Uv Tool Management

uv Tool Management

Purpose

This skill teaches you how to efficiently manage Python command-line tools using uv, including running tools on-demand without installation, installing persistent tools globally, managing versions, and understanding when to use tools versus project dependencies.

Quick Start

Run any CLI tool without installing it:

# Run ruff (Python linter) once without installation
uvx ruff check .

# Equivalent longer form
uv tool run ruff check .

# Install a tool permanently for repeated use
uv tool install ruff

# Then run the installed tool
ruff check .

Instructions

Step 1: Understand the Tool Management Landscape

uv replaces pipx for tool management. There are three main approaches:

uvx (temporary execution): Run a tool once without installation

• Tool is fetched, cached, and executed in an isolated environment
• No modification to your system
• Ideal for: occasional use, trying tools, CI/CD where tools aren't needed repeatedly

uv tool install (persistent installation): Install a tool for repeated use

• Tool is installed globally in a dedicated environment
• Available in PATH after installation
• Ideal for: tools you use regularly (linters, formatters, test runners)

uv run (project environment): Run tools that need access to your project

• Tools run within your project's virtual environment
• Can access your project's installed packages
• Ideal for: testing, linting, formatting your project code

Step 2: Choose Between uvx and uv tool install

Use uvx (ephemeral) when:

• Running a tool for the first time to test it
• Tool is used rarely or on-demand
• You want no installation footprint
• Running in CI/CD pipelines (cleaner, no persistent state)
• Tool has conflicting dependencies with other tools

# Try a new tool without committing to it
uvx httpie https://api.github.com/users/github

# Run a tool on-demand in CI
uvx mypy src/

# Run tool from different package
uvx --from httpie http https://example.com

Use uv tool install (persistent) when:

• Tool is part of your regular workflow
• Team uses it consistently (document in README)
• Tool provides utility functions beyond single invocation
• You want faster execution (no download overhead each time)
• Tool is referenced in project docs or scripts

# Install tools you use daily
uv tool install ruff
uv tool install black
uv tool install mypy

# Then run directly without prefix
ruff check .
black --check src/
mypy src/

Use uv run (project environment) when:

• Running tests, linters, or formatters on your project
• Tool needs access to project dependencies
• Running from within project directory
• Tool is listed in project's dev dependencies

# Test runner needs access to project (test libraries, modules)
uv run pytest tests/

# Linter running on project code
uv run mypy src/

# Format project code
uv run black src/

Step 3: Run Tools with uvx

Basic execution without arguments:

uvx ruff check .
uvx black --check src/

Specify exact version:

# Run specific version of a tool
uvx ruff@0.3.0 check .

# Use version constraint
uvx --from 'ruff>=0.3.0,<0.4.0' ruff check .

Run tools from different packages:

# httpie is in package 'httpie', command is 'http'
uvx --from httpie http https://api.github.com

# mkdocs is in 'mkdocs', command is 'mkdocs'
uvx mkdocs serve

Include optional dependencies (extras):

# mypy with optional faster caching
uvx --from 'mypy[faster-cache]' mypy src/

# mkdocs with material theme
uvx --with mkdocs-material mkdocs serve

Run with specific Python version:

# Run tool with Python 3.10 (useful for compatibility testing)
uvx --python 3.10 ruff check .

# Ensure tool runs on minimum supported version
uvx --python 3.9 pytest tests/

Run from git repository:

# Install directly from GitHub
uvx --from git+https://github.com/httpie/cli httpie

Step 4: Install and Manage Persistent Tools

Install tools:

# Install latest version
uv tool install ruff

# Install specific version
uv tool install ruff@0.3.0

# Install with extras
uv tool install 'mypy[faster-cache]'

# Install from git
uv tool install git+https://github.com/user/tool

List installed tools:

uv tool list

# Example output:
# black           0.23.11  /Users/user/.local/bin/black
# mypy            1.7.0    /Users/user/.local/bin/mypy
# ruff            0.3.0    /Users/user/.local/bin/ruff

Upgrade tools:

# Upgrade specific tool to latest
uv tool upgrade ruff

# Upgrade all tools
uv tool upgrade --all

# Upgrade to specific version
uv tool upgrade ruff@0.4.0

Uninstall tools:

# Remove installed tool
uv tool uninstall ruff

# Remove multiple tools
uv tool uninstall ruff black mypy

Step 5: Understand Tool vs Project Dependencies

Critical distinction for your workflow:

# pyproject.toml

[project]
# Main project dependencies - needed to run your application
dependencies = [
    "fastapi>=0.104.0",
    "httpx>=0.27.0",
]

[project.optional-dependencies]
# Optional features for your application (not development tools)
aws = ["boto3>=1.34.0"]
database = ["sqlalchemy>=2.0.0"]

[dependency-groups]
# Development tools - only needed while developing
test = [
    "pytest>=8.0.0",
    "pytest-cov>=4.1.0",
]
lint = [
    "ruff>=0.1.0",
    "mypy>=1.7.0",
]
format = [
    "black>=23.11.0",
]

Decision matrix:

Step 6: Manage Tool Versions and Upgrades

Check installed version:

# Show version of installed tool
ruff --version

# Or via uv
uv tool list | grep ruff

Upgrade specific tool:

# Upgrade to latest
uv tool upgrade ruff

# Keep all tools up to date
uv tool upgrade --all

Pin tool version:

# Use specific version (best practice for team consistency)
uv tool install ruff@0.3.0

# Override installed version
uv tool install ruff@0.4.0

Clean up old tools:

# Uninstall unused tools
uv tool uninstall old-tool

# Check what's installed
uv tool list

# Free up disk space
uv cache prune

Step 7: Handle Tool Dependencies and Conflicts

Tools with conflicting dependencies:

# These tools both depend on different versions of a library
# uvx creates isolated environments, avoiding conflicts
uvx tool-a
uvx tool-b

# Both run in separate, isolated environments
# No dependency conflicts

Tools requiring additional packages:

# Add extra packages to tool execution
uvx --with mkdocs-material mkdocs serve

# Tool runs with mkdocs + mkdocs-material installed

Specific Python version for tool:

# Some tools require specific Python versions
# Ensure compatibility
uvx --python 3.9 older-tool

# Run with minimum supported Python
uvx --python 3.10 modern-tool

Examples

Example 1: One-Time Tool Usage (uvx)

You need to check code quality but don't use ruff regularly:

# Run ruff once to check your code
uvx ruff check .

# Output analysis but don't install anything
# After execution, no system changes
# Next time you run it, it's fetched again (but cached locally)

Example 2: Regular Linting in Project (uv run)

Your project uses ruff as a dev dependency:

# In your project directory
cd my-project

# Edit pyproject.toml to add ruff to dev dependencies
# [dependency-groups]
# lint = ["ruff>=0.1.0"]

# Sync environment
uv sync --group lint

# Run linter from project environment
uv run ruff check .

# Everyone on team uses same ruff version (from uv.lock)

Example 3: Global Tool Installation (uv tool install)

You use ruff across multiple projects:

# Install once globally
uv tool install ruff

# Use in any directory
cd project-a && ruff check .
cd ../project-b && ruff check .

# No project setup needed
# Tool always available in PATH

Example 4: Test Different Python Versions

You need to verify code works on Python 3.10 and 3.12:

# Run with Python 3.10
uvx --python 3.10 pytest tests/

# Run with Python 3.12
uvx --python 3.12 pytest tests/

# Each uses different Python version
# No installation overhead

Example 5: Tool with Extras

mypy runs faster with optional faster-cache feature:

# Via uvx (temporary)
uvx --from 'mypy[faster-cache]' mypy src/

# Via uv tool install (persistent)
uv tool install 'mypy[faster-cache]'
mypy src/

Example 6: CI/CD Pipeline

Your CI uses different tools without installation:

# .github/workflows/ci.yml
- name: Lint code
  run: uvx ruff check .

- name: Type check
  run: uvx mypy src/

- name: Format check
  run: uvx black --check .

- name: Test
  run: |
    uv sync --group test
    uv run pytest tests/

Each step is clean, isolated, no tool installation overhead.

Example 7: Cleanup and Maintenance

Remove old tools and free disk space:

# See what's installed
uv tool list

# Remove tool you no longer use
uv tool uninstall old-formatter

# Prune cache of unused packages
uv cache prune

# Check cache location and size
uv cache dir

Requirements

• uv installed (install via: curl -LsSf https://astral.sh/uv/install.sh | sh)
• Python 3.8+ available (for running tools)
• Understanding of your project's dependency structure

See Also

• references/tool-comparison.md - Detailed comparison of uvx vs uv tool vs uv run
• references/common-workflows.md - Copy-paste ready tool usage patterns
• examples/tool-scenarios.md - Real-world tool management examples
• uv Documentation - Official tool management guide