nul-cli

Northwestern University Libraries command-line tooling.

nul installs AI-assistant skills for Northwestern University Libraries workflows. It reads the NUL community catalog — a Claude Code plugin marketplace — and writes each plugin's SKILL.md files into the agent skill directories used by Codex, ChatGPT, Cursor, and similar tools.

Two install paths from one source of truth:

• Claude Code users can add the catalog directly with /plugin marketplace add nulib-labs/nul-skills and then /plugin install <plugin>@nul-skills — nul-cli is not required.
• Codex, ChatGPT, Cursor, and other clients use nul skills add <plugin> to install the plugin's skills into .agents/skills/.

nul also installs a generated nul-cli skill that documents the CLI's own command tree.

Installation

Installation via uv:

uv tool install nul-cli
nul --help

Run without installing:

uvx --from nul-cli nul --help

Installation via pip:

pip install nul-cli
nul --help

Usage

nul --help
nul skills --help

List available plugins (community catalog + the generated nul-cli skill):

nul skills list

Preview a plugin's skill (defaults to the only skill if there's just one; otherwise pass <plugin>:<skill>):

nul skills preview meadow
nul skills preview meadow:run-tests

Install the generated nul-cli skill:

nul skills add

Install all skills from a community plugin. Community skills are installed into flat namespaced directories (<plugin>-<skill>) to avoid collisions across plugins:

nul skills add meadow
# installs .agents/skills/meadow-run-tests/

Install one specific skill from a multi-skill plugin:

nul skills add meadow:run-tests

Upgrade installed skills (compares the recorded revision against the upstream commit SHA at each plugin's path):

nul skills upgrade

Community Catalog Source

The catalog is fetched from nulib-labs/nul-skills (branch main). Each install records the resolved commit SHA in .nul-skill-manifest.json, and upgrade re-resolves to detect new commits touching that plugin's path.

Naming note. The catalog file is .claude-plugin/marketplace.json and each entry is a plugin with its own .claude-plugin/plugin.json manifest. These are Claude Code plugin marketplace conventions, kept verbatim so the same nul-skills repo can be added as a Claude plugin source. We use "community" as the user-facing term throughout the CLI.

Plugins may also bundle commands, hooks, or MCP servers for Claude Code. nul-cli ignores those and only installs SKILL.md files — non-Claude clients will use those skills via their own agent skill discovery.

Override via env vars:

• NUL_SKILLS_REPO — <owner>/<repo> to fetch from (default nulib-labs/nul-skills).
• NUL_SKILLS_REF — branch, tag, or commit SHA (default main).
• NUL_SKILLS_PATH — local checkout to use instead of fetching. Useful when iterating on skills locally.
• GITHUB_TOKEN / GH_TOKEN — used (if set) to lift GitHub API rate limits.

Development

uv sync
uv run nul --help
uv run nul skills add --help

Running Tests

uv run pytest

Building

uv build
uv run twine check dist/*