      `<div data-type="htmlEmbed" data-source="${ENC}"></div>`,
-    );
-  });
-});
-
-describe("htmlEmbed marked tokenizer — markdownToHtml round-trip", () => {
-  it("splits a marker out of surrounding same-line text into its own embed div", async () => {
-    const html = await markdownToHtml(`before <!--html-embed:${ENC}--> after`);
-    // The marker became the embed div...
-    expect(html).toContain(
-      `<div data-type="htmlEmbed" data-source="${ENC}"></div>`,
-    );
-    // ...and the surrounding text survived as ordinary paragraph content.
-    expect(html).toContain("before");
-    expect(html).toContain("after");
-  });
-
-  it("leaves a marker with non-base64 chars as a literal comment (NOT an embed div)", async () => {
-    const html = await markdownToHtml("<!--html-embed:ab$cd-->");
-    // It is NOT tokenized into an embed div the server would strip...
-    expect(html).not.toContain('data-type="htmlEmbed"');
-    // ...it passes through unchanged as a literal HTML comment.
-    expect(html).toContain("<!--html-embed:ab$cd-->");
-  });
-});

packages/editor-ext/src/lib/markdown/index.ts

@@ -1,2 +0,0 @@
-export * from "./utils/marked.utils";
-export * from "./utils/turndown.utils";

packages/editor-ext/src/lib/markdown/markdown-html-embed.spec.ts

@@ -1,112 +0,0 @@
-import { describe, it, expect } from "vitest";
-import { markdownToHtml, htmlToMarkdown } from "./index";
-import {
-  encodeHtmlEmbedSource,
-  decodeHtmlEmbedSource,
-} from "../html-embed/html-embed";
-
-// SECURITY (Variant C admin gate, import attack surface).
-//
-// The markdown import path is the only write path where an htmlEmbed reaches
-// the server purely from file bytes (no editor / collab socket). The marked
-// tokenizer in `html-embed.marked.ts` and the turndown rule in
-// `turndown.utils.ts` are what materialize the `<!--html-embed:BASE64-->`
-// marker into the `<div data-type="htmlEmbed" data-source="BASE64">` element
-// that the server then parses into an htmlEmbed node and the admin gate strips.
-//
-// If either the tokenizer regex or the turndown rule shape drifts, the marker
-// would either (a) stop becoming an htmlEmbed node (silently dropping admin
-// content) or (b) become some OTHER tag the server's `hasHtmlEmbedNode` no
-// longer recognizes (a strip bypass). These tests pin the marker <-> embed-div
-// contract that the server-side strip relies on. editor-ext had ZERO tests
-// before this file; this adds the runner + the round-trip coverage.
-
-// The server parses the embed div by matching `data-type="htmlEmbed"` and
-// decoding `data-source`; mirror that here so the assertion is exactly what the
-// real `htmlToJson` -> htmlEmbed node parse depends on (the node's parseHTML in
-// html-embed.ts uses the same selector + decodeHtmlEmbedSource).
-const EMBED_DIV_RE = /<div[^>]*\bdata-type="htmlEmbed"[^>]*>/;
-function extractEmbedSource(html: string): string | undefined {
-  const div = EMBED_DIV_RE.exec(html);
-  if (!div) return undefined;
-  const enc = /data-source="([^"]*)"/.exec(div[0]);
-  if (!enc) return undefined;
-  return decodeHtmlEmbedSource(enc[1]);
-}
-
-// Replicates the server's `hasHtmlEmbedNode` decision against the embed *div*
-// (the HTML form the server immediately converts to JSON). If this matches, the
-// server's JSON-level `hasHtmlEmbedNode` will too, because htmlToJson maps this
-// exact div to an htmlEmbed node.
-function htmlHasHtmlEmbed(html: string): boolean {
-  return EMBED_DIV_RE.test(html);
-}
-
-describe("markdown <!--html-embed--> import round-trip", () => {
-  const source = "<script>x</script>";
-
-  it("markdownToHtml turns the marker into an htmlEmbed div carrying the source", async () => {
-    const md = "<!--html-embed:" + encodeHtmlEmbedSource(source) + "-->";
-    const html = await markdownToHtml(md);
-
-    // The marker became the embed div the server recognizes as an htmlEmbed
-    // node (so the server's hasHtmlEmbedNode would match it after htmlToJson).
-    expect(htmlHasHtmlEmbed(html)).toBe(true);
-    // The decoded source is the original script, intact.
-    expect(extractEmbedSource(html)).toBe(source);
-    // The raw script is NOT inlined into the HTML — it stays base64 in the
-    // attribute (the marker itself must not be a direct injection vector).
-    expect(html).not.toContain("<script>x</script>");
-  });
-
-  it("preserves UTF-8 / special chars in the embedded source", async () => {
-    const utf8 = '<script>console.log("héllo → 世界")</script>';
-    const md = "<!--html-embed:" + encodeHtmlEmbedSource(utf8) + "-->";
-    const html = await markdownToHtml(md);
-    expect(htmlHasHtmlEmbed(html)).toBe(true);
-    expect(extractEmbedSource(html)).toBe(utf8);
-  });
-
-  it("an empty marker still produces an htmlEmbed div (empty source)", async () => {
-    const html = await markdownToHtml("<!--html-embed:-->");
-    expect(htmlHasHtmlEmbed(html)).toBe(true);
-    expect(extractEmbedSource(html)).toBe("");
-  });
-
-  it("round-trips htmlToMarkdown -> markdownToHtml preserving the embed marker", async () => {
-    const encoded = encodeHtmlEmbedSource(source);
-    // NOTE: turndown drops a *blank* (childless) element before any custom rule
-    // runs, and the htmlEmbed div is normally childless. The export pipeline
-    // therefore must give the rule a non-blank div to fire on; we add an inert
-    // text child here to exercise the real turndown htmlEmbed rule. (A blank
-    // embed div serializing to "" is asserted separately below as a documented
-    // edge so this contract drift is visible.)
-    const startHtml = `<div data-type="htmlEmbed" data-source="${encoded}">x</div>`;
-
-    // Export to markdown: the turndown rule emits the <!--html-embed:..-->
-    // marker (lossless, inert in plain markdown viewers).
-    const md = htmlToMarkdown(startHtml);
-    expect(md).toContain("<!--html-embed:" + encoded + "-->");
-
-    // Re-import: the marker round-trips back into an embed div with the same
-    // decoded source — this is the marker <-> embed-div contract the server's
-    // import strip depends on.
-    const html = await markdownToHtml(md);
-    expect(htmlHasHtmlEmbed(html)).toBe(true);
-    expect(extractEmbedSource(html)).toBe(source);
-  });
-
-  it("documents that a BLANK embed div serializes to empty markdown (turndown drops childless blocks)", () => {
-    const encoded = encodeHtmlEmbedSource(source);
-    const blank = `<div data-type="htmlEmbed" data-source="${encoded}"></div>`;
-    // This pins current behavior so a future change to the turndown rule (e.g.
-    // making it fire on blank nodes) is caught rather than silently shipping.
-    expect(htmlToMarkdown(blank)).toBe("");
-  });
-
-  it("the base64 codec itself round-trips (no '<' leaks into the attribute)", () => {
-    const encoded = encodeHtmlEmbedSource(source);
-    expect(encoded).not.toContain("<");
-    expect(decodeHtmlEmbedSource(encoded)).toBe(source);
-  });
-});

packages/editor-ext/src/lib/markdown/utils/basename.ts

@@ -1,29 +0,0 @@
-/**
- * Flexible `basename` implementation for node and the browser
- * @see https://stackoverflow.com/a/59907288/2228771
- */
-export function getBasename(path: string) {
-  // make sure the basename is not empty, if string ends with separator
-  let end = path.length - 1;
-  while (path[end] === '/' || path[end] === '\\') {
-    --end;
-  }
-
-  // support mixing of Win + Unix path separators
-  const i1 = path.lastIndexOf('/', end);
-  const i2 = path.lastIndexOf('\\', end);
-
-  let start: number;
-  if (i1 === -1) {
-    if (i2 === -1) {
-      // no separator in the whole thing
-      return path;
-    }
-    start = i2;
-  } else if (i2 === -1) {
-    start = i1;
-  } else {
-    start = Math.max(i1, i2);
-  }
-  return path.substring(start + 1, end + 1);
-}

packages/editor-ext/src/lib/markdown/utils/callout-common.marked.ts

@@ -1,33 +0,0 @@
-/**
- * Shared pieces for the two callout tokenizers — `callout.marked.ts` (the
- * `:::type` fenced form) and `github-callout.marked.ts` (the `> [!type]` GitHub
- * alert form). Both emit the SAME callout node, so the banner type dictionary
- * and the HTML renderer live here once instead of drifting apart in two files.
- * The tokenizers themselves stay separate (different syntaxes / source matching).
- */
-
-/** The four callout banner types the editor schema supports. */
-export const CALLOUT_TYPES = ['info', 'success', 'warning', 'danger'] as const;
-
-export type CalloutType = (typeof CALLOUT_TYPES)[number];
-
-/**
- * Coerce an arbitrary type name onto a supported banner type, defaulting to
- * `info` for anything unrecognized (the shared fallback both tokenizers use).
- */
-export function normalizeCalloutType(type: string): CalloutType {
-  return (CALLOUT_TYPES as readonly string[]).includes(type)
-    ? (type as CalloutType)
-    : 'info';
-}
-
-/**
- * Render a callout node to the editor's HTML shape. `body` is the already
- * markdown-parsed inner content (marked may hand back a string synchronously).
- */
-export function renderCalloutHtml(
-  type: string,
-  body: string | Promise<string>,
-): string {
-  return `<div data-type="callout" data-callout-type="${type}">${body}</div>`;
-}

packages/editor-ext/src/lib/markdown/utils/callout.marked.ts

@@ -1,37 +0,0 @@
-import { Token, marked } from 'marked';
-import { normalizeCalloutType, renderCalloutHtml } from './callout-common.marked';
-
-interface CalloutToken {
-  type: 'callout';
-  calloutType: string;
-  text: string;
-  raw: string;
-}
-
-export const calloutExtension = {
-  name: 'callout',
-  level: 'block',
-  start(src: string) {
-    return src.match(/:::/)?.index ?? -1;
-  },
-  tokenizer(src: string): CalloutToken | undefined {
-    const rule = /^:::([a-zA-Z0-9]+)\s+([\s\S]+?):::/;
-    const match = rule.exec(src);
-
-    if (match) {
-      return {
-        type: 'callout',
-        calloutType: normalizeCalloutType(match[1]),
-        raw: match[0],
-        text: match[2].trim(),
-      };
-    }
-  },
-  renderer(token: Token) {
-    const calloutToken = token as CalloutToken;
-    return renderCalloutHtml(
-      calloutToken.calloutType,
-      marked.parse(calloutToken.text),
-    );
-  },
-};

packages/editor-ext/src/lib/markdown/utils/footnote.marked.orphan.test.ts

@@ -1,72 +0,0 @@
-import { describe, it, expect } from "vitest";
-import { extractFootnoteDefinitions } from "./footnote.marked";
-
-/** Pull the ordered list of `data-footnote-def` ids out of the rendered section. */
-function defIds(section: string): string[] {
-  return [...section.matchAll(/data-footnote-def data-id="([^"]+)"/g)].map(
-    (m) => m[1],
-  );
-}
-
-/** Pull the ordered list of `[^id]` markers that remain in the body. */
-function bodyMarkers(body: string): string[] {
-  return [...body.matchAll(/\[\^([^\]\s]+)\]/g)].map((m) => m[1]);
-}
-
-describe("extractFootnoteDefinitions: duplicate definition ids (first-wins)", () => {
-  // Body has ONE `[^d]` reference but THREE `[^d]:` definitions. Under the
-  // import model (#166) a duplicate definition id is FIRST-WINS: only the first
-  // definition is kept; the rest are DROPPED (and surfaced by analyzeFootnotes,
-  // not silently re-id'd into orphan footnotes as before). Reference markers are
-  // never rewritten, so repeated references would reuse the single footnote.
-  const md = ["See[^d].", "", "[^d]: a", "[^d]: b", "[^d]: c"].join("\n");
-
-  it("keeps only the FIRST definition for the id (first-wins)", () => {
-    const { section } = extractFootnoteDefinitions(md);
-    const ids = defIds(section);
-    expect(ids).toEqual(["d"]);
-  });
-
-  it("keeps the first definition's text and drops the duplicates", () => {
-    const { section } = extractFootnoteDefinitions(md);
-    expect(section).toContain('data-footnote-def data-id="d"><p>a</p>');
-    // No derived `d__2` / `d__3` ids are emitted anymore.
-    expect(section).not.toContain("d__2");
-    expect(section).not.toContain("d__3");
-    // The dropped duplicate texts are not in the section.
-    expect(section).not.toContain("<p>b</p>");
-    expect(section).not.toContain("<p>c</p>");
-  });
-
-  it("leaves the SINGLE body marker as [^d] (markers are never rewritten)", () => {
-    const { body } = extractFootnoteDefinitions(md);
-    expect(bodyMarkers(body)).toEqual(["d"]);
-    expect(body).toContain("See[^d].");
-    // The definition lines themselves were pulled OUT of the body.
-    expect(body).not.toContain("[^d]: a");
-    expect(body).not.toContain("[^d]: b");
-    expect(body).not.toContain("[^d]: c");
-  });
-
-  it("does not crash and produces a well-formed footnotes section", () => {
-    const { section } = extractFootnoteDefinitions(md);
-    expect(section.startsWith("<section data-footnotes>")).toBe(true);
-    expect(section.endsWith("</section>")).toBe(true);
-    // Exactly one definition div (first-wins).
-    expect([...section.matchAll(/<div data-footnote-def/g)]).toHaveLength(1);
-  });
-});
-
-describe("extractFootnoteDefinitions: reuse (repeated references, one definition)", () => {
-  // Pandoc semantics: many `[^a]` references + one `[^a]:` definition = one
-  // footnote, shared. Markers are left intact so the editor numbers them as one.
-  const md = ["A[^a] B[^a] C[^a].", "", "[^a]: shared note"].join("\n");
-
-  it("emits exactly one definition and leaves every reference marker as [^a]", () => {
-    const { section, body } = extractFootnoteDefinitions(md);
-    expect(defIds(section)).toEqual(["a"]);
-    expect(section).toContain('data-footnote-def data-id="a"><p>shared note</p>');
-    // All three reference markers stay `a` (no `a__2`/`a__3` minting).
-    expect(bodyMarkers(body)).toEqual(["a", "a", "a"]);
-  });
-});

packages/editor-ext/src/lib/markdown/utils/footnote.marked.ts

@@ -1,131 +0,0 @@
-import { marked } from "marked";
-
-/**
- * Pandoc/GFM footnote support for the marked (Markdown -> HTML) pipeline.
- *
- * Two pieces:
- *  - an INLINE tokenizer for `[^id]` references -> <sup data-footnote-ref
- *    data-id="id"> (matches the editor-ext FootnoteReference renderHTML);
- *  - a document hook (`preprocess`/`walkTokens` is awkward for collecting +
- *    removing definitions, so we use a regex preprocessing step instead) that
- *    pulls every `[^id]: text` definition line out of the body and appends a
- *    single <section data-footnotes> with one <div data-footnote-def> per
- *    definition, so the round-trip rebuilds footnotesList + footnoteDefinition.
- *
- * Every FIRST definition line is emitted — duplicate ids are first-wins (the
- * rest are dropped, and surfaced via analyzeFootnotes), and reference markers are
- * left untouched so repeated `[^a]` references reuse the one footnote (#166).
- * Orphan definitions (no matching reference) are still emitted here; the editor's
- * sync plugin reconciles the final reference/definition set (drops orphans,
- * synthesizes a single empty definition for a reference that lacks one).
- */
-
-const DEFINITION_RE = /^\[\^([^\]\s]+)\]:[ \t]*(.*)$/;
-const REFERENCE_RE = /\[\^([^\]\s]+)\]/;
-
-interface FootnoteRefToken {
-  type: "footnoteRef";
-  raw: string;
-  id: string;
-}
-
-export const footnoteReferenceExtension = {
-  name: "footnoteRef",
-  level: "inline" as const,
-  start(src: string) {
-    return src.match(/\[\^/)?.index ?? -1;
-  },
-  tokenizer(src: string): FootnoteRefToken | undefined {
-    const match = REFERENCE_RE.exec(src);
-    // Only match at the very start of the remaining inline source.
-    if (match && match.index === 0) {
-      return {
-        type: "footnoteRef",
-        raw: match[0],
-        id: match[1],
-      };
-    }
-    return undefined;
-  },
-  renderer(token: FootnoteRefToken) {
-    return `<sup data-footnote-ref data-id="${escapeAttr(token.id)}"></sup>`;
-  },
-};
-
-function escapeAttr(value: string): string {
-  return String(value).replace(/&/g, "&amp;").replace(/"/g, "&quot;");
-}
-
-/**
- * Extract `[^id]: text` definition lines from the markdown body, returning the
- * cleaned body plus a rendered <section data-footnotes> (empty string when no
- * definitions). Call this BEFORE marked.parse and append the section to the
- * resulting HTML.
- */
-export function extractFootnoteDefinitions(markdown: string): {
-  body: string;
-  section: string;
-} {
-  const lines = markdown.split("\n");
-  const bodyLines: string[] = [];
-  const definitions: Array<{ id: string; text: string }> = [];
-
-  // Track fenced-code state so a `[^id]: ...` line that merely SHOWS footnote
-  // syntax inside a ``` / ~~~ code block is left in the body verbatim and not
-  // mistaken for a real definition.
-  let fence: string | null = null;
-
-  for (const line of lines) {
-    const fenceMatch = /^(\s*)(`{3,}|~{3,})/.exec(line);
-    if (fenceMatch) {
-      const marker = fenceMatch[2][0];
-      if (fence === null) {
-        fence = marker; // opening fence
-      } else if (marker === fence) {
-        fence = null; // closing fence (matching delimiter type)
-      }
-      bodyLines.push(line);
-      continue;
-    }
-
-    const m = fence === null ? DEFINITION_RE.exec(line) : null;
-    if (m) {
-      definitions.push({ id: m[1], text: m[2] });
-    } else {
-      bodyLines.push(line);
-    }
-  }
-
-  if (definitions.length === 0) {
-    return { body: markdown, section: "" };
-  }
-
-  // Duplicate definition ids (e.g. `[^d]: first` / `[^d]: second`): FIRST WINS,
-  // the rest are DROPPED. Reference markers are left UNTOUCHED so repeated `[^a]`
-  // references reuse the single footnote (Pandoc semantics, #166). This differs
-  // from the live editor's never-lose policy (resolveCollisions re-ids a
-  // duplicate definition into an orphan) on purpose: an import is an
-  // agent-authored artifact we sanitize, and the dropped duplicate is surfaced
-  // to the caller via analyzeFootnotes' `duplicateDefinitions` warning instead.
-  const firstById = new Map<string, string>(); // id -> first definition text
-  for (const def of definitions) {
-    if (!firstById.has(def.id)) firstById.set(def.id, def.text);
-  }
-
-  const defsHtml = [...firstById.entries()]
-    .map(([id, text]) => {
-      // Render the definition text as inline markdown so emphasis/links inside
-      // a footnote survive the round-trip; wrap in a paragraph (the node's
-      // content is paragraph+).
-      const inner = marked.parseInline(text || "");
-      return `<div data-footnote-def data-id="${escapeAttr(
-        id,
-      )}"><p>${inner}</p></div>`;
-    })
-    .join("");
-
-  return {
-    body: bodyLines.join("\n"),
-    section: `<section data-footnotes>${defsHtml}</section>`,
-  };
-}

packages/editor-ext/src/lib/markdown/utils/github-callout.marked.test.ts

@@ -1,54 +0,0 @@
-import { describe, it, expect } from "vitest";
-import { markdownToHtml } from "./marked.utils";
-
-/**
- * Regression for issue #192: pasting a GitHub-style `> [!type]` alert produced a
- * literal `<blockquote>` containing `[!info]` instead of a callout node, because
- * only the `:::type` form was tokenized. The editor paste path runs the same
- * `markdownToHtml`, so these assertions pin the conversion at the source.
- */
-function html(md: string): string {
-  const out = markdownToHtml(md);
-  if (typeof out !== "string") throw new Error("expected sync string output");
-  return out;
-}
-
-describe("markdownToHtml: GitHub `> [!type]` callouts", () => {
-  it("converts `> [!info]` to a callout node, not a literal blockquote", () => {
-    const out = html("> [!info]\n> Callout body text here");
-    expect(out).toContain('data-type="callout"');
-    expect(out).toContain('data-callout-type="info"');
-    expect(out).toContain("Callout body text here");
-    expect(out).not.toContain("[!info]");
-    expect(out).not.toContain("<blockquote");
-  });
-
-  it("maps GitHub alert aliases onto the supported banner types", () => {
-    expect(html("> [!NOTE]\n> x")).toContain('data-callout-type="info"');
-    expect(html("> [!TIP]\n> x")).toContain('data-callout-type="success"');
-    expect(html("> [!WARNING]\n> x")).toContain('data-callout-type="warning"');
-    expect(html("> [!CAUTION]\n> x")).toContain('data-callout-type="danger"');
-  });
-
-  it("accepts the editor's own type names directly", () => {
-    expect(html("> [!success]\n> x")).toContain('data-callout-type="success"');
-    expect(html("> [!danger]\n> x")).toContain('data-callout-type="danger"');
-  });
-
-  it("falls back to info for an unknown type", () => {
-    expect(html("> [!bogus]\n> x")).toContain('data-callout-type="info"');
-  });
-
-  it("preserves multi-line callout bodies", () => {
-    const out = html("> [!warning]\n> line one\n> line two");
-    expect(out).toContain('data-callout-type="warning"');
-    expect(out).toContain("line one");
-    expect(out).toContain("line two");
-  });
-
-  it("still converts the `:::type` form", () => {
-    const out = html(":::info\nbody\n:::");
-    expect(out).toContain('data-type="callout"');
-    expect(out).toContain('data-callout-type="info"');
-  });
-});

packages/editor-ext/src/lib/markdown/utils/github-callout.marked.ts

@@ -1,81 +0,0 @@
-import { Token, marked } from 'marked';
-import { renderCalloutHtml } from './callout-common.marked';
-
-interface GithubCalloutToken {
-  type: 'githubCallout';
-  calloutType: string;
-  text: string;
-  raw: string;
-}
-
-/**
- * Map GitHub "alert" blockquote markers (`> [!NOTE]`, `> [!WARNING]`, …) onto
- * the four callout banner types the editor schema supports. The editor's own
- * type names (`info`/`success`/`warning`/`danger`) are also accepted directly,
- * because users paste both forms. Anything unrecognized falls back to `info`,
- * matching the `:::type` callout tokenizer.
- */
-const GITHUB_ALERT_TYPE_MAP: Record<string, string> = {
-  note: 'info',
-  tip: 'success',
-  important: 'info',
-  warning: 'warning',
-  caution: 'danger',
-  info: 'info',
-  success: 'success',
-  danger: 'danger',
-};
-
-/**
- * Tokenizer for GitHub-flavored alert callouts written as a blockquote whose
- * first line is `[!type]`:
- *
- *   > [!info]
- *   > body line one
- *   > body line two
- *
- * Without this, the default blockquote tokenizer wins and the marker renders as
- * a literal `[!info]` inside a `<blockquote>`. The editor's paste path runs the
- * same `markdownToHtml`, so registering this here also fixes pasting the syntax
- * into the editor (issue #192), not just markdown import.
- */
-export const githubCalloutExtension = {
-  name: 'githubCallout',
-  level: 'block' as const,
-  start(src: string) {
-    return src.match(/^ {0,3}>[ \t]*\[!/m)?.index ?? -1;
-  },
-  tokenizer(src: string): GithubCalloutToken | undefined {
-    const rule =
-      /^ {0,3}>[ \t]*\[!([a-zA-Z]+)\][^\n]*(?:\n {0,3}>[^\n]*)*(?:\n|$)/;
-    const match = rule.exec(src);
-    if (!match) return undefined;
-
-    const rawType = match[1].toLowerCase();
-    const calloutType = GITHUB_ALERT_TYPE_MAP[rawType] ?? 'info';
-
-    const text = match[0]
-      .replace(/\n+$/, '')
-      .split('\n')
-      // Strip the blockquote marker (`>` + optional space) from every line.
-      .map((line) => line.replace(/^ {0,3}>[ \t]?/, ''))
-      // Drop the `[!type]` marker that opens the first line.
-      .map((line, i) => (i === 0 ? line.replace(/^\[![a-zA-Z]+\][ \t]*/, '') : line))
-      .join('\n')
-      .trim();
-
-    return {
-      type: 'githubCallout',
-      calloutType,
-      raw: match[0],
-      text,
-    };
-  },
-  renderer(token: Token) {
-    const calloutToken = token as GithubCalloutToken;
-    return renderCalloutHtml(
-      calloutToken.calloutType,
-      marked.parse(calloutToken.text),
-    );
-  },
-};

packages/editor-ext/src/lib/markdown/utils/html-embed.marked.ts

@@ -1,41 +0,0 @@
-import { Token } from "marked";
-
-interface HtmlEmbedToken {
-  type: "htmlEmbed";
-  raw: string;
-  encoded: string;
-}
-
-/**
- * Marked extension that rebuilds an `htmlEmbed` node from the HTML comment
- * marker produced by the turndown rule (`<!--html-embed:<base64>-->`).
- *
- * It emits the same marker div the node's `parseHTML` recognizes, so the
- * pipeline MD -> HTML -> ProseMirror JSON restores the node (and its
- * base64 `data-source`) exactly. We do NOT expand the raw markup here; the
- * source stays base64-encoded in the attribute and is only executed by the
- * client NodeView.
- */
-export const htmlEmbedExtension = {
-  name: "htmlEmbed",
-  level: "block" as const,
-  start(src: string) {
-    return src.indexOf("<!--html-embed:");
-  },
-  tokenizer(src: string): HtmlEmbedToken | undefined {
-    const rule = /^<!--html-embed:([A-Za-z0-9+/=]*)-->/;
-    const match = rule.exec(src);
-
-    if (match) {
-      return {
-        type: "htmlEmbed",
-        raw: match[0],
-        encoded: match[1] ?? "",
-      };
-    }
-  },
-  renderer(token: Token) {
-    const htmlEmbedToken = token as HtmlEmbedToken;
-    return `<div data-type="htmlEmbed" data-source="${htmlEmbedToken.encoded}"></div>`;
-  },
-};

packages/editor-ext/src/lib/markdown/utils/marked.utils.ts

@@ -1,76 +0,0 @@
-import { marked } from "marked";
-import { calloutExtension } from "./callout.marked";
-import { githubCalloutExtension } from "./github-callout.marked";
-import { mathBlockExtension } from "./math-block.marked";
-import { mathInlineExtension } from "./math-inline.marked";
-import {
-  footnoteReferenceExtension,
-  extractFootnoteDefinitions,
-} from "./footnote.marked";
-import { htmlEmbedExtension } from "./html-embed.marked";
-
-marked.use({
-  renderer: {
-    list({ ordered, start, items }) {
-      let body = "";
-      for (const item of items) {
-        body += this.listitem(item);
-      }
-
-      if (ordered) {
-        const startAttr = start !== 1 ? ` start="${start}"` : "";
-        return `<ol${startAttr}>\n${body}</ol>\n`;
-      }
-
-      const isTaskList = items.some((item) => item.task);
-      const dataType = isTaskList ? ' data-type="taskList"' : "";
-      return `<ul${dataType}>\n${body}</ul>\n`;
-    },
-    listitem({ tokens, task: isTask, checked: isChecked }) {
-      const text = this.parser.parse(tokens);
-      if (!isTask) {
-        return `<li>${text}</li>\n`;
-      }
-      const checkedAttr = isChecked
-        ? 'data-checked="true"'
-        : 'data-checked="false"';
-      return `<li data-type="taskItem" ${checkedAttr}>${text}</li>\n`;
-    },
-  },
-});
-
-marked.use({
-  extensions: [
-    calloutExtension,
-    githubCalloutExtension,
-    mathBlockExtension,
-    mathInlineExtension,
-    footnoteReferenceExtension,
-    htmlEmbedExtension,
-  ],
-});
-
-marked.setOptions({ breaks: true });
-
-export function markdownToHtml(
-  markdownInput: string,
-): string | Promise<string> {
-  const YAML_FONT_MATTER_REGEX = /^\s*---[\s\S]*?---\s*/;
-
-  const markdown = markdownInput
-    .replace(YAML_FONT_MATTER_REGEX, "")
-    .trimStart();
-
-  // Pull `[^id]: ...` definition lines out of the body, render the body, then
-  // append a single <section data-footnotes> so the round-trip rebuilds the
-  // footnotesList + footnoteDefinition nodes.
-  const { body, section } = extractFootnoteDefinitions(markdown);
-
-  const parsed = marked.parse(body);
-  if (!section) return parsed;
-
-  if (typeof parsed === "string") {
-    return parsed + section;
-  }
-  return parsed.then((html) => html + section);
-}

packages/editor-ext/src/lib/markdown/utils/math-block.marked.ts

@@ -1,37 +0,0 @@
-import { Token, marked } from 'marked';
-
-interface MathBlockToken {
-  type: 'mathBlock';
-  text: string;
-  raw: string;
-}
-
-export const mathBlockExtension = {
-  name: 'mathBlock',
-  level: 'block',
-  start(src: string) {
-    return src.match(/\$\$/)?.index ?? -1;
-  },
-  tokenizer(src: string): MathBlockToken | undefined {
-    const rule = /^\$\$(?!(\$))([\s\S]+?)\$\$/;
-    const match = rule.exec(src);
-
-    if (match) {
-      return {
-        type: 'mathBlock',
-        raw: match[0],
-        text: match[2]?.trim(),
-      };
-    }
-  },
-  renderer(token: Token) {
-    const mathBlockToken = token as MathBlockToken;
-    // parse to prevent escaping slashes
-    const latex = marked
-      .parse(mathBlockToken.text)
-      .toString()
-      .replace(/<(\/)?p>/g, '');
-
-    return `<div data-type="${mathBlockToken.type}" data-katex="true">${latex}</div>`;
-  },
-};

packages/editor-ext/src/lib/markdown/utils/math-inline.marked.falsepositive.test.ts

