ML-42

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.

architecture.md — My Project PROJECTS agent-setup ml-42 docs architecture.md features.md vision.md FAVORITES README.md CLAUDE.md agent-setup / docs Architecture Edited 2 hours ago · 1,240 words · 6 min read System Overview The application follows a three-layer architecture with a clear separation between the presentation, domain, and data layers. Each service is independently testable. Data Flow Events propagate from the view layer through observable services. State changes trigger SwiftUI view updates. ContentView → ViewModel → Service ↓ state changes propagate back Service → ViewModel → View SUMMARY A three-layer architecture for the app, covering data flow and error-handling strategy. TABLE OF CONTENTS System Overview Data Flow Error Handling Services FileTreeService SearchService Navigation

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 — fast. The sidebar shows your project tree. The inspector gives you a table of contents and an on-device summary from Apple Intelligence. You're reading your library, not staring at syntax.

architecture.md — My Project PROJECTS agent-setup ml-42 docs architecture.md features.md vision.md FAVORITES README.md CLAUDE.md agent-setup / docs Architecture Edited just now · 1,240 words · 6 min read 1 # System Overview 2 3 The application follows a three-layer architecture 4 with a clear separation between layers. 5 6 ## Data Flow 7 8 ``` 9 ContentView → ViewModel → Service 10 ↓ state changes propagate back 11 ```|

Editor

Edit the raw markdown, with line numbers

Flip any document to its raw markdown in a clean monospaced editor with a line-number gutter. Choose the mono font, size, and line height in Settings. It saves as you type.

docs — My Project PROJECTS agent-setup ml-42 docs src tests APP Settings Feedback ml-42 docs Edited 2 hours ago · 4 documents · 2 folders DOCUMENTS Architecture The application follows a three-layer architecture... 2 hours ago Features ML-42 is a native macOS app that turns your markdown... Yesterday Vision Markdown is the lingua franca of working with AI... 3 days ago README ML-42 — a markdown library for macOS. Built with SwiftUI... Last week FOLDERS src tests RECENT ACTIVITY Architecture Modified 2 hours ago Features Modified yesterday Vision Modified 3 days ago

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.

Command Palette

Find anything in seconds

Cmd+K searches across every project at once — by filename and by content. Each hit shows its project and path, so you can jump from a memory file in one repo to a blog draft in another without losing your place.

Writi| 4 results in 4 projects RESULTS writing-style.md agent-setup / memory DOC on-writing-clearly.mdx fieldhub / src / content / blog DOC writing-voice.md notes / drafts DOC WRITING_GUIDE.md tr-1 / docs DOC ↑↓ navigate ↵ open ⌘1–4 jump to project esc to dismiss

01 — Fast Preview

Documents render instantly

Open a file and it's already rendered. Headings, code, tables, front matter — all styled, no delay. Scroll a thousand-line document and it stays buttery. The preview is the default view, and it never makes you wait.

02 — Fast Raw Editing

Raw markdown at native speed

Flip to raw with a keystroke and edit plain text the way it was meant to be edited — no rendering layer between your fingers and the file. Switching back is instant.

03 — On-Device Summaries

Apple Intelligence in the inspector

Every document gets a short summary generated automatically by Apple Intelligence, on-device. Nothing leaves your machine. Glance at the inspector to know what a file is about before you open it.

04 — 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.

05 — 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.

06 — 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.

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.

  1. No database. No sync layer. No lock-in. No subscription.
  2. A native app optimized for speed, fully owned by you.
  3. Nothing leaves your local machine.

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 Primer

Philosophy

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.

Read the documentation →

Native macOS app · macOS 26+ · Apple Silicon and Intel

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