xtralab 0.2.0

An opinionated JupyterLab meta-package that bundles a curated set of extensions, ships a path-first file browser and a VS Code-style git changes panel, and applies a quieter default workspace configuration.

xtralab

An opinionated JupyterLab meta-package.

xtralab bundles a curated set of JupyterLab extensions, ships its own JupyterLab extension with a path-first file browser and a VS Code-style git changes panel, and applies a quieter default workspace configuration. The defaults are shipped under etc/jupyter/labconfig and the bundled labextension is shipped under share/jupyter/labextensions/xtralab.

The goal is to keep the package easy to inspect: most behavior comes from the upstream Jupyter packages, while xtralab defines the default environment we want out of the box.

Approach

The package brings together:

• The ajlab meta-package (agent-ready JupyterLab — collaboration plumbing, MCP support, command tooling, and its own quieter defaults)
• JupyterLab 4.6+
• Git server integration (jupyterlab-git — backs the bundled changes panel)
• Quick file opening (jupyterlab-quickopen)
• Cursor styling helpers (jupyterlab-cursor-light, jupyterlab-cursor-theme)
• Day and night themes (jupyterlab-day, jupyterlab-night)

These are installed as normal Python dependencies, so deployments can still override versions and Jupyter configuration in the usual ways.

Bundled labextension

xtralab ships its own prebuilt labextension that contributes:

• A path-first file browser in the left sidebar, built on @pierre/trees.
• A VS Code-style "Source Control" panel in the left sidebar, powered by the jupyterlab-git server REST API and @pierre/diffs. The bundled @jupyterlab/git frontend is disabled automatically so the two panels do not coexist.
• An agent-focused launcher that replaces the stock JupyterLab launcher. The launcher tab shows an optional initial-prompt textarea, a row of agent buttons (Claude, Codex, Gemini, Copilot, Goose, OpenCode, Kiro, and Mistral Vibe), and a collapsible list of changed files (each clickable into the diff viewer) below them. Clicking an agent opens a fresh terminal and runs the agent's CLI; if the prompt textarea is non-empty, the prompt is shell-quoted and spliced into the launch line for agents that accept one. Agents are filtered by a which-based availability check at activation, so only the ones actually installed on the machine show up.

Customizing the launcher

The launcher reads xtralab:launcher settings from the JupyterLab settings registry. Open the Settings Editor (Settings → Settings Editor → xtralab launcher) and edit the agents array; xtralab merges your entries with the defaults by id.

{
  "agents": [
    // Hide an agent you never want to see, even if it's installed:
    { "id": "kiro", "enabled": false },

    // Override an agent's command — e.g. point Claude at a shell alias.
    // `requireAvailable: false` keeps the card visible even though
    // `which cl` returns nothing (interactive shells expand the alias).
    { "id": "claude", "command": "cl", "requireAvailable": false },

    // Add a brand-new agent. `iconSvg` is optional; without it the card
    // falls back to a generic terminal icon. `promptArgs: []` means the
    // launcher's prompt textarea is appended as a positional argument.
    {
      "id": "aider",
      "label": "Aider",
      "command": "aider",
      "promptArgs": []
    }
  ]
}

Field reference (every field except id is optional):

Field	Effect
id	Built-in id to override, or a new id to define a new card.
label	Card title.
caption	Subtitle shown beneath the title.
command	Literal text typed into the new terminal.
iconSvg	Inline SVG for the card icon (only needed for new agents).
rank	Sort order on the launcher; lower comes first.
enabled	false hides the card from the launcher and palette.
requireAvailable	false skips the which check (use for shell aliases that aren't on PATH but expand at runtime).
promptArgs	How to splice the launcher's optional prompt into the command. [] appends it as a positional argument (<command> 'PROMPT'); ["-i"] or ["--prompt"] puts it after a flag. Set to null to opt out — the agent button is dimmed when the prompt textarea is non-empty so a typed prompt is never silently dropped. Defaults vary per agent.

Default settings

xtralab ships the following JupyterLab defaults:

• The announcements plugin is disabled, so JupyterLab does not prompt to fetch news from the Jupyter news feed and does not check for application updates.
• The Table of Contents, Debugger, and Notebook Tools panels are disabled so they do not show up in the right sidebar by default.
• dockPanelPadding is off, so the main dock area is flush with the surrounding chrome.
• The terminal fontFamily defaults to MesloLGS NF, ui-monospace, monospace so Powerline / Nerd Font glyphs (used by Oh My Zsh themes such as powerlevel10k) render correctly when the font is installed; the ui-monospace, monospace fallback keeps things readable when it is not.

The JupyterLab frontend defaults are shipped as labconfig/*.d/00-xtralab.json fragments so downstream meta-packages can add their own Lab configuration fragments without replacing xtralab's files.

Install

pip install xtralab

Run as a desktop app

xtralab ships a tiny launcher that opens JupyterLab in a dedicated Chrome window (via Chrome's --app mode), with an isolated user-data directory so it does not share cookies, extensions, or history with your normal browser.

Requires Chrome or Chromium installed. macOS only for now; other platforms will be added later.

The simplest way, no install needed:

uvx xtralab

Or, after pip install xtralab into an environment:

xtralab

The launcher starts a local Jupyter server on a random port with a fresh token, waits for it to come up, opens the app window, and shuts the server down when you close the window. Ctrl-C in the launching terminal also shuts everything down cleanly.

Development

# Install dependencies and the package in editable mode
uv pip install -e ".[dev]"
jlpm
jlpm build

License

BSD-3-Clause