@@ -1,50 +0,0 @@
-import { describe, it, expect } from "vitest";
-import { markdownToHtml } from "./marked.utils";
-
-/**
- * Data-integrity regression (issue #204, Phase 2): plain prose that mentions
- * prices like `$5 and $6` must NOT be misread as inline math. The inline-math
- * tokenizer mutates a global `marked` singleton at import time
- * (`marked.utils.ts`), so math behaviour can only be exercised safely through
- * the public `markdownToHtml`; importing the tokenizer in isolation would give
- * a different, non-representative result. These assertions therefore drive the
- * real conversion path.
- */
-function html(md: string): string {
-  const out = markdownToHtml(md);
-  if (typeof out !== "string") throw new Error("expected sync string output");
-  return out;
-}
-
-const MATH_MARKERS = ['data-type="mathInline"', 'data-katex="true"'];
-
-function hasInlineMath(out: string): boolean {
-  return MATH_MARKERS.some((m) => out.includes(m));
-}
-
-describe("markdownToHtml: inline-math false positives", () => {
-  it("does not treat prices `$5 and $6` as inline math", () => {
-    const out = html("It costs $5 and $6 today.");
-    expect(hasInlineMath(out)).toBe(false);
-    // The text survives verbatim (no katex span swallowing it).
-    expect(out).toContain("$5 and $6");
-  });
-
-  it("does not treat a single trailing price `$5` as inline math", () => {
-    const out = html("Lunch was $5.");
-    expect(hasInlineMath(out)).toBe(false);
-    expect(out).toContain("$5");
-  });
-
-  it("does not treat `$5, $6, $7` (multiple prices) as inline math", () => {
-    const out = html("Choose $5, $6, $7 plans.");
-    expect(hasInlineMath(out)).toBe(false);
-  });
-
-  it("STILL converts a genuine inline-math expression `$x + y$`", () => {
-    // Guard the positive path so the false-positive guard above can't be
-    // satisfied by simply disabling math entirely.
-    const out = html("The sum $x + y$ is shown.");
-    expect(hasInlineMath(out)).toBe(true);
-  });
-});

packages/editor-ext/src/lib/markdown/utils/math-inline.marked.ts

@@ -1,55 +0,0 @@
-import { Token, marked } from 'marked';
-
-interface MathInlineToken {
-  type: 'mathInline';
-  text: string;
-  raw: string;
-}
-
-const inlineMathRegex = /^\$(?!\s)(.+?)(?<!\s)\$(?!\d)/;
-
-export const mathInlineExtension = {
-  name: 'mathInline',
-  level: 'inline',
-  start(src: string) {
-    let index: number;
-    let indexSrc = src;
-
-    while (indexSrc) {
-      index = indexSrc.indexOf('$');
-      if (index === -1) {
-        return;
-      }
-      const f = index === 0 || indexSrc.charAt(index - 1) === ' ';
-      if (f) {
-        const possibleKatex = indexSrc.substring(index);
-        if (possibleKatex.match(inlineMathRegex)) {
-          return index;
-        }
-      }
-
-      indexSrc = indexSrc.substring(index + 1).replace(/^\$+/, '');
-    }
-  },
-  tokenizer(src: string): MathInlineToken | undefined {
-    const match = inlineMathRegex.exec(src);
-
-    if (match) {
-      return {
-        type: 'mathInline',
-        raw: match[0],
-        text: match[1]?.trim(),
-      };
-    }
-  },
-  renderer(token: Token) {
-    const mathInlineToken = token as MathInlineToken;
-    // parse to prevent escaping slashes
-    const latex = marked
-      .parse(mathInlineToken.text)
-      .toString()
-      .replace(/<(\/)?p>/g, '');
-
-    return `<span data-type="${mathInlineToken.type}" data-katex="true">${latex}</span>`;
-  },
-};

packages/editor-ext/src/lib/markdown/utils/spoiler.marked.test.ts

@@ -1,128 +0,0 @@
-import { describe, it, expect } from "vitest";
-import { getSchema } from "@tiptap/core";
-import { generateHTML, generateJSON } from "@tiptap/html";
-import { Document } from "@tiptap/extension-document";
-import { Paragraph } from "@tiptap/extension-paragraph";
-import { Text } from "@tiptap/extension-text";
-import { Bold } from "@tiptap/extension-bold";
-import { htmlToMarkdown } from "./turndown.utils";
-import { markdownToHtml } from "./marked.utils";
-import { Spoiler } from "../../spoiler/spoiler";
-
-// The spoiler mark has no native Markdown syntax, so it is preserved losslessly
-// as raw inline HTML (`<span data-spoiler="true">…</span>`), the same approach
-// htmlEmbed uses. This test drives the full editor round-trip:
-//   JSON -> HTML -> Markdown -> HTML -> JSON
-// and asserts the `spoiler` mark survives end to end. We use the same
-// getSchema + @tiptap/html generateHTML/generateJSON utilities the other
-// editor-ext schema tests use.
-
-const extensions = [Document, Paragraph, Text, Bold, Spoiler];
-
-function html(md: string): string {
-  const out = markdownToHtml(md);
-  if (typeof out !== "string") throw new Error("expected sync string output");
-  return out;
-}
-
-// Count text nodes carrying a `spoiler` mark anywhere in a ProseMirror JSON doc.
-function countSpoilerMarks(doc: any): number {
-  let count = 0;
-  const walk = (node: any) => {
-    if (!node || typeof node !== "object") return;
-    if (Array.isArray(node.marks)) {
-      for (const mark of node.marks) {
-        if (mark?.type === "spoiler") count++;
-      }
-    }
-    if (Array.isArray(node.content)) node.content.forEach(walk);
-  };
-  walk(doc);
-  return count;
-}
-
-describe("Spoiler mark schema", () => {
-  it("registers the spoiler mark in the schema", () => {
-    const schema = getSchema(extensions);
-    expect(schema.marks.spoiler).toBeTruthy();
-  });
-
-  it("recovers the spoiler mark from span[data-spoiler] (HTML -> JSON)", () => {
-    const json = generateJSON(
-      '<p>before <span data-spoiler="true">hidden</span> after</p>',
-      extensions,
-    );
-    expect(countSpoilerMarks(json)).toBe(1);
-  });
-
-  it("emits data-spoiler + class on render (JSON -> HTML)", () => {
-    const doc = {
-      type: "doc",
-      content: [
-        {
-          type: "paragraph",
-          content: [
-            {
-              type: "text",
-              text: "hidden",
-              marks: [{ type: "spoiler" }],
-            },
-          ],
-        },
-      ],
-    };
-    const out = generateHTML(doc, extensions);
-    expect(out).toContain('data-spoiler="true"');
-    expect(out).toContain('class="spoiler"');
-  });
-});
-
-describe("Spoiler Markdown round-trip is lossless", () => {
-  const docWith = (textNode: any) => ({
-    type: "doc",
-    content: [
-      {
-        type: "paragraph",
-        content: [{ type: "text", text: "before " }, textNode, { type: "text", text: " after" }],
-      },
-    ],
-  });
-
-  it("preserves the spoiler mark through JSON -> MD -> HTML -> JSON", () => {
-    const startDoc = docWith({
-      type: "text",
-      text: "hidden",
-      marks: [{ type: "spoiler" }],
-    });
-
-    // JSON -> HTML
-    const html1 = generateHTML(startDoc, extensions);
-    expect(html1).toContain('data-spoiler="true"');
-
-    // HTML -> Markdown (raw inline HTML, lossless)
-    const md = htmlToMarkdown(html1);
-    expect(md).toContain('<span data-spoiler="true">hidden</span>');
-
-    // MD -> HTML -> JSON (mark restored via parseHTML)
-    const endJson = generateJSON(html(md), extensions);
-    expect(countSpoilerMarks(endJson)).toBe(1);
-    // The visible text survives.
-    expect(JSON.stringify(endJson)).toContain("hidden");
-  });
-
-  it("keeps the spoiler intact when it intersects a bold mark", () => {
-    const startDoc = docWith({
-      type: "text",
-      text: "secret",
-      marks: [{ type: "bold" }, { type: "spoiler" }],
-    });
-
-    const md = htmlToMarkdown(generateHTML(startDoc, extensions));
-    expect(md).toContain("data-spoiler=\"true\"");
-
-    const endJson = generateJSON(html(md), extensions);
-    expect(countSpoilerMarks(endJson)).toBe(1);
-    // Bold survives alongside the spoiler.
-    expect(JSON.stringify(endJson)).toContain('"bold"');
-  });
-});

packages/editor-ext/src/lib/markdown/utils/turndown.d.ts

@@ -1,12 +0,0 @@
-// Map @joplin/turndown types to @types/turndown
-declare module "@joplin/turndown" {
-  import TurndownService from "turndown";
-  export = TurndownService;
-}
-
-declare module "@joplin/turndown-plugin-gfm" {
-  import TurndownService from "turndown";
-  export const tables: TurndownService.Plugin;
-  export const strikethrough: TurndownService.Plugin;
-  export const highlightedCodeBlock: TurndownService.Plugin;
-}

packages/editor-ext/src/lib/markdown/utils/turndown.dataloss.test.ts

@@ -1,147 +0,0 @@
-import { describe, it, expect } from "vitest";
-import { htmlToMarkdown } from "./turndown.utils";
-import { markdownToHtml } from "./marked.utils";
-
-/**
- * #206 mdrt-2 — Markdown export must never SILENTLY drop a block. (FIXED)
- *
- * `htmlToMarkdown` (turndown) historically only registered rules for a fixed
- * set of custom nodes (callout, taskItem, details, math, iframe, htmlEmbed,
- * image, video, footnote). Any other custom node — `transclusionReference`,
- * `pageBreak`, `mention`, `status` — fell through to turndown's default
- * handling: an empty wrapper is "blank" and removed, so the block disappeared
- * from the exported Markdown with no trace, and `mention`/`status` collapsed to
- * bare text, losing their identity (data-id / data-color). The invariant
- * "never silently lose a block" was broken.
- *
- * The fix adds lossless turndown rules that re-emit each of these nodes as raw
- * HTML carrying every `data-*` attribute. Plain-Markdown viewers ignore the
- * inert tag; the import path round-trips it (`markdownToHtml` passes the raw
- * HTML through and each node's `parseHTML` rebuilds the ProseMirror node). These
- * tests assert the surviving contract (the block is preserved AND its identity
- * round-trips back through import).
- */
-describe("htmlToMarkdown — custom nodes are preserved losslessly (#206 mdrt-2)", () => {
-  const wrap = (inner: string) => `<p>before</p>${inner}<p>after</p>`;
-
-  it("preserves a pageBreak block on Markdown export", () => {
-    const md = htmlToMarkdown(
-      wrap('<div data-type="pageBreak" class="page-break"></div>'),
-    );
-    expect(md).toContain("before");
-    expect(md).toContain("after");
-    // The break survives as an inert raw-HTML tag, not silently dropped.
-    expect(md).toMatch(/data-type="pageBreak"/);
-    expect(md).toMatch(/page-?break/i);
-  });
-
-  it("preserves a transclusionReference's identity on Markdown export", () => {
-    const md = htmlToMarkdown(
-      wrap('<div data-type="transclusionReference" data-id="abc"></div>'),
-    );
-    expect(md).toContain("before");
-    expect(md).toContain("after");
-    // The data-id (the only thing that gives the reference identity) survives.
-    expect(md).toContain("abc");
-    expect(md).toMatch(/data-type="transclusionReference"/);
-  });
-
-  it("preserves a mention's data-id (stable identity) on Markdown export", () => {
-    const md = htmlToMarkdown(
-      '<p>hi <span data-type="mention" data-id="u1" data-label="Bob">@Bob</span> there</p>',
-    );
-    // The mention keeps its stable identity (data-id), not just the text.
-    expect(md).toContain("u1");
-    expect(md).toContain("Bob");
-    expect(md).toMatch(/data-type="mention"/);
-  });
-
-  it("preserves a status chip's color on Markdown export", () => {
-    const md = htmlToMarkdown(
-      '<p>s <span data-type="status" data-color="green">Done</span></p>',
-    );
-    // The chip's color (its identity) survives, not just the visible text.
-    expect(md).toContain("green");
-    expect(md).toContain("Done");
-    expect(md).toMatch(/data-type="status"/);
-  });
-
-  // The export form is only lossless if the import path can rebuild it. These
-  // assert the full MD -> HTML round-trip restores the node + its attributes,
-  // which is the marker <-> node contract each `parseHTML` relies on.
-  describe("import round-trip (markdownToHtml restores the node)", () => {
-    it("round-trips a pageBreak through export + import", async () => {
-      const md = htmlToMarkdown(
-        wrap('<div data-type="pageBreak" class="page-break"></div>'),
-      );
-      const html = await markdownToHtml(md);
-      expect(html).toMatch(/<div[^>]*data-type="pageBreak"[^>]*>/);
-      expect(html).toContain("before");
-      expect(html).toContain("after");
-    });
-
-    it("round-trips a transclusionReference (keeps data-id)", async () => {
-      const md = htmlToMarkdown(
-        wrap('<div data-type="transclusionReference" data-id="abc"></div>'),
-      );
-      const html = await markdownToHtml(md);
-      expect(html).toMatch(/<div[^>]*data-type="transclusionReference"[^>]*>/);
-      expect(html).toContain("abc");
-    });
-
-    it("round-trips a mention (keeps data-id + data-label)", async () => {
-      const md = htmlToMarkdown(
-        '<p>hi <span data-type="mention" data-id="u1" data-label="Bob">@Bob</span> there</p>',
-      );
-      const html = await markdownToHtml(md);
-      expect(html).toMatch(/<span[^>]*data-type="mention"[^>]*>/);
-      expect(html).toContain("u1");
-      expect(html).toContain("Bob");
-    });
-
-    it("round-trips a status chip (keeps data-color)", async () => {
-      const md = htmlToMarkdown(
-        '<p>s <span data-type="status" data-color="green">Done</span></p>',
-      );
-      const html = await markdownToHtml(md);
-      expect(html).toMatch(/<span[^>]*data-type="status"[^>]*>/);
-      expect(html).toContain("green");
-    });
-
-    // HTML special chars in an attribute value or in a node's text must be
-    // ESCAPED when re-emitted as raw HTML, otherwise the exported tag is
-    // malformed and `markdownToHtml`'s parser cannot restore the original value
-    // (the same silent data loss this PR fixes). Dropping `<`/`>` escaping is the
-    // dangerous regression: a stray `<` or `>` corrupts the tag (or injects new
-    // markup), so the test data carries ALL of `&`, `"`, `<`, `>` in BOTH the
-    // data-label attribute and the visible text. That fully exercises
-    // escapeHtmlAttr's `&,",<,>` branches and escapeHtmlText's `&,<,>` branches
-    // (escapeHtmlText leaves `"` literal); the alphanumeric-only cases above hit
-    // none of them.
-    it("escapes HTML special chars (& \" < >) in attrs + text and round-trips them", async () => {
-      const md = htmlToMarkdown(
-        `<p>hi <span data-type="mention" data-id="u1" data-label="A &amp; &lt;B&gt; &quot;C&quot;">@A &amp; &lt;B&gt; "C"</span> there</p>`,
-      );
-
-      // (a) The exported Markdown carries a WELL-FORMED, correctly-escaped tag:
-      // the attribute escapes `&`, `<`, `>` AND `"`; the text escapes `&`, `<`,
-      // `>` (a `"` inside text content is legal, so it stays literal).
-      expect(md).toContain('data-label="A &amp; &lt;B&gt; &quot;C&quot;"');
-      expect(md).toContain('>@A &amp; &lt;B&gt; "C"</span>');
-      // And explicitly NOT the raw, tag-corrupting forms: a literal `<B>` (would
-      // mean `<`/`>` escaping was dropped in either the attr or the text)...
-      expect(md).not.toContain("<B>");
-      // ...nor the malformed attribute that an unescaped `"` would produce.
-      expect(md).not.toContain('data-label="A &amp; &lt;B&gt; "C""');
-
-      // (b) Import restores the ORIGINAL (unescaped) values, attribute and text.
-      const html = await markdownToHtml(md);
-      const dom = new DOMParser().parseFromString(html as string, "text/html");
-      const span = dom.querySelector('span[data-type="mention"]');
-      expect(span).not.toBeNull();
-      expect(span!.getAttribute("data-id")).toBe("u1");
-      expect(span!.getAttribute("data-label")).toBe('A & <B> "C"');
-      expect(span!.textContent).toBe('@A & <B> "C"');
-    });
-  });
-});

