Brief

A focused markdown reader and annotation tool. Drop in a .md file or paste a URL — clean typography, no distractions. Select any text to strike it, comment on it, and export your notes to paste into an LLM.

Open Brief →

What it does

• Renders any Markdown file with beautiful typography (Lora serif, proper line heights, generous whitespace)
• Supports syntax highlighting, Mermaid diagrams, YAML frontmatter, and GitHub Flavored Markdown — see the feature tour for examples
• Works offline after first load — nothing leaves your device
• Defaults to your system light/dark preference; also supports Sepia
• Adjustable font size, line width, and font choice
• Auto-generated table of contents for long documents
• Reading progress bar
• Copy buttons on code blocks
• Remembers your last dropped file or folder — reopening shows it immediately

How to use it

Open the link above on your phone or desktop. Then either:

1. Drop a file or folder — drag and drop any .md or .txt file (or a folder of them) onto the page, or tap "Choose File". Links between files in a folder work automatically.
2. Paste a URL — paste a raw markdown URL (GitHub blob links are auto-converted) and hit Go
3. Paste a GitHub commit or PR URL — loads all changed files as a browseable set with an index page
4. Link directly — append ?url= to load a document on open, e.g.:

   https://dereklucas.github.io/brief?url=https://raw.githubusercontent.com/dereklucas/brief/main/README.md
   

Your reading preferences (theme, font size, line width) are saved locally and persist between sessions.

Annotations

Select any text to mark it up:

• Strike — marks text for deletion
• Comment — highlights text and attaches a note
• Note — the note icon in the toolbar adds a comment on the whole document

Annotations persist across page reloads (stored locally, keyed to the document content). The export button copies a structured summary to your clipboard:

<source>
https://raw.githubusercontent.com/…/doc.md
</source>

<annotations>
1. [DELETE] "the old approach"
2. [COMMENT on "we should revisit this"] worth a follow-up with the team
3. [NOTE] Overall this section needs a rewrite
</annotations>

Paste that directly into Claude or another LLM to apply the edits.

GitHub

Paste any GitHub commit or PR URL and Brief fetches all changed files, generates a linked index, and lets you browse them with browser back/forward:

https://github.com/owner/repo/commit/abc1234
https://github.com/owner/repo/pull/123

Private repos require a GitHub personal access token. Add it in Settings (the gear icon). Get yours with:

gh auth token

The token is stored in your browser's localStorage — nothing is sent anywhere except directly to the GitHub API.

Annotate on any page

The same strike/comment/export workflow works on any webpage, not just in Brief.

Chrome / Arc — load the extension in developer mode:

1. Go to chrome://extensions → enable Developer mode
2. Load unpacked → select the extension/ folder

Safari / Firefox — use the bookmarklet (annotate.js). Save this as a bookmark and click it on any page:

javascript:void(function(){var s=document.createElement('script');s.src='https://dereklucas.github.io/brief/annotate.js?_='+Date.now();document.head.appendChild(s);}());

Examples

Try these in Brief to see what it can do:

• Feature tour — syntax highlighting, Mermaid diagrams, tables, task lists, frontmatter
• Essay — long-form reading with drop caps and typographic details
• This README

It's one file

The entire app is a single HTML file — no build step, no dependencies to install, no server needed. Open index.html directly in a browser and it works.

License

MIT