Make FileRouter the default handler
Install FileRouter into /Applications (the supported path after scripts/mkapp.sh or an installer). Quit any older copy so only one menu bar icon is running.
From the FileRouter menu, choose Make Default for all types. macOS will associate FileRouter’s built-in routes (and any custom types you have added) so double-clicked files land in FileRouter first — then FileRouter opens the editor your rules select.
If a specific type still opens elsewhere, check Finder’s Get Info → Open with for that file, or re-run Make Default for all types after adding a custom type.
Setting a default editor
The menu bar shows one submenu per route (Markdown, Plain Text, and any custom types). Each submenu lists the editors enabled for that route; the active item is the route default.
In Settings → Editors, curate which discovered apps appear for each route. Use Add App… for apps that Launch Services never offers (for example apps that open folders rather than files). Viewer-only apps stay disabled until you enable them.
The permanent Default Rule on the Rules tab always opens that same fallback editor. Changing the menu pick or the Default Rule’s editor updates the other.
Editing Rules
Open Settings → Rules. Rules are ordered per route; the first enabled matching rule wins.
Combine conditions with AND/OR. Conditions can include file name, extension, parent folder (subtree), creator app metadata, held modifiers (⌘ ⇧), and how many of the route’s enabled editors are currently running.
Actions can open a specific editor, the route default, the best running editor (from a preference list), or show a HUD to pick from all / running enabled editors.
Every route ends with a permanent Default Rule (no criteria) that cannot be reordered, disabled, or removed. Legacy Path Rules migrate automatically into equivalent folder rules.
Custom file types
Drop an unrouted file onto FileRouter, or use Add Type… in Settings, to teach a new type from the file’s extension and UTI. You can also drag a file over the menu bar icon and drop it on the Route File Type palette.
If the type overlaps an existing route, FileRouter offers a merge instead of a duplicate. Custom types can be removed; built-in routes cannot. After adding, pick an editor for that route in Settings.
URL scheme templates
On an Editors row, open the gear to attach an optional open URL. When set, FileRouter always opens that editor via the expanded URL (a URL badge appears on the row).
Placeholders: {filepath}, {folderpath}, {filename}, tilde forms {filepath~} / {folderpath~}, and .urlencoded variants of each.
Example for nvUltra:
x-nvultra://open?notebook={folderpath~.urlencoded}¬e={filename.urlencoded}