packages/editor-ext/src/lib/markdown/utils/turndown.utils.ts

@@ -1,488 +0,0 @@
-import * as _TurndownService from '@joplin/turndown';
-import * as TurndownPluginGfm from '@joplin/turndown-plugin-gfm';
-import { getBasename } from './basename';
-
-// CJS/ESM interop: .default exists in Vite, not in NestJS
-const TurndownService = (_TurndownService as any).default || _TurndownService;
-
-function sanitizeMdLinkText(value: string): string {
-  return value
-    .replace(/\\/g, '\\\\')
-    .replace(/([\[\]!])/g, '\\$1')
-    .replace(/[\r\n]+/g, ' ');
-}
-
-// Tags turndown treats as void (self-closing). Footnote references render as an
-// empty <sup data-footnote-ref> whose meaning lives entirely in its data-id;
-// without marking it void, turndown's blank-node removal drops it before our
-// rule runs, losing the `[^id]` marker. Mirrors turndown's built-in list.
-const TURNDOWN_VOID_ELEMENTS = [
-  'AREA', 'BASE', 'BR', 'COL', 'COMMAND', 'EMBED', 'HR', 'IMG', 'INPUT',
-  'KEYGEN', 'LINK', 'META', 'PARAM', 'SOURCE', 'TRACK', 'WBR',
-];
-
-function isVoidNode(node: any): boolean {
-  const name = node?.nodeName?.toUpperCase?.();
-  if (!name) return false;
-  if (name === 'SUP' && node.hasAttribute?.('data-footnote-ref')) {
-    return true;
-  }
-  return TURNDOWN_VOID_ELEMENTS.indexOf(name) !== -1;
-}
-
-/**
- * An empty <sup data-footnote-ref> is "blank" to turndown, which removes blank
- * inline nodes (RootNode/Node use a module-level isVoid the options cannot
- * override). To survive, inject the id as text content so the node is non-blank;
- * the footnoteReference rule then reads data-id and emits `[^id]`.
- */
-function fillEmptyFootnoteRefs(html: string): string {
-  return html.replace(
-    /<sup\b([^>]*\bdata-footnote-ref\b[^>]*)>\s*<\/sup>/gi,
-    (_m, attrs) => `<sup${attrs}>​</sup>`,
-  );
-}
-
-/**
- * `pageBreak` and `transclusionReference` are childless atom <div>s. Like an
- * empty footnote ref (see above), turndown treats a childless block as "blank"
- * and replaces it with the blankRule BEFORE any custom rule can fire — so the
- * node disappears from the export with no trace (#206 mdrt-2). Inject a
- * zero-width space so the node is non-blank and our lossless rule runs; the
- * rule rebuilds the tag from the element's attributes, so the injected char
- * never reaches the output.
- */
-function fillEmptyAtomBlocks(html: string): string {
-  return html.replace(
-    /<div\b([^>]*\bdata-type="(?:pageBreak|transclusionReference)"[^>]*)>\s*<\/div>/gi,
-    (_m, attrs) => `<div${attrs}>​</div>`,
-  );
-}
-
-/** HTML-escape an attribute value so a re-emitted raw-HTML tag is well-formed. */
-function escapeHtmlAttr(value: string): string {
-  return value
-    .replace(/&/g, '&amp;')
-    .replace(/"/g, '&quot;')
-    .replace(/</g, '&lt;')
-    .replace(/>/g, '&gt;');
-}
-
-/** HTML-escape text placed inside a re-emitted raw-HTML element. */
-function escapeHtmlText(value: string): string {
-  return value
-    .replace(/&/g, '&amp;')
-    .replace(/</g, '&lt;')
-    .replace(/>/g, '&gt;');
-}
-
-/**
- * Serialize ALL of an element's attributes back to a raw-HTML attribute string
- * (leading space included). Generic on purpose: a custom node's identity lives
- * entirely in its `data-*` attributes (data-id, data-color, data-source-page-id,
- * data-transclusion-id, …), and serializing every attribute keeps the export
- * lossless regardless of which attributes a given node carries.
- */
-function serializeAttrs(node: any): string {
-  const attrs = node?.attributes;
-  if (!attrs) return '';
-  return Array.from(attrs as ArrayLike<{ name: string; value: string }>)
-    .map((attr) => ` ${attr.name}="${escapeHtmlAttr(attr.value ?? '')}"`)
-    .join('');
-}
-
-export function htmlToMarkdown(html: string): string {
-  const turndownService = new TurndownService({
-    headingStyle: 'atx',
-    codeBlockStyle: 'fenced',
-    hr: '---',
-    bulletListMarker: '-',
-    isVoid: isVoidNode,
-  });
-
-  turndownService.use([
-    TurndownPluginGfm.tables,
-    TurndownPluginGfm.strikethrough,
-    TurndownPluginGfm.highlightedCodeBlock,
-    taskList,
-    callout,
-    preserveDetail,
-    listParagraph,
-    orderedListItem,
-    mathInline,
-    mathBlock,
-    iframeEmbed,
-    htmlEmbed,
-    spoiler,
-    image,
-    video,
-    footnoteReference,
-    footnotesList,
-    pageBreak,
-    transclusionReference,
-    mention,
-    status,
-  ]);
-  return turndownService
-    .turndown(fillEmptyAtomBlocks(fillEmptyFootnoteRefs(html)))
-    .replaceAll('<br>', ' ');
-}
-
-/**
- * Lossless export rules for custom nodes that have NO native Markdown syntax
- * (#206 mdrt-2). Markdown cannot represent a page break, a transclusion
- * reference, a mention's stable id, or a status chip's color — so rather than
- * letting turndown silently drop them, each rule re-emits the node as raw HTML
- * carrying every `data-*` attribute. Plain-Markdown viewers ignore the inert
- * tag, and the import path round-trips it: `markdownToHtml` passes raw HTML
- * through and each node's `parseHTML` (`div[data-type="…"]`, `span[…]`) rebuilds
- * the ProseMirror node with its attributes intact.
- */
-function pageBreak(turndownService: _TurndownService) {
-  turndownService.addRule('pageBreak', {
-    filter: function (node: HTMLInputElement) {
-      return (
-        node.nodeName === 'DIV' &&
-        node.getAttribute('data-type') === 'pageBreak'
-      );
-    },
-    replacement: function (_content: string, node: HTMLInputElement) {
-      return `\n\n<div${serializeAttrs(node)}></div>\n\n`;
-    },
-  });
-}
-
-function transclusionReference(turndownService: _TurndownService) {
-  turndownService.addRule('transclusionReference', {
-    filter: function (node: HTMLInputElement) {
-      return (
-        node.nodeName === 'DIV' &&
-        node.getAttribute('data-type') === 'transclusionReference'
-      );
-    },
-    replacement: function (_content: string, node: HTMLInputElement) {
-      return `\n\n<div${serializeAttrs(node)}></div>\n\n`;
-    },
-  });
-}
-
-function mention(turndownService: _TurndownService) {
-  turndownService.addRule('mention', {
-    filter: function (node: HTMLInputElement) {
-      return (
-        node.nodeName === 'SPAN' &&
-        node.getAttribute('data-type') === 'mention'
-      );
-    },
-    replacement: function (_content: string, node: HTMLInputElement) {
-      const text = escapeHtmlText(node.textContent || '');
-      return `<span${serializeAttrs(node)}>${text}</span>`;
-    },
-  });
-}
-
-function status(turndownService: _TurndownService) {
-  turndownService.addRule('status', {
-    filter: function (node: HTMLInputElement) {
-      return (
-        node.nodeName === 'SPAN' && node.getAttribute('data-type') === 'status'
-      );
-    },
-    replacement: function (_content: string, node: HTMLInputElement) {
-      const text = escapeHtmlText(node.textContent || '');
-      return `<span${serializeAttrs(node)}>${text}</span>`;
-    },
-  });
-}
-
-/**
- * Serialize the `htmlEmbed` node to Markdown.
- *
- * Markdown has no native representation for an arbitrary-HTML block, so we
- * preserve the node losslessly as an HTML comment carrying the base64-encoded
- * source (the same `data-source` payload the node stores). `markdownToHtml`
- * recognizes the same marker and rebuilds the node, so the round-trip
- * MD -> HTML -> JSON keeps the source intact. The comment also keeps the raw
- * markup inert in the exported `.md` file (it does not render in plain Markdown
- * viewers).
- */
-function htmlEmbed(turndownService: _TurndownService) {
-  turndownService.addRule('htmlEmbed', {
-    filter: function (node: HTMLInputElement) {
-      return (
-        node.nodeName === 'DIV' &&
-        node.getAttribute('data-type') === 'htmlEmbed'
-      );
-    },
-    replacement: function (_content: string, node: HTMLInputElement) {
-      const encoded = node.getAttribute('data-source') || '';
-      return `\n\n<!--html-embed:${encoded}-->\n\n`;
-    },
-  });
-}
-
-/**
- * Serialize the `spoiler` inline mark to lossless raw inline HTML.
- *
- * Markdown has no native spoiler syntax, so we emit the same `<span
- * data-spoiler="true">…</span>` the mark renders. `marked` passes inline raw HTML
- * through untouched, and `generateJSON` restores the mark via its parseHTML, so
- * the round-trip MD -> HTML -> JSON keeps the spoiler intact. The UI-only
- * `is-revealed` state is never serialized.
- */
-function spoiler(turndownService: _TurndownService) {
-  turndownService.addRule('spoiler', {
-    filter: function (node: HTMLInputElement) {
-      return (
-        node.nodeName === 'SPAN' &&
-        node.getAttribute('data-spoiler') === 'true'
-      );
-    },
-    replacement: function (content: string) {
-      return `<span data-spoiler="true">${content}</span>`;
-    },
-  });
-}
-
-function listParagraph(turndownService: _TurndownService) {
-  turndownService.addRule('paragraph', {
-    filter: ['p'],
-    replacement: (content: string, node: HTMLInputElement) => {
-      if (node.parentElement?.nodeName === 'LI') {
-        return content;
-      }
-      return `\n\n${content}\n\n`;
-    },
-  });
-}
-
-function orderedListItem(turndownService: _TurndownService) {
-  turndownService.addRule('orderedListItem', {
-    filter: function (node: HTMLInputElement) {
-      return node.nodeName === 'LI' && node.getAttribute('data-type') !== 'taskItem';
-    },
-    replacement: (content: string, node: HTMLInputElement, options: any) => {
-      const parent = node.parentNode as HTMLElement;
-      if (parent.nodeName !== 'OL' && parent.nodeName !== 'UL') {
-        return content;
-      }
-
-      content = content
-        .replace(/^\n+/, '')
-        .replace(/\n+$/, '\n')
-        .replace(/\n/gm, '\n  ');
-
-      let prefix: string;
-      if (parent.nodeName === 'OL') {
-        const start = parseInt(parent.getAttribute('start') || '1', 10);
-        const index = Array.prototype.indexOf.call(parent.children, node);
-        prefix = `${start + index}. `;
-      } else {
-        prefix = `${options.bulletListMarker} `;
-      }
-
-      return (
-        prefix +
-        content +
-        (node.nextSibling && !/\n$/.test(content) ? '\n' : '')
-      );
-    },
-  });
-}
-
-function callout(turndownService: _TurndownService) {
-  turndownService.addRule('callout', {
-    filter: function (node: HTMLInputElement) {
-      return (
-        node.nodeName === 'DIV' && node.getAttribute('data-type') === 'callout'
-      );
-    },
-    replacement: function (content: string, node: HTMLInputElement) {
-      const calloutType = node.getAttribute('data-callout-type');
-      return `\n\n:::${calloutType}\n${content.trim()}\n:::\n\n`;
-    },
-  });
-}
-
-function taskList(turndownService: _TurndownService) {
-  turndownService.addRule('taskListItem', {
-    filter: function (node: HTMLInputElement) {
-      return (
-        node.getAttribute('data-type') === 'taskItem' &&
-        node.parentNode.nodeName === 'UL'
-      );
-    },
-    replacement: function (_content: string, node: HTMLInputElement) {
-      const isChecked = node.getAttribute('data-checked') === 'true';
-      const div = node.querySelector('div');
-      const text = div ? div.textContent.trim() : node.textContent.trim();
-
-      const prefix = `- ${isChecked ? '[x]' : '[ ]'} `;
-
-      return (
-        prefix +
-        text +
-        (node.nextSibling && !/\n$/.test(text) ? '\n' : '')
-      );
-    },
-  });
-}
-
-function preserveDetail(turndownService: _TurndownService) {
-  turndownService.addRule('preserveDetail', {
-    filter: function (node: HTMLInputElement) {
-      return node.nodeName === 'DETAILS';
-    },
-    replacement: function (_content: string, node: HTMLInputElement) {
-      const summary = node.querySelector(':scope > summary');
-      let detailSummary = '';
-
-      if (summary) {
-        detailSummary = `<summary>${turndownService.turndown(summary.innerHTML)}</summary>`;
-      }
-
-      const detailsContent = Array.from(node.childNodes)
-        .filter((child) => child.nodeName !== 'SUMMARY')
-        .map((child) =>
-          child.nodeType === 1
-            ? turndownService.turndown((child as HTMLElement).outerHTML)
-            : child.textContent,
-        )
-        .join('');
-
-      return `\n<details>\n${detailSummary}\n\n${detailsContent}\n\n</details>\n`;
-    },
-  });
-}
-
-function mathInline(turndownService: _TurndownService) {
-  turndownService.addRule('mathInline', {
-    filter: function (node: HTMLInputElement) {
-      return (
-        node.nodeName === 'SPAN' &&
-        node.getAttribute('data-type') === 'mathInline'
-      );
-    },
-    replacement: function (content: string) {
-      return `$${content}$`;
-    },
-  });
-}
-
-function mathBlock(turndownService: _TurndownService) {
-  turndownService.addRule('mathBlock', {
-    filter: function (node: HTMLInputElement) {
-      return (
-        node.nodeName === 'DIV' &&
-        node.getAttribute('data-type') === 'mathBlock'
-      );
-    },
-    replacement: function (content: string) {
-      return `\n$$\n${content}\n$$\n`;
-    },
-  });
-}
-
-function iframeEmbed(turndownService: _TurndownService) {
-  turndownService.addRule('iframeEmbed', {
-    filter: function (node: HTMLInputElement) {
-      return node.nodeName === 'IFRAME';
-    },
-    replacement: function (_content: string, node: HTMLInputElement) {
-      const src = node.getAttribute('src');
-      return '[' + src + '](' + src + ')';
-    },
-  });
-}
-
-function image(turndownService: _TurndownService) {
-  turndownService.addRule('image', {
-    filter: 'img',
-    replacement: function (_content: string, node: HTMLInputElement) {
-      const src = node.getAttribute('src') || '';
-      if (!src) return '';
-      const caption = node.getAttribute('data-caption') || '';
-      if (caption) {
-        // ![]() can't carry a caption, so emit a raw <img> wrapped in a block
-        // <div>. marked passes it through and the image extension's parseHTML
-        // restores the caption from data-caption.
-        const parts = [`src="${escapeHtmlAttr(src)}"`];
-        const alt = node.getAttribute('alt') || '';
-        if (alt) parts.push(`alt="${escapeHtmlAttr(alt)}"`);
-        parts.push(`data-caption="${escapeHtmlAttr(caption)}"`);
-        return `<div><img ${parts.join(' ')}></div>`;
-      }
-      const alt = sanitizeMdLinkText(node.getAttribute('alt') || '');
-      const title = node.getAttribute('title') || '';
-      const titlePart = title ? ' "' + title.replace(/"/g, '\\"') + '"' : '';
-      return '![' + alt + '](' + src + titlePart + ')';
-    },
-  });
-}
-
-/**
- * Footnote reference (inline atom) -> pandoc/GFM marker `[^id]`.
- * The visible number is derived (not stored), so the id is the stable anchor.
- */
-function footnoteReference(turndownService: _TurndownService) {
-  turndownService.addRule('footnoteReference', {
-    filter: function (node: HTMLInputElement) {
-      return (
-        node.nodeName === 'SUP' && node.hasAttribute('data-footnote-ref')
-      );
-    },
-    replacement: function (_content: string, node: HTMLInputElement) {
-      const id = node.getAttribute('data-id') || '';
-      return id ? `[^${id}]` : '';
-    },
-  });
-}
-
-/**
- * Footnotes container -> the list of `[^id]: text` definitions at the end of
- * the document (one per line). Each footnoteDefinition inside emits its own
- * `[^id]: ...` line; turndown joins them with the surrounding block spacing.
- */
-function footnotesList(turndownService: _TurndownService) {
-  turndownService.addRule('footnoteDefinition', {
-    filter: function (node: HTMLInputElement) {
-      return (
-        node.nodeName === 'DIV' && node.hasAttribute('data-footnote-def')
-      );
-    },
-    replacement: function (content: string, node: HTMLInputElement) {
-      const id = node.getAttribute('data-id') || '';
-      // Collapse internal newlines so the definition stays a single MD line;
-      // continuation lines are a v2 refinement.
-      const text = content.replace(/\s*\n+\s*/g, ' ').trim();
-      return id ? `\n[^${id}]: ${text}\n` : '';
-    },
-  });
-
-  turndownService.addRule('footnotesList', {
-    filter: function (node: HTMLInputElement) {
-      return (
-        node.nodeName === 'SECTION' && node.hasAttribute('data-footnotes')
-      );
-    },
-    replacement: function (content: string) {
-      return `\n\n${content.trim()}\n`;
-    },
-  });
-}
-
-function video(turndownService: _TurndownService) {
-  turndownService.addRule('video', {
-    filter: function (node: HTMLInputElement) {
-      return node.tagName === 'VIDEO';
-    },
-    replacement: function (_content: string, node: HTMLInputElement) {
-      const src = node.getAttribute('src') || '';
-      const ariaLabel = node.getAttribute('aria-label');
-      const name = sanitizeMdLinkText(
-        ariaLabel || getBasename(src) || src,
-      );
-      return '[' + name + '](' + src + ')';
-    },
-  });
-}

packages/editor-ext/vitest.config.ts

@@ -14,10 +14,15 @@ export default defineConfig({
       provider: "v8",
       reporter: ["text-summary", "text"],
       all: false,
+      // functions lowered 60 -> 57 after issue #347 removed the editor-ext
+      // markdown layer (src/lib/markdown) and its image/footnote round-trip
+      // specs: that markdown behavior now lives in — and is tested by —
+      // @docmost/prosemirror-markdown, so the editor-ext baseline shifts down.
+      // Still a real gate (a few points below the post-removal measured level).
       thresholds: {
         statements: 54,
         branches: 44,
-        functions: 60,
+        functions: 57,
         lines: 54,
       },
     },

packages/git-sync/src/engine/stabilize.ts

@@ -72,7 +72,13 @@ export async function stabilizePageFile(
  * keeps re-pulls of an unchanged page byte-identical (no churn, loop-guard).
  */
 export async function stabilizePageBody(content: unknown): Promise<string> {
-  const md1 = convertProseMirrorToMarkdown(content);
+  // git-sync is the LOSSLESS mirror path, so run the serializer in `strict`
+  // mode: a node/mark type the converter has no case for (e.g. one added to the
+  // schema without a matching serializer arm) throws a ConverterLossError here
+  // rather than silently degrading — surfacing the loss loudly at write time
+  // instead of committing a lossy file. Valid content (every current schema type
+  // has a case) is unaffected.
+  const md1 = convertProseMirrorToMarkdown(content, { strict: true });
   const doc2 = await markdownToProseMirror(md1);
-  return convertProseMirrorToMarkdown(doc2);
+  return convertProseMirrorToMarkdown(doc2, { strict: true });
 }

packages/git-sync/test/stabilize.test.ts

@@ -4,6 +4,7 @@ import { stabilizePageFile, type PageMeta } from '../src/engine/stabilize.js';
 // global DOM via jsdom at module load time (required for @tiptap/html under Node).
 import { markdownToProseMirror } from '@docmost/prosemirror-markdown';
 import { parseDocmostMarkdown } from '@docmost/prosemirror-markdown';
+import { ConverterLossError } from '@docmost/prosemirror-markdown';
 
 // stabilize.ts (SPEC §11 normalize-on-write) was 0% covered (only the gated e2e
 // touched it). stabilizePageFile is import-testable: build a small ProseMirror
@@ -66,6 +67,23 @@ describe('stabilizePageFile — normalize-on-write fixpoint (SPEC §11)', () =>
     expect(body1).toContain('data-src="/d.drawio"');
   });
 
+  it('runs the serializer in STRICT mode — an unmappable node throws, not a lossy write (#493)', async () => {
+    // git-sync is the lossless mirror path: a node type the converter has no
+    // case for (here a fabricated one, standing in for a schema type added
+    // without a matching serializer arm) must surface loudly at write time
+    // rather than being silently flattened into a lossy .md file.
+    const content = {
+      type: 'doc',
+      content: [
+        { type: 'paragraph', content: [{ type: 'text', text: 'ok' }] },
+        { type: 'quantumWidget', content: [{ type: 'text', text: 'lost?' }] },
+      ],
+    };
+    await expect(stabilizePageFile(content, meta)).rejects.toBeInstanceOf(
+      ConverterLossError,
+    );
+  });
+
   it('already-stable content is unchanged by the pass (idempotent)', async () => {
     // Plain prose is already a fixpoint; stabilizing it once and twice agree.
     const content = {

packages/mcp/src/lib/collaboration.ts

@@ -10,7 +10,10 @@ import { JSDOM } from "jsdom";
 // handled there). MCP consumes it directly instead of maintaining its own
 // drifted marked pipeline; only the collab/yjs write glue and the footnote
 // canonicalization wrapper stay mcp-side.
-import { markdownToProseMirror } from "@docmost/prosemirror-markdown";
+import {
+  markdownToProseMirror,
+  normalizeAgentMarkdown,
+} from "@docmost/prosemirror-markdown";
 import { docmostExtensions, docmostSchema } from "./docmost-schema.js";
 import { withPageLock } from "./page-lock.js";
 import {
@@ -20,6 +23,7 @@ import {
 } from "@docmost/prosemirror-markdown";
 import { canonicalizeFootnotes } from "./footnote-canonicalize.js";
 import { normalizeAndMergeFootnotes } from "./footnote-normalize-merge.js";
+import { regraftResolvedComments } from "./comment-anchor.js";
 import { VerifyReport } from "./diff.js";
 import { acquireCollabSession } from "./collab-session.js";
 
@@ -97,6 +101,15 @@ global.WebSocket = WebSocket;
  * plain `markdownToProseMirror` (no canonicalization) — safe now because inline
  * `^[body]` footnotes carry their body at the reference point, so a comment can
  * no longer produce a reference-less footnote definition to be dropped.
+ *
+ * #493: `normalizeAgentMarkdown` runs FIRST, so an agent's `updatePageMarkdown`
+ * body gets the SAME GFM `[^id]` reference-footnote -> inline `^[body]` rewrite as
+ * the server import path (instead of the reference leaking as literal text / a
+ * bogus link). It DELIBERATELY does NOT strip a leading YAML front-matter block:
+ * a full-body agent rewrite that opens with a `---…---` is (almost) always a
+ * horizontalRule the serializer emitted, and stripping it would silently drop the
+ * page's leading content (#493 review). The front-matter strip stays on the
+ * server FILE-import boundary only (`normalizeForeignMarkdown`).
  */
 export async function markdownToProseMirrorCanonical(
   markdownContent: string,
@@ -105,7 +118,9 @@ export async function markdownToProseMirrorCanonical(
   // canonicalizing, so the canonicalizer re-hangs references and drops the
   // now-orphaned duplicate definitions.
   return canonicalizeFootnotes(
-    normalizeAndMergeFootnotes(await markdownToProseMirror(markdownContent)),
+    normalizeAndMergeFootnotes(
+      await markdownToProseMirror(normalizeAgentMarkdown(markdownContent)),
+    ),
   );
 }
 
@@ -328,6 +343,12 @@ export async function updatePageContentRealtime(
     pageId,
     collabToken,
     baseUrl,
-    () => tiptapJson,
+    // #493: an agent read HIDES resolved-comment anchors (#337), so the markdown
+    // it sends here no longer carries them — a naive full rewrite would erase
+    // every resolved comment mark. Re-graft the resolved marks from the LIVE doc
+    // onto the matching text in the freshly-imported body. Active comments are
+    // untouched (they ride through the markdown themselves); a resolved span whose
+    // text the agent changed simply does not re-anchor and is dropped.
+    (liveDoc) => regraftResolvedComments(liveDoc, tiptapJson),
   );
 }

packages/mcp/src/lib/comment-anchor.ts

@@ -312,10 +312,9 @@ export function canAnchorInDoc(doc: any, selection: string): boolean {
 function spliceCommentMark(
   blockContent: any[],
   match: AnchorMatch,
-  commentId: string,
+  commentMark: any,
 ): void {
   const { startChild, startOffset, endChild, endOffset } = match;
-  const commentMark = makeCommentMark(commentId);
   const fragments: any[] = [];
 
   for (let k = startChild; k <= endChild; k++) {
@@ -451,6 +450,22 @@ export function applyAnchorInDoc(
   doc: any,
   selection: string,
   commentId: string,
+): boolean {
+  return applyCommentMarkInDoc(doc, selection, makeCommentMark(commentId));
+}
+
+/**
+ * Core of {@link applyAnchorInDoc}, but splices an ARBITRARY comment mark object
+ * (not just a fresh `{ commentId, resolved:false }`) across the first matching
+ * range. This lets a caller re-apply a mark that carries `resolved:true` and any
+ * other stored attrs. Depth-first (same order as canAnchorInDoc); mutates in
+ * place on the first matching block and returns true, else returns false without
+ * mutating.
+ */
+export function applyCommentMarkInDoc(
+  doc: any,
+  selection: string,
+  commentMark: any,
 ): boolean {
   const { selection: effective, found } = resolveAnchorSelection(doc, selection);
   if (!found) return false;
@@ -459,7 +474,7 @@ export function applyAnchorInDoc(
     if (!Array.isArray(node.content)) return false;
     const match = findAnchorInBlock(node.content, effective);
     if (match) {
-      spliceCommentMark(node.content, match, commentId);
+      spliceCommentMark(node.content, match, commentMark);
       return true;
     }
     for (const child of node.content) {
@@ -471,3 +486,97 @@ export function applyAnchorInDoc(
   };
   return visit(doc, 0);
 }
+
+/** A resolved inline-comment span lifted from a doc: its mark + anchored text. */
+export interface ResolvedCommentSpan {
+  commentId: string;
+  /** The full comment mark (carrying `resolved:true` + any stored attrs). */
+  mark: any;
+  /** The concatenated raw text the mark spans — used as the re-anchor selection. */
+  text: string;
+}
+
+/** True when a text node carries a RESOLVED comment mark; returns that mark. */
+function resolvedCommentMarkOf(node: any): any | null {
+  if (!node || node.type !== "text" || !Array.isArray(node.marks)) return null;
+  return (
+    node.marks.find(
+      (m: any) =>
+        m && m.type === "comment" && m.attrs?.resolved === true && m.attrs?.commentId,
+    ) || null
+  );
+}
+
+/**
+ * Collect every RESOLVED inline-comment span in `doc`, in document order. Within
+ * each block's direct content, a maximal run of consecutive text nodes sharing
+ * the same resolved `commentId` is ONE span; its concatenated raw text is the
+ * selection used to re-anchor it elsewhere. Active (unresolved) comment marks are
+ * ignored — they survive a markdown round-trip on their own (a page read emits
+ * their `<span data-comment-id>` wrapper), whereas resolved anchors are hidden
+ * from agent reads (#337) and would be erased by a full-body markdown rewrite.
+ */
+export function collectResolvedCommentSpans(doc: any): ResolvedCommentSpan[] {
+  const spans: ResolvedCommentSpan[] = [];
+  const visit = (node: any, depth: number): void => {
+    if (depth > MAX_DEPTH || !node || typeof node !== "object") return;
+    if (!Array.isArray(node.content)) return;
+    const content = node.content;
+    let i = 0;
+    while (i < content.length) {
+      const mark = resolvedCommentMarkOf(content[i]);
+      if (mark) {
+        const commentId = mark.attrs.commentId;
+        let text = "";
+        let j = i;
+        while (j < content.length) {
+          const mj = resolvedCommentMarkOf(content[j]);
+          if (!mj || mj.attrs.commentId !== commentId) break;
+          text += typeof content[j].text === "string" ? content[j].text : "";
+          j++;
+        }
+        if (text.length > 0) spans.push({ commentId, mark, text });
+        i = j > i ? j : i + 1;
+      } else {
+        i++;
+      }
+    }
+    for (const child of content) {
+      if (child && typeof child === "object" && Array.isArray(child.content)) {
+        visit(child, depth + 1);
+      }
+    }
+  };
+  visit(doc, 0);
+  return spans;
+}
+
+/**
+ * Re-graft RESOLVED comment marks from `oldDoc` onto matching text ranges in
+ * `newDoc`, returning a NEW doc (never mutates the inputs).
+ *
+ * WHY (#493): an agent read hides resolved-comment anchors (#337), so the
+ * markdown it sends to a FULL-body rewrite (`updatePageMarkdown`) no longer
+ * carries them — a naive full write would erase every resolved comment mark.
+ * This restores them: each resolved span from the previous document is re-anchored
+ * onto the SAME text in the newly-imported body (first occurrence, using the
+ * shared anchoring / markdown-strip fallback), preserving `resolved:true` and the
+ * stored attrs. A span whose text the agent changed or deleted simply does not
+ * re-anchor and is dropped (its anchor is gone; it was already resolved). Active
+ * comments are untouched — they ride through the markdown themselves.
+ */
+export function regraftResolvedComments<T = any>(oldDoc: any, newDoc: T): T {
+  if (!newDoc || typeof newDoc !== "object") return newDoc;
+  const spans = collectResolvedCommentSpans(oldDoc);
+  if (spans.length === 0) return newDoc;
+  const out =
+    typeof structuredClone === "function"
+      ? structuredClone(newDoc)
+      : (JSON.parse(JSON.stringify(newDoc)) as T);
+  for (const span of spans) {
+    // Clone the mark so the new document never shares a mark object with oldDoc.
+    const markClone = { type: "comment", attrs: { ...span.mark.attrs } };
+    applyCommentMarkInDoc(out, span.text, markClone);
+  }
+  return out;
+}

packages/mcp/src/lib/text-normalize.ts

@@ -1,64 +1,30 @@
 /**
- * Locator normalization: strip inline markdown wrappers and trailing
- * decoration from a LOCATOR string so a find/anchor that the model wrote with
- * markdown (or a stray emoji) can still match the document's plain text.
+ * Locator normalization helpers for mcp. The two PRIMITIVES —
+ * `stripInlineMarkdown` (lenient locator normalizer) and `stripWrappersAndLinks`
+ * (strict balanced-wrapper/link collapse) — live in the canonical package
+ * `@docmost/prosemirror-markdown` (#493 dedup: they used to be forked verbatim
+ * here). This module now only re-exports `stripInlineMarkdown` and adds the two
+ * mcp-only helpers built on top: `stripBalancedWrappers` and `closestBlockHint`.
  *
- * This is used ONLY as a fallback for LOCATING (after an exact match fails);
- * it is never applied to replacement text or inserted node content, so no
- * formatting is ever lost.
+ * They are used ONLY as a fallback for LOCATING (after an exact match fails) and
+ * for formatting-vs-plain intent detection; never applied to replacement text or
+ * inserted node content, so no formatting is ever lost.
  */
+import {
+  stripInlineMarkdown,
+  stripWrappersAndLinks,
+} from "@docmost/prosemirror-markdown";
 
-/** Maximum unwrap passes, so pathological/nested input cannot loop forever. */
-const MAX_PASSES = 8;
+// Re-export the canonical locator normalizer so mcp call sites keep importing it
+// from `./text-normalize.js` unchanged.
+export { stripInlineMarkdown };
 
 /**
- * Inline emphasis/code/strikethrough wrappers, strong BEFORE emphasis so
- * `**x**` collapses to `x` rather than leaving a stray `*x*`. Each pattern is
- * non-greedy and capture group 1 is the inner text. Applied repeatedly until
- * the string stops changing (nested wrappers like `**_x_**`).
- */
-const WRAPPER_PATTERNS: RegExp[] = [
-  /\*\*([^*]+?)\*\*/g, // **x**
-  /__([^_]+?)__/g, // __x__
-  /~~([^~]+?)~~/g, // ~~x~~
-  /\*([^*]+?)\*/g, // *x*
-  /_([^_]+?)_/g, // _x_
-  /``([^`]+?)``/g, // ``x``
-  /`([^`]+?)`/g, // `x`
-];
-
-/** Links/images -> their visible text. `!?` covers both `[t](u)` and `![a](s)`. */
-const LINK_IMAGE_RE = /!?\[([^\]]*)\]\([^)]*\)/g;
-
-/**
- * Apply ONLY the two balanced/link passes shared by both normalizers: first
- * collapse links/images to their visible text, then collapse balanced inline
- * wrappers repeatedly until stable. Does NOT trim decoration, does NOT guard
- * against an empty result — it returns exactly the transformed string.
- */
-function stripWrappersAndLinks(s: string): string {
-  // 1. Links/images -> their visible text.
-  let out = s.replace(LINK_IMAGE_RE, "$1");
-
-  // 2. Strip balanced wrappers, repeating until the string is stable so nested
-  //    wrappers (`**_x_**`) and adjacent runs both collapse.
-  for (let pass = 0; pass < MAX_PASSES; pass++) {
-    const before = out;
-    for (const re of WRAPPER_PATTERNS) {
-      out = out.replace(re, "$1");
-    }
-    if (out === before) break;
-  }
-  return out;
-}
-
-/**
- * STRICT formatting detector — distinct from the lenient locator
- * normalization below. It strips ONLY what unambiguously is markdown markup:
- *  1. links/images `[text](url)` -> `text`, `![alt](src)` -> `alt`, and
- *  2. balanced inline `**`/`__`/`~~`/`*`/`_`/`` ` `` wrappers (repeat-until-stable),
- * and DELIBERATELY does NOT trim leading/trailing whitespace, emoji, or lone
- * marker chars (the lenient extras `stripInlineMarkdown` does in its step 3).
+ * STRICT formatting detector — distinct from the lenient locator normalization.
+ * It strips ONLY what unambiguously is markdown markup (links/images to visible
+ * text, and balanced inline `**`/`__`/`~~`/`*`/`_`/`` ` `` wrappers) and
+ * DELIBERATELY does NOT trim leading/trailing whitespace, emoji, or lone marker
+ * chars (the lenient extras `stripInlineMarkdown` does).
  *
  * It exists ONLY to recognize formatting-vs-plain INTENT in `applyTextEdits`
  * (deciding whether find/replace differ purely by markdown markers). Because it
@@ -77,44 +43,6 @@ export function stripBalancedWrappers(s: string): string {
   return stripWrappersAndLinks(s);
 }
 
