Agent Skills: Python Development Best Practices

Python Development Best Practices

Overview

Python scripts in this repository use uv for dependency management and follow a standalone script pattern with inline PEP 723 dependency declarations when external packages are needed.

Always Use uv

• NEVER use pip, pipenv, poetry, or venv directly
• ALWAYS use uv for all Python package management
• Script shebang: #!/usr/bin/env -S uv run --quiet --script

Script Templates

Script with Dependencies

#!/usr/bin/env -S uv run --quiet --script
# /// script
# requires-python = ">=3.11"
# dependencies = [
#     "click",
#     "rich",
#     "questionary",
# ]
# ///

"""Brief script description."""

import click
from rich.console import Console

console = Console()

@click.command()
def main():
    """Main entry point."""
    console.print("[green]Hello![/green]")

if __name__ == "__main__":
    main()

Simple Script (No Dependencies)

#!/usr/bin/env python3

"""Brief script description."""

def main():
    """Main entry point."""
    print("Hello!")

if __name__ == "__main__":
    main()

PEP 723 Inline Script Metadata

When external packages are needed, use inline dependency declarations:

# /// script
# requires-python = ">=3.11"
# dependencies = [
#     "package-name>=1.0.0",
# ]
# ///

Benefits:

• No separate requirements.txt needed
• Script is self-contained and portable
• uv run automatically installs dependencies in isolated environment

Common Dependencies

CLI Tools

"click>=8.1.0",          # Command-line interface
"typer>=0.9.0",          # Alternative CLI framework
"questionary>=2.0.0",    # Interactive prompts

Output & Formatting

"rich>=13.0.0",          # Rich terminal output
"tabulate>=0.9.0",       # Table formatting

Data Handling

"pyyaml>=6.0",           # YAML parsing
"pydantic>=2.0",         # Data validation
"python-dateutil>=2.8",  # Date/time parsing

HTTP & APIs

"httpx>=0.27.0",         # Modern HTTP client
"requests>=2.31.0",      # Traditional HTTP client

Running Scripts

# Direct execution
./script_name.py

# With arguments
./script_name.py --option value

Anti-Patterns (DO NOT USE)

❌ pip install ❌ python -m venv ❌ requirements.txt for standalone scripts ❌ Global package installs

Best Practices

✅ Use uv for all package management ✅ Use inline # /// script block when dependencies needed ✅ Use type hints (Python 3.11+) ✅ Make scripts executable: chmod +x script.py ✅ Use pathlib.Path instead of string paths ✅ Handle errors with try/except ✅ Use rich.console for colored output ✅ Use click or typer for CLI parsing

Common Patterns

CLI Tool

#!/usr/bin/env -S uv run --quiet --script
# /// script
# requires-python = ">=3.11"
# dependencies = ["click>=8.1.0", "rich>=13.0.0"]
# ///

import click
from rich.console import Console

console = Console()

@click.command()
@click.option('--verbose', is_flag=True)
@click.argument('name')
def main(verbose: bool, name: str):
    """Greet NAME."""
    if verbose:
        console.print("[dim]Verbose mode[/dim]")
    console.print(f"[green]Hello, {name}![/green]")

if __name__ == "__main__":
    main()

Interactive Prompts

#!/usr/bin/env -S uv run --quiet --script
# /// script
# requires-python = ">=3.11"
# dependencies = ["questionary>=2.0.0", "rich>=13.0.0"]
# ///

import questionary
from rich.console import Console

console = Console()

def main():
    """Interactive tool."""
    name = questionary.text("Name?").ask()
    choice = questionary.select(
        "Pick one:",
        choices=["A", "B", "C"]
    ).ask()
    console.print(f"[green]{choice}[/green]")

if __name__ == "__main__":
    main()

When NOT to Use Python

Use bash/fish for:

• Simple file operations
• Git operations
• Single-command wrappers

Use Python for:

• Complex logic
• Data transformation
• API interactions
• Interactive CLI tools