nb-margin

A JupyterLab 4 extension that lets you annotate notebook cells with comments and submit them to Claude Code for automatic editing — without leaving the browser.

How it works

1. Open a notebook in JupyterLab
2. Select a cell and press Ctrl+Shift+A (or right-click → "Annotate Cell for Claude")
3. Describe the change you want in the dialog
4. Annotate as many cells as you like — annotations accumulate in the sidebar
5. Press Ctrl+Shift+Enter (or click "Submit to Claude Code")
6. Claude Code edits the .ipynb file directly; the notebook reloads when done

Requirements

• JupyterLab >= 4.0
• Claude Code CLI installed and available on $PATH

Install

pip install nb-margin

Development

# Clone and install in development mode
git clone https://github.com/anthropics/nb-margin.git
cd nb-margin
pip install -e "."
jupyter labextension develop . --overwrite
jlpm build

# Watch for changes (two terminals)
jlpm watch          # terminal 1
jupyter lab         # terminal 2

Permission modes

The sidebar includes a permission mode selector:

• Safe (default) — Claude Code can only read and write files
• Bash — also allows shell commands (for linters, tests, etc.)
• Skip — no permission restrictions (--dangerouslySkipPermissions)

Set the default via the NB_MARGIN_PERMISSION_MODE environment variable (safe, bash, or skip).

Keyboard shortcuts

Uninstall

pip uninstall nb-margin

License

MIT