-/**
- * Conservatively strip inline markdown from a locator string.
- *
- * Deterministic, order-fixed steps:
- *  1. Links/images: `[text](url)` -> `text`, `![alt](src)` -> `alt`.
- *  2. Balanced inline wrappers (strong before emphasis, code, strikethrough),
- *     applied repeatedly until stable for nested cases.
- *  3. Trim leading/trailing decoration only: whitespace, leftover marker chars
- *     (`* _ ~ \``) and emoji. Letters/digits and sentence punctuation (`.`/`,`
- *     etc.) are NEVER trimmed.
- *
- * If the result is empty (e.g. the input was only markers like `***`), the
- * ORIGINAL string is returned so a locator can never normalize down to "" and
- * match everything.
- */
-export function stripInlineMarkdown(s: string): string {
-  if (typeof s !== "string" || s.length === 0) return s;
-
-  // 1 + 2. Shared link/image and balanced-wrapper passes.
-  let out = stripWrappersAndLinks(s);
-
-  // 3. Trim leading/trailing decoration: whitespace, leftover markdown markers,
-  //    and emoji (Extended_Pictographic plus the VS16 / ZWJ joiners, plus the
-  //    regional-indicator range U+1F1E6–U+1F1FF for flag emoji, which are NOT
-  //    Extended_Pictographic). The `u` flag enables the Unicode property escape.
-  //    Anchored runs only — interior text and sentence punctuation are untouched.
-  const DECORATION =
-    "[\\s*_~\\x60\\p{Extended_Pictographic}\\u{1F1E6}-\\u{1F1FF}\\u{FE0F}\\u{200D}]+";
-  out = out
-    .replace(new RegExp("^" + DECORATION, "u"), "")
-    .replace(new RegExp(DECORATION + "$", "u"), "");
-
-  // 4. Never normalize a locator down to nothing.
-  if (out.length === 0) return s;
-
-  return out;
-}
-
 /**
  * Build a bounded "closest text" hint for an anchor/find MISS, shared by
  * editPageText (json-edit) and createComment (client) so both surface the

packages/mcp/test/mock/markdown-patch-insert.test.mjs

@@ -108,6 +108,17 @@ async function spawnCollabStack(seedDoc) {
   return { state, baseURL };
 }
 
+// y-prosemirror stores an OVERLAPPING mark (one whose type does not exclude
+// itself — e.g. `comment`, and since #515 `code` with `excludes: ""`) under a
+// HASHED Yjs attribute key `name--<8-char hash>` so several may coexist on a
+// range. The real read path (yDocToProsemirrorJSON) strips that suffix back to
+// the bare mark name via this exact regex; mirror it here so this minimal decoder
+// reports the same mark names Docmost actually returns (without it an overlapping
+// `code` would leak as `code--<hash>`).
+const hashedMarkNameRegex = /(.*)(--[a-zA-Z0-9+/=]{8})$/;
+const yattr2markname = (attrName) =>
+  hashedMarkNameRegex.exec(attrName)?.[1] ?? attrName;
+
 // Minimal XmlFragment -> ProseMirror JSON decode, mirroring the shape Docmost
 // stores. Reads element name as node type, attributes as attrs, and recurses into
 // children; text nodes carry their string.
@@ -121,8 +132,8 @@ function fragmentToJson(frag) {
         if (d.attributes && Object.keys(d.attributes).length) {
           node.marks = Object.entries(d.attributes).map(([type, attrs]) =>
             attrs && typeof attrs === "object" && Object.keys(attrs).length
-              ? { type, attrs }
-              : { type },
+              ? { type: yattr2markname(type), attrs }
+              : { type: yattr2markname(type) },
           );
         }
         return node;

packages/mcp/test/unit/regraft-resolved-comments.test.mjs

@@ -0,0 +1,107 @@
+import { test } from "node:test";
+import assert from "node:assert/strict";
+
+import {
+  collectResolvedCommentSpans,
+  regraftResolvedComments,
+  applyCommentMarkInDoc,
+} from "../../build/lib/comment-anchor.js";
+
+/**
+ * #493 commit 6 — resolved-comment anchors must survive a full markdown rewrite
+ * (updatePageMarkdown). An agent read HIDES resolved anchors (#337), so its
+ * markdown drops them; a naive full write would erase the resolved comment marks.
+ * `regraftResolvedComments(oldDoc, newDoc)` re-anchors them onto the matching
+ * text. These exercise the real anchoring (no mock).
+ */
+
+const doc = (...content) => ({ type: "doc", content });
+const para = (...content) => ({ type: "paragraph", content });
+const text = (t, marks) => (marks ? { type: "text", text: t, marks } : { type: "text", text: t });
+const resolvedComment = (commentId) => ({ type: "comment", attrs: { commentId, resolved: true } });
+const activeComment = (commentId) => ({ type: "comment", attrs: { commentId, resolved: false } });
+
+/** The comment mark on a text node, or null. */
+function commentMarkOf(node) {
+  const marks = Array.isArray(node?.marks) ? node.marks : [];
+  return marks.find((m) => m && m.type === "comment") || null;
+}
+/** Flatten every text node in a doc (deep). */
+function textNodes(node, out = []) {
+  if (!node || typeof node !== "object") return out;
+  if (node.type === "text") out.push(node);
+  if (Array.isArray(node.content)) for (const c of node.content) textNodes(c, out);
+  return out;
+}
+
+test("collectResolvedCommentSpans: only resolved marks, concatenated across a run", () => {
+  const old = doc(
+    para(
+      text("keep "),
+      text("resolved bit", [resolvedComment("r1")]),
+      text(" and "),
+      text("active bit", [activeComment("a1")]),
+    ),
+  );
+  const spans = collectResolvedCommentSpans(old);
+  assert.equal(spans.length, 1);
+  assert.equal(spans[0].commentId, "r1");
+  assert.equal(spans[0].text, "resolved bit");
+  assert.equal(spans[0].mark.attrs.resolved, true);
+});
+
+test("regraft restores a resolved mark the agent's markdown dropped", () => {
+  // OLD doc has a resolved comment on "important note".
+  const old = doc(para(text("An "), text("important note", [resolvedComment("r1")]), text(" here.")));
+  // NEW doc (re-imported from the agent's markdown) has the SAME text but NO
+  // comment mark — the resolved anchor was hidden on read.
+  const fresh = doc(para(text("An important note here.")));
+
+  const out = regraftResolvedComments(old, fresh);
+  // Inputs are not mutated.
+  assert.equal(commentMarkOf(textNodes(fresh)[0]), null);
+  // The resolved mark is back on exactly "important note".
+  const marked = textNodes(out).filter((n) => commentMarkOf(n));
+  assert.equal(marked.length, 1);
+  assert.equal(marked[0].text, "important note");
+  assert.equal(commentMarkOf(marked[0]).attrs.commentId, "r1");
+  assert.equal(commentMarkOf(marked[0]).attrs.resolved, true);
+});
+
+test("a resolved span whose text the agent changed is dropped (no re-anchor)", () => {
+  const old = doc(para(text("stale text", [resolvedComment("r1")])));
+  const fresh = doc(para(text("completely rewritten body")));
+  const out = regraftResolvedComments(old, fresh);
+  assert.equal(textNodes(out).filter((n) => commentMarkOf(n)).length, 0);
+});
+
+test("regraft is a no-op when the old doc has no resolved comments", () => {
+  const old = doc(para(text("plain "), text("active", [activeComment("a1")])));
+  const fresh = doc(para(text("plain active")));
+  const out = regraftResolvedComments(old, fresh);
+  assert.equal(textNodes(out).filter((n) => commentMarkOf(n)).length, 0);
+});
+
+test("multiple distinct resolved comments are all restored", () => {
+  const old = doc(
+    para(text("first", [resolvedComment("r1")]), text(" middle "), text("second", [resolvedComment("r2")])),
+  );
+  const fresh = doc(para(text("first middle second")));
+  const out = regraftResolvedComments(old, fresh);
+  const byId = Object.fromEntries(
+    textNodes(out)
+      .filter((n) => commentMarkOf(n))
+      .map((n) => [commentMarkOf(n).attrs.commentId, n.text]),
+  );
+  assert.equal(byId["r1"], "first");
+  assert.equal(byId["r2"], "second");
+});
+
+test("applyCommentMarkInDoc preserves an arbitrary mark's attrs (resolved:true)", () => {
+  const d = doc(para(text("anchor me somewhere")));
+  const ok = applyCommentMarkInDoc(d, "anchor me", { type: "comment", attrs: { commentId: "x9", resolved: true } });
+  assert.equal(ok, true);
+  const marked = textNodes(d).filter((n) => commentMarkOf(n));
+  assert.equal(marked[0].text, "anchor me");
+  assert.equal(commentMarkOf(marked[0]).attrs.resolved, true);
+});

packages/prosemirror-markdown/README.md

@@ -1,12 +1,31 @@
 # @docmost/prosemirror-markdown
 
 The single, canonical **ProseMirror ↔ Markdown converter** plus the Docmost
-schema mirror (#293/#345). Headless and framework-free: no React, no browser
-runtime. There is exactly ONE copy of this converter in the repo, consumed by:
+schema mirror (#293/#345/#347). Headless and framework-free: no React. There is
+exactly ONE copy of this converter in the repo, consumed by:
 
 - `packages/mcp` (the MCP server),
 - `packages/git-sync` (two-way Git sync),
-- `apps/server` (server-side markdown import/export, #345).
+- `apps/server` (server-side markdown import/export, #345),
+- `apps/client` (markdown paste/copy + AI-chat render, #347).
+
+### Node vs browser entry
+
+The HTML→DOM stage of markdown import runs on `jsdom` in Node and the native
+`DOMParser` in the browser, injected per environment so **jsdom never enters a
+client bundle**:
+
+- default entry (`@docmost/prosemirror-markdown`) — Node: registers jsdom +
+  `@tiptap/html`'s happy-dom `server` `generateJSON`. Used by mcp / git-sync /
+  apps/server.
+- `browser` entry (`@docmost/prosemirror-markdown/browser`, via the `"browser"`
+  exports condition) — registers the native `DOMParser` + `@tiptap/html`'s
+  browser `generateJSON`. Used by `apps/client`; carries no jsdom/happy-dom.
+
+Both entries expose the identical converter surface; only the injected
+DOM/`generateJSON` implementations differ (`src/lib/dom-parser.ts`). A
+`markdownToProseMirrorSync` variant exists for callers that cannot await (the
+client's synchronous chat renderer).
 
 `src/lib/docmost-schema.ts` **mirrors** the upstream Tiptap schema that lives in
 `packages/editor-ext`. The mirror is not free-floating: `serializer-contract.test.ts`

packages/prosemirror-markdown/package.json

@@ -9,7 +9,12 @@
   "exports": {
     ".": {
       "types": "./build/index.d.ts",
+      "browser": "./build/browser.js",
       "default": "./build/index.js"
+    },
+    "./browser": {
+      "types": "./build/browser.d.ts",
+      "default": "./build/browser.js"
     }
   },
   "scripts": {
@@ -30,6 +35,7 @@
     "@tiptap/html": "3.20.4",
     "@tiptap/pm": "3.20.4",
     "@tiptap/starter-kit": "3.20.4",
+    "happy-dom": "20.8.9",
     "jsdom": "25.0.0",
     "marked": "17.0.5",
     "zod": "4.3.6"

packages/prosemirror-markdown/src/browser.ts

@@ -0,0 +1,17 @@
+/**
+ * BROWSER entry of `@docmost/prosemirror-markdown`.
+ *
+ * Selected via the package's `"browser"` exports condition (bundlers) so the
+ * client gets the SAME public converter surface as the Node entry, but the
+ * markdown-import DOM passes run on the native `window.DOMParser` instead of
+ * jsdom. This module installs the native parser as a side effect BEFORE
+ * re-exporting, and imports NO jsdom — so a client bundle that resolves this
+ * entry carries no `jsdom` (nor any transitive jsdom import).
+ *
+ * The re-exported surface is identical to the default (Node) entry — the only
+ * difference is which HTML-DOM parser is registered — so a browser consumer can
+ * call `markdownToProseMirror` (and everything else) exactly as the server does.
+ */
+import "./lib/dom-parser.browser.js";
+
+export * from "./lib/index.js";

packages/prosemirror-markdown/src/index.ts

@@ -6,4 +6,11 @@
  * this top-level barrel simply re-exports that surface so the package entry is
  * the converter surface.
  */
+// DEFAULT (Node) entry: install the jsdom-backed HTML parser as a side effect
+// BEFORE re-exporting the converter surface, so every Node consumer (server,
+// mcp, git-sync) keeps the identical jsdom import behaviour with no code change.
+// The browser entry (`./browser.js`) installs the native-`DOMParser` parser
+// instead and never loads this module, so jsdom stays out of client bundles.
+import "./lib/dom-parser.node.js";
+
 export * from "./lib/index.js";

packages/prosemirror-markdown/src/lib/docmost-schema.ts

@@ -16,6 +16,7 @@
  * `@docmost/editor-ext` before updating the snapshot.
  */
 import StarterKit from "@tiptap/starter-kit";
+import { Code } from "@tiptap/extension-code";
 import Image from "@tiptap/extension-image";
 import TaskList from "@tiptap/extension-task-list";
 import TaskItem from "@tiptap/extension-task-item";
@@ -63,10 +64,9 @@ function getStyleProperty(element: HTMLElement, propertyName: string): string |
  * The editor SCHEMA genuinely only supports these six banner types — there is no
  * `tip`/`caution`/`important`/`question` callout node. So those are NOT first-
  * class types we can round-trip literally; they are INPUT ALIASES (GitHub/Obsidian
- * alert syntax). The editor's own paste/import path maps them onto the supported
- * set (see `GITHUB_ALERT_TYPE_MAP` in
- * `@docmost/editor-ext` markdown/utils/github-callout.marked.ts:
- * tip -> success, caution -> danger, important -> info). We mirror that aliasing
+ * alert syntax). This package's own `> [!type]` import path maps them onto the
+ * supported set (see `CALLOUT_TYPE_ALIASES` below: tip -> success, caution ->
+ * danger, important -> info). We apply that aliasing
  * here so an ingested `> [!tip]` / `> [!caution]` lands on the closest real banner
  * (success / danger) instead of flatly collapsing to `info` — matching exactly how
  * the editor itself would interpret the same alias. A schema type always maps to
@@ -75,11 +75,11 @@ function getStyleProperty(element: HTMLElement, propertyName: string): string |
  */
 const CALLOUT_TYPES = ["default", "info", "note", "success", "warning", "danger"];
 /**
- * NON-schema callout aliases -> their closest supported banner. Mirrors the
- * editor's `GITHUB_ALERT_TYPE_MAP` for the names that are NOT already schema
- * types (a schema type is preserved as-is and never consulted here). Keeping
- * these in lockstep means git-sync ingest and an editor paste interpret the same
- * `> [!alias]` identically.
+ * NON-schema callout aliases -> their closest supported banner, for the names
+ * that are NOT already schema types (a schema type is preserved as-is and never
+ * consulted here). This is the single canonical alias map now that the editor's
+ * old marked layer is gone; git-sync ingest and an editor paste both go through
+ * this package, so they interpret the same `> [!alias]` identically.
  */
 const CALLOUT_TYPE_ALIASES: Record<string, string> = {
   tip: "success",
@@ -1482,7 +1482,20 @@ export const docmostExtensions = [
     codeBlock: {},
     heading: {},
     link: { openOnClick: false },
+    // #515: disable StarterKit's bundled inline `code` mark so it can be replaced
+    // by the local override below. StarterKit's `code` inherits tiptap's
+    // `excludes: "_"`, which strips every co-occurring mark on HTML->PM import
+    // (`generateJSON`) — so `` **`--flag`** `` lost its bold. This mirror is a
+    // DELIBERATE standalone copy (it must not pull @docmost/editor-ext into the
+    // node import runtime — that would drag in React/node-views; see #293), so
+    // the `excludes: ""` override is declared LOCALLY here and kept in lockstep
+    // with the canonical `Code` in @docmost/editor-ext by a parity test.
+    code: false,
   }),
+  // #515: inline code that COMBINES with other marks (CommonMark-consistent).
+  // `excludes: ""` means the mark excludes nothing, so bold/italic/strike/… may
+  // co-occur with `code` and survive import.
+  Code.extend({ excludes: "" }),
   // Preserve image width/height as the AUTHORED string. Without an explicit
   // parseHTML the stock Image node attribute falls back to tiptap core's
   // `fromString`, which coerces a numeric width like "320" into the number 320

packages/prosemirror-markdown/src/lib/dom-parser.browser.ts

@@ -0,0 +1,27 @@
+/**
+ * BROWSER registration of the injectable HTML parser (native `DOMParser`).
+ *
+ * Importing this module for its SIDE EFFECT installs a `window.DOMParser`-backed
+ * {@link HtmlDocumentParser}. It is loaded by the package's `browser.ts` barrel
+ * (selected via the `"browser"` exports condition). It imports NO `jsdom`, so a
+ * client bundle that resolves the browser entry never pulls jsdom in.
+ *
+ * The returned `Document` is a real browser document, so it exposes exactly the
+ * same query/mutation surface the import passes use (`querySelector(All)`,
+ * `createElement`, `createTreeWalker`/`NodeFilter` via `defaultView`,
+ * `body.innerHTML`) as jsdom did on the Node path.
+ */
+// @tiptap/html's default (browser) entry: its `generateJSON` uses the native
+// `window.DOMParser`, so it carries NO jsdom/happy-dom — keeping the client
+// bundle free of Node-only DOM libs.
+import { generateJSON } from "@tiptap/html";
+import { setHtmlDocumentParser, setGenerateJson } from "./dom-parser.js";
+
+setHtmlDocumentParser((html: string): Document => {
+  // Native, always available in a browser (and in a jsdom/happy-dom test
+  // environment, which is what the client vitest suite runs under). `text/html`
+  // parsing matches jsdom's `new JSDOM(html)` behaviour for our fragments.
+  return new DOMParser().parseFromString(html, "text/html");
+});
+
+setGenerateJson(generateJSON);

packages/prosemirror-markdown/src/lib/dom-parser.node.ts

@@ -0,0 +1,30 @@
+/**
+ * NODE registration of the injectable HTML parser (jsdom-backed).
+ *
+ * Importing this module for its SIDE EFFECT installs a jsdom-backed
+ * {@link HtmlDocumentParser}. It is loaded by the package's default entry
+ * (`index.ts`) so every existing Node consumer (server, mcp, git-sync) keeps
+ * the identical jsdom behaviour with no code change. This is the ONLY module in
+ * the import chain that imports `jsdom`; the browser entry never loads it, so
+ * `jsdom` cannot reach the client bundle.
+ */
+import { JSDOM } from "jsdom";
+// Use @tiptap/html's EXPLICIT server entry (happy-dom backed): it builds its own
+// DOM internally and needs NO ambient global `window`, so the Node path never
+// depends on which of @tiptap/html's conditional exports a resolver picks (Jest
+// selects the browser entry, which would throw without a global window). This
+// avoids the old module-level `global.window` jsdom shim entirely — that shim
+// was timing-fragile (it had to be installed AFTER prosemirror-view's
+// import-time env detection, or prosemirror-view reads an undefined `navigator`).
+import { generateJSON } from "@tiptap/html/server";
+import { setHtmlDocumentParser, setGenerateJson } from "./dom-parser.js";
+
+setHtmlDocumentParser((html: string): Document => {
+  // A fresh JSDOM per call mirrors the previous `new JSDOM(html)` usage in each
+  // import pass — no shared mutable document between conversions, so concurrent
+  // conversions never interfere.
+  const dom = new JSDOM(html);
+  return dom.window.document as unknown as Document;
+});
+
+setGenerateJson(generateJSON);

packages/prosemirror-markdown/src/lib/dom-parser.ts

@@ -0,0 +1,87 @@
+/**
+ * Injectable HTML-string -> DOM parser for the markdown import path.
+ *
+ * The markdown -> ProseMirror chain (`markdown-to-prosemirror.ts`) does three
+ * post-`marked` DOM passes (task-list bridge, comment directives, footnote
+ * assembly) that need a real DOM to query/mutate an HTML fragment. On the NODE
+ * path that DOM comes from `jsdom`; in the BROWSER the platform already provides
+ * a native `DOMParser` and `document`, and `jsdom` must NOT be bundled (size +
+ * it is Node-only). So the concrete parser is INJECTED per environment rather
+ * than imported statically here — this module carries no `jsdom` (or any DOM)
+ * import, so nothing on the browser code path can transitively pull `jsdom` in.
+ *
+ * The Node entry (`./dom-parser.node.js`, loaded by the package's default
+ * `index.js`) registers a jsdom-backed parser; the browser entry
+ * (`./dom-parser.browser.js`, loaded by the `browser.js` barrel) registers a
+ * `window.DOMParser`-backed one. A consumer that forgets to load an entry (e.g.
+ * a raw deep import) gets a clear error instead of a silent wrong-environment
+ * crash.
+ */
+
+/**
+ * Parse an HTML string into a `Document`. The returned document must support the
+ * standard query/mutation surface the import passes use: `querySelector(All)`,
+ * `createElement`, `createTreeWalker` + `NodeFilter` (read off the document's
+ * `defaultView`), and `body.innerHTML`.
+ */
+export type HtmlDocumentParser = (html: string) => Document;
+
+/**
+ * Convert an HTML string to a ProseMirror JSON doc against the given TipTap
+ * extension set. This is `@tiptap/html`'s `generateJSON`, injected per
+ * environment so the Node path binds its happy-dom `server` entry and the
+ * browser path its native-`DOMParser` entry — neither leaking the other's DOM
+ * lib into the wrong bundle.
+ */
+export type GenerateJsonFn = (html: string, extensions: any[]) => any;
+
+let injectedParser: HtmlDocumentParser | null = null;
+let injectedGenerateJson: GenerateJsonFn | null = null;
+
+/**
+ * Register the environment's HTML parser. Called ONCE at import time by the
+ * Node or browser entry module. Idempotent-friendly: the last registration
+ * wins, so a test harness can override it.
+ */
+export function setHtmlDocumentParser(parser: HtmlDocumentParser): void {
+  injectedParser = parser;
+}
+
+/**
+ * Parse `html` into a `Document` using the registered parser. Throws a clear
+ * error when no environment entry has registered one (the caller imported the
+ * converter without going through the Node/browser barrel).
+ */
+export function parseHtmlDocument(html: string): Document {
+  if (!injectedParser) {
+    throw new Error(
+      "No HTML DOM parser registered. Import `@docmost/prosemirror-markdown` " +
+        "(Node) or `@docmost/prosemirror-markdown/browser` (browser) so the " +
+        "environment's DOM parser is installed before calling the converter.",
+    );
+  }
+  return injectedParser(html);
+}
+
+/**
+ * Register the environment's `generateJSON` (HTML -> ProseMirror JSON). Called
+ * ONCE at import time by the Node or browser entry module.
+ */
+export function setGenerateJson(fn: GenerateJsonFn): void {
+  injectedGenerateJson = fn;
+}
+
+/**
+ * Run the registered `generateJSON`. Throws a clear error when no environment
+ * entry has registered one (same cause as {@link parseHtmlDocument}).
+ */
+export function generateJsonWith(html: string, extensions: any[]): any {
+  if (!injectedGenerateJson) {
+    throw new Error(
+      "No generateJSON registered. Import `@docmost/prosemirror-markdown` " +
+        "(Node) or `@docmost/prosemirror-markdown/browser` (browser) so the " +
+        "environment's generateJSON is installed before calling the converter.",
+    );
+  }
+  return injectedGenerateJson(html, extensions);
+}

packages/prosemirror-markdown/src/lib/foreign-markdown.ts

@@ -1,7 +1,14 @@
 /**
  * Foreign-markdown normalizer — an input-liberal / output-canonical adapter that
  * runs at the IMPORT boundary, BEFORE the canonical parser
- * (`markdownToProseMirror` from `@docmost/prosemirror-markdown`).
+ * (`markdownToProseMirror`, this package).
+ *
+ * OWNED BY THIS PACKAGE (#493): the normalizer used to live only in
+ * apps/server's import path, so the MCP page-write path (`updatePageMarkdown` ->
+ * `markdownToProseMirrorCanonical`) handled the SAME foreign input differently
+ * (no front-matter strip, no `[^id]` reference-footnote rewrite) than the server
+ * importer. Moving it here — and calling it from `markdownToProseMirrorCanonical`
+ * — makes every canonical import boundary treat foreign markdown identically.
  *
  * The canonical parser is deliberately STRICT: it only understands Docmost's
  * canonical markdown surface (Obsidian-style `> [!type]` callouts, Pandoc/Obsidian
@@ -238,19 +245,27 @@ function convertReferenceFootnotes(markdown: string): string {
  *
  * LINE-ANCHORED (the same shape the canonical parser uses in
  * prosemirror-markdown/page-file.ts): the block opens only on `---\n` at the
- * very start and closes only on a `\n---` line. The retired `markdownToHtml`
- * strip closed on the FIRST `---` ANYWHERE (an unanchored close), so a value
+ * very start and closes only on a `\n---` line. The retired editor-ext
+ * `markdownToHtml` front-matter strip (removed in #347) closed on the FIRST
+ * `---` ANYWHERE (an unanchored close), so a value
  * containing a triple-dash (e.g. `title: Q1 --- Q2`) truncated the front-matter
  * and leaked the rest into the body. An optional leading BOM is tolerated.
  */
 const YAML_FRONT_MATTER_RE = /^\uFEFF?---\n[\s\S]*?\n---\n?/;
 
 /**
- * Normalize a foreign markdown string into Docmost's canonical markdown surface
- * so the strict canonical parser accepts it losslessly: normalize line endings,
- * strip a leading YAML front-matter block, then rewrite GFM reference footnotes
- * into inline footnotes. Add further fixture-driven foreign-surface cases here as
- * they are found.
+ * Normalize a foreign markdown string from a FILE IMPORT into Docmost's canonical
+ * markdown surface so the strict canonical parser accepts it losslessly: normalize
+ * line endings, strip a leading YAML front-matter block, then rewrite GFM reference
+ * footnotes into inline footnotes. Add further fixture-driven foreign-surface cases
+ * here as they are found.
+ *
+ * FRONT-MATTER STRIP IS IMPORT-ONLY (#493 review): use this ONLY at the server
+ * file-import boundary, where a `.md` file really can open with an Obsidian/Hugo
+ * YAML header. Do NOT use it on the canonical AGENT-WRITE path — see
+ * {@link normalizeAgentMarkdown} for why a full-body agent rewrite must NOT strip
+ * a leading `---…---` (it is normally a horizontalRule the serializer emitted, and
+ * stripping it would silently drop the page's leading content).
  */
 export function normalizeForeignMarkdown(markdown: string): string {
   if (!markdown) return markdown;
@@ -263,3 +278,26 @@ export function normalizeForeignMarkdown(markdown: string): string {
   const withoutFrontMatter = src.replace(YAML_FRONT_MATTER_RE, '').trimStart();
   return convertReferenceFootnotes(withoutFrontMatter);
 }
+
+/**
+ * Canonical AGENT-WRITE normalization: normalize line endings and rewrite GFM
+ * `[^id]` reference footnotes to inline `^[body]` — but DELIBERATELY NOT strip a
+ * leading YAML front-matter block.
+ *
+ * WHY the split (#493 review): the reference-footnote rewrite is the drift the
+ * MCP page-write path (`updatePageMarkdown` -> `markdownToProseMirrorCanonical`)
+ * needed unified with the server import (an agent may paste GFM footnotes). The
+ * front-matter strip, however, is a FILE-import concern: on a full-body agent
+ * rewrite a leading `---…---` is (almost) always a `horizontalRule` the
+ * serializer emitted plus a later rule/heading — NOT a foreign YAML header — so
+ * `YAML_FRONT_MATTER_RE` would match it and SILENTLY DELETE the page's leading
+ * content (a page that starts with a horizontal rule and contains a second `---`
+ * lost everything up to it). Agent writes must never lose already-stored content,
+ * so this variant skips the strip. It IS a no-op on canonical serialized content
+ * (which never emits `[^id]:` reference-definition lines).
+ */
+export function normalizeAgentMarkdown(markdown: string): string {
+  if (!markdown) return markdown;
+  const src = markdown.replace(/\r\n/g, '\n');
+  return convertReferenceFootnotes(src);
+}

packages/prosemirror-markdown/src/lib/index.ts

@@ -15,10 +15,29 @@ export {
 } from "./markdown-document.js";
 export type { DocmostMdMeta } from "./markdown-document.js";
 
