Quoll

Edit Markdown in VS Code with a Notion/Obsidian-style WYSIWYG editor, right inside your editor tabs.

Quoll registers an opt-in custom editor for .md files. Instead of plain text, your Markdown renders as rich text — headings, lists, tables, and formatting — while the file on disk stays the source of truth.

Features

• WYSIWYG Markdown editing — .md files open in a CodeMirror-based live editor. The raw Markdown stays canonical; move the caret into a construct to reveal and edit its source, and away to re-render.
• Rich blocks, rendered in place — headings, lists, blockquotes, callouts ([!TIP], [!NOTE], …), images, and fenced code.
• Interactive task lists — toggle - [ ] / - [x] checkboxes directly in the rendered view.
• Editable GFM tables — render and edit tables from the Markdown source.
• Frontmatter panel — YAML frontmatter renders as a metadata block.
• Fenced-code tools — one-click copy; long blocks collapse behind a "Show more" bar.
• Document outline — a toggle-able overlay lists the document's headings; click one to jump straight to it. Open it with the top-right button or Ctrl/Cmd+Alt+O.
• Switch to the text editor — flip the active Markdown file to VS Code's built-in text editor (and back) with a top-right button or Ctrl/Cmd+Alt+E; your caret position carries across.
• Image paste & drop — pasted or dropped images save under ./assets/ and insert a relative link (writable file-scheme documents).
• Markdown lint — advisory findings as inline underlines, with an optional gutter dot and an optional Problems-panel mirror.
• Live editing — edits sync to the document as you type; VS Code owns the file and saves as usual.
• Theme-aware & opt-in — follows your light/dark theme, and registers with priority: option so it never hijacks .md from other extensions.

Requirements

• VS Code 1.94.0 or newer.
• A trusted, local workspace. Quoll writes files via WorkspaceEdit and does not support untrusted or virtual workspaces.

Install

Install from the VS Code Marketplace:

• Extensions view: open the Extensions view (Ctrl/Cmd+Shift+X), search for Quoll, and click Install.
• Quick Open: press Ctrl/Cmd+P and run ext install mtskf.quoll.
• Command line: code --install-extension mtskf.quoll.

Prefer to build from source? Clone the repo and package the .vsix yourself:

git clone https://github.com/mtskf/quoll.git
cd quoll
pnpm install
pnpm package        # produces quoll-<version>.vsix
code --install-extension quoll-*.vsix

Reload the VS Code window after installing.

Usage

.md files keep opening in your usual editor by default. Open one in Quoll explicitly:

• Per file: right-click a Markdown file → Open With… → Markdown (Quoll).
• As the default: right-click → Open With… → Configure default editor… → pick Markdown (Quoll).
• From the palette: run Edit with Quoll (Ctrl/Cmd+Shift+P) to open the active file in Quoll.

Commands and keybindings

Two overlay affordances sit in the editor's top-right corner: a button to toggle the document outline (Ctrl/Cmd+Alt+O) and a button to switch to the text editor (Ctrl/Cmd+Alt+E). Like the live-reveal below, the outline toggle is editor-internal behavior rather than a VS Code command, so it does not appear in the keybindings UI.

Inline formatting is plain Markdown — type **bold**, *italic*, or `code` and the editor live-renders it. Move the caret into a construct to reveal its raw Markdown markers for editing; move the caret away to re-render. This live-reveal is editor-internal behavior rather than a set of VS Code commands, so it does not appear in the keybindings UI.

Settings

Quoll contributes two settings (Settings UI → search "Quoll", or settings.json):

• quoll.lint.problems.enabled (default true) — mirror Quoll's advisory Markdown lint findings into VS Code's Problems panel. Turning it off clears those entries and suppresses new ones; the in-editor underlines stay on.
• quoll.lint.gutter.enabled (default false) — show a severity-coloured dot in a thin left gutter on each line that has an advisory lint finding. Off by default so the clean centred reading column is unchanged; turning it on adds the gutter without touching the underlines or the Problems mirror.

Known limitations

Quoll is early software. Be aware of the following before relying on it:

• Markdown round-trips byte-for-byte. The raw text is canonical, so what you edit equals what's on disk for every construct.
  • Line endings: a file that mixes CRLF/LF, or is CR-only, is shown with one normalized separator (VS Code normalizes on load); opening and saving it without edits leaves the on-disk bytes unchanged.
  • Unsafe URLs: the write-gate refuses to save (a "Cannot save" notice) until an out-of-allowlist link/image destination is fixed — see Images.
• Raw HTML is shown as inert source — displayed as its source, never rendered as live HTML, and preserved byte-for-byte on save. Open with the default text editor for raw-HTML syntax highlighting.
• Images have partial support.
  • Relative images (![](https://github.com/mtskf/quoll/raw/HEAD/img.png)) resolve against the document folder and render for file-scheme documents only; untitled/git-scheme documents show inert placeholders.
  • Paste or drop into a writable file-scheme document saves under ./assets/ as a content-hashed PNG/JPEG/GIF/WebP (10 MB cap, type sniffed host-side); read-only documents ignore it.
  • Images outside the document folder (../sibling/img.png) and remote (https://…) images are not loaded (localResourceRoots scope + CSP); a remote-image opt-in is tracked for a follow-up.
  • URL allowlist: link/image/autolink destinations pass only when schemeless (relative or #fragment) or http: / https: / mailto:. Everything else (javascript:, data:, file:, protocol-relative //host, control chars) renders an inert placeholder and blocks the save until fixed. The check is by scheme name and covers Markdown destinations only — URLs inside raw HTML aren't checked.
• MDX (.mdx) is not supported — only .md files open with the rich editor.
• Not implemented: slash/block-insert menu (no UI to insert tables / lists / headings from scratch), column resizing for tables, diff/git views, and collaborative editing. Single file, single editor only.
• Visual rendering is verified by manual smoke. Automated tests cover the CodeMirror decoration/widget behavior, GFM table round-trips, the host write-gate, the message protocol, and host-side message flows (a @vscode/test-electron E2E suite); in-webview visual rendering is not asserted by CI and is checked by manual smoke.

Contributing

Contributions are welcome. The project is a single-root pnpm package (extension host + webview bundled together via esbuild).

pnpm install        # install all deps
pnpm build          # full build (tsc + esbuild → dist/)
pnpm package        # produce a .vsix via vsce
pnpm test           # run the vitest unit suite

Press F5 in VS Code to launch an Extension Development Host with Quoll loaded. See CONTRIBUTING.md for the full contributor guide.

License

MIT — © 2026 Mitsuki Fukunaga and Quoll contributors.