What is ML-42?
Markdown became the lingua franca of working with AI. Every context file, every spec, every agent output, every decision log — markdown. But the tools haven’t kept up. Code editors treat it as just another text file. Note-taking apps want to own your data. Preview tools are read-only.
ML-42 is a native macOS app for people who live in markdown. Open your project folders, browse everything visually, read with a live preview that stays out of the way, edit naturally — and move between projects without friction. Your files stay on disk, in your repos, exactly where they belong.
Installation
ML-42 is a native macOS app. Download it from the Mac App Store or TestFlight during the beta period. ML-42 requires macOS 26+.
Open Your First Project
Launch ML-42 and click “Add Project” in the sidebar (or use the + button in the toolbar). Select any folder containing markdown files — a project repo, a docs directory, a notes folder. ML-42 remembers your projects between sessions using security-scoped bookmarks, so sandboxed access persists without re-granting permission.
Your project appears in the sidebar with its full folder hierarchy, filtered to show only markdown files. No noise from source code, images, or config files — just the documents you came for.
Navigating Your Files
The sidebar shows your projects as collapsible trees. Click a folder to see a visual overview with document cards, subfolder counts, and recent activity. Click a file to open it in the editor.
As you navigate, the sidebar follows — expanding the tree to reflect where you are. Breadcrumb paths at the top of every view let you jump back up the hierarchy. Back and forward buttons (Cmd+[ and Cmd+]) work like a browser.
Star important files from the toolbar and they appear in the Favorites section at the top of the sidebar for one-click access.
Reading and Editing
ML-42 uses an Obsidian-style live preview. Markdown syntax fades away as you read — headings render as headings, bold is bold, links are clickable. Move your cursor into any block and the raw syntax appears for editing. You never switch modes.
Code blocks render with syntax highlighting for 15+ languages. Tables render with aligned columns and clean headers. Front matter displays as a structured property list.
Select text and a floating toolbar appears with formatting options — bold, italic, headings, lists, links. Or use keyboard shortcuts: Cmd+B for bold, Cmd+I for italic, Cmd+K for links.
Finding Things
Cmd+K opens the command palette. It searches across all your projects at once — by filename (instant) and by content (as you type). Results show the full path and type (project, folder, or document). Arrow keys to navigate, Enter to jump.
Within a document, Cmd+F opens the n tative find bar with match highlighting and navigation.
The Inspector
Toggle the right-hand inspector panel with Cmd+Option+I. When viewing a document, it shows a table of contents built from your headings — click any entry to scroll there. When viewing a folder, it shows recent file activity across that directory.
Light and Dark Mode
Click the moon/sun toggle in the sidebar to switch between light and dark mode, or set it to follow the system in Settings. The editor, syntax highlighting, and all UI elements adapt to your preference.
Next Steps
- Read The Workflow for a deeper look at how the pieces fit together
- See Features for a complete reference of everything ML-42 does