-export { convertProseMirrorToMarkdown } from "./markdown-converter.js";
+export {
+  convertProseMirrorToMarkdown,
+  ConverterLossError,
+} from "./markdown-converter.js";
 export type { ConvertProseMirrorToMarkdownOptions } from "./markdown-converter.js";
 
-export { markdownToProseMirror } from "./markdown-to-prosemirror.js";
+export {
+  markdownToProseMirror,
+  markdownToProseMirrorSync,
+} from "./markdown-to-prosemirror.js";
+
+// Foreign-markdown normalizer (#493): the input-liberal pre-pass that rewrites
+// GFM `[^id]` reference footnotes to canonical inline `^[body]`. Two variants:
+// `normalizeForeignMarkdown` (server FILE-import boundary) ALSO strips a leading
+// YAML front-matter block; `normalizeAgentMarkdown` (canonical AGENT-WRITE path,
+// mcp `markdownToProseMirrorCanonical`) does NOT — a full-body agent rewrite must
+// not lose a leading `---…---` horizontalRule to the front-matter strip (#493
+// review). The reference-footnote rewrite is shared so agent + import stay unified
+// where it matters, without the content-losing strip on the write path.
+export {
+  normalizeForeignMarkdown,
+  normalizeAgentMarkdown,
+} from "./foreign-markdown.js";
 
 // The Docmost tiptap schema mirror. Exposed so consumers (and the sync
 // engine's schema-validity regression tests) can build the exact ProseMirror
@@ -73,6 +92,17 @@ export type { OutlineEntry } from "./node-ops.js";
 // string (#414: single copy shared by mcp and the CommonJS server app).
 export { parseNodeArg } from "./parse-node-arg.js";
 
+// Locator markdown-stripping (#493 dedup): the single canonical copy of the
+// markdown-tolerant anchor-normalization primitives, imported by mcp's
+// text-normalize.ts instead of a forked duplicate. `stripInlineMarkdown` is the
+// lenient locator normalizer (trims stray decoration); `stripWrappersAndLinks`
+// is the strict balanced-wrapper/link primitive mcp builds `stripBalancedWrappers`
+// on top of.
+export {
+  stripInlineMarkdown,
+  stripWrappersAndLinks,
+} from "./text-normalize.js";
+
 // Inline-footnote authoring convention (#414: single copy, formerly the mcp
 // `footnote-authoring.ts` fork), shared with the importer's `assembleFootnotes`.
 export {

packages/prosemirror-markdown/src/lib/markdown-converter.ts

@@ -33,6 +33,26 @@ import {
  */
 const MAX_NODE_DEPTH = 400;
 
+/**
+ * Thrown by {@link convertProseMirrorToMarkdown} in `strict` mode when it hits a
+ * node or mark type it has no lossless markdown form for (the serializer would
+ * otherwise silently degrade it — drop an unknown mark, flatten an unknown node
+ * to its children). Carries the offending kind/name so a caller (git-sync) can
+ * surface exactly what would have been lost.
+ */
+export class ConverterLossError extends Error {
+  readonly kind: "node" | "mark";
+  readonly typeName: string;
+  constructor(kind: "node" | "mark", typeName: string) {
+    super(
+      `convertProseMirrorToMarkdown: unknown ${kind} type "${typeName}" has no lossless markdown representation (strict mode)`,
+    );
+    this.name = "ConverterLossError";
+    this.kind = kind;
+    this.typeName = typeName;
+  }
+}
+
 /**
  * Options for {@link convertProseMirrorToMarkdown}.
  */
@@ -46,6 +66,23 @@ export interface ConvertProseMirrorToMarkdownOptions {
    * path where resolved anchors MUST be preserved for round-tripping.
    */
   dropResolvedCommentAnchors?: boolean;
+  /**
+   * Optional sink for LOSS warnings. When the serializer reaches a node or mark
+   * type it has no dedicated case for, it degrades gracefully (flattens an
+   * unknown node to its children, drops an unknown mark) — historically a SILENT
+   * data loss. When this array is provided, one human-readable message per such
+   * event is pushed here so the caller can observe (and log) what was degraded.
+   * Not provided by default -> behavior is byte-identical to before for existing
+   * callers.
+   */
+  warnings?: string[];
+  /**
+   * When true, THROW a {@link ConverterLossError} on the FIRST unknown node/mark
+   * instead of degrading silently — a warning becomes a hard error. Used by the
+   * lossless git-sync export path and the converter tests, where an unmapped
+   * type is a bug to surface, not data to quietly drop.
+   */
+  strict?: boolean;
 }
 
 /**
@@ -63,6 +100,70 @@ export interface ConvertProseMirrorToMarkdownOptions {
  * separator is emitted for any other join, so non-list output is unchanged.
  */
 const LIST_MARKER_SEPARATOR = "<!-- -->";
+
+/**
+ * Backslash-escape a leading markdown BLOCK trigger so a serialized paragraph
+ * line re-parses as a PARAGRAPH, not another block. Without this, a paragraph
+ * whose text begins at column 0 with an ATX heading `#`, a blockquote/callout
+ * `>`, a bullet marker `-`/`*`/`+`, an ordered marker `N.`/`N)`, a code fence
+ * (```` ``` ````/`~~~`), a table `|`, or a thematic break (`---`/`***`/`___`,
+ * solid or spaced) silently becomes a heading/list/quote/code block/table/rule
+ * on the next markdown -> ProseMirror import — a known data-loss class (the
+ * thematic-break case drops the text entirely, since a horizontalRule carries
+ * none). CommonMark's escape tokenizer decodes the inserted `\` back to the
+ * literal character on import AND stops the block interpretation, so the line
+ * round-trips byte-exact as paragraph text. Only the FIRST offending character
+ * is escaped (the minimum needed to break block recognition); a line that does
+ * NOT open a block — emphasis `**x**`, an inline code span, ordinary prose — is
+ * returned verbatim, so there is no backslash churn for the common case.
+ *
+ * Applied ONLY to paragraph text, once per `\n`-separated LINE (the paragraph
+ * case splits on `\n` — each hardBreak emits `  \n` — so a trigger on a
+ * continuation line is escaped too): headings/lists/blockquotes legitimately
+ * open with these markers and render them from their own cases. This is the
+ * single, canonical fix for the class the client bridge worked around with a
+ * ZWSP (`gitmost-recording.ts`) and the generative suite self-censored around
+ * (`text-arbitraries.ts`) — both now removed.
+ */
+function escapeLeadingBlockTrigger(line: string): string {
+  // ATX heading: 1..6 `#` then whitespace/EOL.
+  if (/^#{1,6}(?:\s|$)/.test(line)) return "\\" + line;
+  // Blockquote / Docmost callout opener (`>` or `> [!info]`).
+  if (line.startsWith(">")) return "\\" + line;
+  // Bullet list marker then whitespace/EOL. Emphasis (`*x*`, `**x**`) has no
+  // space after the leading marker and is intentionally left verbatim.
+  if (/^[-*+](?:\s|$)/.test(line)) return "\\" + line;
+  // Ordered list marker `N.` / `N)`: escape the DELIMITER so the digits stay
+  // literal (`1. x` -> `1\. x`, which imports back as the text `1. x`).
+  const ordered = line.match(/^(\d+)[.)](?:\s|$)/);
+  if (ordered) {
+    const digits = ordered[1].length;
+    return line.slice(0, digits) + "\\" + line.slice(digits);
+  }
+  // Fenced code block: 3+ backticks or tildes. A single/double backtick is an
+  // inline code span and is left verbatim.
+  if (/^(?:`{3,}|~{3,})/.test(line)) return "\\" + line;
+  // Thematic break: a WHOLE line of 3+ identical `-`/`*`/`_`, optionally spaced.
+  if (/^([-*_])(?:\s*\1){2,}\s*$/.test(line)) return "\\" + line;
+  // Setext underline: a continuation line (after a hardBreak) that is ONLY `-`
+  // or ONLY `=` (any count, trailing spaces allowed). Under a paragraph line
+  // such a line re-parses as a SETEXT HEADING and SILENTLY DROPS its own text
+  // (`a\n--` -> heading "a", the `--` is LOST; `a\n=` -> heading "a", `=` LOST).
+  // The bullet arm above catches a lone `-` (via its `$`) and the thematic arm
+  // catches 3+ dashes, but exactly TWO dashes (`--`) fall through both; and no
+  // arm covers a lone `=` at all (a `==` pair is neutralized earlier by the
+  // inline `==`->`\=\=` escape, so only a single `=` line reaches here). Escaping
+  // the leading char (`\--`, `\=`) breaks the setext interpretation so the line
+  // round-trips as paragraph text. The WHOLE line must be the marker (anchored
+  // `^-+`/`^=+` to EOL), so a mid-content `-`/`=` is never spuriously escaped;
+  // and a `---`/`----` already handled by the thematic arm never reaches here,
+  // so there is no double-escape.
+  if (/^-+[ \t]*$/.test(line) || /^=+[ \t]*$/.test(line)) return "\\" + line;
+  // GFM table row opener.
+  if (line.startsWith("|")) return "\\" + line;
+  return line;
+}
+
 function listMarkerFamily(type: string | undefined): "ul" | "ol" | null {
   if (type === "bulletList" || type === "taskList") return "ul";
   if (type === "orderedList") return "ol";
@@ -109,6 +210,26 @@ export function convertProseMirrorToMarkdown(
   // callers (mcp getPage / in-app AI chat) pass it true.
   const dropResolvedCommentAnchors = options.dropResolvedCommentAnchors === true;
 
+  // Loss reporting for node/mark types with no dedicated serializer case. In
+  // `strict` mode the FIRST such type throws (git-sync, tests); otherwise the
+  // serializer degrades gracefully (as it always has) but records one warning
+  // per unmapped type into the optional sink so the loss is observable, not
+  // silent. Deduped per type so a document with many unknown nodes of one type
+  // produces one message.
+  const strict = options.strict === true;
+  const warningsSink = options.warnings;
+  const seenLossTypes = new Set<string>();
+  const warnLoss = (kind: "node" | "mark", typeName: string): void => {
+    if (strict) throw new ConverterLossError(kind, typeName);
+    if (!warningsSink) return;
+    const key = `${kind}:${typeName}`;
+    if (seenLossTypes.has(key)) return;
+    seenLossTypes.add(key);
+    warningsSink.push(
+      `Unknown ${kind} type "${typeName}" has no lossless markdown form; it was degraded on export.`,
+    );
+  };
+
   // Escape a value interpolated into an HTML double-quoted attribute value
   // (textAlign, colors, image src, math `text`, all data-* attrs, etc.). In the
   // ATTRIBUTE context only the quote that delimits the value and the ampersand
@@ -362,6 +483,99 @@ export function convertProseMirrorToMarkdown(
     return `<table><tbody>${htmlRows}</tbody></table>`;
   };
 
+  // Layer the intentional inline escapes onto a NON-code text run BEFORE its
+  // marks are applied. Extracted so both `case "text"` and the #515 code-emphasis
+  // run factoring (renderInlineChildren) escape the inner text identically. NEVER
+  // called on code content (a code span is literal — see the gating in the text
+  // case and the run helper). Order is load-bearing: the footnote raw-backslash
+  // doubling MUST precede the `==`/`$`/`^[` escapes (see inFootnoteBody).
+  const escapeInlineText = (text: string): string => {
+    let t = text;
+    if (inFootnoteBody) t = t.replace(/\\/g, "\\\\");
+    t = t.replace(/==/g, "\\=\\=");
+    t = escapeProseMath(t);
+    t = t.replace(/\^\[/g, "^\\[");
+    return t;
+  };
+
+  // Wrap `text` with the markdown/HTML form of a SINGLE inline mark. Extracted
+  // from `case "text"` so the same per-mark emission is reused when the #515
+  // run factoring layers a shared outer mark over a code-emphasis run. `code` is
+  // handled by the callers (wrapped innermost, before this runs), so this branch
+  // is defensive only. For any non-code mark the output is byte-identical to the
+  // pre-#515 inline switch.
+  const applyInlineMark = (text: string, mark: any): string => {
+    switch (mark.type) {
+      case "bold":
+        return `**${text}**`;
+      case "italic":
+        return `*${text}*`;
+      case "code":
+        // Callers wrap the code span innermost themselves; reached only if a
+        // mark list is applied through here directly. Emit the backtick span.
+        return `\`${text}\``;
+      case "link": {
+        const href = mark.attrs?.href || "";
+        const title = mark.attrs?.title;
+        if (title) {
+          // Emit the optional markdown link title; escape an embedded double-
+          // quote so it cannot terminate the title string early.
+          const safeTitle = String(title).replace(/"/g, '\\"');
+          return `[${text}](${href} "${safeTitle}")`;
+        }
+        return `[${text}](${href})`;
+      }
+      case "strike":
+        return `~~${text}~~`;
+      case "underline":
+        return `<u>${text}</u>`;
+      case "subscript":
+        return `<sub>${text}</sub>`;
+      case "superscript":
+        return `<sup>${text}</sup>`;
+      case "highlight": {
+        // #293 canon #7: a highlight WITHOUT a color serializes as the
+        // Obsidian/GFM `==text==` syntax; a colored highlight keeps the `<mark
+        // style>` HTML form. The inner text already had any literal `==`
+        // backslash-escaped upstream.
+        const color = mark.attrs?.color;
+        return color
+          ? `<mark style="background-color: ${escapeAttr(color)}">${text}</mark>`
+          : `==${text}==`;
+      }
+      case "textStyle":
+        if (mark.attrs?.color) {
+          return `<span style="color: ${escapeAttr(mark.attrs.color)}">${text}</span>`;
+        }
+        return text;
+      case "spoiler":
+        // Markdown has no native spoiler syntax, so emit the same raw inline HTML
+        // the editor-ext/MCP stack uses (span[data-spoiler] round-trips).
+        return `<span data-spoiler="true">${text}</span>`;
+      case "comment": {
+        // Inline comment anchor (span[data-comment-id]); resolved anchors are
+        // optionally dropped for agent reads, keeping only the bare text.
+        const cid = mark.attrs?.commentId;
+        if (cid) {
+          if (mark.attrs?.resolved && dropResolvedCommentAnchors) {
+            return text;
+          }
+          const resolvedAttr = mark.attrs?.resolved
+            ? ` data-resolved="true"`
+            : "";
+          return `<span data-comment-id="${escapeAttr(cid)}"${resolvedAttr}>${text}</span>`;
+        }
+        return text;
+      }
+      default:
+        // Unknown mark: no dedicated case, so it has no markdown form and is
+        // dropped from the run. Report the loss (throws in strict mode) then
+        // leave the text unwrapped — the historical behavior.
+        warnLoss("mark", String(mark.type));
+        return text;
+    }
+  };
+
   const processNode = (node: any): string => {
     if (nodeDepth >= MAX_NODE_DEPTH) {
       // Bail out of deeper recursion without throwing. A text node still has
@@ -412,7 +626,17 @@ export function convertProseMirrorToMarkdown(
       }
 
       case "paragraph": {
-        const text = renderInlineChildren(nodeContent);
+        // Escape a leading block trigger on EVERY line of the paragraph, not
+        // just the first: a hardBreak serializes as `  \n`, so a `#`/`-`/`>`/
+        // `1.`/`|`/fence/`---` at the start of a CONTINUATION line would also
+        // re-parse into another block on the next import (a heading/list/table/
+        // setext-`---`), and for the text-less thematic/setext case would LOSE
+        // that line's text entirely. Escaping each `\n`-separated line closes
+        // the class for multi-line paragraphs too.
+        const text = renderInlineChildren(nodeContent)
+          .split("\n")
+          .map(escapeLeadingBlockTrigger)
+          .join("\n");
         const align = node.attrs?.textAlign;
         // Non-default alignment round-trips as an ATTACHED HTML comment at the
         // END of the block line (#293 canon #9):
@@ -451,154 +675,38 @@ export function convertProseMirrorToMarkdown(
         return headingLine;
       }
 
-      case "text":
+      case "text": {
         let textContent = node.text || "";
-        // #293 canon #7: `==` is now a LIVE inline highlight syntax on import (a
-        // marked inline extension turns `==text==` into a color-less highlight
-        // mark). A LITERAL `==` in a text run would therefore be misparsed as a
-        // highlight on the next import, so backslash-escape each `=` of a `==`
-        // pair; marked's escape tokenizer decodes `\=` back to a literal `=`, so
-        // a literal `==` round-trips as text (never materializes a phantom mark).
-        // This runs for BOTH unmarked text and marked non-code runs, but NOT for
-        // an inline code span (a run carrying the `code` mark returns a backtick
-        // span below with `==` verbatim, matching `` `a == b` `` staying code).
-        // A highlight run's own `==` delimiters are appended AFTER this in the
-        // marks loop, so they are never escaped; only the run's inner text is.
-        if (!(node.marks || []).some((m: any) => m.type === "code")) {
-          // #293 canon #2 (F2): inside a footnote body, DOUBLE every RAW user
-          // backslash FIRST, so it survives `^[…]` (the import tokenizer treats
-          // `\<char>` as an escape when balancing brackets, and `parseInline`
-          // decodes escapes). Doing it before the intentional escapes below keeps
-          // the serializer's own single escapes (`\=` `\$` `^\[`, and the `\[`/
-          // `\]` balanceBrackets adds) single; only genuine user backslashes are
-          // doubled. Skipped for code runs (a code span's content is NOT decoded
-          // by parseInline, so its backslashes must stay verbatim).
-          if (inFootnoteBody) {
-            textContent = textContent.replace(/\\/g, "\\\\");
-          }
-          textContent = textContent.replace(/==/g, "\\=\\=");
-          // #293 canon #6: escape a would-be inline-math `$…$` span so it stays
-          // literal text on re-import (currency `$5` is left clean — see
-          // escapeProseMath). Runs on the SAME non-code runs as the `==` escape
-          // above; an inline `code` run returns verbatim below, matching the
-          // codeBlock path (a `$…$` inside code must stay code, never math).
-          textContent = escapeProseMath(textContent);
-          // #293 canon #2: `^[` opens a LIVE inline-footnote span on import
-          // (`^[text]` -> a footnote reference). A LITERAL `^[` in prose text
-          // would therefore materialize a phantom footnote on the next import, so
-          // backslash-escape the bracket (`^[` -> `^\[`); marked's escape
-          // tokenizer decodes `\[` back to `[`, so a literal `^[…]` round-trips
-          // as text and never opens a footnote. Only the OPENING `^[` needs
-          // breaking (the tokenizer requires it), so this is a minimal, idempotent
-          // escape. A real footnoteReference node emits `^[body]` from its own
-          // case, never through here.
-          textContent = textContent.replace(/\^\[/g, "^\\[");
+        // #515: `code` is no longer exclusive (`excludes: ""`), so a run may
+        // carry `code` TOGETHER with other marks. The inner escapes below apply
+        // ONLY to a NON-code run (a code span's content is literal — `==`, `$…$`,
+        // `^[` must stay verbatim, matching `` `a == b` `` staying code). See
+        // #293 canon #2/#6/#7 for why each escape exists (extracted into
+        // escapeInlineText). A code run's `==`/`$`/`^[` are protected by the
+        // backticks, so they are never misparsed on re-import.
+        const hasCode = (node.marks || []).some((m: any) => m.type === "code");
+        if (!hasCode) {
+          textContent = escapeInlineText(textContent);
         }
-        // Apply marks (bold, italic, code, etc.)
         if (node.marks) {
-          // The schema's `code` mark declares `excludes: "_"` — it excludes every
-          // other inline mark — so the editor can NEVER produce a text run that
-          // carries `code` together with another mark, and on import any
-          // co-occurring mark is always dropped (the run comes back as code-only).
-          // The lossless, byte-stable behavior is therefore: when a run has the
-          // `code` mark, emit ONLY the backtick code span and ignore every other
-          // mark, so md1 is already code-only and md2 === md1. Runs WITHOUT a code
-          // mark are rendered exactly as before.
-          const markTypes = node.marks.map((m: any) => m.type);
-          const hasCode = markTypes.includes("code");
+          // #515: wrap the backtick code span FIRST (innermost mark), then layer
+          // the REMAINING marks in array order. For a run WITHOUT a code mark the
+          // loop applies every mark exactly as the pre-#515 switch did, so the
+          // output is byte-identical. For a code+emphasis run the code span sits
+          // inside the emphasis delimiters (`` **`code`** ``), matching CommonMark.
+          // The shared-mark grouping across ADJACENT nodes (`` **`a` + `b`** ``)
+          // lives in renderInlineChildren; this direct path handles a lone run
+          // and the table/`default` callers that invoke processNode per node.
           if (hasCode) {
             textContent = `\`${textContent}\``;
-            return textContent;
           }
           for (const mark of node.marks) {
-            switch (mark.type) {
-              case "bold":
-                textContent = `**${textContent}**`;
-                break;
-              case "italic":
-                textContent = `*${textContent}*`;
-                break;
-              case "code":
-                // A `code` run already returned above (hasCode early return), so
-                // this branch is only reached for a non-code run that somehow
-                // still lists `code`; emit the plain backtick span.
-                textContent = `\`${textContent}\``;
-                break;
-              case "link": {
-                const href = mark.attrs?.href || "";
-                const title = mark.attrs?.title;
-                if (title) {
-                  // Emit the optional markdown link title; escape an embedded
-                  // double-quote so it cannot terminate the title string early.
-                  const safeTitle = String(title).replace(/"/g, '\\"');
-                  textContent = `[${textContent}](${href} "${safeTitle}")`;
-                } else {
-                  textContent = `[${textContent}](${href})`;
-                }
-                break;
-              }
-              case "strike":
-                textContent = `~~${textContent}~~`;
-                break;
-              case "underline":
-                textContent = `<u>${textContent}</u>`;
-                break;
-              case "subscript":
-                textContent = `<sub>${textContent}</sub>`;
-                break;
-              case "superscript":
-                textContent = `<sup>${textContent}</sup>`;
-                break;
-              case "highlight": {
-                // #293 canon #7: a highlight WITHOUT a color serializes as the
-                // Obsidian/GFM `==text==` syntax (the importer's marked inline
-                // `==` extension parses it back to a color-less highlight mark).
-                // A highlight WITH a color keeps the `<mark style="background-
-                // color: …">` HTML form (the condition is deterministic on the
-                // `color` attr), so a colored highlight is not flattened. The
-                // inner textContent already had any literal `==` backslash-
-                // escaped above, so a highlight over text containing `==` still
-                // round-trips.
-                const color = mark.attrs?.color;
-                textContent = color
-                  ? `<mark style="background-color: ${escapeAttr(color)}">${textContent}</mark>`
-                  : `==${textContent}==`;
-                break;
-              }
-              case "textStyle":
-                if (mark.attrs?.color) {
-                  textContent = `<span style="color: ${escapeAttr(mark.attrs.color)}">${textContent}</span>`;
-                }
-                break;
-              case "spoiler":
-                // Markdown has no native spoiler syntax, so emit the same raw
-                // inline HTML the editor-ext/MCP stack uses. The schema's Spoiler
-                // mark parses span[data-spoiler] back on import, so the mark
-                // survives the PM -> MD -> PM round-trip.
-                textContent = `<span data-spoiler="true">${textContent}</span>`;
-                break;
-              case "comment": {
-                // Emit the inline comment anchor so highlights round-trip. The
-                // schema's Comment mark parses span[data-comment-id] (attrs
-                // commentId/resolved).
-                const cid = mark.attrs?.commentId;
-                if (cid) {
-                  // Hide resolved anchors from agent reads: drop the wrapper and
-                  // keep only the bare text. Active anchors keep their wrapper.
-                  if (mark.attrs?.resolved && dropResolvedCommentAnchors) {
-                    break;
-                  }
-                  const resolvedAttr = mark.attrs?.resolved
-                    ? ` data-resolved="true"`
-                    : "";
-                  textContent = `<span data-comment-id="${escapeAttr(cid)}"${resolvedAttr}>${textContent}</span>`;
-                }
-                break;
-              }
-            }
+            if (mark.type === "code") continue; // wrapped innermost above
+            textContent = applyInlineMark(textContent, mark);
           }
         }
         return textContent;
+      }
 
       case "codeBlock":
         const language = node.attrs?.language || "";
@@ -1173,7 +1281,11 @@ export function convertProseMirrorToMarkdown(
       }
 
