Typer adapter

base-cli can wrap an existing Typer app without making Typer a core dependency:

python -m pip install 'base-cli[typer]'

The extra supports Typer 0.12 through 0.27.x. Typer 0.26 and later ship a private Click fork, so the adapter selects the Click dialect that owns the generated command tree. Lifecycle options, parameter types, command instrumentation, and exception handling are always created and interpreted by that same dialect; base-cli never mixes public Click objects into a vendored Typer tree.

Use attach_typer() at the same boundary where a Click app would use attach():

import typer
import base_cli

cli = typer.Typer()


@cli.command()
def status(verbose: bool = typer.Option(False, "--verbose")) -> None:
    ctx = base_cli.get_current_context()
    if verbose:
        ctx.log.info("checking status")
    typer.echo("ready")


command = base_cli.attach_typer(cli, name="example")

if __name__ == "__main__":
    raise SystemExit(base_cli.run_app(command))

The adapter calls Typer's supported command materializer and returns that same Click command object. Typer remains responsible for command decorators, typed parameters, nested apps, dependency injection, help, completion, and Typer/Click exceptions. Base-cli adds its normal lifecycle options, context, logging, redaction, runtime state, cleanup, and outcome handling.

For an application that needs a custom profile or factories, pass an explicit base_cli.App:

lifecycle = base_cli.App(name="example", profile=my_profile)
command = base_cli.attach_typer(cli, app=lifecycle)

Typer's single-command form normally derives a root name from the callback. Pass name= when the lifecycle should use a different program name. A multi-command Typer app with no explicit name produces an unnamed group, so name= (or a named App) is required. The generated command is renamed in place; callbacks and Typer parameter metadata are not copied or rewritten.

TyperAdapter is available when the generated command needs to be retained:

adapter = base_cli.TyperAdapter(cli)
command = adapter.attach(name="example")

Typer is an optional extra and is imported lazily. Importing base_cli and using the Click integration never imports or requires Typer.

The compatibility workflow exercises the adapter and a typed consumer against Typer 0.25.1, 0.26.0, and 0.27.1 on Python 3.10 through 3.14. Keep this matrix green before widening the supported Typer range again.