I'm creating an ai_context submodule for document loader integration: ai_context#3586275+s and ran into an issue. **Composer 2.5 analysis:** You're right to question that — I shouldn't have patched `document_loader` locally. I've **reverted those changes**. ## Is a fix required? **Yes**, but it belongs in **Document Loader**, not in `ai_context`. The error is real. When `document_loader_mdx` loads a `.md` file into MDXEditor, content hits `sanitizeForMdx()` in `DocumentLoaderMdxForm.php`, then is inserted via `setMarkdown()`. MDXEditor only accepts fenced code blocks whose language is in its configured list (from the AI module's `Editor.jsx`: `javascript`, `python`, `bash`, etc.) and that have **no fence meta**. Markdown with common tags like ` ```php `, ` ```yaml `, or ` ```javascript lineNumbers ` fails with: > Parsing of the following markdown structure failed: {"type":"code","name":"N/A"} That is a gap in **`document_loader_mdx`'s sanitizer**, which its own `ARCHITECTURE.md` describes as responsible for MDX compatibility. This is not something `ai_context_document_loader` should own long term. ## Why not fix it in `ai_context`? `hook_document_loader_post_load_alter()` runs **before** `document_loader_mdx` sanitizes. You could normalize code fences there, but `sanitizeForMdx()` would still run afterward and: - strip HTML inside code blocks (its regex doesn't respect fences) - leave no hook for downstream modules to alter the final MDX-safe content So a proper fix needs to happen in **`document_loader_mdx`** (or a new alter hook there). ## What to ask the Document Loader maintainer File an issue on [document_loader](https://www.drupal.org/project/issues/document_loader) along these lines: **Title:** MDXEditor parse error when loading Markdown with unsupported code fence languages **Summary:** Loading `.md` files via the Load Document button inserts content, but MDXEditor shows a parse error for code blocks. MDXEditor's `codeMirrorPlugin` only imports fences whose language is in its allowlist and that have no meta. **Steps:** 1. Enable `document_loader_mdx` and use an MDXEditor field (e.g. Context Item content). 2. Load a Markdown file with ` ```php ` or ` ```yaml ` fences. 3. Editor shows: `Parsing of the following markdown structure failed: {"type":"code","name":"N/A"}` **Expected:** Content loads and renders in rich-text mode. **Proposed fix:** Extend `sanitizeForMdx()` to: 1. Normalize unsupported fence languages to plain ` ``` ` (or map aliases like `shell` → `sh`) 2. Strip fence meta (e.g. ` ```javascript lineNumbers `) 3. Apply HTML/image/comment stripping only **outside** code fences **Reference:** AI module languages in `ui/mdxeditor/src/components/Editor.jsx`; MDXEditor matching logic in `@mdxeditor/editor` `MdastCodeVisitor`. ## AI usage - [x] AI assisted issue - [x] AI assisted code