       default:
-        // Fallback: process children
+        // Unknown node type: no dedicated case, so the node's identity + attrs
+        // have no lossless markdown form. Report the loss (throws in strict
+        // mode) then degrade by flattening to its children — the historical
+        // graceful fallback.
+        warnLoss("node", String(type));
         return nodeContent.map(processNode).join("");
     }
   };
@@ -1186,18 +1298,165 @@ export function convertProseMirrorToMarkdown(
   // For that node ONLY we fall back to the lossless schema-HTML `<span>` form.
   // Every other inline node is rendered exactly as processNode would, so output
   // is unchanged whenever no math sits directly before a digit.
+  // #515: a "bare-delimiter" emphasis mark is one that serializes as a naked
+  // markdown delimiter run (`**` `*` `~~` `==`) — bold / italic / strike /
+  // UNCOLORED highlight. These delimiters COLLIDE with the backtick-flanking
+  // delimiters emitted around a code+emphasis run: rendering `[code,bold]` next
+  // to `[italic]` node-by-node would produce `` **`a`***b* `` (a `***` run that
+  // re-imports wrong). Every OTHER mark (underline/sub/sup/spoiler/comment/
+  // textStyle/colored-highlight/link) emits an HTML/bracket form whose boundaries
+  // do NOT collapse, so those neighbors never join a run.
+  const isBareEmphasisMark = (mark: any): boolean => {
+    switch (mark?.type) {
+      case "bold":
+      case "italic":
+      case "strike":
+        return true;
+      case "highlight":
+        return !mark.attrs?.color; // colored highlight emits <mark>, not `==`
+      default:
+        return false;
+    }
+  };
+
+  // A text node participates in a code-emphasis run iff it carries at least one
+  // bare-delimiter emphasis mark. A code-ONLY node (no emphasis) does NOT — so a
+  // plain `` `code` `` next to `**bold**` keeps its clean, byte-identical
+  // markdown (they share no colliding delimiter). Existing pages, where a code
+  // node could never carry emphasis, therefore serialize exactly as before.
+  const isEmphasisMember = (node: any): boolean =>
+    node?.type === "text" &&
+    (node.marks || []).some((m: any) => isBareEmphasisMark(m));
+
+  // The run's non-code marks (order preserved) — the candidate marks to factor.
+  const nonCodeMarks = (node: any): any[] =>
+    (node.marks || []).filter((m: any) => m.type !== "code");
+
+  // Deep structural equality of two marks (type + full attrs). Two `link` marks
+  // are equal only when EVERY attr matches (class/href/internal/rel/target/title
+  // — not just href), so a homogeneous run never merges links that differ.
+  const marksEqual = (a: any, b: any): boolean =>
+    a.type === b.type &&
+    JSON.stringify(a.attrs ?? null) === JSON.stringify(b.attrs ?? null);
+
+  // Two non-code mark lists are equal AS SETS (a run is homogeneous when every
+  // node shares the identical non-code mark set — order-independent).
+  const markSetsEqual = (a: any[], b: any[]): boolean =>
+    a.length === b.length &&
+    a.every((ma) => b.some((mb) => marksEqual(ma, mb))) &&
+    b.every((mb) => a.some((ma) => marksEqual(mb, ma)));
+
+  // Serialize one node's INNER form for a homogeneous run: the factored marks are
+  // applied by the caller, so here a code node emits only its literal backtick
+  // span and a non-code node emits only its (escaped) text.
+  const renderRunInner = (node: any): string => {
+    const text = node.text || "";
+    if ((node.marks || []).some((m: any) => m.type === "code")) {
+      return `\`${text}\``; // code content is literal
+    }
+    return escapeInlineText(text);
+  };
+
+  // A markdown emphasis delimiter (`**`/`*`/`~~`/`==`) wrapping a code span opens
+  // with the delimiter immediately followed by a backtick and closes immediately
+  // preceded by one. A backtick is CommonMark punctuation, so such a delimiter is
+  // only left/right-flanking — able to open/close emphasis — when the character
+  // on its OUTER side is start/end, whitespace or punctuation. If a run boundary
+  // abuts a word character, the delimiter would NOT flank (`a**` `code` `**`
+  // never opens) and the emphasis silently degrades on re-import. This checks the
+  // outer boundary char conservatively: ASCII whitespace or ASCII punctuation (or
+  // the string edge) is safe; anything else (a letter/number, unicode letter or
+  // emoji) is treated as unsafe so the run takes the lossless HTML fallback.
+  const SAFE_BOUNDARY = /[\s!-/:-@[-`{-~]/;
+  const isSafeBoundary = (c: string): boolean => c === "" || SAFE_BOUNDARY.test(c);
+
+  // Serialize a maximal run of adjacent emphasis-member text nodes that contains
+  // at least one `code` node (#515). HOMOGENEOUS (all share the identical
+  // non-code mark set) AND flank-safe on both boundaries: factor the common marks
+  // ONCE around the concatenated inner spans — `` **`aaa` + `bbb`** ``, code
+  // innermost. Otherwise — HETEROGENEOUS (non-code sets differ, e.g. `[code,bold]`
+  // next to `[italic]`) OR a boundary abuts a word char — emit the whole run as
+  // schema-HTML via the lossless inlineToHtml fallback, avoiding a colliding
+  // `***` delimiter run or a non-flanking `a**` that would drop the emphasis.
+  const renderCodeEmphasisRun = (
+    run: any[],
+    prevChar: string,
+    nextChar: string,
+  ): string => {
+    const firstNonCode = nonCodeMarks(run[0]);
+    const homogeneous = run.every((n) =>
+      markSetsEqual(nonCodeMarks(n), firstNonCode),
+    );
+    if (!homogeneous || !isSafeBoundary(prevChar) || !isSafeBoundary(nextChar)) {
+      return inlineToHtml(run);
+    }
+    let out = run.map(renderRunInner).join("");
+    // Apply the common non-code marks in the FIRST node's array order (code is
+    // already innermost inside each span).
+    for (const mark of firstNonCode) out = applyInlineMark(out, mark);
+    return out;
+  };
+
   const renderInlineChildren = (nodes: any[]): string => {
-    const parts = nodes.map(processNode);
-    for (let i = 0; i < nodes.length - 1; i++) {
-      if (
-        nodes[i]?.type === "mathInline" &&
-        parts[i].startsWith("$") &&
-        /^[0-9]/.test(parts[i + 1] || "")
-      ) {
-        parts[i] = mathInlineHtml(nodes[i].attrs?.text || "");
+    // Pass 1: segment the nodes. Each segment is either an already-rendered
+    // non-run node / pure-emphasis node (byte-identical to the pre-#515 output),
+    // or a DEFERRED code-emphasis run (a maximal block of consecutive
+    // emphasis-member text nodes containing a code node) — its markdown-vs-HTML
+    // choice needs the neighbor boundary chars, resolved in pass 2.
+    type Seg = { firstNode: any; text?: string; run?: any[] };
+    const segs: Seg[] = [];
+    let i = 0;
+    while (i < nodes.length) {
+      const node = nodes[i];
+      if (isEmphasisMember(node)) {
+        let j = i;
+        while (j < nodes.length && isEmphasisMember(nodes[j])) j++;
+        const run = nodes.slice(i, j);
+        const hasCode = run.some((n: any) =>
+          (n.marks || []).some((m: any) => m.type === "code"),
+        );
+        if (hasCode) {
+          segs.push({ firstNode: run[0], run });
+        } else {
+          // Pure-emphasis run (no code): render each node as before.
+          for (const n of run) segs.push({ firstNode: n, text: processNode(n) });
+        }
+        i = j;
+      } else {
+        segs.push({ firstNode: node, text: processNode(node) });
+        i++;
       }
     }
-    return parts.join("");
+    // A deferred run always emits either a delimiter/backtick (markdown) or `<`
+    // (HTML) first — both punctuation — so a following run counts as a safe
+    // boundary for the current one without resolving it first.
+    const firstCharOf = (seg: Seg): string =>
+      seg.text !== undefined ? seg.text[0] || "" : "*";
+    // Pass 2: resolve deferred runs left-to-right, tracking the previous emitted
+    // char (for the opening boundary) and peeking the next segment (for closing).
+    let prevChar = "";
+    for (let k = 0; k < segs.length; k++) {
+      const seg = segs[k];
+      if (seg.text === undefined) {
+        const nextChar = k + 1 < segs.length ? firstCharOf(segs[k + 1]) : "";
+        seg.text = renderCodeEmphasisRun(seg.run!, prevChar, nextChar);
+      }
+      if (seg.text.length > 0) prevChar = seg.text[seg.text.length - 1];
+    }
+    // Preserve the mathInline-before-digit guard: a `$…$` immediately followed by
+    // a digit-leading segment would re-tokenize as a longer math span, so emit
+    // that math node as HTML instead. A code-emphasis run never starts with a
+    // digit (it opens with a delimiter or `<`), so segment granularity is safe.
+    for (let k = 0; k < segs.length - 1; k++) {
+      if (
+        segs[k].firstNode?.type === "mathInline" &&
+        (segs[k].text || "").startsWith("$") &&
+        /^[0-9]/.test(segs[k + 1].text || "")
+      ) {
+        segs[k].text = mathInlineHtml(segs[k].firstNode.attrs?.text || "");
+      }
+    }
+    return segs.map((s) => s.text).join("");
   };
 
   // Render inline content (text runs + their marks) to HTML. Used by the raw
@@ -1232,7 +1491,22 @@ export function convertProseMirrorToMarkdown(
           return processNode(n);
         }
         let t = escapeHtmlText(n.text || "");
+        // #515: wrap `<code>` INNERMOST first (before the array-order mark loop),
+        // then skip `code` in the loop. The imported mark order is NOT fixed — it
+        // DEPENDS on the emphasis extension: import (`generateJSON`) yields code
+        // LAST for bold/italic/strike (`[emphasis, code]`) but code FIRST for the
+        // `==`-highlight extension (`[code, highlight]`). So we cannot rely on a
+        // fixed array position; the invariant is instead "wrap `<code>` innermost
+        // regardless of the imported order". That keeps `<code>` nested inside the
+        // emphasis tag both directions (preserving the byte fixpoint — an order-
+        // sensitive loop would flip `<strong><code>`↔`<code><strong>` depending on
+        // which order it happened to see) and matches the markdown path (case
+        // "text" / run factoring).
+        if ((n.marks || []).some((m: any) => m.type === "code")) {
+          t = `<code>${t}</code>`;
+        }
         for (const mark of n.marks || []) {
+          if (mark.type === "code") continue; // wrapped innermost above
           switch (mark.type) {
             case "bold":
               t = `<strong>${t}</strong>`;
@@ -1297,6 +1571,12 @@ export function convertProseMirrorToMarkdown(
                 t = `<span data-comment-id="${escapeAttr(mark.attrs.commentId)}"${r}>${t}</span>`;
               }
               break;
+            default:
+              // Unknown mark on the raw-HTML path: dropped (no HTML form). Report
+              // the loss (throws in strict mode) — same policy as the markdown
+              // path's marks loop above.
+              warnLoss("mark", String(mark.type));
+              break;
           }
         }
         return t;

packages/prosemirror-markdown/src/lib/markdown-to-prosemirror.ts

@@ -7,9 +7,8 @@
  * natively through the collab gateway, so no websocket/Yjs write-path lives
  * here.
  */
-import { generateJSON } from "@tiptap/html";
-import { JSDOM } from "jsdom";
 import { Marked } from "marked";
+import { parseHtmlDocument, generateJsonWith } from "./dom-parser.js";
 import type { TokenizerExtension, RendererExtension } from "marked";
 import { docmostExtensions } from "./docmost-schema.js";
 import { parseAttachedComment } from "./attached-comment.js";
@@ -245,12 +244,13 @@ const markedInstance = new Marked().use({
   ],
 });
 
-// Setup DOM environment for Tiptap HTML parsing in Node.js
-const dom = new JSDOM("<!DOCTYPE html><html><body></body></html>");
-global.window = dom.window as any;
-global.document = dom.window.document;
-// @ts-ignore
-global.Element = dom.window.Element;
+// NOTE: this module no longer installs a module-level `global.window`/`document`
+// jsdom shim. The HTML->DOM passes below (bridgeTaskLists / applyCommentDirectives
+// / assembleFootnotes) parse via the INJECTED `parseHtmlDocument` (jsdom on the
+// Node entry, native `DOMParser` on the browser entry), and `@tiptap/html`'s v3
+// `generateJSON` supplies its OWN DOM per environment (happy-dom in Node, native
+// `DOMParser` in the browser) — so no ambient global DOM is needed here, and
+// nothing on the browser code path statically imports jsdom.
 
 /**
  * Hard ceiling above which we skip callout preprocessing entirely. The linear
@@ -295,7 +295,13 @@ const CODE_FENCE_RE = /^(\s*)(`{3,}|~{3,})/;
  *   - emits the same `<div data-type="callout" data-callout-type="TYPE">` output
  *     (inner rendered through marked) as the previous regex implementation.
  */
-async function preprocessCallouts(markdown: string): Promise<string> {
+// SYNCHRONOUS by construction: the only formerly-awaited call is
+// `markedInstance.parse`, which returns a string synchronously for this
+// instance (no async marked extensions are registered), so the whole callout
+// preprocess is sync. Keeping it sync lets a sync converter entry
+// (`markdownToProseMirrorSync`, used by the client's chat renderer which must
+// stay synchronous) share this exact logic with the async entry.
+function preprocessCallouts(markdown: string): string {
   // Defensive cap: skip preprocessing for pathologically large inputs.
   if (markdown.length > MAX_CALLOUT_PREPROCESS_BYTES) {
     return markdown;
@@ -304,7 +310,7 @@ async function preprocessCallouts(markdown: string): Promise<string> {
   // Recursively transform a slice of lines, converting top-level callouts in
   // that slice into <div> blocks and rendering their inner content (which may
   // itself contain nested callouts) through this same function.
-  const transform = async (lines: string[]): Promise<string> => {
+  const transform = (lines: string[]): string => {
     const out: string[] = [];
     let inCodeFence = false;
     let codeFenceMarker = ""; // the exact run of backticks/tildes that opened it
@@ -383,8 +389,8 @@ async function preprocessCallouts(markdown: string): Promise<string> {
         if (j < lines.length) {
           // Found the matching closing fence: render the body (recursively, so
           // nested callouts are handled) and emit the callout div.
-          const inner = await transform(bodyLines);
-          const renderedInner = await markedInstance.parse(inner);
+          const inner = transform(bodyLines);
+          const renderedInner = markedInstance.parse(inner) as string;
           out.push(
             `\n<div data-type="callout" data-callout-type="${type}">${renderedInner}</div>\n`,
           );
@@ -423,8 +429,8 @@ async function preprocessCallouts(markdown: string): Promise<string> {
           // Drop the prefix + `>` + one optional space, leaving the body content.
           bodyLines.push(lines[j].slice(prefix.length).replace(/^>\s?/, ""));
         }
-        const inner = await transform(bodyLines);
-        const renderedInner = await markedInstance.parse(inner);
+        const inner = transform(bodyLines);
+        const renderedInner = markedInstance.parse(inner) as string;
         const block = `<div data-type="callout" data-callout-type="${type}">${renderedInner}</div>`;
         if (prefix.length === 0) {
           // Top-level callout: blank lines isolate the HTML block.
@@ -491,8 +497,7 @@ function bridgeTaskLists(html: string): string {
   if (html.length > MAX_CALLOUT_PREPROCESS_BYTES) {
     return html;
   }
-  const dom = new JSDOM(html);
-  const document = dom.window.document;
+  const document = parseHtmlDocument(html);
   // Collect the checkbox(es) that belong to THIS <li> directly: either direct
   // child <input type="checkbox"> elements or ones inside the <li>'s direct <p>
   // child (the shape marked emits: `<li><p><input type="checkbox"> text</p></li>`).
@@ -662,15 +667,23 @@ function placeStandalone(
 function applyCommentDirectives(html: string): string {
   // Cheap early-out: no comments at all -> nothing to intercept.
   if (!html.includes("<!--")) return html;
-  const dom = new JSDOM(html);
-  const document = dom.window.document;
-  const nodeFilter = dom.window.NodeFilter;
+  const document = parseHtmlDocument(html);
+  // `SHOW_COMMENT` (128) is a stable DOM constant. Read it from whichever holder
+  // exists — the document's window (jsdom: `defaultView`), the ambient global
+  // `NodeFilter` (browsers / test envs), else the literal — because a document
+  // produced by `DOMParser.parseFromString` has NO browsing context, so its
+  // `defaultView` is `null` (unlike a jsdom `new JSDOM(html).window.document`).
+  // `createTreeWalker` takes the numeric `whatToShow` mask directly.
+  const SHOW_COMMENT =
+    (document.defaultView as any)?.NodeFilter?.SHOW_COMMENT ??
+    (globalThis as any).NodeFilter?.SHOW_COMMENT ??
+    0x80;
   // Walk the WHOLE document, not just <body>: when a standalone machinery
   // comment is the FIRST thing in the output (before any body content), the
   // HTML parser places it at document level (a child of `#document`, before
   // `<html>`), where it is outside `document.body` and would be lost. Attached
   // attrs comments always live inside body, so this wider walk still finds them.
-  const walker = document.createTreeWalker(document, nodeFilter.SHOW_COMMENT);
+  const walker = document.createTreeWalker(document, SHOW_COMMENT);
   const comments: any[] = [];
   let current: any;
   while ((current = walker.nextNode())) comments.push(current);
@@ -945,8 +958,7 @@ const MAX_FOOTNOTE_ROUNDS = 10000;
 function assembleFootnotes(html: string): string {
   // Cheap early-out: nothing carries a footnote body -> nothing to assemble.
   if (!html.includes("data-fn-text")) return html;
-  const dom = new JSDOM(html);
-  const document = dom.window.document;
+  const document = parseHtmlDocument(html);
   if (document.querySelector("sup[data-footnote-ref][data-fn-text]") == null) {
     return html;
   }
@@ -1060,12 +1072,18 @@ function stripEmptyParagraphs(node: any): any {
   return { ...node, content: cleaned };
 }
 
-/** Convert markdown to a ProseMirror doc using the full Docmost schema. */
-export async function markdownToProseMirror(
-  markdownContent: string,
-): Promise<any> {
-  const withCallouts = await preprocessCallouts(markdownContent);
-  const html = await markedInstance.parse(withCallouts);
+/**
+ * Convert markdown to a ProseMirror doc using the full Docmost schema
+ * (SYNCHRONOUS core). Every stage — callout preprocess, `marked` parse, the
+ * three DOM passes, and generateJSON — is synchronous for this configuration
+ * (no async marked extensions), so the conversion needs no `await`. The async
+ * `markdownToProseMirror` below delegates here (its Promise return is preserved
+ * for every existing Node consumer). A sync entry is REQUIRED by the client's
+ * chat renderer, which runs inside a React render/useMemo and cannot await.
+ */
+export function markdownToProseMirrorSync(markdownContent: string): any {
+  const withCallouts = preprocessCallouts(markdownContent);
+  const html = markedInstance.parse(withCallouts) as string;
   // Materialize comment directives (#293 #9 attached textAlign; #5 standalone
   // subpages/pageBreak) while the comment nodes still exist, before generateJSON
   // drops them.
@@ -1075,6 +1093,17 @@ export async function markdownToProseMirror(
   // generateJSON, so references + definitions materialize into the schema model.
   const withFootnotes = assembleFootnotes(withAttrs);
   const bridged = bridgeTaskLists(withFootnotes);
-  const doc = generateJSON(bridged, docmostExtensions);
+  const doc = generateJsonWith(bridged, docmostExtensions);
   return stripEmptyParagraphs(doc);
 }
+
+/**
+ * Convert markdown to a ProseMirror doc (async entry, unchanged contract). Kept
+ * async so every existing Node consumer (server, mcp, git-sync) that `await`s
+ * it is untouched; it simply delegates to the synchronous core.
+ */
+export async function markdownToProseMirror(
+  markdownContent: string,
+): Promise<any> {
+  return markdownToProseMirrorSync(markdownContent);
+}

packages/prosemirror-markdown/src/lib/text-normalize.ts

@@ -7,13 +7,12 @@
  * it is never applied to replacement text or inserted node content, so no
  * formatting is ever lost.
  *
- * Scope note (#414): this package-local copy exists so `node-ops.ts` — which
- * lives here now (the single canonical copy) — can resolve its markdown-tolerant
- * anchor fallback without a circular dependency back on `@docmost/mcp`. It
- * intentionally carries ONLY `stripInlineMarkdown` (the primitive `node-ops`
- * needs); the mcp-side `text-normalize.ts` (which additionally serves
- * `json-edit.ts` via `stripBalancedWrappers`) is the subject of a separate
- * dedup task and is left untouched here.
+ * CANONICAL HOME (#414/#493): this is the single source of truth for locator
+ * markdown-stripping. `node-ops.ts` (which lives here) uses it directly, and the
+ * mcp-side `text-normalize.ts` now IMPORTS `stripInlineMarkdown` and the shared
+ * `stripWrappersAndLinks` primitive from here (via `@docmost/prosemirror-markdown`)
+ * instead of keeping a drifting copy — mcp only adds its own thin
+ * `stripBalancedWrappers`/`closestBlockHint` on top.
  */
 
 /** Maximum unwrap passes, so pathological/nested input cannot loop forever. */
@@ -44,7 +43,7 @@ const LINK_IMAGE_RE = /!?\[([^\]]*)\]\([^)]*\)/g;
  * Does NOT trim decoration, does NOT guard against an empty result — it returns
  * exactly the transformed string.
  */
-function stripWrappersAndLinks(s: string): string {
+export function stripWrappersAndLinks(s: string): string {
   // 1. Links/images -> their visible text.
   let out = s.replace(LINK_IMAGE_RE, "$1");
 

packages/prosemirror-markdown/test/converter-loss-warnings.test.ts

@@ -0,0 +1,112 @@
+import { describe, expect, it } from "vitest";
+import {
+  convertProseMirrorToMarkdown,
+  ConverterLossError,
+} from "../src/lib/markdown-converter.js";
+
+/**
+ * #493 commit 3 — a node/mark type the serializer has no dedicated case for used
+ * to be degraded SILENTLY (an unknown node flattened to its children, an unknown
+ * mark dropped from the run). The serializer now REPORTS the loss:
+ *   - default (non-strict): unchanged graceful degradation, but one warning per
+ *     unmapped type is pushed into an optional `warnings` sink so callers can
+ *     observe it;
+ *   - strict: the FIRST unmapped type throws a ConverterLossError (git-sync +
+ *     tests), turning a silent loss into a hard, surfaced error.
+ *
+ * Exercised through the REAL converter (no mock): the observable properties are
+ * the emitted markdown, the warnings collected, and the thrown error.
+ */
+
+const doc = (...nodes: any[]) => ({ type: "doc", content: nodes });
+
+describe("converter loss reporting — unknown node types", () => {
+  const unknownNode = doc({
+    type: "quantumWidget",
+    content: [{ type: "text", text: "inner text" }],
+  });
+
+  it("degrades to children AND records a warning (non-strict, sink provided)", () => {
+    const warnings: string[] = [];
+    const md = convertProseMirrorToMarkdown(unknownNode, { warnings });
+    // Graceful degrade: the child text still survives (historical behavior).
+    expect(md).toContain("inner text");
+    // The loss is now observable.
+    expect(warnings).toHaveLength(1);
+    expect(warnings[0]).toContain("quantumWidget");
+    expect(warnings[0]).toContain("node");
+  });
+
+  it("stays byte-identical for callers that pass no sink (zero behavior change)", () => {
+    const withSink: string[] = [];
+    const a = convertProseMirrorToMarkdown(unknownNode, { warnings: withSink });
+    const b = convertProseMirrorToMarkdown(unknownNode);
+    expect(b).toBe(a); // the sink does not alter the produced markdown
+  });
+
+  it("throws ConverterLossError in strict mode", () => {
+    try {
+      convertProseMirrorToMarkdown(unknownNode, { strict: true });
+      expect.unreachable("strict mode must throw on an unknown node");
+    } catch (e) {
+      expect(e).toBeInstanceOf(ConverterLossError);
+      expect((e as ConverterLossError).kind).toBe("node");
+      expect((e as ConverterLossError).typeName).toBe("quantumWidget");
+    }
+  });
+
+  it("dedupes the warning per type (many unknown nodes -> one message)", () => {
+    const warnings: string[] = [];
+    convertProseMirrorToMarkdown(
+      doc(
+        { type: "quantumWidget", content: [{ type: "text", text: "a" }] },
+        { type: "quantumWidget", content: [{ type: "text", text: "b" }] },
+      ),
+      { warnings },
+    );
+    expect(warnings).toHaveLength(1);
+  });
+});
+
+describe("converter loss reporting — unknown mark types", () => {
+  const unknownMark = doc({
+    type: "paragraph",
+    content: [{ type: "text", text: "glowing", marks: [{ type: "glow" }] }],
+  });
+
+  it("drops the mark but keeps the text AND records a warning (non-strict)", () => {
+    const warnings: string[] = [];
+    const md = convertProseMirrorToMarkdown(unknownMark, { warnings });
+    expect(md).toBe("glowing"); // text survives, mark silently had no form
+    expect(warnings).toHaveLength(1);
+    expect(warnings[0]).toContain("glow");
+    expect(warnings[0]).toContain("mark");
+  });
+
+  it("throws ConverterLossError in strict mode", () => {
+    expect(() =>
+      convertProseMirrorToMarkdown(unknownMark, { strict: true }),
+    ).toThrow(ConverterLossError);
+  });
+});
+
+describe("converter loss reporting — known content is never flagged", () => {
+  it("a fully-mapped document produces no warnings and does not throw in strict mode", () => {
+    const d = doc(
+      { type: "heading", attrs: { level: 2 }, content: [{ type: "text", text: "Title" }] },
+      {
+        type: "paragraph",
+        content: [
+          { type: "text", text: "bold", marks: [{ type: "bold" }] },
+          { type: "text", text: " and " },
+          { type: "text", text: "link", marks: [{ type: "link", attrs: { href: "https://x.y" } }] },
+        ],
+      },
+      { type: "bulletList", content: [{ type: "listItem", content: [{ type: "paragraph", content: [{ type: "text", text: "item" }] }] }] },
+    );
+    const warnings: string[] = [];
+    const md = convertProseMirrorToMarkdown(d, { warnings, strict: true });
+    expect(warnings).toEqual([]);
+    expect(md).toContain("## Title");
+  });
+});

packages/prosemirror-markdown/test/dom-parser-both-paths.test.ts

@@ -0,0 +1,101 @@
+import { afterEach, beforeEach, describe, expect, it } from "vitest";
+import { JSDOM } from "jsdom";
+import {
+  setHtmlDocumentParser,
+  parseHtmlDocument,
+} from "../src/lib/dom-parser.js";
+import { markdownToProseMirror } from "../src/lib/markdown-to-prosemirror.js";
+
+/**
+ * The markdown import path parses its post-`marked` HTML through an INJECTED
+ * DOM parser: jsdom on the Node entry, native `DOMParser` on the browser entry
+ * (see dom-parser.node.ts / dom-parser.browser.ts). These tests exercise BOTH
+ * registrations against the same canonical inputs — the three DOM passes
+ * (task-list bridge, comment directives, footnote assembly) — and assert the
+ * converter produces the IDENTICAL ProseMirror doc regardless of which DOM
+ * parser is installed. That is the guarantee the client paste path relies on:
+ * pasting in the browser must yield the same nodes the server import produces.
+ */
+
+// A jsdom-backed parser (the Node entry's registration).
+const jsdomParser = (html: string): Document =>
+  new JSDOM(html).window.document as unknown as Document;
+
+// A `DOMParser`-backed parser standing in for the BROWSER entry's registration.
+// We drive a real `DOMParser` from a jsdom window (jsdom exposes the same
+// `new DOMParser().parseFromString(html, "text/html")` API the browser and the
+// client's jsdom vitest environment provide), so this path uses the exact code
+// dom-parser.browser.ts runs — a native `DOMParser`, no `JSDOM` document glue.
+const browserWindow = new JSDOM("").window;
+const domParserBackedParser = (html: string): Document =>
+  new browserWindow.DOMParser().parseFromString(
+    html,
+    "text/html",
+  ) as unknown as Document;
+
+// Canonical inputs, each hitting a different post-marked DOM pass.
+const CASES: Record<string, string> = {
+  // footnote assembly (assembleFootnotes): `^[…]` -> sup + section/def
+  "inline footnote ^[…]": "Body^[a note].",
+  // task-list bridge (bridgeTaskLists): checkbox list -> taskList/taskItem
+  "task list": "- [x] done\n- [ ] todo",
+  // comment directives (applyCommentDirectives): standalone machinery comment
+  "standalone subpages comment": "text\n\n<!--subpages-->\n\ntext2",
+  // attached image comment (applyCommentDirectives img form)
+  "attached image comment": '![alt](img.png) <!--img {"align":"left"}-->',
+  // github callout (preprocessCallouts bq path) + comment pass
+  "obsidian callout": "> [!info]\n> hello",
+  // highlight + math (marked extensions; still parsed through the DOM stage)
+  "highlight + math": "A ==mark== and $x^2$ end",
+};
+
+async function convertWith(
+  parser: (html: string) => Document,
+  md: string,
+): Promise<any> {
+  setHtmlDocumentParser(parser);
+  return markdownToProseMirror(md);
+}
+
+describe("markdown import: Node (jsdom) and browser (DOMParser) DOM paths agree", () => {
+  afterEach(() => {
+    // Restore the jsdom parser the suite-wide setup file installs, so later
+    // tests in the run are unaffected by our per-case swaps.
+    setHtmlDocumentParser(jsdomParser);
+  });
+
+  for (const [name, md] of Object.entries(CASES)) {
+    it(`produces identical nodes for: ${name}`, async () => {
+      const viaJsdom = await convertWith(jsdomParser, md);
+      const viaDomParser = await convertWith(domParserBackedParser, md);
+      expect(viaDomParser).toEqual(viaJsdom);
+    });
+  }
+});
+
+describe("dom-parser injection contract", () => {
+  let saved: (html: string) => Document;
+  beforeEach(() => {
+    saved = jsdomParser;
+  });
+  afterEach(() => {
+    setHtmlDocumentParser(saved);
+  });
+
+  it("throws a clear error when no parser is registered", () => {
+    // Install a thrower to simulate the unregistered state, then assert
+    // parseHtmlDocument surfaces the guidance error (we cannot un-set the
+    // module singleton, so we assert via a registration that throws the same).
+    setHtmlDocumentParser(() => {
+      throw new Error("No HTML DOM parser registered.");
+    });
+    expect(() => parseHtmlDocument("<p>x</p>")).toThrow(/No HTML DOM parser/);
+  });
+
+  it("uses the most-recently registered parser", () => {
+    const marker = new JSDOM("<!DOCTYPE html><body><b>marker</b></body>").window
+      .document as unknown as Document;
+    setHtmlDocumentParser(() => marker);
+    expect(parseHtmlDocument("<i>ignored</i>")).toBe(marker);
+  });
+});

packages/prosemirror-markdown/test/foreign-markdown.test.ts

@@ -1,12 +1,15 @@
+import { describe, it, expect } from 'vitest';
+import { convertProseMirrorToMarkdown } from '../src/lib/markdown-converter.js';
+import { markdownToProseMirror } from '../src/lib/markdown-to-prosemirror.js';
 import {
-  convertProseMirrorToMarkdown,
-  markdownToProseMirror,
-} from '@docmost/prosemirror-markdown';
-import { normalizeForeignMarkdown } from './foreign-markdown';
+  normalizeForeignMarkdown,
+  normalizeAgentMarkdown,
+} from '../src/lib/foreign-markdown.js';
 
