Marginalius

Marginalius is an Obsidian plugin for Tufte/Cornell-style side notes. On a wide screen the notes sit in the page margins. When space is tight, they turn into small boxes embedded in the text.

You write a note once with an inline marker, and the plugin picks the layout from the width of the editor pane.

Part of the Noetic Suite.

Features

• One syntax gives two layouts. When there is room, the note sits in the side gutter beside the text column, borderless and in muted text, like a printed margin note. When there isn't, it becomes a small rounded box floated into the text, styled as liquid glass: an even translucent tint with blur, a bright rim fading from the upper-left and a lifted shadow. With Reduce transparency or Increase contrast turned on in your system settings, the box is solid instead.
• %%> text %% goes to the left margin and %%< text %% to the right.
• Markers can go anywhere in a paragraph. In the margin view the note sits at the middle of its paragraph's height, so a note on a one-line block such as a list item stays on that line. Two notes on the same side of one paragraph overlap.
• The syntax reuses Obsidian's comment delimiters (%% … %%), so if Marginalius is disabled, Obsidian treats the notes as ordinary comments and leaves no broken markup.
• Each note decides for itself. It stays in the margin while it fits there, and turns into a box only when its outer edge would come closer to the edge of the pane (for example a sidebar) than the Pane edge gap setting. The box appears where the margin note was, keeping that gap to the pane edge, with its top at the top of the paragraph, and slides further into the text as the pane narrows (for example when you widen a sidebar). Widening the pane moves it back out the same way.
• Words don't split across lines in a narrow margin. Non-breaking spaces in your notes (often typed with Option+Space on macOS, or pasted from rich text) are replaced at render time, so phrases wrap at real word boundaries. Your note is never changed.
• Selecting a rendered note in the editor puts the cursor at the start of its text, so you can type right away.
• A settings tab controls the widths and spacing.
• Text colors, borders and the readable line width come from your theme, in both Reading view and Live Preview.

Usage

Put a marker inline in your text:

%%> Result: only the mysql-backup pod can assume that role and write to S3;
other pods cannot. So yes: it's access control and least privilege. %%

Your main body text goes here. On a wide screen the note above is rendered
in the left margin next to this paragraph.

%%< This note is pulled into the right-hand margin instead. %%

Marker	Side
%%> text %%	Left margin
%%< text %%	Right margin

• The character right after the opening %% (> or <) sets the side.
• Everything between the markers is rendered as Markdown, so bold, italic and links work.
• Markers inside inline code or fenced code blocks are ignored, so you can write about the syntax without triggering it.
• A note can span several paragraphs, or sit in a list item or callout.
• In Live Preview, a note inside a callout is always a box beside the callout: Obsidian draws a callout as one block and shows nothing outside it. In Reading view, and while you edit the callout, the note can sit in the margin like any other.
• A note inside an embedded note (![[other note]]) is always a box: Obsidian clips an embed to its own area.
• In Live Preview, a note inside a table isn't shown, because Obsidian draws a table as one block. Reading view shows it.
• The first %% after the marker ends a note, even inside inline code, because that's where Obsidian ends a comment in Reading view.
• If a note that started in an earlier paragraph ends in the same paragraph where another note starts, Reading view doesn't show the text between them. Obsidian reads the two %% around that text as a comment.
• To insert a marker, run Insert left marginalia or Insert right marginalia from the command palette. Selected text becomes the note, and with several selections each one becomes its own note. With nothing selected, you get an empty note with the cursor inside. The command does nothing when a selection contains a note or comment, or when the cursor is inside one.

Edit a note

Select a rendered note in the editor (Live Preview or Source mode) to edit it. It switches back to its source, and the cursor lands at the start of the text, right after the %%> or %%< marker. Links inside a note still open normally, and right-clicking a note leaves the cursor where it was.

Move the cursor out of the note and it renders again.

Install

Marginalius is in Obsidian's community plugin directory. It needs Obsidian 1.13 or later.

1. Open Settings → Community plugins. If community plugins are off, select Turn on community plugins.
2. Select Browse and search for Marginalius.
3. Select Install, then Enable.

Install manually

Download main.js, manifest.json and styles.css from the latest release and copy them into your vault's plugin folder:

cp main.js manifest.json styles.css "<Vault>/.obsidian/plugins/marginalius/"

Then reload Obsidian and enable the plugin in Settings → Community plugins.

Settings

Settings → Community plugins → Marginalius

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