hot-notebook-patching 0.2.1

JupyterLab extension for hot patching externally modified notebooks

hot-notebook-patching

A JupyterLab extension for hot patching notebooks that are edited externally — for example by an AI coding agent like Claude Code.

Instead of triggering a full notebook reload (which restarts the kernel and clears widget state), only the cells that actually changed are patched into the live notebook model.

What it does

Claude Code edits notebook.ipynb on disk
          ↓
Extension detects the file change
          ↓
Only modified cells are patched
          ↓
Kernel keeps running · Widget state intact · Scroll position preserved

Installation

Requires JupyterLab 4.

pip install hot-notebook-patching

Then restart JupyterLab (or start it fresh) — the extension is prebuilt, no jupyter labextension build step needed.

To uninstall:

pip uninstall hot-notebook-patching

Usage

Toolbar button

Each notebook gets a ⚡ bolt button in the toolbar. Click it to toggle auto-patch mode — the extension will watch the file for changes and patch automatically.

Commands

Action	How
Patch once from disk	Toolbar ⚡ button (when auto-patch is off) · Shift+P inside a notebook · Command Palette → Patch Notebook From Disk
Toggle auto-patch	Toolbar ⚡ button · Command Palette → Toggle Auto-Patch on File Change

What is preserved

• Running kernel
• Widget state (ipywidgets, anywidget, …)
• Cell outputs and execution counts
• Scroll position

What is updated

• Cell source code (with line-level diff indicators)
• Cell metadata
• Added / deleted / reordered cells

Development

# Terminal 1: rebuild on every source change
source .venv/bin/activate
jlpm watch

# Terminal 2: start JupyterLab
source .venv/bin/activate
jupyter lab

After each rebuild, hard-refresh the browser tab (Cmd+Shift+R) — no server restart needed.