 /**
- * STEP 2 goldens for issue #345: the foreign-markdown normalizer that runs at the
- * import boundary BEFORE the strict canonical parser (`markdownToProseMirror`).
+ * STEP 2 goldens for issue #345 (moved into the package with the normalizer in
+ * #493): 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
@@ -216,3 +219,53 @@ describe('foreign markdown import acceptance (normalizer + canonical parser)', (
     ).toHaveLength(1);
   });
 });
+
+describe('normalizeAgentMarkdown vs normalizeForeignMarkdown — front-matter strip is IMPORT-only (#493 review)', () => {
+  // A page that OPENS with a horizontalRule and contains a later `---` serializes
+  // to a `---…---`-shaped body. On a full-body AGENT rewrite this must NOT be
+  // mistaken for YAML front-matter and stripped — that silently dropped the
+  // page's leading content.
+  const rulePage = '---\n\nIntro\n\nMore\n\n---\n\nRest';
+
+  it('normalizeAgentMarkdown does NOT strip a leading ---…--- (no content loss)', () => {
+    expect(normalizeAgentMarkdown(rulePage)).toBe(rulePage);
+  });
+
+  it('normalizeForeignMarkdown (file import) STILL strips a real leading YAML front-matter block', () => {
+    const withYaml = '---\ntitle: My Page\ntags: [a, b]\n---\n\nBody here.';
+    const out = normalizeForeignMarkdown(withYaml);
+    expect(out).toBe('Body here.');
+    // And the horizontalRule-shaped body IS stripped on the import path (its
+    // documented file-import behavior) — the two variants differ ONLY here.
+    expect(normalizeForeignMarkdown(rulePage)).not.toContain('Intro');
+  });
+
+  it('agent-write round-trip keeps a horizontalRule-led doc with a second rule intact', async () => {
+    // Simulate the serializer output for [horizontalRule, para, para, horizontalRule, para].
+    const doc = {
+      type: 'doc',
+      content: [
+        { type: 'horizontalRule' },
+        { type: 'paragraph', content: [{ type: 'text', text: 'Intro' }] },
+        { type: 'paragraph', content: [{ type: 'text', text: 'More' }] },
+        { type: 'horizontalRule' },
+        { type: 'paragraph', content: [{ type: 'text', text: 'Rest' }] },
+      ],
+    };
+    const body = convertProseMirrorToMarkdown(doc);
+    // The agent-write normalization must NOT eat the head; re-import keeps every
+    // paragraph's text.
+    const back = await markdownToProseMirror(normalizeAgentMarkdown(body));
+    const texts = JSON.stringify(back);
+    for (const t of ['Intro', 'More', 'Rest']) expect(texts).toContain(t);
+    // Both horizontal rules survive.
+    expect(back.content.filter((n: any) => n.type === 'horizontalRule')).toHaveLength(2);
+  });
+
+  it('agent-write STILL rewrites GFM reference footnotes (the shared drift-fix)', () => {
+    const gfm = 'See[^1].\n\n[^1]: the note.';
+    const out = normalizeAgentMarkdown(gfm);
+    expect(out).toContain('^[the note.]');
+    expect(out).not.toMatch(/\[\^1\]:/);
+  });
+});

packages/prosemirror-markdown/test/generative/text-arbitraries.ts

@@ -11,9 +11,11 @@
  *
  * The corpus deliberately spans the CommonMark / canon hostile alphabet
  * (`* _ [ ] ( ) { } | < > & # ! ~ = + -`), unicode / emoji / RTL, and the legal
- * mark combinations on runs (including the `code` mark, which the schema's
- * `excludes: "_"` makes suppress every co-occurring mark — so it is never
- * combined with another mark in the byte-stable space).
+ * mark combinations on runs. As of #515 the `code` mark no longer excludes other
+ * marks (`excludes: ""`), so the corpus ALSO combines `code` with bold / italic /
+ * strike / highlight — exercising both the HOMOGENEOUS run factoring (adjacent
+ * code+bold spans -> `` **`a` `b`** ``) and the HETEROGENEOUS anti-collision
+ * fallback (`[code,bold]` next to `[italic]` -> schema-HTML, never `` `a`***b* ``).
  */
 import fc from 'fast-check';
 
@@ -106,16 +108,16 @@ export const urlArb: fc.Arbitrary<string> = fc
 /**
  * A text run with an OPTIONAL single non-code formatting mark (bold/italic/
  * strike/underline/superscript/subscript/spoiler), or a SOLE `code` mark, or a
- * link, or an inline comment anchor. `code` is NEVER combined with another mark
- * in the byte-stable space (that combination is a documented converter
- * limitation — the schema's `code` mark declares `excludes: "_"`). Marks wrap
- * `safeTextArb`, which stays stable even when it contains isolated specials.
+ * `code` mark COMBINED with a bare-delimiter emphasis mark (#515), or a link, or
+ * an inline comment anchor. Marks wrap `safeTextArb`, which stays stable even
+ * when it contains isolated specials.
  *
- * The mark set here is broadened past the sibling test's {bold,italic,strike}
- * to also cover underline / superscript / subscript / spoiler / textStyle /
- * highlight (all single, non-code marks), so the marks-on-text generator
- * exercises every mark the schema declares except the deliberately-excluded
- * `code`+other combination.
+ * The mark set here is broadened past the sibling test's {bold,italic,strike} to
+ * also cover underline / superscript / subscript / spoiler / textStyle /
+ * highlight (all single, non-code marks). As of #515 it ALSO emits `code`
+ * combined with bold/italic/strike, so the assembled inline content exercises the
+ * converter's code-emphasis run detection (adjacent combos -> homogeneous
+ * factoring or heterogeneous HTML fallback, both lossless).
  */
 export const markedTextRunArb: fc.Arbitrary<any> = fc.oneof(
   // Plain text.
@@ -138,6 +140,25 @@ export const markedTextRunArb: fc.Arbitrary<any> = fc.oneof(
   // Sole code mark (backtick span). safeTextArb is backtick-free, so the span
   // content cannot contain an inner backtick.
   safeTextArb.map((t) => ({ type: 'text', text: t, marks: [{ type: 'code' }] })),
+  // #515: code COMBINED with a bare-delimiter emphasis mark. The converter nests
+  // the backtick span inside the emphasis delimiters (`` **`x`** ``) and, when
+  // such runs sit adjacent, factors a shared mark or falls back to schema-HTML.
+  // Mark order here is `[emphasis, code]` — the order the HTML->PM import yields
+  // for bold/italic/strike specifically (code last). This is NOT universal: the
+  // `==`-highlight case below imports code FIRST — so match each case to its own
+  // imported order for the order-exact P1 round-trip (do not assume a fixed order).
+  fc
+    .tuple(safeTextArb, fc.constantFrom('bold', 'italic', 'strike'))
+    .map(([t, m]) => ({ type: 'text', text: t, marks: [{ type: m }, { type: 'code' }] })),
+  // #515: code combined with an UNCOLORED highlight (also a bare-delimiter mark,
+  // `==…==`), so the highlight+code delimiter interaction is covered too. Import
+  // yields `[code, highlight]` here (the `==` inline extension nests code first),
+  // so the generator matches that order for the order-exact P1 round-trip.
+  safeTextArb.map((t) => ({
+    type: 'text',
+    text: t,
+    marks: [{ type: 'code' }, { type: 'highlight' }],
+  })),
   // Link with safe text, a paren/space-free href, optionally a letter-bearing
   // title (a purely numeric title is coerced to a number and dropped).
   fc
@@ -212,25 +233,93 @@ export function normalizeInline(nodes: any[]): any[] {
   return out;
 }
 
+/**
+ * #493 commit 1: a plain-text run whose text DELIBERATELY OPENS with a markdown
+ * BLOCK trigger — ATX heading `#`, bullet `-`/`*`/`+`, blockquote `>`, ordered
+ * `N.`/`N)`, or a table `|` — followed by safe text. Pre-#493 the corpus
+ * self-censored these away (safeTextArb's leading-word guarantee); the paragraph
+ * serializer now BLOCK-ESCAPES a leading trigger, so the generative round-trip
+ * itself proves the data-loss class is closed rather than avoiding it.
+ *
+ * DELIBERATELY excludes the code-fence (backtick) trigger — the backtick is a
+ * code-span delimiter that re-pairs globally (see specialCharArb's note), an
+ * instability UNRELATED to block-escape — and the whole-line thematic break
+ * (`---`), which only triggers when the line is ONLY dashes; both are covered by
+ * the deterministic pin (gitmost-transcript-neutralization.test.ts). Each still
+ * ENDS in a word (safeTextArb) so adjacent-run concatenation stays safe.
+ */
+export const blockTriggerLeadRunArb: fc.Arbitrary<any> = fc
+  .tuple(
+    fc.constantFrom('# ', '## ', '- ', '* ', '+ ', '> ', '1. ', '1) ', '| '),
+    safeTextArb,
+  )
+  .map(([trigger, rest]) => ({ type: 'text', text: trigger + rest }));
+
+/**
+ * A hardBreak IMMEDIATELY followed by a block-trigger-leading run — a two-node
+ * segment. Because a hardBreak serializes as `  \n`, the trigger then sits at
+ * the START of a CONTINUATION line, exercising the serializer's PER-LINE block
+ * escape (not just the first line). #493 review: without this the fuzzer never
+ * placed a trigger after a hardBreak, so a single-line-only escape passed P1–P3.
+ */
+export const hardBreakThenTriggerArb: fc.Arbitrary<any[]> = fc
+  .tuple(hardBreakArb, blockTriggerLeadRunArb)
+  .map(([hb, trigger]) => [hb, trigger]);
+
+/**
+ * #493 (setext data-loss): a WHOLE-LINE setext underline landing on a
+ * continuation line. A setext underline is a line of ONLY `-` (any count) or
+ * ONLY `=` (any count) that FOLLOWS a paragraph line; on re-parse it turns the
+ * preceding line into a heading and DROPS its own text. The block-escape must
+ * neutralize it. Unlike blockTriggerLeadRunArb, the underline must occupy the
+ * whole line, so we sandwich it between two hardBreaks (underline on its own
+ * line, preceded by earlier paragraph content, followed by a trailing word so
+ * the closing hardBreak is not dropped by normalizeInline). Covers underlines
+ * of every length: `--` (the two-dash case the bullet/thematic arms miss), a
+ * lone `=`, `==`/`====` (neutralized by the inline `==` escape), and `---`/
+ * `----` (regression for the existing thematic case).
+ */
+export const hardBreakThenSetextArb: fc.Arbitrary<any[]> = fc
+  .tuple(
+    fc.constantFrom('--', '=', '==', '====', '---', '----'),
+    safeTextArb,
+  )
+  .map(([underline, rest]) => [
+    { type: 'hardBreak' },
+    { type: 'text', text: underline },
+    { type: 'hardBreak' },
+    { type: 'text', text: rest },
+  ]);
+
 /**
  * Inline content for a paragraph: at least one marked text run, optionally with
- * inline atoms (math/mention) and hard breaks interspersed. Always starts with a
- * text run so the paragraph never opens with a block trigger. (Ported.)
+ * inline atoms (math/mention) and hard breaks interspersed. The FIRST run is
+ * usually an ordinary marked run, but sometimes a block-trigger-leading run
+ * (blockTriggerLeadRunArb) so the paragraph OPENS with a markdown block trigger;
+ * and a `hardBreak + trigger` segment can appear anywhere in the rest, so a
+ * trigger also lands at the start of a CONTINUATION line — both exercising the
+ * serializer's per-line block-escape end-to-end. (Ported, with the #493
+ * leading-trigger + post-hardBreak dimensions added.)
  */
 export const inlineContentArb: fc.Arbitrary<any[]> = fc
   .tuple(
-    markedTextRunArb,
+    fc.oneof(
+      { weight: 5, arbitrary: markedTextRunArb },
+      { weight: 1, arbitrary: blockTriggerLeadRunArb },
+    ),
     fc.array(
       fc.oneof(
-        { weight: 5, arbitrary: markedTextRunArb },
-        { weight: 1, arbitrary: mathInlineArb },
-        { weight: 1, arbitrary: mentionArb },
-        { weight: 1, arbitrary: hardBreakArb },
+        { weight: 5, arbitrary: markedTextRunArb.map((n) => [n]) },
+        { weight: 1, arbitrary: mathInlineArb.map((n) => [n]) },
+        { weight: 1, arbitrary: mentionArb.map((n) => [n]) },
+        { weight: 1, arbitrary: hardBreakArb.map((n) => [n]) },
+        { weight: 2, arbitrary: hardBreakThenTriggerArb },
+        { weight: 2, arbitrary: hardBreakThenSetextArb },
       ),
       { minLength: 0, maxLength: 4 },
     ),
   )
-  .map(([first, rest]) => normalizeInline([first, ...rest]));
+  .map(([first, rest]) => normalizeInline([first, ...rest.flat()]));
 
 /**
  * Inline content for a HEADING — identical to a paragraph's, but WITHOUT hard

packages/prosemirror-markdown/test/gitmost-transcript-neutralization.test.ts

@@ -5,32 +5,21 @@ import { convertProseMirrorToMarkdown } from "../src/lib/markdown-converter.js";
 import { markdownToProseMirror } from "../src/lib/markdown-to-prosemirror.js";
 
 /**
- * gitmost #377 (round-1 review, finding #1) — proof, against the REAL
- * converter, that the transcript-insert boundary defense survives git-sync.
+ * #493 commit 1 — the paragraph serializer's leading-block-escape closes the
+ * data-loss class where a paragraph whose text opens at column 0 with a markdown
+ * block trigger (`#`/`-`/`*`/`+`/`>`, an ordered `N.`/`N)`, a code fence, a
+ * table `|`, a callout opener, or a thematic break) silently re-parsed into a
+ * heading / list / quote / code block / table / horizontalRule on the git-sync
+ * doc -> markdown -> doc cycle. The thematic-break case was the worst: a
+ * horizontalRule carries NO text, so the line's text was lost entirely.
  *
- * The web bridge (apps/client .../gitmost/gitmost-recording.ts,
- * `gitmostInsertTranscriptIntoEditor`) appends each transcript line as a
- * PARAGRAPH text node. The paragraph serializer here (`case "paragraph"`) emits
- * that text VERBATIM with no block-escape, so a line whose text begins with a
- * col-0 markdown block trigger would, on the doc -> markdown -> doc git-sync
- * cycle, silently re-parse into a heading / list / quote / callout / code block.
- * That missing block-escape is the pre-existing root cause; the bridge's
- * boundary defense prepends an invisible zero-width space (U+200B) to a line
- * that begins with such a trigger, shifting it off column 0.
- *
- * This test keeps a COPY of the bridge's trigger regex (the bridge is in a
- * different package and can't be imported here) and asserts:
- *   1. bare trigger lines DO corrupt (documents the root cause), and
- *   2. the ZWSP-neutralized form round-trips as a single PARAGRAPH with the
- *      text byte-preserved.
+ * This is the deterministic PIN, one assertion per trigger, exercised through
+ * the REAL converter round-trip (not a mock): each bare trigger line now
+ * round-trips as a SINGLE paragraph with its text byte-preserved — proving the
+ * class is closed WITHOUT the former client-side ZWSP workaround (removed) or
+ * the generative suite's leading-word self-censorship (removed).
  */
 
-const ZWSP = "​"; // U+200B
-
-// MUST stay in sync with GITMOST_MD_BLOCK_TRIGGER_RE in the client bridge.
-const MD_BLOCK_TRIGGER_RE =
-  /^(?:#{1,6}(?:\s|$)|[-*+](?:\s|$)|>|\d+[.)](?:\s|$)|```|~~~|\||([-*_])(?:\s*\1){2,}\s*$)/;
-
 const doc = (...nodes: any[]) => ({ type: "doc", content: nodes });
 const para = (t: string) => ({
   type: "paragraph",
@@ -43,78 +32,117 @@ const roundtrip = async (text: string) => {
   return back.content as any[];
 };
 
-describe("gitmost transcript neutralization (git-sync round-trip)", () => {
-  // Lines that, at column 0, the serializer's missing block-escape would let
-  // git-sync re-parse into a non-paragraph block.
+describe("paragraph block-escape (git-sync round-trip)", () => {
+  // Every line here, at column 0, WOULD (pre-fix) re-parse into a non-paragraph
+  // block. Each is now block-escaped by the serializer and round-trips clean.
   const triggerLines = [
     "- dash",
     "* star",
     "+ plus",
     "> quote",
     "# hash",
+    "## two hash",
+    "###### six hash",
     "1. one",
     "1) one",
     "> [!info] note",
     "```js",
     "~~~",
-    // Solid + spaced thematic breaks — these re-parse into a `horizontalRule`,
-    // which carries NO text, so a bare separator line LOSES its text entirely
-    // (round-2 finding). `_` also only forms a block via this construct.
+    "| a | b |",
+    // Solid + spaced thematic breaks — the text-LOSING case pre-fix.
     "---",
     "***",
     "___",
-    "- - -", // spaced dash break (solid form is caught by [-*+]\s too, but this is the break)
+    "- - -",
     "_ _ _",
   ];
 
-  it("BARE trigger lines corrupt into non-paragraph blocks (root cause)", async () => {
+  it("every bare trigger line round-trips as a single paragraph, text byte-preserved", async () => {
     for (const line of triggerLines) {
       const blocks = await roundtrip(line);
-      // At least one produced block is NOT a paragraph — i.e. corruption.
-      const allParagraphs = blocks.every((b) => b.type === "paragraph");
-      expect(
-        allParagraphs,
-        `expected "${line}" to corrupt when inserted bare`,
-      ).toBe(false);
-    }
-  });
-
-  it("BARE solid thematic breaks corrupt into a text-LOSING horizontalRule", async () => {
-    // The severe case: no text node survives. Documents why neutralization
-    // matters more here than for list/quote (where the text survived).
-    for (const line of ["---", "***", "___"]) {
-      const blocks = await roundtrip(line);
-      expect(blocks.map((b) => b.type)).toContain("horizontalRule");
-      // No block carries the original text anywhere.
-      const flat = JSON.stringify(blocks);
-      expect(flat).not.toContain(line);
-    }
-  });
-
-  it("ZWSP-neutralized trigger lines round-trip as a single paragraph, text preserved", async () => {
-    for (const line of triggerLines) {
-      // The regex must actually classify each as a trigger.
-      expect(MD_BLOCK_TRIGGER_RE.test(line), `regex missed "${line}"`).toBe(
-        true,
+      expect(blocks, `"${line}" should be one block`).toHaveLength(1);
+      expect(blocks[0].type, `"${line}" should stay a paragraph`).toBe(
+        "paragraph",
       );
-      const neutralized = ZWSP + line;
-      const blocks = await roundtrip(neutralized);
-
-      expect(blocks).toHaveLength(1);
-      expect(blocks[0].type).toBe("paragraph");
-      // Text is byte-preserved (ZWSP + original line), so the display is the
-      // original line with only an invisible leading character.
-      expect(blocks[0].content[0].text).toBe(neutralized);
+      expect(
+        blocks[0].content?.[0]?.text,
+        `"${line}" text should survive byte-exact`,
+      ).toBe(line);
     }
   });
 
-  it("normal host-prefixed lines never match the trigger regex and round-trip byte-exact", async () => {
+  it("emphasis / inline-code paragraphs are NOT escaped (no backslash churn)", async () => {
+    // These open with `*`/`` ` `` but are NOT block triggers; the serialized
+    // markdown must not gain a stray leading backslash, and they round-trip.
+    for (const [text, mark] of [
+      ["bold", "bold"],
+      ["italic", "italic"],
+      ["code", "code"],
+    ] as const) {
+      const node = doc({
+        type: "paragraph",
+        content: [{ type: "text", text, marks: [{ type: mark }] }],
+      });
+      const md = convertProseMirrorToMarkdown(node);
+      expect(md.startsWith("\\"), `${mark} must not be block-escaped`).toBe(
+        false,
+      );
+      const back = await markdownToProseMirror(md);
+      expect(back.content[0].type).toBe("paragraph");
+      expect(back.content[0].content[0].text).toBe(text);
+      expect(back.content[0].content[0].marks?.[0]?.type).toBe(mark);
+    }
+  });
+
+  it("a block trigger on a CONTINUATION line (after a hardBreak) is escaped too", async () => {
+    // A hardBreak serializes as `  \n`, so a trigger on the second line would,
+    // without a per-line escape, re-parse into another block. The worst case is
+    // `---`: a setext underline would turn the first line into a heading and LOSE
+    // the `---` text entirely. Each pair round-trips as ONE paragraph with the
+    // hardBreak and both texts preserved.
+    for (const [first, second] of [
+      ["a", "# b"],
+      ["a", "- b"],
+      ["a", "> b"],
+      ["a", "1. b"],
+      ["a", "| b |"],
+      ["a", "---"], // setext / thematic (3 dashes) — the text-losing case
+      ["a", "--"], // setext underline, EXACTLY two dashes (bullet/thematic miss it)
+      ["a", "----"], // setext / thematic (4 dashes)
+      ["a", "="], // setext H1 underline, a lone `=` (no other arm covers it)
+      ["a", "===="], // setext H1 underline, run of `=`
+    ]) {
+      const d = doc({
+        type: "paragraph",
+        content: [
+          { type: "text", text: first },
+          { type: "hardBreak" },
+          { type: "text", text: second },
+        ],
+      });
+      const back = await markdownToProseMirror(convertProseMirrorToMarkdown(d));
+      expect(back.content, `"${first}⏎${second}" should be one block`).toHaveLength(1);
+      expect(back.content[0].type).toBe("paragraph");
+      const texts = (back.content[0].content as any[])
+        .filter((n) => n.type === "text")
+        .map((n) => n.text);
+      const hasBreak = (back.content[0].content as any[]).some(
+        (n) => n.type === "hardBreak",
+      );
+      expect(hasBreak, `"${first}⏎${second}" should keep the hardBreak`).toBe(true);
+      expect(texts, `"${first}⏎${second}" should preserve both line texts`).toEqual([
+        first,
+        second,
+      ]);
+    }
+  });
+
+  it("normal host-prefixed lines round-trip byte-exact (unaffected)", async () => {
     for (const line of [
       "You: hello there",
       "Speaker 1: - and then a dash mid-line",
       "Speaker 2: 1. not a list",
     ]) {
-      expect(MD_BLOCK_TRIGGER_RE.test(line)).toBe(false);
       const blocks = await roundtrip(line);
       expect(blocks).toHaveLength(1);
       expect(blocks[0].type).toBe("paragraph");

packages/prosemirror-markdown/test/markdown-converter-gaps.test.ts

@@ -294,10 +294,11 @@ describe('converter gap coverage — emission branches (specs 1–11)', () => {
     );
   });
 
-  // 5. code + link co-occur: the schema's `code` mark excludes all other marks
-  //    (including link), so the link cannot survive import. The lossless,
-  //    byte-stable behavior is to emit ONLY the backtick code span (code wins).
-  it('a code+link run emits the backtick code form (code wins, link dropped)', () => {
+  // 5. code + link co-occur (#515): `code` no longer excludes other marks, so a
+  //    link can wrap inline code. The code span is emitted innermost and the link
+  //    wraps it — CommonMark allows inline code inside link text, so it survives
+  //    the round trip.
+  it('a code+link run nests the backtick span inside the link (#515)', () => {
     const out = convertProseMirrorToMarkdown(
       doc(
         para({
@@ -310,7 +311,7 @@ describe('converter gap coverage — emission branches (specs 1–11)', () => {
         }),
       ),
     );
-    expect(out).toBe('`x`');
+    expect(out).toBe('[`x`](http://a?b&c"d)');
   });
 
   // 6. hardBreak inside a heading: prefix applied once, "  \n" between a and b.
@@ -430,7 +431,7 @@ describe('converter gap coverage — emission branches (specs 1–11)', () => {
   });
 });
 
-describe('converter gap coverage — documented round-trip data loss (specs 12–14)', () => {
+describe('converter gap coverage — formerly-lossy round-trips, now closed (specs 12–14)', () => {
   // 12. A 3-backtick fence inside a codeBlock body is now lengthened: the outer
   //     fence widens to (longest inner run + 1) backticks per CommonMark, so the
   //     inner ``` is treated as content and the block survives as ONE node.
@@ -460,25 +461,24 @@ describe('converter gap coverage — documented round-trip data loss (specs 12
     expect(docsCanonicallyEqual(d, doc2)).toBe(false);
   });
 
