October 1, 2021 - While building a Typer app that has only one @app.command() decorated function that function is treated as the default command. import typer app = typer.Typer(add_completion=False) @app.command() def foo(lat: float = None, long: float = None, ...

We can also use typer.Argument() to make a CLI argument have a default value other than None: Python 3.10+ from typing import Annotated import typer app = typer.Typer() @app.command() def main(name: Annotated[str, typer.Argument()] = "Wade Wilson"): print(f"Hello {name}") if __name__ == "__main__": app() 🤓 Other versions and variants ·

January 10, 2024 - # main.py import typer app = typer.Typer(no_args_is_help=True) @app.command() def hello(name: str): "Say hello" print(f"Hello {name}") @app.command() def goodbye(name: str, formal: bool = False): "Say goodbye" if formal: print(f"Goodbye Ms. {name}. Have a good day.") else: print(f"Bye {name}!") if __name__ == "__main__": app() $ python main.py Usage: main.py [OPTIONS] COMMAND [ARGS]... Options: --install-completion [bash|zsh|fish|powershell|pwsh] Install completion for the specified shell.

import typer app = typer.Typer() @app.command() def main( fullname: str = typer.Option( "Wade Wilson", show_default="Deadpoolio the amazing's name" ), ): print(f"Hello {fullname}") if __name__ == "__main__": app() ... $ uv run python main.py Hello Wade Wilson // Show the help $ uv run python main.py --help Usage: main.py [OPTIONS] Options: --fullname <str> [default: (Deadpoolio the amazing's name)] --help Show this message and exit.

🎉 · Notice that the help text now shows the 2 commands: create and delete. ... By default, the names of the commands are generated from the function name. By default, we need to specify --help to get the command's help page. However, by setting no_args_is_help=True when defining the ...

You need to change command() into callback(invoke_without_command=True) in cli_a.py and it will treat main() as default command. Copyimport typer app = typer.Typer() @app.callback(invoke_without_command=True) def main(): print('This is the output of main') if __name__ == '__main__': app()

Nope not natively possible according to https://github.com/tiangolo/typer/issues/279 though there are workarounds mentioned in that thread.

As we no longer have the Python function default value (or its absence) to tell if something is required or not and what is the default value, typer.Argument() receives a first parameter default that serves the same purpose of defining that default value, or making it required.

import typer app = typer.Typer() @app.command() def main(name: str, lastname: str = typer.Option(default=...)): print(f"Hello {name} {lastname}") if __name__ == "__main__": app() ... If you hadn't seen that ... before: it is a special single value, it is part of Python and is called "Ellipsis".

In fact, each command can have different CLI arguments and CLI options: Python 3.10+ from typing import Annotated import typer app = typer.Typer() @app.command() def create(username: str): print(f"Creating user: {username}") @app.command() def delete( username: str, force: Annotated[ bool, typer.Option(prompt="Are you sure you want to delete the user?") ], ): if force: print(f"Deleting user: {username}") else: print("Operation cancelled") @app.command() def delete_all( force: Annotated[ bool, typer.Option(prompt="Are you sure you want to delete ALL users?") ], ): if force: print("Deleting all users") else: print("Operation cancelled") @app.command() def init(): print("Initializing user database") if __name__ == "__main__": app() 🤓 Other versions and variants ·

When you create a command with @app.command(), by default, it generates the name from the function name. And by default, the help text is extracted from the function's docstring. ... The same way, if you define a callback in a typer.Typer(), the help text is extracted from the callback function's ...

February 7, 2025 - A more elegant way to display default help. ... import typer app = typer.Typer() @app.command() def create(): """Creates a user""" typer.echoint("Creating user") @app.command() def delete(): """Deletes a user""" typer.echo("Deleting user") if __name__ == "__main__": app() ... $ python cli.py Usage: cli.py [OPTIONS] COMMAND [ARGS]... Try 'cli.py --help' for help.

June 5, 2025 - import time from typing import Optional import typer from rich import print, progress, prompt app = typer.Typer() # Callback definition: https://typer.tiangolo.com/tutorial/commands/callback/ @app.callback(help="App callback definition") def callback( arg1: str = typer.Argument(..., help="Required argument for the entire app"), option1: bool = typer.Option(default=False, help="Optional argument for the entire app"), ) -> None: print(f"{arg1=}") print(f"{option1=}") # Required arguments: https://typer.tiangolo.com/tutorial/commands/arguments/…

If you have a CLI argument with a default value, like "World": Python 3.10+ from typing import Annotated import typer app = typer.Typer() @app.command() def main(name: Annotated[str, typer.Argument(help="Who to greet")] = "World"): """ Say hi to 'name' very gently, like Dirk.

Instead of using python directly you use the typer command.

Python 3.10+ - non-Annotated · Tip · Prefer to use the Annotated version if possible. import typer app = typer.Typer() @app.command() def main(user_name: str = typer.Option(..., "--name", "-n")): print(f"Hello {user_name}") if __name__ == "__main__": app() Here we are overwriting the CLI option name that by default would be --user-name, and we are defining it to be --name.

When you declare a CLI parameter with some type Typer will convert the data received in the command line to that data type. For example: Python 3.10+ import typer app = typer.Typer() @app.command() def main(name: str, age: int = 20, height_meters: float = 1.89, female: bool = True): print(f"NAME is {name}, of type: {type(name)}") print(f"--age is {age}, of type: {type(age)}") print(f"--height-meters is {height_meters}, of type: {type(height_meters)}") print(f"--female is {female}, of type: {type(female)}") if __name__ == "__main__": app() In this example, the value received for the CLI argument name will be treated as str.

Your CLI application built with Typer won't need the typer command to have auto completion once you create a Python package.