UV Run

Run Python scripts with uv - no manual venv activation needed.

Core Capabilities

Direct execution: uv run script.py handles environment automatically
Temporary dependencies: uv run --with requests script.py for one-off needs
Inline dependencies: PEP 723 metadata blocks for self-contained scripts
Ephemeral tools: uvx tool runs CLI tools without installation

Essential Commands

Running Scripts

# Run script (uv manages environment automatically)
uv run script.py

# Run with arguments
uv run script.py --input data.csv --output results.json

# Run a specific module
uv run -m http.server 8000

# Run with specific Python version
uv run --python 3.12 script.py

Temporary Dependencies

Add dependencies for a single run without modifying project:

# Single dependency
uv run --with requests fetch_data.py

# Multiple dependencies
uv run --with requests --with rich api_client.py

# Version constraints
uv run --with 'requests>=2.31' --with 'rich>12,<14' script.py

# Combine with project dependencies
uv run --with pytest-benchmark pytest  # Add benchmark to existing pytest

Inline Script Dependencies (PEP 723)

Create self-contained scripts with embedded dependencies:

#!/usr/bin/env -S uv run --script
# /// script
# requires-python = ">=3.11"
# dependencies = [
#   "requests>=2.31",
#   "rich>=13.0",
# ]
# ///

import requests
from rich import print

response = requests.get("https://api.github.com")
print(response.json())

Run directly:

uv run script.py

# Or make executable:
chmod +x script.py
./script.py

Managing Script Dependencies

# Initialize script with metadata
uv init --script example.py --python 3.12

# Add dependency to script
uv add --script example.py requests rich

# Lock script dependencies for reproducibility
uv lock --script example.py

Ephemeral Tool Execution (uvx)

Run CLI tools without installation:

# Run tool once
uvx pycowsay "Hello from uv!"
uvx httpie https://api.github.com
uvx ruff check .

# With specific version
uvx ruff@0.1.0 check .

# uvx is shorthand for:
uv tool run pycowsay "Hello"

Shebang Patterns

Self-Contained Executable Script

#!/usr/bin/env -S uv run --script
# /// script
# dependencies = ["click", "rich"]
# ///

import click
from rich import print

@click.command()
@click.argument('name')
def hello(name):
    print(f"[green]Hello, {name}![/green]")

if __name__ == "__main__":
    hello()

Script with Python Version Requirement

#!/usr/bin/env -S uv run --script --python 3.12
# /// script
# requires-python = ">=3.12"
# dependencies = ["httpx"]
# ///

import httpx
# Uses Python 3.12+ features

When to Use Each Pattern

Scenario	Approach
Quick one-off task	`uv run --with pkg script.py`
Reusable script	Inline deps (PEP 723)
Shareable utility	PEP 723 + shebang
Team collaboration	Inline deps + `uv lock --script`
Run CLI tool once	`uvx tool`
Project scripts	`uv run` (uses project deps)

uvx vs uv run --with

uvx tool: Run a CLI tool without installation (e.g., uvx ruff check .)
uv run --with pkg: Run a script with temporary dependencies (e.g., uv run --with requests script.py)

# Run a tool (CLI application)
uvx httpie https://api.github.com

# Run a script with dependencies
uv run --with httpx api_test.py

Profiling and Debugging

# CPU profiling
uv run python -m cProfile -s cumtime script.py | head -20

# Line-by-line profiling (temporary dependency)
uv run --with line-profiler kernprof -l -v script.py

# Memory profiling
uv run --with memory-profiler python -m memory_profiler script.py

# Real-time profiling (ephemeral tool)
uvx py-spy top -- python script.py

# Quick profiling
uv run --with scalene python -m scalene script.py

References

Official docs: https://docs.astral.sh/uv/guides/scripts/
PEP 723: https://peps.python.org/pep-0723/
Tools: https://docs.astral.sh/uv/guides/tools/

uv-run