-  // 13. A leading ordered-list marker in paragraph text is NOT escaped, so a
-  //     plain paragraph silently becomes an orderedList on re-import.
-  it('a paragraph starting with "1. " is promoted to an orderedList on re-import', async () => {
+  // 13. #493 commit 1: a leading ordered-list marker in paragraph text is now
+  //     BLOCK-ESCAPED, so the paragraph round-trips as a paragraph instead of
+  //     silently becoming an orderedList (was documented data loss, now closed).
+  it('a paragraph starting with "1. " is block-escaped and stays a paragraph', async () => {
     const d = doc({
       type: 'paragraph',
       content: [{ type: 'text', text: '1. not a list' }],
     });
     const md1 = convertProseMirrorToMarkdown(d);
-    expect(md1).toBe('1. not a list'); // no backslash escape
+    expect(md1).toBe('1\\. not a list'); // the ordered-list delimiter is escaped
 
     const doc2 = await markdownToProseMirror(md1);
-    expect(doc2.content?.[0]?.type).toBe('orderedList');
-    const li = doc2.content[0].content?.[0];
-    expect(li?.type).toBe('listItem');
-    expect(li.content?.[0]?.content?.[0]).toMatchObject({
+    expect(doc2.content?.[0]?.type).toBe('paragraph');
+    expect(doc2.content[0].content?.[0]).toMatchObject({
       type: 'text',
-      text: 'not a list', // the "1. " was consumed as a list marker
+      text: '1. not a list', // the escape decodes back to the literal text
     });
-    expect(docsCanonicallyEqual(d, doc2)).toBe(false);
+    expect(docsCanonicallyEqual(d, doc2)).toBe(true);
   });
 
   // 14. #293 canon #4: the image title now round-trips via the attached

packages/prosemirror-markdown/test/markdown-converter.test.ts

@@ -59,22 +59,21 @@ describe('convertProseMirrorToMarkdown', () => {
       ).toBe('`x`');
     });
 
-    it('code + another mark emits the backtick code form (code wins)', () => {
-      // The schema's `code` mark excludes all other marks, so the editor can
-      // never produce code+bold on one run and import always drops the co-mark.
-      // The lossless, byte-stable behavior is to emit ONLY the backtick code
-      // span and ignore the co-occurring mark.
+    it('code + bold nests the backtick span inside the emphasis (#515)', () => {
+      // #515: the `code` mark no longer excludes other marks (`excludes: ""`), so
+      // a run can carry code+bold. CommonMark nests them (`<strong><code>`), so
+      // the code span is emitted innermost and the bold delimiters wrap it.
       const out = convertProseMirrorToMarkdown(
         doc(para(text('x', [{ type: 'bold' }, { type: 'code' }]))),
       );
-      expect(out).toBe('`x`');
+      expect(out).toBe('**`x`**');
     });
 
-    it('code + strike combo emits the backtick code form (code wins)', () => {
+    it('code + strike nests the backtick span inside the emphasis (#515)', () => {
       const out = convertProseMirrorToMarkdown(
         doc(para(text('x', [{ type: 'strike' }, { type: 'code' }]))),
       );
-      expect(out).toBe('`x`');
+      expect(out).toBe('~~`x`~~');
     });
   });
 

packages/prosemirror-markdown/test/markdown-roundtrip.property.test.ts

@@ -80,13 +80,7 @@ import { stripBlockIds } from './roundtrip-helpers.js';
 // `it.fails` blocks below (so the suite stays green only because they are marked
 // expected-to-fail, never by hiding them):
 //
-//   1. The `code` mark COMBINED with any other mark. The converter emits nested
-//      HTML (`<strong><code>x</code></strong>`), but the schema's `code` mark
-//      declares `excludes: "_"`, so on import every co-occurring mark is dropped
-//      and the run comes back as `code` only -> md2 == "`x`". Acknowledged in
-//      markdown-converter.ts (the long comment above the marks switch);
-//      impossible to round-trip both while `code` excludes them.
-//   2. A BLOCK-level `image` placed BETWEEN other blocks. The Docmost image node
+//   1. A BLOCK-level `image` placed BETWEEN other blocks. The Docmost image node
 //      is block-level but `![](url)` is inline; marked wraps it in a <p>, the
 //      schema hoists the <img> out and leaves an empty paragraph sibling, which
 //      injects an extra blank gap on the second export. An image IS byte-stable
@@ -625,7 +619,7 @@ describe('markdown <-> ProseMirror round-trip (property-based)', () => {
   });
 
   // -------------------------------------------------------------------------
-  // KNOWN, DOCUMENTED non-roundtrip bug #2 (kept honest as it.fails).
+  // KNOWN, DOCUMENTED non-roundtrip bug #1 (kept honest as it.fails).
   //
   // BUG: a block-level `image` placed BETWEEN other blocks is not byte-stable.
   // The Docmost image node is BLOCK-level but its markdown form `![](url)` is
@@ -655,23 +649,18 @@ describe('markdown <-> ProseMirror round-trip (property-based)', () => {
   });
 
   // -------------------------------------------------------------------------
-  // KNOWN, DOCUMENTED non-roundtrip bug #1 (kept honest as it.fails).
+  // #515 ROUND-TRIP PIN: `code` combined with another mark.
   //
-  // BUG: the `code` mark combined with ANY other mark does NOT round-trip.
-  // The converter emits nested HTML so the output is well-formed, e.g.
-  //   marks [code, bold]  ->  md1 = "<strong><code>x</code></strong>"
-  // but the schema's `code` mark declares `excludes: "_"`, so on import the
-  // co-occurring mark is dropped and the run comes back as code-only:
-  //   md2 = "`x`"   (=> md2 !== md1).
-  // Minimal repro doc:
-  //   { type:'doc', content:[ { type:'paragraph', content:[
-  //       { type:'text', text:'x', marks:[{type:'code'},{type:'bold'}] } ] } ] }
-  // This is acknowledged in markdown-converter.ts (the long comment above the
-  // marks switch): preserving both marks is impossible while `code` excludes
-  // them. Documented here, not "fixed", because the source must not change.
+  // Before #515 the `code` mark declared `excludes: "_"`, dropping every co-
+  // occurring mark on import so `` **`x`** `` came back as code-only. Now
+  // `excludes: ""` lets code combine with all marks (CommonMark nests them,
+  // `<strong><code>x</code></strong>`), so the run BOTH round-trips byte-stably
+  // AND preserves the co-occurring mark. This asserts the observable property in
+  // both directions: md2 === md1 (idempotent export) and the imported doc still
+  // carries [code, other].
   // -------------------------------------------------------------------------
   it(
-    'code mark combined with another mark is byte-stable',
+    'code combined with another mark round-trips and keeps both marks (#515)',
     async () => {
       const codeComboArb = fc
         .tuple(safeTextArb, fc.constantFrom('bold', 'italic', 'strike'))
@@ -688,11 +677,90 @@ describe('markdown <-> ProseMirror round-trip (property-based)', () => {
         }));
       await fc.assert(
         fc.asyncProperty(codeComboArb, async (doc) => {
-          const { md1, md2 } = await roundTrip(doc);
+          const { md1, md2, doc2 } = await roundTrip(doc);
           expect(md2).toBe(md1);
+          // The re-imported run carries BOTH code and the co-occurring mark.
+          const run = doc2?.content?.[0]?.content?.[0];
+          const markTypes = (run?.marks || []).map((m: any) => m.type).sort();
+          expect(markTypes).toContain('code');
+          expect(markTypes.length).toBe(2);
         }),
         { numRuns: 20, seed: SEED },
       );
     },
   );
+
+  // -------------------------------------------------------------------------
+  // #515 REPRO CASES: the five markdown inputs from the issue must import to a
+  // code+bold node (import correctness) AND re-export byte-stably with no
+  // dangling `**` (export correctness). Import direction is checked against the
+  // real markdown->PM bridge; export direction via the md->pm->md fixpoint.
+  // -------------------------------------------------------------------------
+  it('the five #515 repro cases import to [code,bold] and round-trip clean', async () => {
+    // Collect every inline text run in a doc with its mark type set.
+    const runs = (node: any): { text: string; marks: string[] }[] => {
+      if (node?.type === 'text') {
+        return [{ text: node.text || '', marks: (node.marks || []).map((m: any) => m.type) }];
+      }
+      return (node?.content || []).flatMap(runs);
+    };
+    const findRun = (doc: any, text: string) =>
+      runs(doc).find((r) => r.text === text);
+
+    // Case 1: **`code1`** -> code1 = [code, bold].
+    {
+      const md = '**`code1`**';
+      const pm = await markdownToProseMirror(md);
+      const r = findRun(pm, 'code1');
+      expect(r?.marks.sort()).toEqual(['bold', 'code']);
+      const md2 = convertProseMirrorToMarkdown(pm);
+      expect(md2).toBe('**`code1`**');
+      // md -> pm -> md fixpoint.
+      expect(convertProseMirrorToMarkdown(await markdownToProseMirror(md2))).toBe(md2);
+    }
+
+    // Case 2: **`aaa` + `bbb`** -> aaa,bbb = [code,bold], "+" carries bold; no
+    // dangling `**` on export.
+    {
+      const md = '**`aaa` + `bbb`**';
+      const pm = await markdownToProseMirror(md);
+      expect(findRun(pm, 'aaa')?.marks.sort()).toEqual(['bold', 'code']);
+      expect(findRun(pm, 'bbb')?.marks.sort()).toEqual(['bold', 'code']);
+      const md2 = convertProseMirrorToMarkdown(pm);
+      expect(md2).toBe('**`aaa` + `bbb`**');
+      // NOT the old broken export with the bold delimiters split onto each span.
+      expect(md2).not.toBe('`aaa`** + **`bbb`');
+      expect(convertProseMirrorToMarkdown(await markdownToProseMirror(md2))).toBe(md2);
+    }
+
+    // Case 3 (control): **bold3** and `code3` -> bold and code stay SEPARATE.
+    {
+      const md = '**bold3** and `code3`';
+      const pm = await markdownToProseMirror(md);
+      expect(findRun(pm, 'bold3')?.marks).toEqual(['bold']);
+      expect(findRun(pm, 'code3')?.marks).toEqual(['code']);
+      const md2 = convertProseMirrorToMarkdown(pm);
+      expect(md2).toBe('**bold3** and `code3`');
+    }
+
+    // Case 4: **`code4` tail** -> code4 = [code,bold], " tail" = [bold].
+    {
+      const md = '**`code4` tail**';
+      const pm = await markdownToProseMirror(md);
+      expect(findRun(pm, 'code4')?.marks.sort()).toEqual(['bold', 'code']);
+      const md2 = convertProseMirrorToMarkdown(pm);
+      expect(md2).toBe('**`code4` tail**');
+      expect(convertProseMirrorToMarkdown(await markdownToProseMirror(md2))).toBe(md2);
+    }
+
+    // Case 5: pre **`code5`** post -> code5 = [code,bold], surroundings plain.
+    {
+      const md = 'pre **`code5`** post';
+      const pm = await markdownToProseMirror(md);
+      expect(findRun(pm, 'code5')?.marks.sort()).toEqual(['bold', 'code']);
+      const md2 = convertProseMirrorToMarkdown(pm);
+      expect(md2).toBe('pre **`code5`** post');
+      expect(convertProseMirrorToMarkdown(await markdownToProseMirror(md2))).toBe(md2);
+    }
+  });
 });

packages/prosemirror-markdown/test/schema-editor-ext-contract.test.ts

@@ -16,14 +16,16 @@ import * as editorExt from "@docmost/editor-ext";
 // or mark added upstream that the mirror forgets to vendor fails CI loudly
 // (otherwise it is silently dropped on the markdown <-> ProseMirror round-trip).
 //
-// LIMITATION (intentional, see schema-surface-snapshot.test.ts): this is a
-// NAME-LEVEL contract only, not a full attribute-level structural compare.
-// editor-ext's Tiptap representation (node views, commands, suggestion plugins,
-// addGlobalAttributes spread across separate extensions) differs from this
-// minimal mirror, so a mechanical attribute-by-attribute equality would be
-// fragile and produce false drift. Attribute parity is guarded by the inline
-// surface snapshot (reviewed in every diff); this test guards that no canonical
-// node/mark TYPE goes unmirrored. StarterKit-provided types (paragraph, bold,
+// This file now holds TWO contracts (see the two describe blocks): the original
+// NAME-LEVEL type contract (no canonical node/mark TYPE goes unmirrored) AND, as
+// of #493, an ATTRIBUTE-LEVEL contract that compares each editor-ext node/mark's
+// OWN declared attributes (names + defaults) against the mirror's built schema.
+// A full mechanical attribute-by-attribute EQUALITY would be fragile (the mirror
+// is a deliberate superset: it injects the global id/textAlign/indent attrs and
+// normalizes some editor-ext defaults to null), so the attribute contract is
+// asymmetric — editor-ext -> mirror — with a small, reasoned, stale-guarded
+// allowlist for the two blessed divergence kinds (non-round-trippable omissions
+// and null-normalized defaults). StarterKit-provided types (paragraph, bold,
 // heading, …) are contributed by @tiptap/starter-kit in the mirror rather than
 // by editor-ext, so they are naturally covered by the mirror's superset.
 //
@@ -85,3 +87,224 @@ describe("docmost schema vs @docmost/editor-ext (name-level contract)", () => {
     expect(missing).toEqual([]);
   });
 });
+
+// ── #515 CODE-MARK `excludes` PARITY (data-loss-sensitive) ──────────────────
+//
+// The `code` mark's `excludes` field decides whether inline code can co-occur
+// with other marks. #515 sets it to "" (excludes nothing) in the canonical
+// `Code` exported by @docmost/editor-ext AND, because the vendored markdown
+// mirror must NOT pull that React-aware package into its node runtime, RE-DECLARES
+// the same override locally in docmost-schema.ts. If the two drift, markdown
+// import would silently strip bold/italic adjacent to inline code again. Guard it
+// mechanically: the mirror's built `code` mark and the canonical editor-ext
+// `Code` must agree on `excludes` (both ""). getSchema surfaces the resolved
+// value on the mark spec.
+describe("docmost schema vs @docmost/editor-ext (#515 code excludes parity)", () => {
+  it("keeps the vendored `code` mark's excludes in lockstep with editor-ext Code", () => {
+    // Mirror side: the value the mirror's BUILT schema resolves for `code`.
+    const mirrorExcludes = getSchema(docmostExtensions as never).marks.code.spec
+      .excludes;
+    // Canonical side: the `excludes` DECLARED on the editor-ext `Code` extension
+    // (read from its config — getSchema needs a full node set, so a lone mark
+    // can't be built into a schema here).
+    const canonicalCode = (
+      editorExt as unknown as { Code?: { config?: { excludes?: unknown } } }
+    ).Code;
+    const canonicalExcludes = canonicalCode?.config?.excludes;
+    // Both must be the empty string: `code` excludes NOTHING, so bold/italic/…
+    // survive alongside inline code (#515). A drift here would silently strip
+    // marks adjacent to code on markdown import again.
+    expect(canonicalCode).toBeDefined();
+    expect(mirrorExcludes).toBe("");
+    expect(canonicalExcludes).toBe("");
+    expect(mirrorExcludes).toBe(canonicalExcludes);
+  });
+});
+
+// ── ATTRIBUTE-LEVEL CONTRACT (#493 commit 2) ────────────────────────────────
+//
+// The name-level contract above catches a WHOLE node/mark type going unmirrored,
+// but not ATTRIBUTE drift within a vendored type — the exact class that silently
+// dropped `subpages.recursive`: editor-ext grew an attribute the hand-synced
+// mirror forgot, so documents using it lost that attribute on a git-sync
+// round-trip while CI stayed green. This closes that gap by comparing each
+// editor-ext node/mark's OWN declared attributes (names + defaults) against the
+// mirror's built ProseMirror schema `spec.attrs`.
+//
+// DIRECTION: editor-ext -> mirror. The mirror is deliberately a SUPERSET (it
+// injects the global `id`/`textAlign`/`indent` attributes and normalizes some
+// editor-ext "required" attrs to a `null` default), so a reverse compare would
+// be pure false drift; the meaningful failure is an editor-ext attribute the
+// mirror DROPS (name) or whose DEFAULT it silently changes. Both directions of
+// staleness are guarded so the allowlists cannot rot.
+
+/**
+ * The attributes an editor-ext Tiptap Node/Mark DECLARES itself, read from its
+ * `config.addAttributes()`. Global attributes injected by separate extensions
+ * (unique-id, indent, textAlign) are NOT included here — they are the mirror's
+ * superset and are not part of a per-type declaration — so this isolates each
+ * type's own contribution. A declared attribute with no explicit `default` is a
+ * required attr (Tiptap default `undefined`); we surface that as-is so the
+ * default compare can skip it (the mirror makes such attrs optional/`null`).
+ */
+function editorExtOwnAttrs(): Map<
+  string,
+  { kind: "node" | "mark"; attrs: Record<string, unknown> }
+> {
+  const out = new Map<
+    string,
+    { kind: "node" | "mark"; attrs: Record<string, unknown> }
+  >();
+  for (const value of Object.values(editorExt)) {
+    if (!isTiptapNodeOrMark(value)) continue;
+    const ext = value as unknown as {
+      name: string;
+      type: "node" | "mark";
+      options?: unknown;
+      storage?: unknown;
+      config?: { addAttributes?: () => Record<string, { default?: unknown }> };
+    };
+    const fn = ext.config?.addAttributes;
+    // addAttributes reads `this.options`/`this.name`; bind a minimal context
+    // (verified sufficient for every editor-ext extension — none reach for
+    // `this.editor` here). A type with no addAttributes contributes no attrs.
+    const declared =
+      typeof fn === "function"
+        ? fn.call({
+            options: ext.options ?? {},
+            name: ext.name,
+            parent: undefined,
+            storage: ext.storage ?? {},
+          } as never)
+        : {};
+    const attrs: Record<string, unknown> = {};
+    for (const [attr, spec] of Object.entries(declared || {})) {
+      // `undefined` marks a required (no-default) attr; keep it so the default
+      // compare can distinguish "no default declared" from "default is null".
+      attrs[attr] = (spec as { default?: unknown })?.default;
+    }
+    out.set(ext.name, { kind: ext.type, attrs });
+  }
+  return out;
+}
+
+/** The mirror's built-schema `spec.attrs` for a type: attr name -> default. */
+function mirrorAttrs(
+  name: string,
+  kind: "node" | "mark",
+): Record<string, unknown> | null {
+  const schema = getSchema(docmostExtensions as never);
+  const spec = kind === "node" ? schema.nodes[name]?.spec : schema.marks[name]?.spec;
+  if (!spec) return null;
+  const out: Record<string, unknown> = {};
+  for (const [attr, def] of Object.entries(spec.attrs || {})) {
+    out[attr] = (def as { default?: unknown }).default;
+  }
+  return out;
+}
+
+// An editor-ext attribute the mirror deliberately does NOT vendor because it has
+// NO markdown round-trip representation — dropping it loses nothing on the
+// git-sync cycle (the same rationale the flat-roundtrip property suite uses to
+// allowlist e.g. `tableCell.backgroundColorName`). Blessed by the hand-curated
+// surface snapshot (schema-surface-snapshot.test.ts), reviewed in every diff.
+const ACCEPTED_ATTR_OMISSIONS = new Set<string>([
+  "highlight.colorName", // only `highlight.color` round-trips (==text==); the
+  // secondary palette-name is presentational and has no markdown form.
+]);
+
+// An editor-ext attribute the mirror vendors but with a DIFFERENT default: the
+// mirror normalizes an "absent" value to `null` (its uniform optional-attr
+// convention) rather than editor-ext's UI-oriented default. None of these attrs
+// is emitted on the markdown surface (the converter round-trips only the
+// serializable ones), so the default never round-trips and the divergence is
+// inert — but pinned here so a NEW default change on either side forces review.
+const ACCEPTED_DEFAULT_DIVERGENCE = new Set<string>([
+  "image.src", // mirror null vs editor "" (an image is never emitted src-less)
+  "link.internal", // mirror null vs editor false (routing attr, not in md link)
+  "pdf.width", // mirror null vs editor 800 (presentational sizing, not in md)
+  "pdf.height", // mirror null vs editor 600 (presentational sizing, not in md)
+]);
+
+describe("docmost schema vs @docmost/editor-ext (attribute-level contract)", () => {
+  it("vendors every editor-ext attribute (name) of every shared type — no silently-dropped attrs", () => {
+    const dropped: string[] = [];
+    for (const [name, { kind, attrs }] of editorExtOwnAttrs()) {
+      const mirror = mirrorAttrs(name, kind);
+      if (!mirror) continue; // whole-type omission is the name-level test's job
+      for (const attr of Object.keys(attrs)) {
+        const key = `${name}.${attr}`;
+        if (!(attr in mirror) && !ACCEPTED_ATTR_OMISSIONS.has(key)) {
+          dropped.push(key);
+        }
+      }
+    }
+    // Any entry here exists on the editor-ext node/mark but NOT in the mirror
+    // (and is not a blessed non-round-trippable omission): documents using it
+    // lose that attribute on a git-sync round-trip — the subpages.recursive
+    // class. Re-sync src/lib/docmost-schema.ts (and the surface snapshot) or add
+    // a reasoned ACCEPTED_ATTR_OMISSIONS entry before clearing.
+    expect(dropped.sort()).toEqual([]);
+  });
+
+  it("keeps every editor-ext attribute DEFAULT in sync — no silent default drift", () => {
+    const drift: string[] = [];
+    for (const [name, { kind, attrs }] of editorExtOwnAttrs()) {
+      const mirror = mirrorAttrs(name, kind);
+      if (!mirror) continue;
+      for (const [attr, extDefault] of Object.entries(attrs)) {
+        const key = `${name}.${attr}`;
+        // Skip attrs editor-ext declares WITHOUT a default (required attrs):
+        // the mirror deliberately makes them optional (`null`), a safe superset.
+        if (extDefault === undefined) continue;
+        if (!(attr in mirror)) continue; // a drop, reported by the name test
+        if (
+          JSON.stringify(mirror[attr]) !== JSON.stringify(extDefault) &&
+          !ACCEPTED_DEFAULT_DIVERGENCE.has(key)
+        ) {
+          drift.push(
+            `${key}: mirror=${JSON.stringify(mirror[attr])} editor-ext=${JSON.stringify(extDefault)}`,
+          );
+        }
+      }
+    }
+    expect(drift.sort()).toEqual([]);
+  });
+
+  it("the attribute allowlists have no stale rows (each is really omitted / divergent)", () => {
+    const ext = editorExtOwnAttrs();
+    const staleOmission: string[] = [];
+    for (const key of ACCEPTED_ATTR_OMISSIONS) {
+      const [name, attr] = key.split(".");
+      const entry = ext.get(name);
+      const mirror = entry ? mirrorAttrs(name, entry.kind) : null;
+      // Stale if editor-ext no longer declares it, or the mirror now DOES vendor
+      // it (so it should be removed from the omission allowlist).
+      if (!entry || !(attr in entry.attrs) || (mirror && attr in mirror)) {
+        staleOmission.push(key);
+      }
+    }
+    expect(staleOmission, "stale ACCEPTED_ATTR_OMISSIONS rows").toEqual([]);
+
+    const staleDivergence: string[] = [];
+    for (const key of ACCEPTED_DEFAULT_DIVERGENCE) {
+      const [name, attr] = key.split(".");
+      const entry = ext.get(name);
+      const mirror = entry ? mirrorAttrs(name, entry.kind) : null;
+      const extDefault = entry?.attrs[attr];
+      // Stale if the divergence no longer exists (attr gone, or defaults now
+      // agree) — the row should be dropped so the allowlist stays honest.
+      if (
+        !entry ||
+        !mirror ||
+        !(attr in entry.attrs) ||
+        !(attr in mirror) ||
+        extDefault === undefined ||
+        JSON.stringify(mirror[attr]) === JSON.stringify(extDefault)
+      ) {
+        staleDivergence.push(key);
+      }
+    }
+    expect(staleDivergence, "stale ACCEPTED_DEFAULT_DIVERGENCE rows").toEqual([]);
+  });
+});

packages/prosemirror-markdown/test/setup.dom-parser.ts

@@ -0,0 +1,13 @@
+/**
+ * Vitest setup: register the Node (jsdom) HTML parser for the whole suite.
+ *
+ * The package's tests import the converter through the RELATIVE `src/lib/*`
+ * modules (or the `docmost-client`/`src/lib/index` barrel), NOT through the
+ * top-level `index.ts` entry that a real Node consumer imports — so the entry's
+ * side-effect registration of the jsdom parser never runs here. This setup file
+ * performs the SAME registration the Node entry does, so `markdownToProseMirror`
+ * has a DOM parser in the (node-environment) tests, matching production Node
+ * behaviour. The browser path is covered separately by the client paste tests
+ * (jsdom vitest env + native DOMParser) and the dedicated dom-parser test.
+ */
+import "../src/lib/dom-parser.node.js";

packages/prosemirror-markdown/vitest.config.ts

@@ -9,15 +9,26 @@ import { defineConfig } from 'vitest/config';
 // envelope, markdownToProseMirror) is re-exported there.
 const here = path.dirname(fileURLToPath(import.meta.url));
 const libBarrel = path.resolve(here, 'src/lib/index.ts');
+// Resolve the cross-package `@docmost/editor-ext` specifier to the SIBLING
+// workspace SOURCE. In a normal checkout this is what pnpm's workspace link +
+// the package's `module` field already yield; pinning it here makes the schema
+// contract tests (incl. the #515 code-excludes parity) hermetic and independent
+// of node_modules layout (e.g. a shared/hoisted store in a git worktree).
+const editorExtBarrel = path.resolve(here, '../editor-ext/src/index.ts');
 
 export default defineConfig({
   resolve: {
     alias: {
       'docmost-client': libBarrel,
+      '@docmost/editor-ext': editorExtBarrel,
     },
   },
   test: {
     environment: 'node',
     include: ['test/**/*.test.ts'],
+    // Register the Node (jsdom) HTML parser before any test runs. Tests import
+    // the converter via relative src/lib modules, bypassing the top-level entry
+    // that normally installs the parser as a side effect (see setup file).
+    setupFiles: ['test/setup.dom-parser.ts'],
   },
 });

pnpm-lock.yaml

@@ -284,6 +284,9 @@ importers:
       '@docmost/editor-ext':
         specifier: workspace:*
         version: link:../../packages/editor-ext
+      '@docmost/prosemirror-markdown':
+        specifier: workspace:*
+        version: link:../../packages/prosemirror-markdown
       '@excalidraw/excalidraw':
         specifier: 0.18.0-3a5ef40
         version: 0.18.0-3a5ef40(@types/react-dom@18.3.1)(@types/react@18.3.12)(react-dom@18.3.1(react@18.3.1))(react@18.3.1)
@@ -912,10 +915,6 @@ importers:
         version: 8.57.1(eslint@9.39.4(jiti@2.4.2))(typescript@5.9.3)
 
   packages/editor-ext:
-    dependencies:
-      marked:
-        specifier: 17.0.5
-        version: 17.0.5
     devDependencies:
       '@vitest/coverage-v8':
         specifier: 4.1.6
@@ -1117,6 +1116,9 @@ importers:
       '@tiptap/starter-kit':
         specifier: 3.20.4
         version: 3.20.4
+      happy-dom:
+        specifier: 20.8.9
+        version: 20.8.9
       jsdom:
         specifier: 25.0.0
         version: 25.0.0
@@ -18490,7 +18492,7 @@ snapshots:
 
   happy-dom@20.8.9:
     dependencies:
-      '@types/node': 22.19.1
+      '@types/node': 25.5.0
       '@types/whatwg-mimetype': 3.0.2
       '@types/ws': 8.18.1
       entities: 7.0.1