jupyterlab_advanced_html_viewer_extension

Read an HTML file in JupyterLab and comment on it. The viewer trusts and refreshes a page as the built-in HTML Viewer does, and adds the marks, comments and notes panel of the advanced Markdown viewer. The comments are stored in the HTML file itself, so an AI agent reading the file reads them too and can answer in it.

Features

• Opens HTML files - double-click an .html file; Trust HTML runs its scripts and Rerender HTML Document reads it again, as in the built-in viewer
• Shows a page on the whole screen - the full-screen button on the toolbar shows the page alone on the whole screen, as it is, with the keyboard on the page; Escape returns to the lab
• Remembers trust in the file - Trust HTML, or the Always trust this page checkbox beside it, writes this lab's signature of the file's path into the file's settings line, so the file opens trusted next time, also after an agent rewrites it, while the line stays; Distrust HTML, or clearing the checkbox, takes it out. A signature made in another lab, or for another path, trusts nothing, so a downloaded file cannot trust itself
• Scrollbar follows the lab theme - the page's scrollbar, and any scrolling area inside it, takes the colours of the current JupyterLab theme; switching the theme recolours it without reloading the page
• Wide pages fit the frame - a page wider than the frame is scaled down to the frame's width before trust as well as after, and a page that fits keeps its own size; opening the notes panel, resizing the window or going full screen fits it again without a reload
• Follows the file - a change another program writes to the file shows within a few seconds; a change to the notes alone leaves the page as it is
• Marks the tab of a changed file - while changes arrive, a half-filled circle before the tab's name swaps its filled half from side to side, faster the more changes arrive. Changes that arrived while the tab was behind another leave a dot in the theme's brand colour until you bring the tab to the front. The tab's tooltip says what the marker means, and the Tab marker setting switches it off
• Marks in six colours - select text, right-click and choose a colour under Mark, or Add Comment to write a note at once; Ctrl Shift M (Cmd Shift M on macOS) marks from the keyboard
• Only text written in the file takes a comment - text a trusted page's scripts produce, and whatever an iframe, object or embed of the page shows, is refused
• Notes are stored in the file - as HTML comments around the passage, which no browser shows, in the same form the advanced Markdown viewer writes
• Notes panel beside the page - a comment and its replies per mark, with edit, delete, colour, close and a note on the whole document

Agent skill

The skill in .agents/skills/jupyterlab-advanced-html-viewer-extension teaches an AI assistant the marks this extension stores in the HTML file. With it, the assistant can:

• mark passages in the six colours, change a mark's colour and hide a mark
• comment on a passage or on the whole page
• answer and close your comments
• watch a file for new comments, with the bundled scripts/watch-marks.py

pip install puts a copy in <sys.prefix>/share/jupyter/agents/skills/, inside the Python environment, not in ~/.agents/skills. No agent reads that directory, so link the copy into ~/.agents/skills yourself, with the Python that runs the lab:

mkdir -p ~/.agents/skills
ln -s "$(python -c 'import sys; print(sys.prefix)')/share/jupyter/agents/skills/jupyterlab-advanced-html-viewer-extension" ~/.agents/skills/jupyterlab-advanced-html-viewer-extension

Agents that read .agents/skills also find it in a clone of this repository; to make it available to Claude Code everywhere, link it into the skills directory from the root of the clone:

mkdir -p ~/.claude/skills && ln -sfn "$PWD/.agents/skills/jupyterlab-advanced-html-viewer-extension" ~/.claude/skills/jupyterlab-advanced-html-viewer-extension

Requirements

• JupyterLab >= 4.6.0

Install

To install the extension, execute:

pip install jupyterlab_advanced_html_viewer_extension

Uninstall

To remove the extension, execute:

pip uninstall jupyterlab_advanced_html_viewer_extension