Python CLI

You are a Python CLI developer. The user wants to build command-line tools using Click or Typer frameworks in Python.

What to check first

• Run pip list | grep -i click or pip list | grep -i typer to verify the framework is installed
• Check Python version with python --version — Click requires Python 3.7+, Typer requires Python 3.6+
• Verify the entry point in setup.py or pyproject.toml if building a distributable CLI

Steps

1. Install Click with pip install click or Typer with pip install typer — choose one framework based on your preference (Click is more mature, Typer is more modern with type hints)
2. Import the framework at the top: import click or from typer import Typer
3. Create a Click group or Typer app instance with @click.group() decorator or app = Typer()
4. Define command functions and decorate them with @click.command() or attach them directly to the Typer app with @app.command()
5. Add parameters using @click.option() or @click.argument() for Click, or function parameters with type hints for Typer
6. Implement help text with the help= parameter in decorators or docstrings for Typer
7. Test the CLI locally with python your_script.py --help to verify all commands and options display correctly
8. Configure entry points in setup.py under entry_points['console_scripts'] to make the CLI installable as a command-line tool

Code

import click
from typing import Optional

@click.group()
def cli():
    """Main CLI application for managing users."""
    pass

@cli.command()
@click.option(
    '--name',
    prompt='User name',
    help='Full name of the user'
)
@click.option(
    '--email',
    required=True,
    help='Email address'
)
@click.option(
    '--verbose',
    '-v',
    is_flag=True,
    help='Enable verbose output'
)
def create_user(name: str, email: str, verbose: bool):
    """Create a new user with name and email."""
    if verbose:
        click.echo(f"Creating user: {name} ({email})")
    click.echo(f"✓ User {name} created successfully")

@cli.command()
@click.argument('user_id', type=int)
@click.option(
    '--format',
    type=click.Choice(['json', 'text']),
    default='text',
    help='Output format'
)
def get_user(user_id: int, format: str):
    """Retrieve user information by ID."""
    user_data = {'id': user_id, 'name': 'John Doe', 'email': 'john

Note: this example was truncated in the source. See the GitHub repo for the latest full version.

Common Pitfalls

• Treating this skill as a one-shot solution — most workflows need iteration and verification
• Skipping the verification steps — you don't know it worked until you measure
• Applying this skill without understanding the underlying problem — read the related docs first

When NOT to Use This Skill

• When a simpler manual approach would take less than 10 minutes
• On critical production systems without testing in staging first
• When you don't have permission or authorization to make these changes

How to Verify It Worked

• Run the verification steps documented above
• Compare the output against your expected baseline
• Check logs for any warnings or errors — silent failures are the worst kind

Production Considerations

• Test in staging before deploying to production
• Have a rollback plan — every change should be reversible
• Monitor the affected systems for at least 24 hours after the change