Browse · Read · Edit
Markdown Library ML‑42
A native macOS app for browsing, reading, and editing markdown files. Point it at your project folders and navigate them the way you'd browse the web — click into documents, hit back to return, search across everything. Your files stay on disk, in your repos, exactly where they belong.
ML-42 is in active development. Sign up and get notified when we launch.
Document View
Every file deserves to be read properly
Your markdown files carry the context that makes AI work — architecture docs, decision records, project briefs, specs. ML-42 renders them as clean, navigable documents with live preview editing. No switching between raw and rendered. The sidebar shows your project tree. The inspector gives you a table of contents. You're not staring at syntax — you're reading your library.
Folder Overview
Navigate like a browser
Open any folder and see your documents as cards with excerpts and modification dates. Click into a file, read it, hit back. Forward and back history works across files and folders — just like a web browser. Breadcrumbs in every header. Favorites for quick access. The more projects you add, the more useful it gets.
01 — Live Preview
Read and write on the same surface
Markdown syntax fades away as you read. Move your cursor into any block and the raw syntax appears for editing. No mode switching, no preview pane — reading and writing are one.
02 — Project Folders
All your markdown, organised
Add any folder as a project. ML-42 remembers them between sessions and shows only markdown files. Switch between repos, docs directories, and notes folders without friction.
03 — Command Palette
Find anything, anywhere
Cmd+K searches across all your projects at once — by filename and by content. Jump to any document in any project in seconds.
04 — Syntax Highlighting
Code that reads like code
Fenced code blocks render with language-specific coloring for 15+ languages. Colors adapt to light and dark mode. The fences hide when you're not editing them.
05 — Table Rendering
Tables that make sense
Markdown tables render as clean, aligned grids with bold headers and subtle separators. Click in to edit the raw markdown. Rendering adapts as you resize.
06 — Front Matter
Metadata that reads cleanly
YAML front matter at the top of a document renders as a structured property list — key-value pairs with subtle dividers — not as raw syntax cluttering the reading experience.
07 — Navigation
Browse like the web
Back and forward history across files and folders. Breadcrumbs in every header. A table of contents in the inspector. Star files for quick access from Favorites.
08 — File Watching
Always the latest version
When an AI agent or another editor modifies a file, ML-42 detects the change and reloads automatically. What you see is what's on disk.
No database. No sync layer. No lock-in.
Just a well-made tool for the files that make everything else work.
The Format
Markdown in the age of AI
John Gruber published the original Markdown spec in 2004 with a simple premise: plain text should be readable as-is. Twenty years later, the format hasn't changed much — and that turned out to be the point.
Every AI assistant reads markdown. Every AI assistant writes markdown. The context files that shape AI behavior, the specs that define what to build, the artifacts agents produce — all markdown. The format that was designed for READMEs became the connective tissue of human-AI collaboration.
Read the Markdown PrimerPhilosophy
Nothing between you and your files
Code editors treat markdown as just another text file. Note-taking apps want to own your data. Preview tools are read-only. None of them are designed for the actual workflow: open a project folder, browse its documents, read and edit naturally, move on to the next.
ML-42 opens your folders where they are. No import, no database, no proprietary format. When files change on disk — from an AI agent or another editor — ML-42 picks up the change automatically. When you close the app, your files are exactly where you left them.
The format is the interface. ML-42 just makes it better to work with.
Beta
Join the beta
ML-42 is in active development. Sign up and get notified when we launch.
Native macOS app · macOS 26+ · Apple Silicon and Intel