Runtime Execution Skill

Name: runtime-exec
Rating: 92
Author: mikeparcewski

Execute Python and Node scripts using the best available package manager.

Python Execution Priority

•uv (preferred) - Fast, reliable, handles dependencies automatically
•poetry - Good for projects with poetry.lock
•.venv/bin/python - Pre-existing virtual environment
•python3 - Last resort, may miss dependencies

Node Execution Priority

•pnpm (preferred) - Fast, disk-efficient
•npm - Standard, widely available
•yarn - Alternative package manager
•npx - For one-off script execution

Usage Patterns

Python Script Execution

bash

# In a directory with pyproject.toml:
cd ${PLUGIN_DIR}/scripts

# Preferred (auto-installs deps)
uv run python script.py [args]

# Alternative
poetry run python script.py [args]

# If venv exists
.venv/bin/python script.py [args]

# Last resort (may fail on deps)
python3 script.py [args]

Node Script Execution

bash

# In a directory with package.json:
cd ${PLUGIN_DIR}/scripts

# Preferred
pnpm run script-name
pnpm exec script.js

# Alternative
npm run script-name
npx script.js

# Yarn
yarn run script-name

Detection Logic

When executing a script, detect the runtime context:

bash

# Python detection
if command -v uv &>/dev/null && [ -f pyproject.toml ]; then
    uv run python "$@"
elif command -v poetry &>/dev/null && [ -f poetry.lock ]; then
    poetry run python "$@"
elif [ -f .venv/bin/python ]; then
    .venv/bin/python "$@"
else
    python3 "$@"
fi

# Node detection
if command -v pnpm &>/dev/null && [ -f pnpm-lock.yaml ]; then
    pnpm exec "$@"
elif command -v npm &>/dev/null && [ -f package-lock.json ]; then
    npx "$@"
elif command -v yarn &>/dev/null && [ -f yarn.lock ]; then
    yarn exec "$@"
else
    node "$@"
fi

Important Notes

•Always cd to the script directory first (where pyproject.toml/package.json lives)
•Use uv run for Python - it auto-syncs dependencies from pyproject.toml
•Warn user if falling back to system Python/Node (deps may be missing)
•For plugins, scripts are in ${CLAUDE_PLUGIN_ROOT}/scripts/

Common Issues

Missing Dependencies

If using system python3 and imports fail:

bash

# Install uv (recommended)
curl -LsSf https://astral.sh/uv/install.sh | sh

# Or create venv manually
python3 -m venv .venv
.venv/bin/pip install -e .

Wrong Python Version

bash

# Check version
uv run python --version

# Specify version in pyproject.toml:
# requires-python = ">=3.10"